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  • 1. Adams, Hieab H. H.
    et al.
    Hibar, Derrek P.
    Chouraki, Vincent
    Stein, Jason L.
    Nyquist, Paul A.
    Renteria, Miguel E.
    Trompet, Stella
    Arias-Vasquez, Alejandro
    Seshadri, Sudha
    Desrivieres, Sylvane
    Beecham, Ashley H.
    Jahanshad, Neda
    Wittfeld, Katharine
    Van der Lee, Sven J.
    Abramovic, Lucija
    Alhusaini, Saud
    Amin, Najaf
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Arfanakis, Konstantinos
    Aribisala, Benjamin S.
    Armstrong, Nicola J.
    Athanasiu, Lavinia
    Axelsson, Tomas
    Beiser, Alexa
    Bernard, Manon
    Bis, Joshua C.
    Blanken, Laura M. E.
    Blanton, Susan H.
    Bohlken, Marc M.
    Boks, Marco P.
    Bralten, Janita
    Brickman, Adam M.
    Carmichael, Owen
    Chakravarty, M. Mallar
    Chauhan, Ganesh
    Chen, Qiang
    Ching, Christopher R. K.
    Cuellar-Partida, Gabriel
    Den Braber, Anouk
    Doan, Nhat Trung
    Ehrlich, Stefan
    Filippi, Irina
    Ge, Tian
    Giddaluru, Sudheer
    Goldman, Aaron L.
    Gottesman, Rebecca F.
    Greven, Corina U.
    Grimm, Oliver
    Griswold, Michael E.
    Guadalupe, Tulio
    Hass, Johanna
    Haukvik, Unn K.
    Hilal, Saima
    Hofer, Edith
    Hoehn, David
    Holmes, Avram J.
    Hoogman, Martine
    Janowitz, Deborah
    Jia, Tianye
    Kasperaviciute, Dalia
    Kim, Sungeun
    Klein, Marieke
    Kraemer, Bernd
    Lee, Phil H.
    Liao, Jiemin
    Liewald, David C. M.
    Lopez, Lorna M.
    Luciano, Michelle
    Macare, Christine
    Marquand, Andre
    Matarin, Mar
    Mather, Karen A.
    Mattheisen, Manuel
    Mazoyer, Bernard
    Mckay, David R.
    McWhirter, Rebekah
    Milaneschi, Yuri
    Mirza-Schreiber, Nazanin
    Muetzel, Ryan L.
    Maniega, Susana Munoz
    Nho, Kwangsik
    Nugent, Allison C.
    Loohuis, Loes M. Olde
    Oosterlaan, Jaap
    Papmeyer, Martina
    Pappa, Irene
    Pirpamer, Lukas
    Pudas, Sara
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Puetz, Benno
    Rajan, Kumar B.
    Ramasamy, Adaikalavan
    Richards, Jennifer S.
    Risacher, Shannon L.
    Roiz-Santianez, Roberto
    Rommelse, Nanda
    Rose, Emma J.
    Royle, Natalie A.
    Rundek, Tatjana
    Saemann, Philipp G.
    Satizabal, Claudia L.
    Schmaal, Lianne
    Schork, Andrew J.
    Shen, Li
    Shin, Jean
    Shumskaya, Elena
    Smith, Albert V.
    Sprooten, Emma
    Strike, Lachlan T.
    Teumer, Alexander
    Thomson, Russell
    Tordesillas-Gutierrez, Diana
    Toro, Roberto
    Trabzuni, Daniah
    Vaidya, Dhananjay
    Van der Grond, Jeroen
    Van der Meer, Dennis
    Van Donkelaar, Marjolein M. J.
    Van Eijk, Kristel R.
    Van Erp, Theo G. M.
    Van Rooij, Daan
    Walton, Esther
    Westlye, Lars T.
    Whelan, Christopher D.
    Windham, Beverly G.
    Winkler, Anderson M.
    Woldehawariat, Girma
    Wolf, Christiane
    Wolfers, Thomas
    Xu, Bing
    Yanek, Lisa R.
    Yang, Jingyun
    Zijdenbos, Alex
    Zwiers, Marcel P.
    Agartz, Ingrid
    Aggarwal, Neelum T.
    Almasy, Laura
    Ames, David
    Amouyel, Philippe
    Andreassen, Ole A.
    Arepalli, Sampath
    Assareh, Amelia A.
    Barral, Sandra
    Bastin, Mark E.
    Becker, Diane M.
    Becker, James T.
    Bennett, David A.
    Blangero, John
    van Bokhoven, Hans
    Boomsma, Dorret I.
    Brodaty, Henry
    Brouwer, Rachel M.
    Brunner, Han G.
    Buckner, Randy L.
    Buitelaar, Jan K.
    Bulayeva, Kazima B.
    Cahn, Wiepke
    Calhoun, Vince D.
    Cannon, Dara M.
    Cavalleri, Gianpiero L.
    Chen, Christopher
    Cheng, Ching -Yu
    Cichon, Sven
    Cookson, Mark R.
    Corvin, Aiden
    Crespo-Facorro, Benedicto
    Curran, Joanne E.
    Czisch, Michael
    Dale, Anders M.
    Davies, Gareth E.
    De Geus, Eco J. C.
    De Jager, Philip L.
    de Zubicaray, Greig I.
    Delanty, Norman
    Depondt, Chantal
    DeStefano, Anita L.
    Dillman, Allissa
    Djurovic, Srdjan
    Donohoe, Gary
    Drevets, Wayne C.
    Duggirala, Ravi
    Dyer, Thomas D.
    Erk, Susanne
    Espeseth, Thomas
    Evans, Denis A.
    Fedko, Iryna
    Fernandez, Guillen
    Ferrucci, Luigi
    Fisher, Simon E.
    Fleischman, Debra A.
    Ford, Ian
    Foroud, Tatiana M.
    Fox, Peter T.
    Francks, Clyde
    Fukunaga, Masaki
    Gibbs, J. Raphael
    Glahn, David C.
    Gollub, Randy L.
    Goring, Harald H. H.
    Grabe, Hans J.
    Green, Robert C.
    Gruber, Oliver
    Gudnason, Vilmundur
    Guelfi, Sebastian
    Hansell, Narelle K.
    Hardy, John
    Hartman, Catharina A.
    Hashimoto, Ryota
    Hegenscheid, Katrin
    Heinz, Andreas
    Le Hellard, Stephanie
    Hernandez, Dena G.
    Heslenfeld, Dirk J.
    Ho, Beng-Choon
    Hoekstra, Pieter J.
    Hoffmann, Wolfgang
    Hofman, Albert
    Holsboer, Florian
    Homuth, Georg
    Hosten, Norbert
    Hottenga, Jouke-Jan
    Pol, Hilleke E. Hulshoff
    Ikeda, Masashi
    Ikram, M. Kamran
    Jack, Clifford R., Jr.
    Jenldnson, Mark
    Johnson, Robert
    Jonsson, Erik G.
    Jukema, J. Wouter
    Kahn, Rene S.
    Kanai, Ryota
    Kloszewska, Iwona
    Knopman, David S.
    Kochunov, Peter
    Kwok, John B.
    Lawrie, Stephen M.
    Lemaitre, Herve
    Liu, Xinmin
    Longo, Dan L.
    Longstreth, W. T., Jr.
    Lopez, Oscar L.
    Lovestone, Simon
    Martinez, Oliver
    Martinot, Jean-Luc
    Mattay, Venkata S.
    McDonald, Colm
    McIntosh, Andrew M.
    McMahon, Katie L.
    McMahon, Francis J.
    Mecocci, Patrizia
    Melle, Ingrid
    Meyer-Lindenberg, Andreas
    Mohnke, Sebastian
    Montgomery, Grant W.
    Morris, Derek W.
    Mosley, Thomas H.
    Muhleisen, Thomas W.
    Mueller-Myhsok, Bertram
    Nalls, Michael A.
    Nauck, Matthias
    Nichols, Thomas E.
    Niessen, Wiro J.
    Noethen, Markus M.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Ohi, Kazutaka
    Olvera, Rene L.
    Ophoff, Roel A.
    Pandolfo, Massimo
    Paus, Tomas
    Pausova, Zdenka
    Penninx, Brenda W. J. H.
    Pike, G. Bruce
    Potkin, Steven G.
    Psaty, Bruce M.
    Reppermund, Simone
    Rietschel, Marcella
    Roffman, Joshua L.
    Romanczuk-Seiferth, Nina
    Rotter, Jerome I.
    Ryten, Mina
    Sacco, Ralph L.
    Sachdev, Perminder S.
    Saykin, Andrew J.
    Schmidt, Reinhold
    Schofield, Peter R.
    Sigurdsson, Sigurdur
    Simmons, Andy
    Singleton, Andrew
    Sisodiya, Sanjay M.
    Smith, Colin
    Smoller, Jordan W.
    Soininen, Hindu.
    Srikanth, Velandai
    Steen, Vidar M.
    Stott, David J.
    Sussmann, Jessika E.
    Thalamuthu, Anbupalam
    Tiemeier, Henning
    Toga, Arthur W.
    Traynor, Bryan J.
    Troncoso, Juan
    Turner, Jessica A.
    Tzourio, Christophe
    Uitterlinden, Andre G.
    Hernandez, Maria C. Valdes
    Van der Brug, Marcel
    Van der Lugt, Aad
    Van der Wee, Nic J. A.
    Van Duijn, Cornelia M.
    Van Haren, Neeltje E. M.
    Van't Ent, Dennis
    Van Tol, Marie Jose
    Vardarajan, Badri N.
    Veltman, Dick J.
    Vernooij, Meike W.
    Voelzke, Henry
    Walter, Henrik
    Wardlaw, Joanna M.
    Wassink, Thomas H.
    Weale, Michael E.
    Weinberger, Daniel R.
    Weiner, Michael W.
    Wen, Wei
    Westman, Eric
    White, Tonya
    Wong, Tien Y.
    Wright, Clinton B.
    Zielke, H. Ronald
    Zonderman, Alan B.
    Deary, Ian J.
    DeCarli, Charles
    Schmidt, Helena
    Martin, Nicholas G.
    De Craen, Anton J. M.
    Wright, Margaret J.
    Launer, Lenore J.
    Schumann, Gunter
    Fornage, Myriam
    Franke, Barbara
    Debette, Stephanie
    Medland, Sarah E.
    Ikram, M. Arfan
    Thompson, Paul M.
    Novel genetic loci underlying human intracranial volume identified through genome-wide association2016In: Nature Neuroscience, ISSN 1097-6256, E-ISSN 1546-1726, Vol. 19, no 12, p. 1569-1582Article in journal (Refereed)
    Abstract [en]

    Intracranial volume reflects the maximally attained brain size during development, and remains stable with loss of tissue in late life. It is highly heritable, but the underlying genes remain largely undetermined. In a genome-wide association study of 32,438 adults, we discovered five previously unknown loci for intracranial volume and confirmed two known signals. Four of the loci were also associated with adult human stature, but these remained associated with intracranial volume after adjusting for height. We found a high genetic correlation with child head circumference (rho(genetic) = 0.748), which indicates a similar genetic background and allowed us to identify four additional loci through meta-analysis (N-combined = 37,345). Variants for intracranial volume were also related to childhood and adult cognitive function, and Parkinson's disease, and were enriched near genes involved in growth pathways, including PI3K-AKT signaling. These findings identify the biological underpinnings of intracranial volume and their link to physiological and pathological traits.

