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  • 201.
    Stomby, Andreas
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Otten, Julia
    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.
    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.
    Boraxbekk, Carl-Johan
    Umeå University, Faculty of Social Sciences, Demographic Data Base.
    A Paleolithic diet alters functional brain responses during an episodic memory task in type 2 diabetesManuscript (preprint) (Other academic)
  • 202.
    Stomby, Andreas
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine. Jönköping County Hospital, Region Jönköping County, Jönköping, Sweden.
    Otten, Julia
    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.
    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.
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Boraxbekk, Carl-Johan
    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). Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark.
    A Paleolithic Diet with and without Combined Aerobic and Resistance Exercise Increases Functional Brain Responses and Hippocampal Volume in Subjects with Type 2 Diabetes2017In: Frontiers in Aging Neuroscience, ISSN 1663-4365, E-ISSN 1663-4365, Vol. 9, article id 391Article in journal (Refereed)
  • 203.
    Stomby, Andreas
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine. Region Jönköping County, Jönköping, Sweden.
    Salami, Alireza
    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, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM).
    Dahlqvist, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Evang, Johan Arild
    Ryberg, Mats
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Bollerslev, Jens
    Olsson, Tommy
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine.
    Johannsson, Gudmundur
    Ragnarsson, Oskar
    Elevated resting-state connectivity in the medial temporal lobe and the prefrontal cortex among patients with Cushing's syndrome in remission2019In: European Journal of Endocrinology, ISSN 0804-4643, E-ISSN 1479-683X, Vol. 180, no 5, p. 329-338Article in journal (Refereed)
    Abstract [en]

    Objective: Cushing's syndrome is associated with long-term cognitive deficits and affective symptoms such as depression and anxiety. The alterations in brain function under lying these deficits after Cushing's syndrome are unclear and therefore we aimed to explore alterations in resting-state functional connectivity in patients with Cushing's syndrome in remission. Design: Cross-sectional case-control study. Methods: Nineteen women with Cushing's syndrome in remission for a median time of 7 years (IQR: 6-10) and a mean age of 45 years were included at three university clinics. These patients and 38 age-matched female controls underwent brain imaging at a single center. The main outcome measure was functional connectivity at rest, measured with functional magnetic resonance imaging. Results: The medial temporal lobe (MTL) and prefrontal cortex networks, exhibited elevated functional connectivity among patients compared to controls. The degree of elevated functional connectivity in the MTL was negatively associated with time in remission. Conclusions: Resting-state functional connectivity within glucocorticoid receptor-rich regions, particularly the MTL and medial prefrontal cortex, was increased in patients. These differences in connectivity may provide a neural basis for the cognitive deficits and affective symptoms commonly experienced by patients with Cushing's syndrome in remission.

  • 204.
    Sundström, Anna
    et al.
    Umeå University, Faculty of Social Sciences, Centre for Population Studies (CPS).
    Nilsson, Lars-Göran
    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.
    Cognitive performance before and after mild head injury.2002In: Journal of cognitive neuroscience, ISSN 0898-929X, E-ISSN 1530-8898, Vol. Suppl, no B77, p. 60-Article in journal (Refereed)
  • 205.
    Sundström, Anna
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    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.
    APOE influences in neuropsychological function after mild head injury: Within-person comparisons - Reply2004In: Neurology, ISSN 0028-3878, E-ISSN 1526-632X, Vol. 63, p. 2460-Article in journal (Refereed)
  • 206.
    Säfström, Daniel
    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).
    Domellöf, Erik
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Brain activations supporting linking of action phases in a sequential manual task2018In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, ., Vol. 172, p. 608-619Article in journal (Refereed)
    Abstract [en]

    Most everyday manual tasks, like grabbing a cup of coffee to drink, are comprised of a sequence of action phases. Efficient phase transitions, or linking, are achieved using a predictive control policy where motor commands for the next phase are specified and released in anticipation of sensory confirmation of goal completion of the current phase. If there is a discrepancy between predicted and actual sensory feedback about goal completion, corrective actions are employed to complete the current action phase before proceeding to the next. However, we lack understanding about brain activations supporting such predictive linking and corrective actions in manual tasks. In this study, during 3-T MRI-scanning, sixteen participants (5 males, 11 females; mean age 27.3 years, range 23–37) performed a sequential manual task, with or without the possibility for predictive linking. We found that predictive linking of action phases was associated with increased activation in a network that included right-sided fronto-parietal areas related to visuospatial attention, eye movements and motor planning, left-sided parietal areas related to implicit timing and shifts of motor attention, occipital regions bilaterally reflecting visual processing related to the attended next target, and finally, the anterior midcingulate cortex involved in continuous performance monitoring. Corrective actions were associated with increased activation in the left dorsolateral prefrontal cortex involved in reestablishing executive control over previously automatized behavior.

  • 207.
    Sörman Eriksson, Daniel
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Rönnlund, Michael
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Sundström, Anna
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Norberg, Margareta
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health. Umeå University, Faculty of Social Sciences, Centre for Demographic and Ageing Research (CEDAR).
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Aging Research Center (ARC), Karolinska Institutet, 113 30 Stockholm, Sweden.
    Social network size and cognitive functioning in middle-aged adults: cross-sectional and longitudinal associations2017In: Journal of Adult Development, ISSN 1068-0667, E-ISSN 1573-3440, Vol. 24, no 2, p. 77-88Article in journal (Refereed)
    Abstract [en]

    The objective of the present study was to examine relations between social network size and three cognitive abilities (episodic memory, semantic memory, visuospatial ability) in middle-aged adults. We analyzed cross-sectional data on social network size and cognitive functioning that were available for 804 participants aged 40–60 years. In addition, we examined 5- and 10-year follow-up measurements of cognitive functioning that were available for 604 and 255 participants, respectively. Cross-sectional analyses revealed a positive association between social network size and each of the three cognitive abilities. Baseline network size was positively related to 5-year changes in semantic memory, and to 10-year changes in semantic as well as episodic memory, but was unrelated to changes in visuospatial performance. A minor portion of the sample (n = 131) had 10-year follow-up data on network size. Cross-lagged panel correlations revealed that baseline network size was associated with follow-up measurement in cognitive functioning (episodic memory, semantic memory), whereas baseline cognitive performance was unrelated to future network size. Together, the results demonstrate a small but positive relation between network size and declarative memory abilities, in line with models proposing a cognitive reserve built up by factors such as the increased cognitive stimulation associated with a more extensive social network.

