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  • 1.
    de Pierrefeu, Amicie
    et al.
    NeuroSpin, CEA, Paris-Saclay, Gif-sur-Yvette, France.
    Fovet, Thomas
    Univ. Lille, CNRS UMR 9193, Laboratoire de Sciences Cognitives et Sciences Affectives (SCALab), PsyCHIC team, Lille F- 59000, France; CHU Lille, Pôle de Psychiatrie, Unité CURE, Lille F-59000, France.
    Hadj-Selem, Fouad
    Energy Transition Institute: VeDeCoM, France.
    Löfstedt, Tommy
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Radiofysik.
    Ciuciu, Philippe
    NeuroSpin, CEA, Paris-Saclay, Gif-sur-Yvette, France; INRIA, CEA, Parietal team, Univ. Paris-Saclay, France.
    Lefebvre, Stephanie
    Univ. Lille, CNRS UMR 9193, Laboratoire de Sciences Cognitives et Sciences Affectives (SCALab), PsyCHIC team, Lille F-59000, France; CHU Lille, Pôle de Psychiatrie, Unité CURE, Lille F-59000, France.
    Thomas, Pierre
    Univ. Lille, CNRS UMR 9193, Laboratoire de Sciences Cognitives et Sciences Affectives (SCALab), PsyCHIC team, Lille F-59000, France; CHU Lille, Pôle de Psychiatrie, Unité CURE, Lille F-59000, France.
    Lopes, Renaud
    Imaging Dpt., Neuroradiology unit, CHU Lille, Lille F-59000, France; U1171 - Degenerative and Vascular Cognitive Disorders, Univ. Lille, INSERM, CHU Lille, Lille F-59000, France.
    Jardri, Renaud
    Univ. Lille, CNRS UMR 9193, Laboratoire de Sciences Cognitives et Sciences Affectives (SCALab), PsyCHIC team, Lille F-59000, France; CHU Lille, Pôle de Psychiatrie, Unité CURE, Lille F-59000, France.
    Duchesnay, Edouard
    NeuroSpin, CEA, Paris-Saclay, Gif-sur-Yvette, France.
    Prediction of activation patterns preceding hallucinations in patients with schizophrenia using machine learning with structured sparsity2018Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 39, nr 4, s. 1777-1788Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Despite significant progress in the field, the detection of fMRI signal changes during hallucinatory events remains difficult and time-consuming. This article first proposes a machine-learning algorithm to automatically identify resting-state fMRI periods that precede hallucinations versus periods that do not. When applied to whole-brain fMRI data, state-of-the-art classification methods, such as support vector machines (SVM), yield dense solutions that are difficult to interpret. We proposed to extend the existing sparse classification methods by taking the spatial structure of brain images into account with structured sparsity using the total variation penalty. Based on this approach, we obtained reliable classifying performances associated with interpretable predictive patterns, composed of two clearly identifiable clusters in speech-related brain regions. The variation in transition-to-hallucination functional patterns not only from one patient to another but also from one occurrence to the next (e.g., also depending on the sensory modalities involved) appeared to be the major difficulty when developing effective classifiers. Consequently, second, this article aimed to characterize the variability within the prehallucination patterns using an extension of principal component analysis with spatial constraints. The principal components (PCs) and the associated basis patterns shed light on the intrinsic structures of the variability present in the dataset. Such results are promising in the scope of innovative fMRI-guided therapy for drug-resistant hallucinations, such as fMRI-based neurofeedback.