  • 2. Alakurtti, Kati
    et al.
    Johansson, Jarkko J.
    Joutsa, Juho
    Laine, Matti
    Backman, Lars
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Rinne, Juha O.
    Long-term test-retest reliability of striatal and extrastriatal dopamine D-2/3 receptor binding: study with [C-11]raclopride and high-resolution PET2015In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 35, no 7, p. 1199-1205Article in journal (Refereed)
    Abstract [en]

    We measured the long-term test-retest reliability of [C-11]raclopride binding in striatal subregions, the thalamus and the cortex using the bolus-plus-infusion method and a high-resolution positron emission scanner. Seven healthy male volunteers underwent two positron emission tomography (PET) [C-11]raclopride assessments, with a 5-week retest interval. D-2/3 receptor availability was quantified as binding potential using the simplified reference tissue model. Absolute variability (VAR) and intraclass correlation coefficient (ICC) values indicated very good reproducibility for the striatum and were 4.5%/0.82, 3.9%/0.83, and 3.9%/0.82, for the caudate nucleus, putamen, and ventral striatum, respectively. Thalamic reliability was also very good, with VAR of 3.7% and ICC of 0.92. Test-retest data for cortical areas showed good to moderate reproducibility (6.1% to 13.1%). Our results are in line with previous test-retest studies of [C-11]raclopride binding in the striatum. A novel finding is the relatively low variability of [C-11]raclopride binding, providing suggestive evidence that extrastriatal D-2/3 binding can be studied in vivo with [C-11]raclopride PET to be verified in future studies.

  • 3.
    Andersson, Linus
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology. Department of Occupational and Public Health Sciences, University of Gävle, Sweden.
    Claeson, Anna-Sara
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Nordin, Steven
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Short-term olfactory sensitization involves brain networks relevant for pain, and indicates chemical intolerance2017In: International journal of hygiene and environmental health (Print), ISSN 1438-4639, E-ISSN 1618-131X, Vol. 220, no 2, p. 503-509Article in journal (Refereed)
    Abstract [en]

    Chemical intolerance is a medically unexplained affliction that implies deleterious reactions to non-toxic everyday chemical exposure. Sensitization (i.e. increased reactivity to repeated, invariant stimulation) to odorous stimulation is an important component in theoretical explanations of chemical intolerance, but empirical evidence is scarce. We hypothesized that (1) individuals who sensitize to repeated olfactory stimulation, compared with those who habituate, would express a lower blood oxygenated level dependent (BOLD) response in key inhibitory areas such as the rACC, and higher signal in pain/saliency detection regions, as well as primary and/or secondary olfactory projection areas; and (2) olfactory sensitization, compared with habituation, would be associated with greater self-reported chemical intolerance. More-over, we assessed whether olfactory sensitization was paralleled by comparable trigeminal processing - in terms of perceptual ratings and BOLD responses. We grouped women from a previous functional magnetic imaging study based on intensity ratings of repeated amyl acetate exposure over time. Fourteen women sensitized to the exposure, 15 habituated, and 20 were considered "intermediate" (i.e. neither sensitizers nor habituaters). Olfactory sensitizers, compared with habituaters, displayed a BOLD-pattern in line with the hypothesis, and reported greater problems with odours in everyday life. They also expressed greater reactions to CO2 in terms of both perceived intensity and BOLD signal. The similarities with pain are discussed.

  • 4.
    Andersson, Linus
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Claesson, Anna-Sara
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Stenberg, Berndt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Dermatology and Venerology.
    Nordin, Steven
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Brain responses to olfactory and trigeminal exposure in idiopathic environmental illness (IEI) attributed to smells: An fMRI study2014In: Journal of Psychosomatic Research, ISSN 0022-3999, E-ISSN 1879-1360, Vol. 77, no 5, p. 401-408Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: Idiopathic environmental intolerance (IEI) to smells is a prevalent medically unexplained illness. Sufferers attribute severe symptoms to low doses of non-toxic chemicals. Despite the label, IEI is not characterized by acute chemical senses. Theoretical models suggest that sensitized responses in the limbic system of the brain constitute an important mechanism behind the symptoms. The aim was to investigate whether and how brain reactions to low-levels of olfactory and trigeminal stimuli differ in individuals with and without IEI. METHODS: Brain responses to intranasally delivered isoamyl acetate and carbon dioxide were assessed in 25 women with IEI and 26 non-ill controls using functional magnetic resonance imaging. RESULTS: The IEI group had higher blood-oxygenated-level-dependent (BOLD) signal than controls in the thalamus and a number of, mainly, parietal areas, and lower BOLD signal in the superior frontal gyrus. The IEI group did not rate the exposures as more intense than the control group did, and there were no BOLD signal differences between groups in the piriform cortex or olfactory regions of the orbitofrontal cortex. CONCLUSIONS: The IEI reactions were not characterized by hyper-responsiveness in sensory areas. The results can be interpreted as a limbic hyperreactivity and speculatively as an inability to inhibit salient extemal stimuli.

  • 5. Athanasiu, Lavinia
    et al.
    Giddaluru, Sudheer
    Fernandes, Carla
    Christoforou, Andrea
    Reinvang, Ivar
    Lundervold, Astri J.
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Aging Research Center, Karolinska Institutet, Stockholm, Sweden.
    Kauppi, Karolina
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Eriksson, Elias
    Sundet, Kjetil
    Djurovic, Srdjan
    Espeseth, Thomas
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Steen, Vidar M.
    Andreassen, Ole A.
    Le Hellard, Stephanie
    A genetic association study of CSMD1 and CSMD2 with cognitive function2017In: Brain, behavior, and immunity, ISSN 0889-1591, E-ISSN 1090-2139, Vol. 61, p. 209-216Article in journal (Refereed)
    Abstract [en]

    The complement cascade plays a role in synaptic pruning and synaptic plasticity, which seem to be involved in cognitive functions and psychiatric disorders. Genetic variants in the closely related CSMD1 and CSMD2 genes, which are implicated in complement regulation, are associated with schizophrenia. Since patients with schizophrenia often show cognitive impairments, we tested whether variants in CSMD1 and CSMD2 are also associated with cognitive functions per se. We took a discovery-replication approach, using well-characterized Scandinavian cohorts. A total of 1637 SNPs in CSMD1 and 206 SNPs in CSMD2 were tested for association with cognitive functions in the NCNG sample (Norwegian Cognitive NeuroGenetics; n = 670). Replication testing of SNPs with p-value < 0.001 (7 in CSMD1 and 3 in CSMD2) was carried out in the TOP sample (Thematically Organized Psychosis; n =1025) and the BETULA sample (Betula Longitudinal Study on aging, memory and dementia; n = 1742). Finally, we conducted a meta-analysis of these SNPs using all three samples. The previously identified schizophrenia marker in CSMD1 (SNP rs10503253) was also included. The strongest association was observed between the CSMDI SNP rs2740931 and performance in immediate episodic memory (p-value = 5 Chi 10(-6), minor allele A, MAF 0.48-0.49, negative direction of effect). This association reached the study-wide significance level (p <= 1.2 Chi 10(-5)). SNP rs10503253 was not significantly associated with cognitive functions in our samples. In conclusion, we studied n = 3437 individuals and found evidence that a variant in CSMD1 is associated with cognitive function. Additional studies of larger samples with cognitive phenotypes will be needed to further clarify the role of CSMD1 in cognitive phenotypes in health and disease.

  • 6.
    Awad, Amar
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Levi, Richard
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Lindgren, Lenita
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Hultling, Claes
    Department of Neurobiology, Care Sciences and Society (Neurorehabilitation), Karolinska Institute, Stockholm, Sweden.
    Westling, Göran
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Eriksson, Johan
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Preserved somatosensory conduction in a patient with complete cervical spinal cord injury2015In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 47, no 5, p. 426-431Article in journal (Refereed)
    Abstract [en]

    Objective: Neurophysiological investigation has shown that patients with clinically complete spinal cord injury can have residual motor sparing ("motor discomplete"). In the current study somatosensory conduction was assessed in a patient with clinically complete spinal cord injury and a novel ethodology for assessing such preservation is described, in this case indicating "sensory discomplete" spinal cord injury. Methods: Blood oxygenation level-dependent functional magnetic resonance imaging (BOLD fMRI) was used to examine the somatosensory system in a healthy subject and in a subject with a clinically complete cervical spinal cord injury, by applying tactile stimulation above and below the level of spinal cord injury, with and without visual feedback. Results: In the participant with spinal cord injury, somatosensory stimulation below the neurological level of the lesion gave rise to BOLD signal changes in the corresponding areas of the somatosensory cortex. Visual feedback of the stimulation strongly modulated the somatosensory BOLD signal, implying that cortico-cortical rather than spino-cortical connections can drive activity in the somatosensory cortex. Critically, BOLD signal change was also evident when the visual feedback of the stimulation was removed, thus demonstrating sensory discomplete spinal cord injury. Conclusion: Given the existence of sensory discomplete spinal cord injury, preserved but hitherto undetected somatosensory conduction might contribute to the unexplained variability related to, for example, the propensity to develop decubitus ulcers and neuropathic pain among patients with clinically complete spinal cord injury.

  • 7.
    Backman, Lars
    et al.
    Aging Research Center, Karolinska Institute and University of Stockholm, Stockholm,.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Dopamine and training-related working-memory improvement2013In: Neuroscience and Biobehavioral Reviews, ISSN 0149-7634, E-ISSN 1873-7528, Vol. 37, no 9, p. 2209-2219Article, review/survey (Refereed)
    Abstract [en]

    Converging evidence indicates that the neurotransmitter dopamine (DA) is implicated in working-memory (WM) functioning and that WM is trainable. We review recent work suggesting that DA is critically involved in the ability to benefit from WM interventions. Functional MRI studies reveal increased striatal BOLD activity following certain forms of WM interventions, such as updating training. Increased striatal BOLD activity has also been linked to transfer of learning to non-trained WM tasks, suggesting a neural signature of transfer. The striatal BOLD signal is partly determined by DA activity. Consistent with this assertion, PET research demonstrates increased striatal DA release during updating of information in WM after training. Genetic studies indicate larger increases in WM performance post training for those who carry advantageous alleles of DA-relevant genes. These patterns of results corroborate the role of DA in WM improvement. Future research avenues include: (a) neuromodulatory correlates of transfer; (b) the potential of WM training to enhance DA release in older adults; (c) comparisons among different WM processes (i.e., updating, switching, inhibition) regarding regional patterns of training-related DA release; and (d) gene-gene interactions in relation to training-related WM gains.

  • 8.
    Bergdahl, Jan
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Larsson, Anne
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Nilsson, Lars-Göran
    Riklund Åhlström, Katrine
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Nyberg, Lars
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Treatment of chronic stress in employees: subjective, cognitive and neural correlates2005In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 46, no 5, p. 395-402Article in journal (Refereed)
    Abstract [en]

    This study reports the effect of an affect-focused intervention program, the Affect School, on stress, psychological symptoms, cognitive functioning and neural activity. Fifty employees in social service and education, with high levels of chronic stress, were randomly divided into a treatment (N= 27) and control (N= 23) group. Complete sets of data were available in 20 participants in the treatment group and 17 in the control group. The Perceived Stress Questionnaire assessed stress and the Symptom Check List-90 psychological symptoms before and after treatment. Episodic-memory functioning under focused and divided attention conditions was also assessed. Prior and after the Affect School, seven participants in the treatment group were studied with functional magnetic resonance imaging (fMRI) during episodic memory processing. After the Affect School there was a reduction in stress and psychological symptoms for the treatment group but not in the control group. The controls showed a reduction in episodic memory functioning whereas the performance of the treatment group remained intact. The fMRI scanning indicated a qualitative change in the neural network subserving episodic memory. These preliminary results suggest that the Affect School is effective on individuals with high stress.