  • 208.
    Theorin, Anna
    et al.
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Johansson, Roland S
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Selection of prime actor in humans during bimanual object manipulation2010In: Journal of Neuroscience, ISSN 0270-6474, E-ISSN 1529-2401, Vol. 30, no 31, p. 10448-10459Article in journal (Refereed)
    Abstract [en]

    In bimanual object manipulation tasks, people flexibly assign one hand as a prime actor while the other assists. Little is known, however, about the neural mechanisms deciding the role assignment. We addressed this issue in a task in which participants moved a cursor to hit targets on a screen by applying precisely coupled symmetrical opposing linear and twist forces on a tool held freely between the hands. In trials presented in an unpredictable order, the action of either the left or the right hand was spatially congruent with the cursor movements, which automatically rendered the left or right hand the dominant actor, respectively. Functional magnetic resonance imaging indicated that the hand-selection process engaged prefrontal cortical areas belonging to an executive control network presumed critical for judgment and decision-making and to a salience network attributed to evaluation of utility of actions. Task initiation, which involved switching between task sets, had a superordinate role with reference to hand selection. Behavioral and brain imaging data indicated that participants initially expressed two competing action representations, matching either mapping rule, before selecting the appropriate one based on the consequences of the initial manual actions. We conclude that implicit processes engaging the prefrontal cortex reconcile selections among action representations that compete for the establishment of a dominant actor in bimanual object manipulation tasks. The representation selected is the one that optimizes performance by relying on the superior capacity of the brain to process spatial congruent, as opposed to noncongruent, mappings between manual actions and desired movement goals.

  • 209. Thompson, Paul M.
    et al.
    Stein, Jason L.
    Medland, Sarah E.
    Hibar, Derrek P.
    Vasquez, Alejandro Arias
    Renteria, Miguel E.
    Toro, Roberto
    Jahanshad, Neda
    Schumann, Gunter
    Franke, Barbara
    Wright, Margaret J.
    Martin, Nicholas G.
    Agartz, Ingrid
    Alda, Martin
    Alhusaini, Saud
    Almasy, Laura
    Almeida, Jorge
    Alpert, Kathryn
    Andreasen, Nancy C.
    Andreassen, Ole A.
    Apostolova, Liana G.
    Appel, Katja
    Armstrong, Nicola J.
    Aribisala, Benjamin
    Bastin, Mark E.
    Bauer, Michael
    Bearden, Carrie E.
    Bergmann, Orjan
    Binder, Elisabeth B.
    Blangero, John
    Bockholt, Henry J.
    Boen, Erlend
    Bois, Catherine
    Boomsma, Dorret I.
    Booth, Tom
    Bowman, Ian J.
    Bralten, Janita
    Brouwer, Rachel M.
    Brunner, Han G.
    Brohawn, David G.
    Buckner, Randy L.
    Buitelaar, Jan
    Bulayeva, Kazima
    Bustillo, Juan R.
    Calhoun, Vince D.
    Cannon, Dara M.
    Cantor, Rita M.
    Carless, Melanie A.
    Caseras, Xavier
    Cavalleri, Gianpiero L.
    Chakravarty, M. Mallar
    Chang, Kiki D.
    Ching, Christopher R. K.
    Christoforou, Andrea
    Cichon, Sven
    Clark, Vincent P.
    Conrod, Patricia
    Coppola, Giovanni
    Crespo-Facorro, Benedicto
    Curran, Joanne E.
    Czisch, Michael
    Deary, Ian J.
    de Geus, Eco J. C.
    den Braber, Anouk
    Delvecchio, Giuseppe
    Depondt, Chantal
    de Haan, Lieuwe
    de Zubicaray, Greig I.
    Dima, Danai
    Dimitrova, Rali
    Djurovic, Srdjan
    Dong, Hongwei
    Donohoe, Gary
    Duggirala, Ravindranath
    Dyer, Thomas D.
    Ehrlich, Stefan
    Ekman, Carl Johan
    Elvsashagen, Torbjorn
    Emsell, Louise
    Erk, Susanne
    Espeseth, Thomas
    Fagerness, Jesen
    Fears, Scott
    Fedko, Iryna
    Fernandez, Guillen
    Fisher, Simon E.
    Foroud, Tatiana
    Fox, Peter T.
    Francks, Clyde
    Frangou, Sophia
    Frey, Eva Maria
    Frodl, Thomas
    Frouin, Vincent
    Garavan, Hugh
    Giddaluru, Sudheer
    Glahn, David C.
    Godlewska, Beata
    Goldstein, Rita Z.
    Gollub, Randy L.
    Grabe, Hans J.
    Grimm, Oliver
    Gruber, Oliver
    Guadalupe, Tulio
    Gur, Raquel E.
    Gur, Ruben C.
    Goering, Harald H. H.
    Hagenaars, Saskia
    Hajek, Tomas
    Hall, Geoffrey B.
    Hall, Jeremy
    Hardy, John
    Hartman, Catharina A.
    Hass, Johanna
    Hatton, Sean N.
    Haukvik, Unn K.
    Hegenscheid, Katrin
    Heinz, Andreas
    Hickie, Ian B.
    Ho, Beng-Choon
    Hoehn, David
    Hoekstra, Pieter J.
    Hollinshead, Marisa
    Holmes, Avram J.
    Homuth, Georg
    Hoogman, Martine
    Hong, L. Elliot
    Hosten, Norbert
    Hottenga, Jouke-Jan
    Pol, Hilleke E. Hulshoff
    Hwang, Kristy S.
    Jack, Clifford R., Jr.
    Jenkinson, Mark
    Johnston, Caroline
    Joensson, Erik G.
    Kahn, Rene S.
    Kasperaviciute, Dalia
    Kelly, Sinead
    Kim, Sungeun
    Kochunov, Peter
    Koenders, Laura
    Kraemer, Bernd
    Kwok, John B. J.
    Lagopoulos, Jim
    Laje, Gonzalo
    Landen, Mikael
    Landman, Bennett A.
    Lauriello, John
    Lawrie, Stephen M.
    Lee, Phil H.
    Le Hellard, Stephanie
    Lemaitre, Herve
    Leonardo, Cassandra D.
    Li, Chiang-shan
    Liberg, Benny
    Liewald, David C.
    Liu, Xinmin
    Lopez, Lorna M.
    Loth, Eva
    Lourdusamy, Anbarasu
    Luciano, Michelle
    Macciardi, Fabio
    Machielsen, Marise W. J.
    MacQueen, Glenda M.
    Malt, Ulrik F.
    Mandl, Rene
    Manoach, Dara S.
    Martinot, Jean-Luc
    Matarin, Mar
    Mather, Karen A.
    Mattheisen, Manuel
    Mattingsdal, Morten
    Meyer-Lindenberg, Andreas
    McDonald, Colm
    McIntosh, Andrew M.
    McMahon, Francis J.
    McMahon, Katie L.
    Meisenzahl, Eva
    Melle, Ingrid
    Milaneschi, Yuri
    Mohnke, Sebastian
    Montgomery, Grant W.
    Morris, Derek W.
    Moses, Eric K.
    Mueller, Bryon A.
    Maniega, Susana Munoz
    Muehleisen, Thomas W.
    Mueller-Myhsok, Bertram
    Mwangi, Benson
    Nauck, Matthias
    Nho, Kwangsik
    Nichols, Thomas E.
    Nilsson, Lars-Goeran
    Nugent, Allison C.
    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).
    Olvera, Rene L.
    Oosterlaan, Jaap
    Ophoff, Roel A.
    Pandolfo, Massimo
    Papalampropoulou-Tsiridou, Melina
    Papmeyer, Martina
    Paus, Tomas
    Pausova, Zdenka
    Pearlson, Godfrey D.
    Penninx, Brenda W.
    Peterson, Charles P.
    Pfennig, Andrea
    Phillips, Mary
    Pike, G. Bruce
    Poline, Jean-Baptiste
    Potkin, Steven G.
    Puetz, Benno
    Ramasamy, Adaikalavan
    Rasmussen, Jerod
    Rietschel, Marcella
    Rijpkema, Mark
    Risacher, Shannon L.
    Roffman, Joshua L.
    Roiz-Santianez, Roberto
    Romanczuk-Seiferth, Nina
    Rose, Emma J.
    Royle, Natalie A.
    Rujescu, Dan
    Ryten, Mina
    Sachdev, Perminder S.
    Salami, Alireza
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Satterthwaite, Theodore D.
    Savitz, Jonathan
    Saykin, Andrew J.
    Scanlon, Cathy
    Schmaal, Lianne
    Schnack, Hugo G.
    Schork, Andrew J.
    Schulz, S. Charles
    Schuer, Remmelt
    Seidman, Larry
    Shen, Li
    Shoemaker, Jody M.
    Simmons, Andrew
    Sisodiya, Sanjay M.
    Smith, Colin
    Smoller, Jordan W.
    Soares, Jair C.
    Sponheim, Scott R.
    Sprooten, Emma
    Starr, John M.
    Steen, Vidar M.
    Strakowski, Stephen
    Strike, Lachlan
    Sussmann, Jessika
    Saemann, Philipp G.
    Teumer, Alexander
    Toga, Arthur W.
    Tordesillas-Gutierrez, Diana
    Trabzuni, Daniah
    Trost, Sarah
    Turner, Jessica
    Van den Heuvel, Martijn
    van der Wee, Nic J.
    van Eijk, Kristel
    van Erp, Theo G. M.
    van Haren, Neeltje E. M.
    van 't Ent, Dennis
    van Tol, Marie-Jose
    Hernandez, Maria C. Valdes
    Veltman, Dick J.
    Versace, Amelia
    Voelzke, Henry
    Walker, Robert
    Walter, Henrik
    Wang, Lei
    Wardlaw, Joanna M.
    Weale, Michael E.
    Weiner, Michael W.
    Wen, Wei
    Westlye, Lars T.
    Whalley, Heather C.
    Whelan, Christopher D.
    White, Tonya
    Winkler, Anderson M.
    Wittfeld, Katharina
    Woldehawariat, Girma
    Wolf, Christiane
    Zilles, David
    Zwiers, Marcel P.
    Thalamuthu, Anbupalam
    Schofield, Peter R.
    Freimer, Nelson B.
    Lawrence, Natalia S.
    Drevets, Wayne
    The ENIGMA Consortium: large-scale collaborative analyses of neuroimaging and genetic data2014In: BRAIN IMAGING BEHAV, ISSN 1931-7557, Vol. 8, no 2, p. 153-182Article in journal (Refereed)
    Abstract [en]