  • 9. Bergdahl, Maud
    et al.
    Bergdahl, Jan
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Nilsson, Lars-Göran
    Psykologiska institutionen, Stockholms universitet.
    Difference in apolipoprotein E type 4 allele (APOE e4) amongdentate and edentulous subjects2008In: Gerodontology, ISSN 0734-0664, E-ISSN 1741-2358, Vol. 25, no 3, p. 179-186Article in journal (Refereed)
    Abstract [en]

    Objectives: To evaluate the frequency of apolipoprotein (APOE) alleles and determine whether APOE type 4 allele (e4) was associated with edentulousness even when certain factors were controlled.Background: The APOE are important in lipid homeostasis, and APOE e4 has been found in many diseases and to have a negative impact on longevity. Tooth loss is more common in ill aged subjects with low income and education.Materials and methods: In a population-based study involving 1860 subjects between 35 and 85 years 1321 dentate (mean age = 54; 54% women, 46% men) and 539 edentulous (mean age = 72; 62% women, 38% men) subjects were studied. Logistic regression was performed with dentate/edentulous as dependent variables and years of education, socio-economic status, social network, stress level, handicap from birth, 23 various diseases and APOE e4 as covariates. Thereafter, APOE e4 frequencies were studied in 342 dentateand 336 edentulous subjects 50–85 years of age. The subjects were matched with regard to age, gender, years of education, living condition, stress level, handicap from birth and 23 various diseases.Results: APOE allele frequency in the total group was e2 = 7.8%, e3 = 76.4% and e4 = 15.8%. Age, living condition, years of education and APOE e4 were significant covariates in edentulous subjects (p £ 0.001).APOE e4 in the matched groups revealed significant differences between the dentate group and the edentulous group (v2 = 5.68; p = 0.017). There was no group effect (F(29,648) = 0.849; p < 0.696; Wilks’ lambda = 0.963). In the dentate group, the frequencies of APOE were: e2 = 8.8%, e3 = 77.9% ande4 = 13.3%. Corresponding frequencies of APOE in the edentulous group were: e2 = 6.6%, e3 = 75.4% and e4 = 18.0%.Conclusion: Despite matching both groups with regard to different background factors, the edentulous group had a higher frequency of APOE e4 than the dentate group. Thus, genetic factors might contribute to greater risk in developing complex oral diseases leading to tooth loss or just be an indication that the subjects in our study carrying APOE e4 are more fragile.

  • 10. Bergdahl, Maud
    et al.
    Habib, Reza
    Bergdahl, Jan
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Nilsson, Lars-Göran
    Natural teeth and cognitive function in humans2007In: Scandinavian Journal of Psychology, ISSN 0036-5564, E-ISSN 1467-9450, Vol. 48, no 6, p. 557-565Article in journal (Refereed)
    Abstract [en]

    A number of neurobiological, psychological and social factors may account for cognitive impairment. In animal studies a relation between dental status and cognitive performance has been found. It is unclear whether such a relation exists for humans. In a first step we compared the performance of 1,351 participants (53% women, 47% men; age M = 54.0) with natural teeth to 487 edentulous participants (59% women, 41% men; age M = 71.3) on 12 cognitive tests. The natural teeth group had a lower mean age, fewer women, more years of education, higher mini-mental state (MMSE), and performed significantly higher on several cognitive tests. In a subsequent analysis, the cognitive performance of a subset of the participants (50–85 years) was examined. In this analysis, 211 had natural dentition and 188 were edentulous. The groups were matched for gender, age, social variables, diseases, stress and MMSE. The cognitive disadvantage of the edentulous group was still apparent. The results suggest that functional natural teeth relate to relatively preserved cognitive functioning in older age.

  • 11.
    Berginström, Nils
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Ekman, Urban
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Karolinska Inst, Dept Neurobiol Care Sci & Soc, Stockholm, Sweden.
    Eriksson, Johan
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Fatigue after traumatic brain injury is linked to altered striato-thalamic-cortical functioning2017In: Brain Injury: Accepted Abstracts from the International Brain Injury Association’s 12th World Congress on Brain Injury, 2017, Vol. 31, p. 755-755Conference paper (Refereed)
    Abstract [en]

    Mental fatigue is a common symptom in the chronic phase of traumatic brain injury. Despite its high prevalence, no treatmentis available for this disabling symptom, and the mechanisms underlying fatigue are poorly understood. Some studies have suggested that fatigue in traumatic brain injury and other neurological disorders might reflect dysfunction within striato-thalamic-cortical loops. In the present study, we investigated whether functional magnetic resonance imaging(fMRI) can be used to detect chronic fatigue after traumatic brain injury (TBI), with emphasis on the striato-thalamic cortical-loops. We included patients who had suffered traumatic brain injury (n = 57, age range 20–64 years) and experienced mental fatigue > 1 year post injury (mean = 8.79 years, SD = 7.35), and age- and sex-matched healthycontrols (n = 27, age range 25–65 years). All participants completed self-assessment scales of fatigue and other symptoms, underwent an extensive neuropsychological test battery and performed a fatiguing 27-minute attention task (the modified Symbol Digit Modalities Test) during fMRI. Accuracy did not differ between groups, but reaction times were slower in the traumatic brain injury group (p < 0.001). Patients showed a greater increase in fatigue than controls from before to after task completion (p < 0.001). Patients showed less fMRI blood oxygen level–dependent activity in several a priori hypothesized regions (family-wise error corrected,p < 0.05), including the bilateral caudate, thalamus and anterior insula. Using the left caudate as a region of interest and testing for sensitivity and specificity, we identified 91% of patients and 81% of controls. As expected, controls showed decreased activation over time in regions of interest—the bilateral caudate and anterior thalamus (p < 0.002, uncorrected)—whereas patients showed no corresponding activity decrease. These results suggest that chronic fatigue after TBI is linked to altered striato-thalamic-cortical functioning. The high precision of fMRI for the detection of fatigue is of great clinical interest, given the lack of objective measures for the diagnosis of fatigue.

  • 12.
    Berginström, Nils
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Ekman, Urban
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Karolinska Inst, Dept Neurobiol Care Sci & Soc, Stockholm, Sweden.
    Eriksson, Johan
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Andersson, Micael
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Using Functional Magnetic Resonance Imaging to Detect Chronic Fatigue in Patients With Previous Traumatic Brain Injury: changes linked to altered Striato-Thalamic-Cortical Functioning2018In: The journal of head trauma rehabilitation, ISSN 0885-9701, E-ISSN 1550-509X, Vol. 33, no 4, p. 266-274Article in journal (Refereed)
    Abstract [en]

    Objective: To investigate whether functional magnetic resonance imaging (fMRI) can be used to detect fatigue after traumatic brain injury (TBI).

    Setting: Neurorehabilitation clinic.

    Participants: Patients with TBI (n = 57) and self-experienced fatigue more than 1 year postinjury, and age- and gender-matched healthy controls (n = 27).

    Main Measures: Self-assessment scales of fatigue, a neuropsychological test battery, and fMRI scanning during performance of a fatiguing 27-minute attention task.

    Results: During testing within the fMRI scanner, patients showed a higher increase in self-reported fatigue than controls from before to after completing the task (P < .001).The patients also showed lower activity in several regions, including bilateral caudate, thalamus, and anterior insula (all P < .05). Furthermore, the patients failed to display decreased activation over time in regions of interest: the bilateral caudate and anterior thalamus (all P < .01). Left caudate activity correctly identified 91% of patients and 81% of controls, resulting in a positive predictive value of 91%.

    Conclusion: The results suggest that chronic fatigue after TBI is associated with altered striato-thalamic-cortical functioning. It would be of interest to study whether fMRI can be used to support the diagnosis of chronic fatigue in future studies.

  • 13.
    Berginström, Nils
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine. School of Sport Sciences, The Arctic University of Norway, Tromsø, Norway Medicine.
    Ekman, Urban
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
    Eriksson, Johan
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Section of Sustainable Health. School of Sport Sciences, The Arctic University of Norway, Tromsø, Norway.
    Pharmaco-fMRI in Patients With Traumatic Brain Injury: A Randomized Controlled Trial With the Monoaminergic Stabilizer (-)-OSU61622019In: The journal of head trauma rehabilitation, ISSN 0885-9701, E-ISSN 1550-509X, Vol. 34, no 3, p. 189-198Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To examine the effects of monoaminergic stabilizer (-)-OSU6162 on brain activity, as measured by blood-oxygen-level-dependent (BOLD) functional magnetic resonance imaging (fMRI), in patients in the chronic phase of traumatic brain injury suffering from fatigue.

    SETTING: Neurorehabilitation clinic.

    PARTICIPANTS: Patients with traumatic brain injury received either placebo (n = 24) or active treatment (n = 28). Healthy controls (n = 27) went through fMRI examination at one point and were used in sensitivity analysis on normalization of BOLD response.

    DESIGN: Randomized, double-blinded, placebo-controlled design.

    MAIN MEASURES: Effects on BOLD signal changes from before to after treatment during performance of a fatiguing attention task.

    RESULTS: The fMRI results revealed treatment effects within the right occipitotemporal cortex and the right orbitofrontal cortex. In these regions, the BOLD response was normalized relative to healthy controls at the postintervention fMRI session. No effects were seen in regions in which we previously observed activity differences between patients and healthy controls while performing this fMRI task, such as the striatum.

    CONCLUSION: (-)-OSU6162 treatment had influences on functional brain activity, although the normalized regional BOLD response was observed in regions that were not a priori hypothesized to be sensitive to this particular treatment, and was not accompanied by any effects on in-scanner test performance or on fatigue.

  • 14.
    Berginström, Nils
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine. Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Rehabilitation Medicine.
    Nordström, Peter
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Nordström, Anna
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    White matter hyperintensities increases with traumatic brain injuryseverity: associations to neuropsychological performance and fatigueManuscript (preprint) (Other academic)
    Abstract [en]

    Objective: To examine the prevalence of white matter hyperintensities (WMHs) in patients with traumatic brain injury (TBI) as compared to healthy controls, and to investigate whether there is an association between WMH lesion burden and performance on neuropsychological tests in patients with TBI.

    Methods: A total of 59 patients with TBI and 27 age- and gender- matched healthy controls underwent thorough neuropsychological testing and magnetic resonance imaging. The quantification of WMH lesions was performed using the fully automated Lesion Segmentation Tool.

    Results: WMH lesions were more common in patients with TBI than in healthy controls (p = 0.032), and increased with higher TBI severity (p = 0.025). Linear regressions showed that WMH lesions in patients with TBI were not related to performance on any neuropsychological tests (p > 0.05 for all). However, a negative relationship between number of WMH lesions in patients with TBI and self-assessed fatigue was found (r = –0.33, p = 0.026).