    The Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Consortium is a collaborative network of researchers working together on a range of large-scale studies that integrate data from 70 institutions worldwide. Organized into Working Groups that tackle questions in neuroscience, genetics, and medicine, ENIGMA studies have analyzed neuroimaging data from over 12,826 subjects. In addition, data from 12,171 individuals were provided by the CHARGE consortium for replication of findings, in a total of 24,997 subjects. By meta-analyzing results from many sites, ENIGMA has detected factors that affect the brain that no individual site could detect on its own, and that require larger numbers of subjects than any individual neuroimaging study has currently collected. ENIGMA's first project was a genome-wide association study identifying common variants in the genome associated with hippocampal volume or intracranial volume. Continuing work is exploring genetic associations with subcortical volumes (ENIGMA2) and white matter microstructure (ENIGMA-DTI). Working groups also focus on understanding how schizophrenia, bipolar illness, major depression and attention deficit/hyperactivity disorder (ADHD) affect the brain. We review the current progress of the ENIGMA Consortium, along with challenges and unexpected discoveries made on the way.

  • 210.
    van den Broek, Gesa
    et al.
    Radboud University, Behavioural Science Institute, Nijmegen, The Netherlands.
    Takashima, Atsuko
    Radboud University, Behavioural Science Institute, Nijmegen, The Netherlands.
    Wiklund-Hörnqvist, Carola
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Karlsson Wirebring, Linnea
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Segers, Eliane
    Radboud University, Behavioural Science Institute, Nijmegen, The Netherlands.
    Verhoeven, Ludo
    Radboud University, Behavioural Science Institute, Nijmegen, The Netherlands.
    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).
    Neurocognitive mechanisms of the "testing effect": a review2016In: Trends in Neuroscience and Education, ISSN 2452-0837, E-ISSN 2211-9493, Vol. 5, no 2, p. 52-66Article, review/survey (Refereed)
    Abstract [en]

    Memory retrieval is an active process that can alter the content and accessibility of stored memories. Of potential relevance for educational practice are findings that memory retrieval fosters better retention than mere studying. This so-called testing effect has been demonstrated for different materials and populations, but there is limited consensus on the neurocognitive mechanisms involved. In this review, we relate cognitive accounts of the testing effect to findings from recent brain-imaging studies to identify neurocognitive factors that could explain the testing effect. Results indicate that testing facilitates later performance through several processes, including effects on semantic memory representations, the selective strengthening of relevant associations and inhibition of irrelevant associations, as well as potentiation of subsequent learning.