    Conclusion: WMH lesions are more common in patients with TBI than in healthy controls, and WMH lesions burden increases with TBI severity. However, these lesions do not seem to explain the decreased cognitive functioning or the increased fatigue in patients with TBI.

  • 15. Bergouignan, Loretxu
    et al.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Ehrsson, H. Henrik
    Out-of-body-induced hippocampal amnesia2014In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 111, no 12, p. 4421-4426Article in journal (Refereed)
    Abstract [en]

    Theoretical models have suggested an association between the ongoing experience of the world from the perspective of one's own body and hippocampus-based episodic memory. This link has been supported by clinical reports of long-term episodic memory impairments in psychiatric conditions with dissociative symptoms, in which individuals feel detached from themselves as if having an out-of-body experience. Here, we introduce an experimental approach to examine the necessary role of perceiving the world from the perspective of one's own body for the successful episodic encoding of real-life events. While participants were involved in a social interaction, an out-of-body illusion was elicited, in which the sense of bodily self was displaced from the real body to the other end of the testing room. This condition was compared with a well-matched in-body illusion condition, in which the sense of bodily self was colocalized with the real body. In separate recall sessions, performed similar to 1 wk later, we assessed the participants' episodic memory of these events. The results revealed an episodic recollection deficit for events encoded out-of-body compared with in-body. Functional magnetic resonance imaging indicated that this impairment was specifically associated with activity changes in the posterior hippocampus. Collectively, these findings show that efficient hippocampus-based episodic-memory encoding requires a first-person perspective of the natural spatial relationship between the body and the world. Our observations have important implications for theoretical models of episodic memory, neurocognitive models of self, embodied cognition, and clinical research into memory deficits in psychiatric disorders.

  • 16.
    Boraxbekk, Carl-Johan
    et al.
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Lundquist, Anders
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nordin, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Nilsson, Lars-Göran
    Aging Research Center, Karolinska Institutet.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Free Recall Episodic Memory Performance Predicts Dementia 10 Years Prior to Clinical Diagnosis: Findings from the Betula Longitudinal Study2015In: Dementia and geriatric cognitive disorders extra, E-ISSN 1664-5464, Vol. 5, no 2, p. 191-202Article in journal (Refereed)
    Abstract [en]

    Background/Aims: Early dementia diagnosis is a considerable challenge. The present study examined the predictive value of cognitive performance for a future clinical diagnosis of late-onset Alzheimer's disease or vascular dementia in a random population sample. Methods: Cognitive performance was retrospectively compared between three groups of participants from the Betula longitudinal cohort. Group 1 developed dementia 11-22 years after baseline testing (n = 111) and group 2 after 1-10 years (n = 280); group 3 showed no deterioration towards dementia during the study period (n = 2,855). Multinomial logistic regression analysis was used to investigate the predictive value of tests reflecting episodic memory performance, semantic memory performance, visuospatial ability, and prospective memory performance. Results: Age-and education-corrected performance on two free recall episodic memory tests significantly predicted dementia 10 years prior to clinical diagnosis. Free recall performance also predicted dementia 11-22 years prior to diagnosis when controlling for education, but not when age was added to the model. Conclusion: The present results support the suggestion that two free recall-based tests of episodic memory function may be useful for detecting individuals at risk of developing dementia 10 years prior to clinical diagnosis.

  • 17.
    Boraxbekk, Carl-Johan
    et al.
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Aging Research Center (ARC), Karolinska Institute, Stockholm, Sweden.
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Physical activity over a decade modifies age-related decline in perfusion, gray matter volume, and functional connectivity of the posterior default mode network: a multimodal approach2016In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 131, p. 133-141Article in journal (Refereed)
    Abstract [en]

    One step toward healthy brain aging may be to entertain a physically active lifestyle. Studies investigating physical activity effects on brain integrity have, however, mainly been based on single brain markers, and few used a multimodal imaging approach. In the present study, we used cohort data from the Betula study to examine the relationships between scores reflecting current and accumulated physical activity and brain health. More specifically, we first examined if physical activity scores modulated negative effects of age on seven resting state networks previously identified by Salami, Pudas, and Nyberg (2014). The results revealed that one of the most age-sensitive RSN was positively altered by physical activity, namely, the posterior default-mode network involving the posterior cingulate cortex (PCC). Second, within this physical activity-sensitive RSN, we further analyzed the association between physical activity and gray matter (GM) volumes, white matter integrity, and cerebral perfusion using linear regression models. Regions within the identified DMN displayed larger GM volumes and stronger perfusion in relation to both current and 10-years accumulated scores of physical activity. No associations of physical activity and white matter integrity were observed. Collectively, our findings demonstrate strengthened PCC–cortical connectivity within the DMN, larger PCC GM volume, and higher PCC perfusion as a function of physical activity. In turn, these findings may provide insights into the mechanisms of how long-term regular exercise can contribute to healthy brain aging.

  • 18.
    Boraxbekk, Carl-Johan
    et al.
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Centre for Population Studies (CPS).
    Stomby, Andreas
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Ryberg, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Lindahl, Bernt
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Larsson, Christel
    Umeå University, Faculty of Social Sciences, Department of Food and Nutrition. Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Göteborgs Universitet.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Diet-Induced Weight Loss alters Functional Brain Responses during an Episodic Memory Task2015In: Obesity Facts, ISSN 1662-4025, E-ISSN 1662-4033, Vol. 8, p. 261-272Article in journal (Refereed)
    Abstract [en]

    Objective: It has been suggested that overweight is negatively associated with cognitive functions. The aim of this study was to investigate whether a reduction in body weight by dietary interventions could improve episodic memory performance and alter associated functional brain responses in overweight and obese women. Methods: 20 overweight postmenopausal women were randomized to either a modified paleolithic diet or a standard diet adhering to the Nordic Nutrition Recommendations for 6 months. We used functional magnetic resonance imaging to examine brain function during an episodic memory task as well as anthropometric and biochemical data before and after the interventions. Results: Episodic memory performance improved significantly (p = 0.010) after the dietary interventions. Concomitantly, brain activity increased in the anterior part of the right hippocampus during memory encoding, without differences between diets. This was associated with decreased levels of plasma free fatty acids (FFA). Brain activity increased in pre-frontal cortex and superior/middle temporal gyri. The magnitude of increase correlated with waist circumference reduction. During episodic retrieval, brain activity decreased in inferior and middle frontal gyri, and increased in middle/superior temporal gyri. Conclusions: Diet-induced weight loss, associated with decreased levels of plasma FFA, improves episodic memory linked to increased hippocampal activity.

  • 19.
    Burzynska, A Z
    et al.
    Max Planck Institute for Human Development, Berlin.
    Preuschhof, C
    Max Planck Institute for Human Development, Berlin.
    Bäckman, L
    Max Planck Institute for Human Development, Berlin, Karolinska Institute.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Li, S-C
    Max Planck Institute for Human Development, Berlin.
    Lindenberger, U
    Max Planck Institute for Human Development, Berlin, .
    Heekeren, H R
    Max Planck Institute for Human Development, Berlin, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig.
    Age-related differences in white matter microstructure: region-specific patterns of diffusivity.2010In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 49, no 3, p. 2104-2112Article in journal (Refereed)
    Abstract [en]

    We collected MRI diffusion tensor imaging data from 80 younger (20-32 years) and 63 older (60-71 years) healthy adults. Tract-based spatial statistics (TBSS) analysis revealed that white matter integrity, as indicated by decreased fractional anisotropy (FA), was disrupted in numerous structures in older compared to younger adults. These regions displayed five distinct region-specific patterns of age-related differences in other diffusivity properties: (1) increases in both radial and mean diffusivity; (2) increases in radial diffusivity; (3) no differences in parameters other than FA; (4) a decrease in axial and an increase in radial diffusivity; and (5) a decrease in axial and mean diffusivity. These patterns suggest different biological underpinnings of age-related decline in FA, such as demyelination, Wallerian degeneration, gliosis, and severe fiber loss, and may represent stages in a cascade of age-related degeneration in white matter microstructure. This first simultaneous description of age-related differences in FA, mean, axial, and radial diffusivity requires histological and functional validation as well as analyses of intermediate age groups and longitudinal samples.

  • 20. Bäckman, L
    et al.
    Nyberg, Lars
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Linderiberger, U
    Li, SC
    Farde, L
    The correlative triad among aging, dopamine, and cognition: Current status and future prospects2006In: NEUROSCIENCE AND BIOBEHAVIORAL REVIEWS, ISSN 0149-7634, Vol. 30, no 6, p. 791-807Article, review/survey (Other (popular science, discussion, etc.))
  • 21.
    Bäckman, Lars
    et al.
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Karlsson, Sari
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Fischer, Håkan
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Karlsson, Per
    Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Stockholm, Sweden.
    Brehmer, Yvonne
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Rieckmann, Anna
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden.
    Macdonald, Stuart WS
    Aging Research Center, Karolinska Institutet, Gävlegatan 16, SE-113 30 Stockholm, Sweden; Department of Psychology, University of Victoria, Canada .
    Farde, Lars
    Department of Clinical Neuroscience, Psychiatry Section, Karolinska Institutet, Stockholm, Sweden.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Dopamine D(1) receptors and age differences in brain activation during working memory2011In: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 32, no 10, p. 1849-1856Article in journal (Refereed)
    Abstract [en]

    In an fMRI study, 20 younger and 20 healthy older adults were scanned while performing a spatial working-memory task under two levels of load. On a separate occasion, the same subjects underwent PET measurements using the radioligand [(11)C] SCH23390 to determine dopamine D(1) receptor binding potential (BP) in caudate nucleus and dorsolateral prefrontal cortex (DLPFC). The fMRI study revealed a significant load modulation of brain activity (higher load>lower load) in frontal and parietal regions for younger, but not older, adults. The PET measurements showed marked age-related reductions of D(1) BP in caudate and DLPFC. Statistical control of caudate and DLPFC D(1) binding eliminated the age-related reduction in load-dependent BOLD signal in left frontal cortex, and attenuated greatly the reduction in right frontal and left parietal cortex. These findings suggest that age-related alterations in dopaminergic neurotransmission may contribute to underrecruitment of task-relevant brain regions during working-memory performance in old age.

  • 22. Bäckman, Lars
    et al.
    Lindenberger, Ulman
    Li, Shu-Chen
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Linking cognitive aging to alterations in dopamine neurotransmitter functioning: Recent data and future avenues2010In: Neuroscience and Biobehavioral Reviews, ISSN 0149-7634, E-ISSN 1873-7528, Vol. 34, no 5, p. 670-677Article, review/survey (Refereed)
    Abstract [en]

    Molecular-imaging studies of dopaminergic neurotransmission measure biomarkers of dopamine (DA), such as the DA transporter and D(1) and D(2) receptor densities in the living brain. These studies indicate that individual differences in DA functions are linked to cognitive performance irrespective of age, and serve as powerful mediators of age-related decline in executive functioning, episodic memory, and perceptual speed. This focused review targets several recent findings pertaining to these relationships. Specifically, we discuss novel evidence concerning (a) the role of DA in within-person cognitive variability; (b) age-related differences in DA release during cognitive processing; (c) DA release following cognitive training in younger and older adults; and (d) the relationship between DA and task-induced functional brain activity. Based on these lines of empirical inquiry, we outline a series of avenues for future research on aging, DA, and cognition.