  • 211.
    Vestergren, Peter
    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).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Testing alters brain activity during subsequent restudy: Evidence for test-potentiated encoding2014In: Trends in Neuroscience and Education, ISSN 2211-9493, Vol. 3, no 2, p. 69-80Article in journal (Refereed)
    Abstract [en]

    Mixed testing/studying lead to better memory retention compared to repeated study only. A potentiating influence of tests on encoding, particularly during restudy of non-retrieved items, may contribute to this effect. This study investigated whether and how testing affects brain activity during subsequent restudy of Swahili–Swedish word pairs after a cued-recall test. Item-events during fMRI were categorized according to history (tested/studied only) and recall outcome at prescan and postscan tests. Activity was higher for tested compared to studied-only items in anterior insula, orbital parts of inferior frontal gyrus and hippocampus, and lower in regions implicated in the default network, such as precuneus, supramarginal gyrus and the posterior middle cingulate. Findings are discussed in terms of top-down biasing of attention to tested items with concomitant deactivation of regions in the default network. Increased/focused attention to tested items during restudy may lead to test-potentiated encoding via deeper semantic processing and increased associative binding.

  • 212. Vidal-Pineiro, Didac
    et al.
    Sneve, Markus H.
    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.
    Mowinckel, Athanasia M.
    Sederevicius, Donatas
    Walhovd, Kristine B.
    Fjell, Anders M.
    Maintained Frontal Activity Underlies High Memory Function Over 8 Years in Aging2019In: Cerebral Cortex, ISSN 1047-3211, E-ISSN 1460-2199, Vol. 29, no 7, p. 3111-3123Article in journal (Refereed)
    Abstract [en]

    Aging is characterized by substantial average decline in memory performance. Yet contradictory explanations have been given for how the brains of high-performing older adults work: either by engagement of compensatory processes such as recruitment of additional networks or by maintaining young adults' patterns of activity. Distinguishing these components requires large experimental samples and longitudinal follow-up. Here, we investigate which features are key to high memory in aging, directly testing these hypotheses by studying a large sample of adult participants (n > 300) with fMRI during an episodic memory experiment where item-context relationships were implicitly encoded. The analyses revealed that low levels of activity in frontal networks-known to be involved in memory encoding-were associated with low memory performance in the older adults only. Importantly, older participants with low memory performance and low frontal activity exhibited a strong longitudinal memory decline in an independent verbal episodic memory task spanning 8 years back (n = 52). These participants were also characterized by lower hippocampal volumes and steeper rates of cortical atrophy. Altogether, maintenance of frontal brain function during encoding seems to be a primary characteristic of preservation of memory function in aging, likely reflecting intact ability to integrate information.

  • 213.
    von Helversen, Bettina
    et al.
    Univ Basel, Ctr Econ Psychol, Dept Psychol, CH-4055 Basel, Switzerland.
    Karlsson, Linnea
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Rasch, Bjoern
    Univ Fribourg, Dept Psychol, CH-1700 Fribourg, Switzerland.
    Rieskamp, Joerg
    Univ Basel, Ctr Econ Psychol, Dept Psychol, CH-4055 Basel, Switzerland.
    Neural substrates of similarity and rule-based strategies in judgment2014In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 8, p. 809-Article in journal (Refereed)
    Abstract [en]

    Making accurate judgments is a core human competence and a prerequisite for success in many areas of life. Plenty of evidence exists that people can employ different judgment strategies to solve identical judgment problems. In categorization, it has been demonstrated that similarity-based and rule-based strategies are associated with activity in different brain regions. Building on this research, the present work tests whether solving two identical judgment problems recruits different neural substrates depending on people's judgment strategies. Combining cognitive modeling of judgment strategies at the behavioral level with functional magnetic resonance imaging (fMRI), we compare brain activity when using two archetypal judgment strategies: a similarity-based exemplar strategy and a rule-based heuristic strategy. Using an exemplar-based strategy should recruit areas involved in long-term memory processes to a larger extent than a heuristic strategy. In contrast, using a heuristic strategy should recruit areas involved in the application of rules to a larger extent than an exemplar-based strategy. Largely consistent with our hypotheses, we found that using an exemplar-based strategy led to relatively higher BOLD activity in the anterior prefrontal and inferior parietal cortex, presumably related to retrieval and selective attention processes. In contrast, using a heuristic strategy led to relatively higher activity in areas in the dorsolateral prefrontal and the temporal-parietal cortex associated with cognitive control and information integration. Thus, even when people solve identical judgment problems, different neural substrates can be recruited depending on the judgment strategy involved.

  • 214. Wachinger, Christian
    et al.
    Nho, Kwangsik
    Saykin, Andrew J.
    Reuter, Martin
    Rieckmann, Anna
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Diagnostic Radiology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    A Longitudinal Imaging Genetics Study of Neuroanatomical Asymmetry in Alzheimer's Disease2018In: Biological Psychiatry, ISSN 0006-3223, E-ISSN 1873-2402, Vol. 84, no 7, p. 522-530Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Contralateral brain structures represent a unique, within-patient reference element for disease, and asymmetries can provide a personalized measure of the accumulation of past disease processes. Neuroanatomical shape asymmetries have recently been associated with the progression of Alzheimer's disease (AD), but the biological basis of asymmetric brain changes in AD remains unknown.

    METHODS: We investigated genetic influences on brain asymmetry by identifying associations between magnetic resonance imaging-derived measures of asymmetry and candidate single nucleotide polymorphisms (SNPs) that have previously been identified in genome-wide association studies for AD diagnosis and for brain subcortical volumes. For analyzing longitudinal neuroimaging data (1241 individuals, 6395 scans), we used a mixed effects model with interaction between genotype and diagnosis.

    RESULTS: Significant associations between asymmetry of the amygdala, hippocampus, and putamen and SNPs in the genes BIN1, CD2AP, ZCWPW1, ABCA7, TNKS, and DLG2 were found.

    CONCLUSIONS: The associations between SNPs in the genes TNKS and DLG2 and AD-related increases in shape asymmetry are of particular interest; these SNPs have previously been associated with subcortical volumes of amygdala and putamen but have not yet been associated with AD pathology. For AD candidate SNPs, we extend previous work to show that their effects on subcortical brain structures are asymmetric. This provides novel evidence about the biological underpinnings of brain asymmetry as a disease marker.

  • 215. Walhovd, K. B.
    et al.
    Fjell, A. M.
    Westerhausen, R.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Ebmeier, K. P.
    Lindenberger, U.
    Bartrés-Faz, D.
    Baaré, W. F. C.
    Siebner, H. R.
    Henson, R.
    Drevon, C. A.
    Knudsen, G. P.
    Budin-Ljøsne, I.
    Penninx, B. W. J. H.
    Ghisletta, P.
    Rogeberg, O.
    Tyler, L.
    Betram, L.
    Healthy minds from 0-100 years: optimising the use of European brain imaging cohorts ("Lifebrain'')2018In: European psychiatry, ISSN 0924-9338, E-ISSN 1778-3585, Vol. 50, p. 47-56Article, review/survey (Refereed)
    Abstract [en]

    The main objective of "Lifebrain'' is to identify the determinants of brain, cognitive and mental (BCM) health at different stages of life. By integrating, harmonising and enriching major European neuroimaging studies across the life span, we will merge fine-grained BCM health measures of more than 5,000 individuals. Longitudinal brain imaging, genetic and health data are available for a major part, as well as cognitive and mental health measures for the broader cohorts, exceeding 27,000 examinations in total. By linking these data to other databases and biobanks, including birth registries, national and regional archives, and by enriching them with a new online data collection and novel measures, we will address the risk factors and protective factors of BCM health. We will identify pathways through which risk and protective factors work and their moderators. Exploiting existing European infrastructures and initiatives, we hope to make major conceptual, methodological and analytical contributions towards large integrative cohorts and their efficient exploitation. We will thus provide novel information on BCM health maintenance, as well as the onset and course of BCM disorders. This will lay a foundation for earlier diagnosis of brain disorders, aberrant development and decline of BCM health, and translate into future preventive and therapeutic strategies. Aiming to improve clinical practice and public health we will work with stakeholders and health authorities, and thus provide the evidence base for prevention and intervention.

  • 216. Wallin, Anders
    et al.
    Kettunen, Petronella
    Johansson, Per M.
    Jonsdottir, Ingibjörg H.
    Nilsson, Christer
    Nilsson, Michael
    Eckerström, Marie
    Nordlund, Arto
    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).
    Sunnerhagen, Katharina S.
    Svensson, Johan
    Terzis, Beata
    Wahlund, Lars-Olof
    Kuhn, H. Georg
    Cognitive medicine: a new approach in health care science2018In: BMC Psychiatry, ISSN 1471-244X, E-ISSN 1471-244X, Vol. 18, article id 42Article in journal (Refereed)
    Abstract [en]

    Background: The challenges of today's society call for more knowledge about how to maintain all aspects of cognitive health, such as speed/attention, memory/learning, visuospatial ability, language, executive capacity and social cognition during the life course. Main text: Medical advances have improved treatments of numerous diseases, but the cognitive implications have not been sufficiently addressed. Disability induced by cognitive dysfunction is also a major issue in groups of patients not suffering from Alzheimer's disease or related disorders. Recent studies indicate that several negative lifestyle factors can contribute to the development of cognitive impairment, but intervention and prevention strategies have not been implemented. Disability due to cognitive failure among the workforce has become a major challenge. Globally, the changing aging pyramid results in increased prevalence of cognitive disorders, and the diversity of cultures influences the expression, manifestation and consequences of cognitive dysfunction. Conclusions: Major tasks in the field of cognitive medicine are basic neuroscience research to uncover diverse disease mechanisms, determinations of the prevalence of cognitive dysfunction, health-economical evaluations, and intervention studies. Raising awareness for cognitive medicine as a clinical topic would also highlight the importance of specialized health care units for an integrative approach to the treatment of cognitive dysfunctions.

  • 217.
    Wiklund-Hörnqvist, Carola
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    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).
    Jonsson, Bert
    Umeå University, Faculty of Social Sciences, Department of Psychology. 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 Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Neural activations associated with feedback and retrieval success2017In: npj Science of Learning, E-ISSN 2056-7936, Vol. 2, no 12Article in journal (Refereed)
    Abstract [en]

    There is substantial behavioral evidence for a phenomenon commonly called “the testing effect”, i.e. superior memory performance after repeated testing compared to re-study of to-be-learned materials. However, considerably less is known about the underlying neuro-cognitive processes that are involved in the initial testing phase and thus underlies the actual testing effect. Here, we investigated functional brain activity related to test-enhanced learning with feedback. Subjects learned foreign vocabulary across three consecutive tests with correct-answer feedback. Functional brain-activity responses were analyzed in relation to retrieval and feedback events, respectively. Results revealed up-regulated activity in fronto-striatal regions during the first successful retrieval, followed by a marked reduction in activity as a function of improved learning. Whereas feedback improved behavioral performance across consecutive tests, feedback had a negligable role after the first successful retrieval for functional brain-activity modulations. It is suggested that the beneficial effects of test-enhanced learning is regulated by feedback-induced updating of memory representations, mediated via the striatum, that might underlie the stabilization of memory commonly seen in behavioral studies of the testing effect.

  • 218.
    Wiklund-Hörnqvist, Carola
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Jonsson, Bert
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    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).
    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).
    An fMRI study of the supportive role of feedback during test-enhanced learning2016In: ICOM-6 Conference Programme: Konferensbidrag. Abstract (Refereegranskat), 2016, 2016, p. 29-29Conference paper (Refereed)
    Abstract [en]

    Considerable research in cognitive psychology has demonstrated that testing improves the performance on later retention tests (i.e., the testing-effect).

    One key factor is the inclusion of feedback which enhances the benefits. Participants (n=21) first studied 60 Swahili-Swedish word-pairs. Subsequently, they underwent fMRI while being tested on each study-item either with or without feedback.

    Contrary to no feedback, several regions were identified as a feedback-network with the strongest contribution from the bilateral MTL regions (anterior hippocampus, amygdala), insula and left IFC. Several of these responses were modulated by type of response (correct/incorrect) and repetition (1,2,3).

    These findings link the effect of feedback on learning to strengthening of semantic representations, providing novel insights about the crucial role of feedback during test-enhanced learning.