  • 23. Bäckman, Lars
    et al.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Integrative Medical Biology, Physiology.
    Lindenberger, Ulman
    Li, Shu-Chen
    Farde, Lars
    The correlative triad among aging, dopamine, and cognition: current status and future prospects.2006In: Neuroscience and Biobehavioral Review, ISSN 0149-7634, Vol. 30, no 6, p. 791-807Article in journal (Other academic)
    Abstract [en]

    The brain neuronal systems defined by the neurotransmitter dopamine (DA) have since long a recognized role in the regulation of motor functions. More recently, converging evidence from patient studies, animal research, pharmacological intervention, and molecular genetics indicates that DA is critically implicated also in higher-order cognitive functioning. Many cognitive functions and multiple markers of striatal and extrastriatal DA systems decline across adulthood and aging. Research examining the correlative triad among adult age, DA, and cognition has found strong support for the view that age-related DA losses are associated with age-related cognitive deficits. Future research strategies for examining the DA-cognitive aging link include assessing (a) the generality/specificity of the effects; (b) the relationship between neuromodulation and functional brain activation; and (c) the release of DA during actual task performance.

  • 24.
    Bäckman, Lars
    et al.
    Aging Research Center, Karolinska Institute, Stockholm, Sweden.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Soveri, Anna
    Department of Psychology and Logopedics, Åbo Akademi University, Turku, Finland.
    Johansson, Jarkko
    Turku PET Center, University of Turku, Turku, Finland.
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Dahlin, Erika
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Neely, Anna S
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Virta, Jere
    Turku PET Center, University of Turku, Turku, Finland.
    Laine, Matti
    Department of Psychology and Logopedics, Åbo Akademi University, Turku, Finland.
    Rinne, Juha O
    Turku PET Center, University of Turku, Turku, Finland.
    Effects of working-memory training on striatal dopamine release2011In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 333, no 6043, p. 718-Article in journal (Refereed)
    Abstract [en]

    Updating of working memory has been associated with striato-frontal brain regions and phasic dopaminergic neurotransmission. We assessed raclopride binding to striatal dopamine (DA) D2 receptors during a letter-updating task and a control condition before and after 5 weeks of updating training. Results showed that updating affected DA activity before training and that training further increased striatal DA release during updating. These findings highlight the pivotal role of transient neural processes associated with D2 receptor activity in working memory.

  • 25. Bäckman, Lars
    et al.
    Waris, Otto
    Johansson, Jarkko
    Andersson, Micael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Rinne, Juha O.
    Alakurtti, Kati
    Soveri, Anna
    Laine, Matti
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Increased dopamine release after working-memory updating training: Neurochemical correlates of transfer2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 7160Article in journal (Refereed)
    Abstract [en]

    Previous work demonstrates that working-memory (WM) updating training results in improved performance on a letter-memory criterion task, transfers to an untrained n-back task, and increases striatal dopamine (DA) activity during the criterion task. Here, we sought to replicate and extend these findings by also examining neurochemical correlates of transfer. Four positron emission tomography (PET) scans using the radioligand raclopride were performed. Two of these assessed DAD2 binding (letter memory; n-back) before 5 weeks of updating training, and the same two scans were performed post training. Key findings were (a) pronounced training-related behavioral gains in the lettermemory criterion task, (b) altered striatal DAD2 binding potential after training during letter-memory performance, suggesting training-induced increases in DA release, and (c) increased striatal DA activity also during the n-back transfer task after the intervention, but no concomitant behavioral transfer. The fact that the training-related DA alterations during the transfer task were not accompanied by behavioral transfer suggests that increased DA release may be a necessary, but not sufficient, condition for behavioral transfer to occur.

  • 26. Cabeza, Roberto
    et al.
    Albert, Marilyn
    Belleville, Sylvie
    Craik, Fergus I. M.
    Duarte, Audrey
    Grady, Cheryl L.
    Lindenberger, Ulman
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Park, Denise C.
    Reuter-Lorenz, Patricia A.
    Rugg, Michael D.
    Steffener, Jason
    Rajah, M. Natasha
    Maintenance, reserve and compensation: the cognitive neuroscience of healthy ageing2018In: Nature Reviews Neuroscience, ISSN 1471-003X, E-ISSN 1471-0048, Vol. 19, no 11, p. 701-710Article, review/survey (Refereed)
    Abstract [en]

    Cognitive ageing research examines the cognitive abilities that are preserved and/or those that decline with advanced age. There is great individual variability in cognitive ageing trajectories. Some older adults show little decline in cognitive ability compared with young adults and are thus termed ‘optimally ageing’. By contrast, others exhibit substantial cognitive decline and may develop dementia. Human neuroimaging research has led to a number of important advances in our understanding of the neural mechanisms underlying these two outcomes. However, interpreting the age-related changes and differences in brain structure, activation and functional connectivity that this research reveals is an ongoing challenge. Ambiguous terminology is a major source of difficulty in this venture. Three terms in particular — compensation, maintenance and reserve — have been used in a number of different ways, and researchers continue to disagree about the kinds of evidence or patterns of results that are required to interpret findings related to these concepts. As such inconsistencies can impede progress in both theoretical and empirical research, here, we aim to clarify and propose consensual definitions of these terms.

  • 27. Cabeza, Roberto
    et al.
    Albert, Marilyn
    Belleville, Sylvie
    Craik, Fergus I. M.
    Duarte, Audrey
    Grady, Cheryl L.
    Lindenberger, Ulman
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Park, Denise C.
    Reuter-Lorenz, Patricia A.
    Rugg, Michael D.
    Steffener, Jason
    Rajah, M. Natasha
    Reply to 'Mechanisms underlying resilience in ageing'2019In: Nature Reviews Neuroscience, ISSN 1471-003X, E-ISSN 1471-0048, Vol. 20, no 4, p. 247-247Article in journal (Refereed)
  • 28. Cabeza, Roberto
    et al.
    Daselaar, Sander M
    Dolcos, Florin
    Prince, Steven E
    Budde, Matthew
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Integrative Medical Biology, Physiology. Umeå University, Faculty of Social Sciences, Department of Psychology.
    Task-independent and task-specific age effects on brain activity during working memory, visual attention and episodic retrieval.2004In: Cerebral Cortex, ISSN 1047-3211, Vol. 14, no 4, p. 364-75Article in journal (Refereed)
    Abstract [en]

    It is controversial whether the effects of aging on various cognitive functions have the same common cause or several different causes. To investigate this issue, we scanned younger and older adults with functional magnetic resonance imaging (fMRI) while performing three different tasks: working memory, visual attention and episodic retrieval. There were three main results. First, in all three tasks, older adults showed weaker occipital activity and stronger prefrontal and parietal activity than younger adults. The occipital reduction is consistent with the view that sensory processing decline is a common cause in cognitive aging, and the prefrontal increase may reflect functional compensation. Secondly, older adults showed more bilateral patterns of prefrontal activity than younger adults during working memory and visual attention tasks. These findings are consistent with the Hemispheric Asymmetry Reduction in Older Adults (HAROLD) model. Finally, compared to younger adults, older adults showed weaker hippocampal formation activity in all three tasks but stronger parahippocampal activity in the episodic retrieval task. The former finding suggests that age-related hippocampal deficits may have a global effect in cognition, and the latter is consistent with an age-related increase in familiarity-based recognition. Taken together, the results indicate that both common and specific factors play an important role in cognitive aging.

  • 29. Cabeza, Roberto
    et al.
    Nyberg, LarsUmeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.Park, Denise
    Cognitive neuroscience of aging: linking cognitive and cerebral aging2005Collection (editor) (Other academic)
    Abstract [en]

    Until recently, the cognitive and neural mechanisms of age-related changes in cognition were usually studied independently of each other.

    On one hand, studies in the domain of cognitive psychology of aging investigated the effects of aging on behavioral measures of cognition and characterized a variety of age-related deficits in memory, attention, and the like. On the other hand, studies in the domain of neuroscience of aging investigated the effects of aging on the anatomy and physiology of the brain and described forms of age-related neural decline, such as cerebral atrophy and synaptic loss. Although it is reasonable to assume that cognitive aging is largely a consequence of cerebral aging, the relationships between these two phenomena are still largely unknown. Fortunately, this void is being rapidly resolved by studies focusing on the relationships between the effects of aging on the cognition and on the brain. This group of studies constitutes the new discipline of cognitive neuroscience of aging (CNA). Although CNA has a long past, only lately has it achieved the critical mass to be considered an autonomous discipline. The main goal of this book is to provide an introduction to this exciting new field.

  • 30.
    Dahlin, Erika
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Bäckman, Lars
    Aging Research Center, Karolinska institutet,Stockholm.
    Stigsdotter Neely, Anna
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Training of the executive component of working memory: subcortial areas mediate transfer effects2009In: Restorative Neurology and Neuroscience, ISSN 0922-6028, E-ISSN 1878-3627, Vol. 27, no 5, p. 405-419Article in journal (Refereed)
    Abstract [en]

    Purpose: Several recent studies show that training can improve working memory (WM) performance. In this review, many issues related to WM training, such as neural basis, transfer effects, and age-related changes are addressed.

    Method: We focus on our own studies investigating training on tasks taxing the executive updating function and discuss our findings in relation to results from other studies investigating training of the executive component of WM.

    Results: The review confirms positive behavioral effects of training on working memory. The most common neural pattern following training is fronto-parietal activity decreases. Increases in sub-cortical areas are also frequently reported after training, and we suggest that such increases indicate changes in the underlying skill following training. Transfer effects are in general difficult to demonstrate. Some studies show that older adults increase their performance after WM training. However, transfer effects are small or nonexistent in old age.

    Conclusions: The main finding in this review is that sub-cortical areas seem to have a critical role in mediating transfer effects to untrained tasks after at least some forms of working memory training (such as updating).

  • 31.
    Dahlin, Erika
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Bäckman, Lars
    Stigsdotter Neely, Anna
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Plasticity of executive functioning in young and older adults: immediative training gains, transfer, and long-term maintenance2008In: Psychology and Aging, ISSN 0882-7974, E-ISSN 1939-1498, Vol. 23, no 4, p. 720-730Article in journal (Refereed)
    Abstract [en]

    The authors investigated immediate training gains, transfer effects, and 18-month maintenance after 5 weeks of computer-based training in updating of information in working memory in young and older subjects. Trained young and older adults improved significantly more than controls on the criterion task (letter memory), and these gains were maintained 18 months later. Transfer effects were in general limited and restricted to the young participants, who showed transfer to an untrained task that required updating (3-back). The findings demonstrate substantial and durable plasticity of executive functioning across adulthood and old age, although there appear to be age-related constraints in the ability to generalize the acquired updating skill.

  • 32.
    Dahlin, Erika
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Stigsdotter-Neely, Anna
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Larsson, Anne
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Bäckman, Lars
    Aging Research Center, Karolinska Institute, 11330 Stockholm, Sweden.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Transfer of learning after updating training mediated by the striatum2008In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 320, no 5882, p. 1510-1512Article in journal (Refereed)
    Abstract [en]

    Process-specific training can improve performance on untrained tasks, but the magnitude of gain is variable and often there is no transfer at all. We demonstrate transfer to a 3-back test of working memory after 5 weeks of training in updating. The transfer effect was based on a joint training-related activity increase for the criterion (letter memory) and transfer tasks in a striatal region that also was recruited pretraining. No transfer was observed to a task that did not engage updating and striatal regions, and age-related striatal changes imposed constraints on transfer. These findings indicate that transfer can occur if the criterion and transfer tasks engage specific overlapping processing components and brain regions.