  • 219.
    Wiklund-Hörnqvist, Carola
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Jonsson, Bert
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Korhonen, Johan
    Faculty of Education and Welfare Studies, Åbo Akademi University, Vaasa, Finland.
    Eklöf, Hanna
    Umeå University, Faculty of Social Sciences, Department of applied educational science.
    Nyroos, Mikaela
    Umeå University, Faculty of Social Sciences, Department of Education.
    Untangling the Contribution of the Subcomponents of Working Memory to Mathematical Proficiency as Measured by the National Tests: A Study among Swedish Third Graders2016In: Frontiers in Psychology, ISSN 1664-1078, E-ISSN 1664-1078, Vol. 7, article id 1062Article in journal (Refereed)
    Abstract [en]

    The aim with the present study was to examine the relationship between the subcomponents in working memory (WM) and mathematical performance, as measured by the National tests in a sample of 597 Swedish third-grade pupils. In line with compelling evidence of other studies, individual differences in WM capacity significantly predicted mathematical performance. Dividing the sample into four groups, based on their mathematical performance, revealed that mathematical ability can be conceptualized in terms of different WM profiles. Pupils categorized as High-math performers particularly differed from the other three groups in having a significant higher phonological ability. In contrast, pupils categorized as Low-math performers were particularly characterized by having a significant lower visuo-spatial ability. Findings suggest that it is important for educators to recognize and acknowledge individual differences in WM to support mathematical achievement at an individual level.

  • 220.
    Wåhlin, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Fordell, Helena
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience.
    Ekman, Urban
    Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden.
    Lenfeldt, Niklas
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience.
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience.
    Rehabilitation in chronic spatial neglect strengthens resting-state connectivity2019In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 139, no 3, p. 254-259Article in journal (Refereed)
    Abstract [en]

    Objectives: Rehabilitation of patients with chronic visuospatial neglect is underexplored, and little is known about neural mechanisms that can be exploited to promote recovery. In this study, we present data on resting-state functional connectivity within the dorsal attention network (DAN) in chronic neglect patients as they underwent training in a virtual reality (VR) environment that improved left-side awareness.

    Methods: The study included 13 patients with visuospatial neglect persisting more than six months after a right-sided stroke. The patients underwent resting-state functional magnetic resonance imaging (fMRI). Scans were collected at baseline and after five weeks of intense training. We specifically examined resting-state functional connectivity within the DAN. In addition, using spatial concordance correlation, we compared changes in the spatial topology of the DAN with that of other networks.

    Results: We found a longitudinal increase in interhemispheric functional connectivity between the right frontal eye field and the left intraparietal sulcus following training (before: 0.33 +/- 0.17 [mean +/- SD]; after: 0.45 +/- 0.13; P = 0.004). The spatial concordance analyses indicated that training influenced the DAN connectivity more than any of the other networks.

    Conclusion: Intense VR training that improved left-sided awareness in chronic stroke patients also increased sporadic interhemispheric functional connectivity within the DAN. Specifically, a region responsible for saccadic eye movement to the left became more integrated with the left posterior parietal cortex. These results highlight a mechanism that should be exploited in the training of patients with chronic visuospatial neglect.

  • 221.
    Wåhlin, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    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).
    At the Heart of Cognitive Functioning in Aging2019In: Trends in cognitive sciences, ISSN 1364-6613, E-ISSN 1879-307X, Vol. 23, no 9, p. 717-720Article in journal (Other academic)
    Abstract [en]

    Several neural and non-neural factors contribute to individual differences in cognitive performance. Here we outline a sequence of vascular events where excessive transfer of arterial-pressure pulsatility damages hippocampal capillaries. We argue that the vascular alterations decrease the ability to sustain neural activity and thereby contribute to episodic-memory impairment in aging.

  • 222.
    Zarrinkoob, Laleh
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Ambarki, Khalid
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Carlberg, Bo
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Medicine.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Aging alters the dampening of pulsatile blood flow in cerebral arteries2016In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 36, no 9, p. 1519-1527Article in journal (Refereed)
    Abstract [en]

    Excessive pulsatile flow caused by aortic stiffness is thought to be a contributing factor for several cerebrovascular diseases. The main purpose of this study was to describe the dampening of the pulsatile flow from the proximal to the distal cerebral arteries, the effect of aging and sex, and its correlation to aortic stiffness. Forty-five healthy elderly (mean age 71 years) and 49 healthy young (mean age 25 years) were included. Phase-contrast magnetic resonance imaging was used for measuring blood flow pulsatility index and dampening factor (proximal artery pulsatility index/distal artery pulsatility index) in 21 cerebral and extra-cerebral arteries. Aortic stiffness was measured as aortic pulse wave velocity. Cerebral arterial pulsatility index increased due to aging and this was more pronounced in distal segments of cerebral arteries. There was no difference in pulsatility index between women and men. Dampening of pulsatility index was observed in all cerebral arteries in both age groups but was significantly higher in young subjects than in elderly. Pulse wave velocity was not correlated with cerebral arterial pulsatility index. The increased pulsatile flow in elderly together with reduced dampening supports the pulse wave encephalopathy theory, since it implies that a higher pulsatile flow is reaching distal arterial segments in older subjects.

  • 223.
    Zarrinkoob, Laleh
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Ambarki, Khalid
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Blood flow distribution in cerebral arteries2015In: Journal of Cerebral Blood Flow and Metabolism, ISSN 0271-678X, E-ISSN 1559-7016, Vol. 35, no 4, p. 648-654Article in journal (Refereed)
    Abstract [en]

    High-resolution phase-contrast magnetic resonance imaging can now assess flow in proximal and distal cerebral arteries. The aim of this study was to describe how total cerebral blood flow (tCBF) is distributed into the vascular tree with regard to age, sex and anatomic variations. Forty-nine healthy young (mean 25 years) and 45 elderly (mean 71 years) individuals were included. Blood flow rate (BFR) in 21 intra-and extracerebral arteries was measured. Total cerebral blood flow was defined as BFR in the internal carotid plus vertebral arteries and mean cerebral perfusion as tCBF/brain volume. Carotid/vertebral distribution was 72%/28% and was not related to age, sex, or brain volume. Total cerebral blood flow (717 +/- 123 mL/min) was distributed to each side as follows: middle cerebral artery (MCA), 21%; distal MCA, 6%; anterior cerebral artery (ACA), 12%, distal ACA, 4%; ophthalmic artery, 2%; posterior cerebral artery (PCA), 8%; and 20% to basilar artery. Deviating distributions were observed in subjects with 'fetal' PCA. Blood flow rate in cerebral arteries decreased with increasing age (P < 0.05) but not in extracerebral arteries. Mean cerebral perfusion was higher in women (women: 61 +/- 8; men: 55 +/- 6 mL/min/100 mL, P < 0.001). The study describes a new method to outline the flow profile of the cerebral vascular tree, including reference values, and should be used for grading the collateral flow system.

  • 224.
    Zarrinkoob, Laleh
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience. Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences.
    Wåhlin, Anders
    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 Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Ambarki, Khalid
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Birgander, Richard
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience.
    Blood flow lateralization and collateral compensatory mechanisms in patients with carotid artery stenosis2019In: Stroke, ISSN 0039-2499, E-ISSN 1524-4628, Vol. 50, no 5, p. 1081-1088Article in journal (Refereed)
    Abstract [en]

    Background and Purpose: Four-dimensional phase-contrast magnetic resonance imaging enables quantification of blood flow rate (BFR; mL/min) in multiple cerebral arteries simultaneously, making it a promising technique for hemodynamic investigation in patients with stroke. The aim of this study was to quantify the hemodynamic disturbance and the compensatory pattern of collateral flow in patients with symptomatic carotid stenosis.

    Methods: Thirty-eight patients (mean, 72 years; 27 men) with symptomatic carotid stenosis (>/=50%) or occlusion were investigated using 4-dimensional phase-contrast magnetic resonance imaging. For each patient, BFR was measured in 19 arteries/locations. The ipsilateral side to the symptomatic carotid stenosis was compared with the contralateral side.

    Results: Internal carotid artery BFR was lower on the ipsilateral side (134+/-87 versus 261+/-95 mL/min; P<0.001). BFR in anterior cerebral artery (A1 segment) was lower on ipsilateral side (35+/-58 versus 119+/-72 mL/min; P<0.001). Anterior cerebral artery territory bilaterally was primarily supplied by contralateral internal carotid artery. The ipsilateral internal carotid artery mainly supplied the ipsilateral middle cerebral artery (MCA) territory. MCA was also supplied by a reversed BFR found in the ophthalmic and the posterior communicating artery routes on the ipsilateral side (-5+/-28 versus 10+/-28 mL/min, P=0.001, and -2+/-12 versus 6+/-6 mL/min, P=0.03, respectively). Despite these compensations, BFR in MCA was lower on the ipsilateral side, and this laterality was more pronounced in patients with severe carotid stenosis (>/=70%). Although comparing ipsilateral MCA BFR between stenosis groups (<70% and >/=70%), there was no difference ( P=0.95).

    Conclusions: With a novel approach using 4-dimensional phase-contrast magnetic resonance imaging, we could simultaneously quantify and rank the importance of collateral routes in patients with carotid stenosis. An important observation was that contralateral internal carotid artery mainly secured the bilateral anterior cerebral artery territory. Because of the collateral recruitment, compromised BFR in MCA is not necessarily related to the degree of carotid stenosis. These findings highlight the importance of simultaneous investigation of the hemodynamics of the entire cerebral arterial tree.

  • 225.
    Zarrinkoob, Laleh
    et al.
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Wåhlin, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Ambarki, Khalid
    Umeå University, Faculty of Medicine, Department of Radiation Sciences.
    Eklund, Anders
    Umeå University, Faculty of Medicine, Department of Radiation Sciences. Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Biomedical Laboratory Science. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Malm, Jan
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Neuroscience.
    Quantification and mapping of cerebral hemodynamics before and after carotid endarterectomy: a 4D PCMRI studyManuscript (preprint) (Other academic)
    Abstract [en]

    Background and purpose: A carotid stenosis can have a profound impact on the cerebral hemodynamics that cannot be inferred from the degree of stenosis by itself. We aimed to quantify and map the distribution of blood flow rate (BFR) in cerebral arteries before and after carotid endarterectomy (CEA), using four-dimensional phase-contrast magnetic resonance imaging (4D PCMRI).

    Methods: Nineteen patients (71±6 years, 2 women) with symptomatic carotid stenosis (≥50%)undergoing CEA were investigated using 4D PCMRI before and after surgery. BFR was measured in 17 cerebral arteries and in the ophthalmic arteries (OA). Collateral recruitment through the anterior and posterior communicating arteries, OA and the leptomeningeal arterial route was identified and quantified. BFR laterality was described as contralateral BFR minus ipsilateral BFR in paired arteries.

    Results: Total cerebral blood flow increased by 15% (p<0.01) after CEA. On the ipsilateral side, increased BFR was found after CEA in internal carotid artery (ICA) (246±62mL/min vs. 135±80mL/min; p<0.001), anterior cerebral artery (87±mL/min vs. 38±58mL/min; p<0.01) and middle cerebral artery (MCA) (149±43mL/min vs. 119±34mL/min; p<0.01), resulting in a postoperative BFR distribution without signs of laterality. In patients with preoperatively recruited collaterals (n=9), BFR laterality was found in MCA before, but not after, CEA (p<0.01). This laterality was not found in patients without collateral recruitment (n=10) (p=0.2). The degree of stenosis did not differ between the groups with vs. without collateral recruitment (p=0.85). 

    Conclusion: 4D PCMRI is a useful technique to quantify cerebral hemodynamic changes seen in patients with carotid stenosis before and after CEA. MCA laterality, seen in patients with collateral recruitment before CEA, pointed towards a hemodynamic disturbance in MCA territory for those patients. This study introduces a new and non-invasive way to evaluate cerebral hemodynamics due to carotid stenosis prior to and after CEA.

  • 226. Zetterberg, H.
    et al.
    Winblad, B.
    Bernick, C.
    Yaffe, K.
    Majdan, M.
    Johansson, G.
    Newcombe, V.
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Sharp, D.
    Tenovuo, O.
    Blennow, K.
    Head trauma in sports - clinical characteristics, epidemiology and biomarkers2019In: Journal of Internal Medicine, ISSN 0954-6820, E-ISSN 1365-2796, Vol. 285, no 6, p. 624-634Article, review/survey (Refereed)
    Abstract [en]

    Traumatic brain injury (TBI) is clinically divided into a spectrum of severities, with mild TBI being the least severe form and a frequent occurrence in contact sports, such as ice hockey, American football, rugby, horse riding and boxing. Mild TBI is caused by blunt nonpenetrating head trauma that causes movement of the brain and stretching and tearing of axons, with diffuse axonal injury being a central pathogenic mechanism. Mild TBI is in principle synonymous with concussion; both have similar criteria in which the most important elements are acute alteration or loss of consciousness and/or post-traumatic amnesia following head trauma and no apparent brain changes on standard neuroimaging. Symptoms in mild TBI are highly variable and there are no validated imaging or fluid biomarkers to determine whether or not a patient with a normal computerized tomography scan of the brain has neuronal damage. Mild TBI typically resolves within a few weeks but 10-15% of concussion patients develop postconcussive syndrome. Repetitive mild TBI, which is frequent in contact sports, is a risk factor for a complicated recovery process. This overview paper discusses the relationships between repetitive head impacts in contact sports, mild TBI and chronic neurological symptoms. What are these conditions, how common are they, how are they linked and can they be objectified using imaging or fluid-based biomarkers? It gives an update on the current state of research on these questions with a specific focus on clinical characteristics, epidemiology and biomarkers.