  • 33. Davies, G.
    et al.
    Armstrong, N.
    Bis, J. C.
    Bressler, J.
    Chouraki, V.
    Giddaluru, S.
    Hofer, E.
    Ibrahim-Verbaas, C. A.
    Kirin, M.
    Lahti, J.
    van der Lee, S. J.
    Le Hellard, S.
    Liu, T.
    Marioni, R. E.
    Oldmeadow, C.
    Postmus, I.
    Smith, A. V.
    Smith, J. A.
    Thalamuthu, A.
    Thomson, R.
    Vitart, V.
    Wang, J.
    Yu, L.
    Zgaga, L.
    Zhao, W.
    Boxall, R.
    Harris, S. E.
    Hill, W. D.
    Liewald, D. C.
    Luciano, M.
    Adams, H.
    Ames, D.
    Amin, N.
    Amouyel, P.
    Assareh, A. A.
    Au, R.
    Becker, J. T.
    Beiser, A.
    Berr, C.
    Bertram, L.
    Boerwinkle, E.
    Buckley, B. M.
    Campbell, H.
    Corley, J.
    De Jager, P. L.
    Dufouil, C.
    Eriksson, J. G.
    Espeseth, T.
    Faul, J. D.
    Ford, I.
    Gottesman, R. F.
    Griswold, M. E.
    Gudnason, V.
    Harris, T. B.
    Heiss, G.
    Hofman, A.
    Holliday, E. G.
    Huffman, J.
    Kardia, S. L. R.
    Kochan, N.
    Knopman, D. S.
    Kwok, J. B.
    Lambert, J-C
    Lee, T.
    Li, G.
    Li, S-C
    Loitfelder, M.
    Lopez, O. L.
    Lundervold, A. J.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Mather, K. A.
    Mirza, S. S.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Oostra, B. A.
    Palotie, A.
    Papenberg, G.
    Pattie, A.
    Petrovic, K.
    Polasek, O.
    Psaty, B. M.
    Redmond, P.
    Reppermund, S.
    Rotter, J. I.
    Schmidt, H.
    Schuur, M.
    Schofield, P. W.
    Scott, R. J.
    Steen, V. M.
    Stott, D. J.
    Van Swieten, J. C.
    Taylor, K. D.
    Trollor, J.
    Trompet, S.
    Uitterlinden, A. G.
    Weinstein, G.
    Widen, E.
    Windham, B. G.
    Jukema, J. W.
    Wright, A. F.
    Wright, M. J.
    Yang, Q.
    Amieva, H.
    Attia, J. R.
    Bennett, D. A.
    Brodaty, H.
    de Craen, A. J. M.
    Hayward, C.
    Ikram, M. A.
    Lindenberger, U.
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). ARC, Karolinska Institutet, Stockholm.
    Porteous, D. J.
    Raikkonen, K.
    Reinvang, I.
    Rudan, I.
    Sachdev, P. S.
    Schmidt, R.
    Schofield, P. R.
    Srikanth, V.
    Starr, J. M.
    Turner, S. T.
    Weir, D. R.
    Wilson, J. F.
    Van Duijn, C.
    Launer, L.
    Fitzpatrick, A. L.
    Seshadri, S.
    Jr, T. H. Mosley
    Deary, I. J.
    Genetic contributions to variation in general cognitive function: a meta-analysis of genome-wide association studies in the CHARGE consortium (N=53 949)2015In: Molecular Psychiatry, ISSN 1359-4184, E-ISSN 1476-5578, Vol. 20, no 2, p. 183-192Article in journal (Refereed)
    Abstract [en]

    General cognitive function is substantially heritable across the human life course from adolescence to old age. We investigated the genetic contribution to variation in this important, health-and well-being-related trait in middle-aged and older adults. We conducted a meta-analysis of genome-wide association studies of 31 cohorts (N = 53 949) in which the participants had undertaken multiple, diverse cognitive tests. A general cognitive function phenotype was tested for, and created in each cohort by principal component analysis. We report 13 genome-wide significant single-nucleotide polymorphism (SNP) associations in three genomic regions, 6q16.1, 14q12 and 19q13.32 (best SNP and closest gene, respectively: rs10457441, P = 3.93 x 10(-9), MIR2113; rs17522122, P = 2.55 x 10(-8), AKAP6; rs10119, P = 5.67 x 10(-9), APOE/TOMM40). We report one gene-based significant association with the HMGN1 gene located on chromosome 21 (P = 1x10(-6)). These genes have previously been associated with neuropsychiatric phenotypes. Meta-analysis results are consistent with a polygenic model of inheritance. To estimate SNP-based heritability, the genome-wide complex trait analysis procedure was applied to two large cohorts, the Atherosclerosis Risk in Communities Study (N = 6617) and the Health and Retirement Study (N = 5976). The proportion of phenotypic variation accounted for by all genotyped common SNPs was 29% (s.e. = 5%) and 28% (s.e. = 7%), respectively. Using polygenic prediction analysis, similar to 1.2% of the variance in general cognitive function was predicted in the Generation Scotland cohort (N = 5487; P = 1.5 x 10(-17)). In hypothesis-driven tests, there was significant association between general cognitive function and four genes previously associated with Alzheimer's disease: TOMM40, APOE, ABCG1 and MEF2C.

  • 34. Davies, Gail
    et al.
    Lam, Max
    Harris, Sarah E.
    Trampush, Joey W.
    Luciano, Michelle
    Hill, W. David
    Hagenaars, Saskia P.
    Ritchie, Stuart J.
    Marioni, Riccardo E.
    Fawns-Ritchie, Chloe
    Liewald, David C. M.
    Okely, Judith A.
    Ahola-Olli, Ari V.
    Barnes, Catriona L. K.
    Bertram, Lars
    Bis, Joshua C.
    Burdick, Katherine E.
    Christoforou, Andrea
    DeRosse, Pamela
    Djurovic, Srdjan
    Espeseth, Thomas
    Giakoumaki, Stella
    Giddaluru, Sudheer
    Gustavson, Daniel E.
    Hayward, Caroline
    Hofer, Edith
    Ikram, M. Arfan
    Karlsson, Robert
    Knowles, Emma
    Lahti, Jari
    Leber, Markus
    Li, Shuo
    Mather, Karen A.
    Melle, Ingrid
    Morris, Derek
    Oldmeadow, Christopher
    Palviainen, Teemu
    Payton, Antony
    Pazoki, Raha
    Petrovic, Katja
    Reynolds, Chandra A.
    Sargurupremraj, Muralidharan
    Scholz, Markus
    Smith, Jennifer A.
    Smith, Albert V.
    Terzikhan, Natalie
    Thalamuthu, Anbupalam
    Trompet, Stella
    van der Lee, Sven J.
    Ware, Erin B.
    Windham, B. Gwen
    Wright, Margaret J.
    Yang, Jingyun
    Yu, Jin
    Ames, David
    Amin, Najaf
    Amouyel, Philippe
    Andreassen, Ole A.
    Armstrong, Nicola J.
    Assareh, Amelia A.
    Attia, John R.
    Attix, Deborah
    Avramopoulos, Dimitrios
    Bennett, David A.
    Boehmer, Anne C.
    Boyle, Patricia A.
    Brodaty, Henry
    Campbell, Harry
    Cannon, Tyrone D.
    Cirulli, Elizabeth T.
    Congdon, Eliza
    Conley, Emily Drabant
    Corley, Janie
    Cox, Simon R.
    Dale, Anders M.
    Dehghan, Abbas
    Dick, Danielle
    Dickinson, Dwight
    Eriksson, Johan G.
    Evangelou, Evangelos
    Faul, Jessica D.
    Ford, Ian
    Freimer, Nelson A.
    Gao, He
    Giegling, Ina
    Gillespie, Nathan A.
    Gordon, Scott D.
    Gottesman, Rebecca F.
    Griswold, Michael E.
    Gudnason, Vilmundur
    Harris, Tamara B.
    Hartmann, Annette M.
    Hatzimanolis, Alex
    Heiss, Gerardo
    Holliday, Elizabeth G.
    Joshi, Peter K.
    Kahonen, Mika
    Kardia, Sharon L. R.
    Karlsson, Ida
    Kleineidam, Luca
    Knopman, David S.
    Kochan, Nicole A.
    Konte, Bettina
    Kwok, John B.
    Le Hellard, Stephanie
    Lee, Teresa
    Lehtimaki, Terho
    Li, Shu-Chen
    Liu, Tian
    Koini, Marisa
    London, Edythe
    Longstreth, Will T., Jr.
    Lopez, Oscar L.
    Loukola, Anu
    Luck, Tobias
    Lundervold, Astri J.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Lyytikainen, Leo-Pekka
    Martin, Nicholas G.
    Montgomery, Grant W.
    Murray, Alison D.
    Need, Anna C.
    Noordam, Raymond
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Ollier, William
    Papenberg, Goran
    Pattie, Alison
    Polasek, Ozren
    Poldrack, Russell A.
    Psaty, Bruce M.
    Reppermund, Simone
    Riedel-Heller, Steffi G.
    Rose, Richard J.
    Rotter, Jerome I.
    Roussos, Panos
    Rovio, Suvi P.
    Saba, Yasaman
    Sabb, Fred W.
    Sachdev, Perminder S.
    Satizabal, Claudia L.
    Schmid, Matthias
    Scott, Rodney J.
    Scult, Matthew A.
    Simino, Jeannette
    Slagboom, P. Eline
    Smyrnis, Nikolaos
    Soumare, Aicha
    Stefanis, Nikos C.
    Stott, David J.
    Straub, Richard E.
    Sundet, Kjetil
    Taylor, Adele M.
    Taylor, Kent D.
    Tzoulaki, Ioanna
    Tzourio, Christophe
    Uitterlinden, Andre
    Vitart, Veronique
    Voineskos, Aristotle N.
    Kaprio, Jaakko
    Wagner, Michael
    Wagner, Holger
    Weinhold, Leonie
    Wen, K. Hoyan
    Widen, Elisabeth
    Yang, Qiong
    Zhao, Wei
    Adams, Hieab H. H.
    Arking, Dan E.
    Bilder, Robert M.
    Bitsios, Panos
    Boerwinkle, Eric
    Chiba-Falek, Ornit
    Corvin, Aiden
    De Jager, Philip L.
    Debette, Stephanie
    Donohoe, Gary
    Elliott, Paul
    Fitzpatrick, Annette L.
    Gill, Michael
    Glahn, David C.
    Hagg, Sara
    Hansell, Narelle K.
    Hariri, Ahmad R.
    Ikram, M. Kamran
    Jukema, J. Wouter
    Vuoksimaa, Eero
    Keller, Matthew C.
    Kremen, William S.
    Launer, Lenore
    Lindenberger, Ulman
    Palotie, Aarno
    Pedersen, Nancy L.
    Pendleton, Neil
    Porteous, David J.
    Raikkonen, Katri
    Raitakari, Olli T.
    Ramirez, Alfredo
    Reinvang, Ivar
    Rudan, Igor
    Rujescu, Dan
    Schmidt, Reinhold
    Schmidt, Helena
    Schofield, Peter W.
    Schofield, Peter R.
    Starr, John M.
    Steen, Vidar M.
    Trollor, Julian N.
    Turner, Steven T.
    Van Duijn, Cornelia M.
    Villringer, Arno
    Weinberger, Daniel R.
    Weir, David R.
    Wilson, James F.
    Malhotra, Anil
    McIntosh, Andrew M.
    Gale, Catharine R.
    Seshadri, Sudha
    Mosley, Thomas H., Jr.
    Bressler, Jan
    Lencz, Todd
    Deary, Ian J.
    Study of 300,486 individuals identifies 148 independent genetic loci influencing general cognitive function2018In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 9, article id 2098Article in journal (Refereed)
    Abstract [en]

    General cognitive function is a prominent and relatively stable human trait that is associated with many important life outcomes. We combine cognitive and genetic data from the CHARGE and COGENT consortia, and UK Biobank (total N = 300,486; age 16-102) and find 148 genome-wide significant independent loci (P < 5 x 10-8) associated with general cognitive function. Within the novel genetic loci are variants associated with neurodegenerative and neurodevelopmental disorders, physical and psychiatric illnesses, and brain structure. Gene-based analyses find 709 genes associated with general cognitive function. Expression levels across the cortex are associated with general cognitive function. Using polygenic scores, up to 4.3% of variance in general cognitive function is predicted in independent samples. We detect significant genetic overlap between general cognitive function, reaction time, and many health variables including eyesight, hypertension, and longevity. In conclusion we identify novel genetic loci and pathways contributing to the heritability of general cognitive function.