  • 227. Ziaei, Maryam
    et al.
    Salami, Alireza
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Aging Research Center (ARC) at Karolinska Institute and Stockholm University, Stockholm, Sweden.
    Persson, Jonas
    Age-related alterations in functional connectivity patterns during working memory encoding of emotional items2017In: Neuropsychologia, ISSN 0028-3932, E-ISSN 1873-3514, Vol. 94, p. 1-12Article in journal (Refereed)
    Abstract [en]

    Previous findings indicate age-related differences in frontal-amygdala connectivity during emotional processing. However, direct evidence for age differences in brain functional activation and connectivity during emotional processing and concomitant behavioral implications is lacking. In the present study, we examined the impact of aging on the neural signature of selective attention to emotional information during working memory (WM) encoding. Participants completed an emotional WM task in which they were asked to attend to emotional targets and ignore irrelevant distractors. Despite an overall reduction in accuracy for older relative to younger adults, no behavioral age effect was observed as a function of emotional valence. The functional connectivity patterns of left ventrolateral prefrontal cortex showed that younger adults recruited one network for encoding of both positive and negative emotional targets and this network contributed to higher memory accuracy in this cohort. Older adults, on the other hand, engaged two distinct networks for encoding of positive and negative targets. The functional connectivity analysis using left amygdala further demonstrated that older adults recruited one single network during encoding of positive as well as negative targets whereas younger adults recruited this network only for encoding of negative items. The engagement of amygdala functional network also contributed to higher memory performance and faster response times in older adults. Our findings provide novel insights into the differential roles of functional brain networks connected to the medial PFC and amygdala during encoding of emotionally-valenced items with advancing age.

  • 228. Ziegelasch, Michael
    et al.
    Forslind, Kristina
    Skogh, Thomas
    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).
    Kastbom, Alf
    Berglin, Ewa
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Rheumatology.
    Decrease in bone mineral density during three months after diagnosis of early rheumatoid arthritis measured by digital X-ray radiogrammetry predicts radiographic joint damage after one year2017In: Arthritis Research & Therapy, ISSN 1478-6354, E-ISSN 1478-6362, Vol. 19, no 1, article id 195Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Periarticular osteopenia is an early sign of incipient joint injury in rheumatoid arthritis (RA), but cannot be accurately quantified using conventional radiography. Digital X-ray radiogrammetry (DXR) is a computerized technique to estimate bone mineral density (BMD) from hand radiographs. The aim of this study was to evaluate whether decrease in BMD of the hands (BMD loss), as determined by DXR 3 months after diagnosis, predicts radiographic joint damage after 1 and 2 years in patients with early RA.

    METHODS: Patients (n = 176) with early RA (<12 months after onset of symptoms) from three different Swedish rheumatology centers were consecutively included in the study, and 167 of these patients were included in the analysis. Medication was given in accordance with Swedish guidelines, and the patients were followed for 2 years. Rheumatoid factor and antibodies to cyclic citrullinated peptides (anti-CCP) were measured at baseline, and 28-joint Disease Activity Score (DAS28) was assessed at each visit. Radiographs of the hands and feet were obtained at baseline, 3 months (hands only) and 1 and 2 years. Baseline and 1-year and 2-year radiographs were evaluated by the Larsen score. Radiographic progression was defined as a difference in Larsen score above the smallest detectable change. DXR-BMD was measured at baseline and after 3 months. BMD loss was defined as moderate when the decrease in BMD was between 0.25 and 2.5 mg/cm2/month and as severe when the decrease was greater than 2.5 mg/cm2/month. Multivariate regression was applied to test the association between DXR-BMD loss and radiographic damage, including adjustments for possible confounders.

    RESULTS: DXR-BMD loss during the initial 3 months occurred in 59% of the patients (44% moderate, 15% severe): 32 patients (19%) had radiographic progression at 1 year and 45 (35%) at 2 years. In multiple regression analyses, the magnitude of DXR-BMD loss was significantly associated with increase in Larsen score between baseline and 1 year (p = 0.033, adjusted R-squared = 0.069).

    CONCLUSION: DXR-BMD loss during the initial 3 months independently predicted radiographic joint damage at 1 year in patients with early RA. Thus, DXR-BMD may be a useful tool to detect ongoing joint damage and thereby to improve individualization of therapy in early RA.

  • 229. Zuo, Nianming
    et al.
    Salami, Alireza
    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, Wallenberg Centre for Molecular Medicine at Umeå University (WCMM). Aging Research Center, Karolinska Institute and Stockholm University, Stockholm, Sweden.
    Yang, Yihong
    Yang, Zhengyi
    Sui, Jing
    Jian, Tianzi
    Activation-based association profiles differentiate network roles across cognitive loads2019In: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 40, no 9, p. 2800-2812Article in journal (Refereed)
    Abstract [en]

    Working memory (WM) is a complex and pivotal cognitive system underlying the performance of many cognitive behaviors. Although individual differences in WM performance have previously been linked to the blood oxygenation level-dependent (BOLD) response across several large-scale brain networks, the unique and shared contributions of each large-scale brain network to efficient WM processes across different cognitive loads remain elusive. Using a WM paradigm and functional magnetic resonance imaging (fMRI) from the Human Connectome Project, we proposed a framework to assess the association and shared-association strength between imaging biomarkers and behavioral scales. Association strength is the capability of individual brain regions to modulate WM performance and shared-association strength measures how different regions share the capability of modulating performance. Under higher cognitive load (2-back), the frontoparietal executive control network (FPN), dorsal attention network (DAN), and salience network showed significant positive activation and positive associations, whereas the default mode network (DMN) showed the opposite pattern, namely, significant deactivation and negative associations. Comparing the different cognitive loads, the DMN and FPN showed predominant associations and globally shared-associations. When investigating the differences in association from lower to higher cognitive loads, the DAN demonstrated enhanced association strength and globally shared-associations, which were significantly greater than those of the other networks. This study characterized how brain regions individually and collaboratively support different cognitive loads.

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