  • 35. de Boer, Lieke
    et al.
    Axelsson, Jan
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Chowdhury, Rumana
    Riklund, Katrine
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Dolan, Raymond J.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Backman, Lars
    Guitart-Masip, Marc
    Dorsal striatal dopamine D1 receptor availability predicts an instrumental bias in action learning2019In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 116, no 1, p. 261-270Article in journal (Refereed)
    Abstract [en]

    Learning to act to obtain reward and inhibit to avoid punishment is easier compared with learning the opposite contingencies. This coupling of action and valence is often thought of as a Pavlovian bias, although recent research has shown it may also emerge through instrumental mechanisms. We measured this learning bias with a rewarded go/no-go task in 60 adults of different ages. Using computational modeling, we characterized the bias as being instrumental. To assess the role of endogenous dopamine (DA) in the expression of this bias, we quantified DA D1 receptor availability using positron emission tomography (PET) with the radioligand [11C]SCH23390. Using principal-component analysis on the binding potentials in a number of cortical and striatal regions of interest, we demonstrated that cortical, dorsal striatal, and ventral striatal areas provide independent sources of variance in DA D1 receptor availability. Interindividual variation in the dorsal striatal component was related to the strength of the instrumental bias during learning. These data suggest at least three anatomical sources of variance in DA D1 receptor availability separable using PET in humans, and we provide evidence that human dorsal striatal DA D1 receptors are involved in the modulation of instrumental learning biases.

  • 36. de Boer, Lieke
    et al.
    Axelsson, Jan
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Riklund, Katrine
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Dayan, Peter
    Backman, Lars
    Guitart-Masip, Marc
    Attenuation of dopamine-modulated prefrontal value signals underlies probabilistic reward learning deficits in old age2017In: eLIFE, E-ISSN 2050-084X, Vol. 6, article id e2642Article in journal (Refereed)
    Abstract [en]

    Probabilistic reward learning is characterised by individual differences that become acute in aging. This may be due to age-related dopamine (DA) decline affecting neural processing in striatum, prefrontal cortex, or both. We examined this by administering a probabilistic reward learning task to younger and older adults, and combining computational modelling of behaviour, fMRI and PET measurements of DA D1 availability. We found that anticipatory value signals in ventromedial prefrontal cortex (vmPFC) were attenuated in older adults. The strength of this signal predicted performance beyond age and was modulated by D1 availability in nucleus accumbens. These results uncover that a value-anticipation mechanism in vmPFC declines in aging, and that this mechanism is associated with DA D1 receptor availability.

  • 37.
    de Frias, Cindy M
    et al.
    Stockholm University.
    Marklund, Petter
    Stockholm University, Stockholm Brain Institute.
    Eriksson, Elias
    Göteborg University.
    Larsson, Anne
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Öman, Lena
    Umeå University.
    Annerbrink, Kristina
    Göteborg University.
    Bäckman, Lars
    Karolinska Institute.
    Nilsson, Lars-Göran
    Stockholm University.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Influence of COMT gene polymorphism on fMRI-assessed sustained and transient activity during a working memory task.2010In: Journal of cognitive neuroscience, ISSN 0898-929X, E-ISSN 1530-8898, Vol. 22, no 7, p. 1614-1622Article in journal (Refereed)
    Abstract [en]

    The catechol O-methyltransferase (COMT) gene--encoding an enzyme that is essential for the degradation of dopamine (DA) in prefrontal cortex (PFC)--contains a single nucleotide polymorphism (val/met) important for cognition. According to the tonic-phasic hypothesis, individuals carrying the low-enzyme-activity allele (met) are characterized by enhanced tonic DA activity in PFC, promoting sustained cognitive representations in working memory. Val carriers have reduced tonic but enhanced phasic dopaminergic activity in subcortical regions, enhancing cognitive flexibility. We tested the tonic-phasic DA hypothesis by dissociating sustained and transient brain activity during performance on a 2-back working memory test using mixed blocked/event-related functional magnetic resonance imaging. Participants were men recruited from a random sample of the population (the Betula study) and consisted of 11 met/met and 11 val/val carriers aged 50 to 65 years, matched on age, education, and cognitive performance. There were no differences in 2-back performance between genotype groups. Met carriers displayed a greater transient medial temporal lobe response in the updating phase of working memory, whereas val carriers showed a greater sustained PFC activation in the maintenance phase. These results support the tonic-phasic theory of DA function in elucidating the specific phenotypic influence of the COMT val(158)met polymorphism on different components of working memory.

  • 38.
    Degerman, Sofie
    et al.
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Josefsson, Maria
    Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Nordin Adolfsson, Annelie
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Wennstedt, Sigrid
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Landfors, Mattias
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Haider, Zahra
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Hultdin, Magnus
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Adolfsson, Rolf
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Maintained memory in aging is associated with young epigenetic age2017In: Neurobiology of Aging, ISSN 0197-4580, E-ISSN 1558-1497, Vol. 55, p. 167-171Article in journal (Refereed)
    Abstract [en]

    Epigenetic alterations during aging have been proposed to contribute to decline in physical and cognitive functions, and accelerated epigenetic aging has been associated with disease and all-cause mortality later in life. In this study, we estimated epigenetic age dynamics in groups with different memory trajectories (maintained high performance, average decline, and accelerated decline) over a 15-year period. Epigenetic (DNA-methylation [DNAm]) age was assessed, and delta age (DNAm age - chronological age) was calculated in blood samples at baseline (age: 55-65 years) and 15 years later in 52 age- and gender-matched individuals from the Betula study in Sweden. A lower delta DNAm age was observed for those with maintained memory functions compared with those with average (p = 0.035) or accelerated decline (p = 0.037). Moreover, separate analyses revealed that DNAm age at follow-up, but not chronologic age, was a significant predictor of dementia (p = 0.019). Our findings suggest that young epigenetic age contributes to maintained memory in aging.

  • 39.
    Ekman, Urban
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Eriksson, Johan
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Forsgren, Lars
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Domellöf, Magdalena
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Elgh, Eva
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Psychiatry.
    Lundquist, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Longitudinal changes in task-evoked brain responses in Parkinson's disease patients with and without mild cognitive impairment2014In: Frontiers in Neuroscience, ISSN 1662-4548, E-ISSN 1662-453X, Vol. 8, article id 207Article in journal (Refereed)
    Abstract [en]

    Cognitive deficits are common in Parkinson's disease. Previous cross-sectional research has demonstrated a link between cognitive impairments and fronto-striatal dopaminergic dysmodulation. However, longitudinal studies that link disease progression with altered task-evoked brain activity are lacking. Therefore, our objective was to longitudinally evaluate working-memory related brain activity changes in Parkinson's disease patients with and without mild cognitive impairment (MCI). Patients were recruited within a longitudinal cohort study of incident patients with idiopathic parkinsonism. We longitudinally (at baseline examination and at 12-months follow-up) compared 28 patients with Parkinson's disease without MCI with 11 patients with Parkinson's disease and MCI. Functional MRI blood oxygen level dependent signal was measured during a verbal two-back working-memory task. Patients with MCI under-recruited bilateral medial prefrontal cortex at both time-points (main effect of group: p < 0.001, uncorrected). Critically, a significant group-by-time interaction effect (p < 0.001, uncorrected) was found in the right fusiform gyrus, indicating that working-memory related activity decreased for patients with Parkinson's disease and MCI between baseline and follow-up, while patients without MCI were stable across time-points. The functional connectivity between right fusiform gyrus and bilateral caudate nucleus was stronger for patients without MCI relative to patients with MCI. Our findings support the view that deficits in working-memory updating are related to persistent fronto-striatal under-recruitments in patients with early phase Parkinson's disease and MCI. The longitudinal evolution of MCI in Parkinson's disease translates into additional task-evoked posterior cortical changes.

  • 40.
    Ekman, Urban
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Eriksson, Johan
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Forsgren, Lars
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Jakobson Mo, Susanna
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Riklund, Katrine
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Functional brain activity and presynaptic dopamine uptake in patients with Parkinson's disease and mild cognitive impairment: a cross-sectional study2012In: Lancet Neurology, ISSN 1474-4422, E-ISSN 1474-4465, Vol. 11, no 8, p. 679-687Article in journal (Refereed)
    Abstract [en]

    Background: Many patients with Parkinson's disease have mild cognitive impairment (MCI). Deficits in executive functions and working memory suggest dysfunctional frontostriatal brain circuitry. We aimed to assess brain responses during a working memory task in a cohort of newly diagnosed drug-naive patients with Parkinson's disease with and without MCI.

    Methods: Participants were recruited within a prospective cohort study of incident patients with idiopathic parkinsonism, including Parkinson's disease. Between Jan 1, 2004, and April 30, 2009, all physicians in the Umea catchment area were requested to refer all individuals with suspected parkinsonism to the Department of Neurology at lima University. Included patients fulfilled the UK Parkinson's Disease Society Brain Bank clinical diagnostic criteria for Parkinson's disease. Control individuals were matched on the basis of age and sex with the first 50 patients included in the study. Participants who scored 1.5 SDs or more below the population mean on at least two cognitive measures were diagnosed with MCI. The primary outcome measures were functional MRI blood-oxygen-level-dependent signal and SPECT presynaptic uptake. Functional MRI was done during a verbal two-back working memory task. Presynaptic dopamine SPECT was done to assess presynaptic striatal dopaminergic system integrity. Event-related transient analyses of functional MRI data were done for the whole brain and for frontostriatal regions of interest, and semi-quantitative SPECT analyses were done for striatal regions of interest.

    Findings: Compared with controls (n=24), patients with Parkinson's disease (n=77) had under-recruitment in an extensive brain network including bilateral striatal and frontal regions (p<0.001). Within the Parkinson's disease group, patients with Parkinson's disease and MCI (n=30) had additional under-recruitment in the right dorsal caudate nucleus (p=0.005) and the bilateral anterior cingulate cortex (p<0.001) compared with patients with Parkinson's disease without MCI (n=26). In patients with Parkinson's disease and MCI, SPECT uptake in the right caudate was lower than in patients with Parkinson's disease without MCI (p=0.008) and correlated with striatal functional MRI blood-oxygen-level-dependent signal (r=0.32, p=0.031).

    Interpretation: These altered brain responses in patients with Parkinson's disease and MCI suggest that cognitive impairment is linked to frontostriatal dysfunction.

  • 41.
    Elgh, Eva
    et al.
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Larsson, Anne
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Eriksson, Sture
    Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Geriatric Medicine.
    Nyberg, Lars
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Altered prefrontal brain activity in persons at risk for Alzheimer's disease: an f-MRI study2003In: International psychogeriatrics, ISSN 1041-6102, E-ISSN 1741-203X, Vol. 15, no 2, p. 121-133Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Early diagnosis of Alzheimer's disease (AD) is critical for adequate treatment and care. Recently it has been shown that functional magnetic resonance imaging (fMRI) can be important in preclinical detection of AD. The purpose of this study was to examine possible differences in memory-related brain activation between persons with high versus low risk for AD. This was achieved by combining a validated neurocognitive screening battery (the 7-minutes test) with memory assessment and fMRI. METHODS: One hundred two healthy community-living persons with subjective memory complaints were recruited through advertisement and tested with the 7-minutes test. Based on their test performance they were classified as having either high (n = 8) or low risk (n = 94) for AD. Six high-risk individuals and six age-, sex-, and education-matched low-risk individuals were investigated with fMRI while engaged in episodic memory tasks. RESULTS: The high-risk individuals performed worse than low-risk individuals on tests of episodic memory. Patterns of brain activity during episodic encoding and retrieval showed significant group differences (p < .05 corrected). During both encoding and retrieval, the low-risk persons showed increased activity relative to a baseline condition in prefrontal brain regions that previously have been implicated in episodic memory. By contrast, the high-risk persons did not significantly activate any prefrontal regions, but instead showed increased activity in visual occipito-temporal regions. CONCLUSION: Patterns of prefrontal brain activity related to episodic memory differ between persons with high versus low risk for AD, and lowered prefrontal activity may predict subsequent disease.

  • 42.
    Elgh, Eva
    et al.
    Umeå University, Faculty of Medicine, Community Medicine and Rehabilitation, Geriatric Medicine.
    Sundström, Torbjörn
    Umeå University, Faculty of Medicine, Radiation Sciences, Diagnostic Radiology.
    Näsman, Birgitta
    Umeå University, Faculty of Medicine, Community Medicine and Rehabilitation, Geriatric Medicine.
    Riklund Åhlström, Katrine
    Umeå University, Faculty of Medicine, Radiation Sciences, Diagnostic Radiology.
    Nyberg, Lars
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Memory functions and rCBF (99m)Tc-HMPAO SPET: developing diagnostics in Alzheimer's disease2002In: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, ISSN 1619-7070, Vol. 29, no 9, p. 1140-1148Article in journal (Refereed)
    Abstract [en]

    Alzheimer's disease (AD) is a primary degenerative disease of the brain. The prevalence increases with age, with devastating consequences for the individual and society. The aim of this study was to evaluate whether patients with early AD show an altered regional cerebral blood flow (rCBF) compared with control persons. Furthermore, we aimed to investigate the correlation between rCBF in sublobar volumes of the brain and performance on memory tests. Memory tests were chosen to evaluate episodic and semantic memory. Fourteen patients (aged 75.2+/-8.8 years) with early AD and 15 control persons (aged 71.4+/-3.2 years) were included. rCBF measurements with single-photon emission tomography (SPET) using technetium-99m hexamethylpropylene amine oxime (HMPAO) were performed. The rCBF (99m)Tc-HMPAO SPET images were spatially transformed to fit a brain atlas and normalised for differences in rCBF (Computerised Brain Atlas software). Cortical and subcortical volumes of interest (VOIs) were analysed and compared. Compared with the controls, AD patients showed a significantly lower rCBF ratio in temporoparietal regions, including the left hippocampus. The diagnostic sensitivity and specificity for AD were high in temporoparietal regions. AD patients had significantly reduced performance on semantic and, in particular, episodic memory tests compared with age-matched normative data, and their performance on several episodic tests correlated with rCBF ratios in parietal and temporal regions, including the left hippocampus. The correlation between rCBF ratio and level of episodic memory performance suggests that abnormalities in rCBF pattern underlie impaired episodic memory functioning in AD.

  • 43.
    Eriksson, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Kalpouzos, Grégoria
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Rewiring the brain with repeated retrieval: A parametric fMRI study of the testing effect2011In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 505, no 1, p. 36-40Article in journal (Refereed)
    Abstract [en]

    The "testing effect" refers to the beneficial effects on memory performance from being tested, a phenomenon of potentially substantial implications in educational settings. While the effect itself is firmly established in previous research, little is known of related brain changes. Here we used fMRI and a parametric design to show that repeated successful retrieval during a memory acquisition phase leads to higher brain activity in the anterior cingulate cortex (ACC) at a subsequent test phase. The extent of ACC activity increase correlated across individuals with memory performance 5 months later. In relation to recent research that associates the ACC with memory consolidation processes, the present results suggest that the testing effect may operate at the systems level by enhancing consolidation of memory representations.

  • 44.
    Eriksson, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Larsson, Anne
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Item-specific training reduces prefrontal cortical involvement in perceptual awareness2008In: Journal of cognitive neuroscience, ISSN 0898-929X, E-ISSN 1530-8898, Vol. 20, no 10, p. 1777-1787Article in journal (Refereed)
    Abstract [en]

    Previous studies on the neural correlates of perceptual awareness implicate sensory-specific regions and higher cortical regions such as the prefrontal cortex (PFC) in this process. The specific role of PFC regions is, however, unknown. PFC activity could be bottom-up driven, integrating signals from sensory regions. Alternatively, PFC regions could serve more active top-down processes that help to define the content of consciousness. To compare these alternative views of PFC function, we used functional magnetic resonance imaging and measured brain activity specifically related to conscious perception of items that varied in ease of identification (by being presented 0, 12, or 60 times previously). A bottom-up account predicts that PFC activity would be largely insensitive to stimulus difficulty, whereas a top-down account predicts reduced PFC activity as identification becomes easier. The results supported the latter prediction by showing reduced activity for previously presented compared to novel items in the PFC and several other regions. This was further confirmed by a functional connectivity analysis showing that the interaction between frontal and visual sensory regions declined as a function of ease of identification. Given the attribution of top-down processing to PFC regions in combination with the marked decline in PFC activity for easy items, these findings challenge the prevailing notion that the PFC is necessary for consciousness.

  • 45.
    Eriksson, Johan
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Larsson, Anne
    Nyberg, Lars
    Item-specific training reduces prefrontal cortical involvement in perceptual awarenessManuscript (Other academic)
  • 46.
    Eriksson, Johan
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Larsson, Anne
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Riklund Åhlström, Katrine
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Similar frontal and distinct posterior cortical regions mediate visual and auditory perceptual awareness2007In: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 17, no 4, p. 760-765Article in journal (Refereed)
    Abstract [en]

    Activity in ventral visual cortex is a consistent neural correlate of visual consciousness. However, activity in this area seems insufficient to produce awareness without additional involvement of frontoparietal regions. To test the generality of the frontoparietal response, neural correlates of auditory awareness were investigated in a paradigm that previously has revealed frontoparietal activity during conscious visual perception. A within-experiment comparison showed that frontal regions were related to both visual and auditory awareness, whereas parietal activity was correlated with visual awareness and superior temporal activity with auditory awareness. These results indicate that frontal regions interact with specific posterior regions to produce awareness in different sensory modalities.

  • 47.
    Eriksson, Johan
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Larsson, Anne
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Riklund Åhlström, Katrine
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Visual consciousness: dissociating the neural correlates of perceptual transitions from sustained perception with fMRI2004In: Consciousness and Cognition, ISSN 1053-8100, E-ISSN 1090-2376, Vol. 13, no 1, p. 61-72Article in journal (Refereed)
    Abstract [en]

    To investigate the possible dichotomy between the neurophysiological bases of perceptual transitions versus sustaining a particular percept over time, an fMRI study was conducted with subjects viewing fragmented pictures. Unlike most other perceptually unstable stimuli, fragmented pictures give rise to only one perceptual transition and a continuous period of sustained perception. Earlier research is inconclusive on the subject of which anatomical regions should be attributed to what temporal aspect of perception, and the aim of the present study was to shed more light on the subject. In this study occipitotemporal and fronto-parietal regions were found to be activated for both aspects. However, regions in the medial-temporal lobe were activated specifically for transitions, whereas medial and dorsolateral prefrontal regions were activated specifically for sustained perception. These results provide further support for the theory that the initial creation of perceptual awareness and upholding perceptual awareness over time are separate processes involving different brain regions.

  • 48.
    Eriksson, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology.
    Details of the construction of perception: a closer look at illusory contours2009In: Frontiers in neuroscience, ISSN 1662-453X, Vol. 3, no 2, p. 159-160Article in journal (Refereed)
  • 49.
    Eriksson, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Stiernstedt, Mikael
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Öhlund, Maria
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Changing Zaire to Congo: The fate of no-longer relevant mnemonic information.2014In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 101, p. 1-7Article in journal (Refereed)
    Abstract [en]

    In an ever-changing world there is constant pressure on revising long-term memory, such when people or countries change name. What happens to the old, pre-existing information? One possibility is that old associations gradually are weakened and eventually lost. Alternatively, old and no longer relevant information may still be an integral part of memory traces. To test the hypothesis that old mnemonic information still becomes activated when people correctly retrieve new, currently relevant information, brain activity was measured with fMRI while participants performed a cued-retrieval task. Paired associates (symbol-sound and symbol-face pairs) were first learned during two days. Half of the associations were then updated during the next two days, followed by fMRI scanning on day 5 and also 18months later. As expected, retrieval reactivated sensory cortex related to the most recently learned association (visual cortex for symbol-face pairs, auditory cortex for symbol-sound pairs). Critically, retrieval also reactivated sensory cortex related to the no-longer relevant associate. Eighteen months later, only non-updated symbol-face associations were intact. Intriguingly, a subset of the updated associations was now treated as though the original association had taken over, in that memory performance was significantly worse than chance and that activity in sensory cortex for the original but not the updated associate correlated (negatively) with performance. Moreover, the degree of "residual" reactivation during day 5 inversely predicted memory performance 18months later. Thus, updating of long-term memory involves adding new information to already existing networks, in which old information can stay resilient for a long time.

  • 50.
    Eriksson, Johan
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Vogel, Edward K.
    Lansner, Anders
    Bergström, Fredrik
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Neurocognitive Architecture of Working Memory2015In: Neuron, ISSN 0896-6273, E-ISSN 1097-4199, Vol. 88, no 1, p. 33-46Article, review/survey (Refereed)
    Abstract [en]

    A crucial role for working memory in temporary information processing and guidance of complex behavior has been recognized for many decades. There is emerging consensus that working-memory maintenance results from the interactions among long-term memory representations and basic processes, including attention, that are instantiated as reentrant loops between frontal and posterior cortical areas, as well as sub-cortical structures. The nature of such interactions can account for capacity limitations, lifespan changes, and restricted transfer after working-memory training. Recent data and models indicate that working memory may also be based on synaptic plasticity and that working memory can operate on non-consciously perceived information.

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