  • 2.
    Kaboodvand, Neda
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet, Stockholm, Sweden.
    Bäckman, Lars
    Nyberg, Lars
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper. Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB).
    Salami, Alireza
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Aging Research Center, Karolinska Institutet, Stockholm, Sweden.
    The retrosplenial cortex: a memory gateway between the cortical default mode network and the medial temporal lobe2018Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 39, nr 5, s. 2020-2034Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The default mode network (DMN) involves interacting cortical areas, including the posterior cingulate cortex (PCC) and the retrosplenial cortex (RSC), and subcortical areas, including the medial temporal lobe (MTL). The degree of functional connectivity (FC) within the DMN, particularly between MTL and medial-parietal subsystems, relates to episodic memory (EM) processes. However, past resting-state studies investigating the link between posterior DMN-MTL FC and EM performance yielded inconsistent results, possibly reflecting heterogeneity in the degree of connectivity between MTL and specific cortical DMN regions. Animal work suggests that RSC has structural connections to both cortical DMN regions and MTL, and may thus serve as an intermediate layer that facilitates information transfer between cortical and subcortical DMNs. We studied 180 healthy old adults (aged 64-68 years), who underwent comprehensive assessment of EM, along with resting-state fMRI. We found greater FC between MTL and RSC than between MTL and the other cortical DMN regions (e.g., PCC), with the only significant association with EM observed for MTL-RSC FC. Mediational analysis showed that MTL-cortical DMN connectivity increased with RSC as a mediator. Further analysis using a graph-theoretical approach on DMN nodes revealed the highest betweenness centrality for RSC, confirming that a high proportion of short paths among DMN regions pass through RSC. Importantly, the degree of RSC mediation was associated with EM performance, suggesting that individuals with greater mediation have an EM advantage. These findings suggest that RSC forms a critical gateway between MTL and cortical DMN to support EM in older adults.

  • 3.
    Lenfeldt, Niklas
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för farmakologi och klinisk neurovetenskap, Klinisk neurovetenskap.
    Johansson, Anna-Maria
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi. Umeå universitet, Medicinska fakulteten, Institutionen för samhällsmedicin och rehabilitering, Fysioterapi.
    Domellöf, Erik
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Riklund, Katrine
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Rönnqvist, Louise
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Alterations in white matter microstructure are associated with goal-directed upper-limb movement segmentation in children born extremely preterm2017Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 38, nr 10, s. 5051-5068Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Altered white matter microstructure is commonly found in children born preterm (PT), especially those born at an extremely low gestational age (GA). These children also commonly show disturbed motor function. This study explores the relation between white matter alterations and upperlimb movement segmentation in 41 children born PT (19 girls), and 41 children born at term (18 girls) at 8 years. The PT group was subdivided into extremely PT (E-PT; GA = 25–27 weeks, N = 10), very PT (V-PT; GA = 28–32 weeks, N = 13), and moderately PT (M-PT; GA = 33–35 weeks, N = 18). Arm/hand preference (preferred/non-preferred) was determined through object interactions and the brain hemispheres were designated accordingly. White matter alterations were assessed using diffusion tensor imaging in nine areas, and movement segmentation of the body-parts head, shoulder, elbow, and wrist were registered during a unimanual goal-directed task. Increased movement segmentation was demonstrated consistently on the preferred side in the E-PT group compared with the term born group. Also compared with the term born peers, the E-PT group demonstrated reduced fractional anisotropy (FA) in the cerebral peduncle (targeting the corticospinal tract) in the hemisphere on the non-preferred side and in the splenium of corpus callosum. In contrast, in the anterior internal capsule on the preferred side, the E-PT group had increased FA. Lower FA in the cerebral peduncle, but higher FA in the anterior internal capsule, was associated with increased movement segmentation across body-parts in a contralateral manner. The results suggest that impaired development of sensorimotor tracts in E-PT children could explain a sub-optimal spatiotemporal organization of upper-limb movements.

  • 4. Lövdén, Martin
    et al.
    Laukka, Erika Jonsson
    Rieckmann, Anna
    Kalpouzos, Grégoria
    Li, Tie-Qiang
    Jonsson, Tomas
    Wahlund, Lars-Olof
    Fratiglioni, Laura
    Bäckman, Lars
    The dimensionality of between-person differences in white matter microstructure in old age.2013Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 34, nr 6, s. 1386-98Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Between-person differences in white matter microstructure may partly generalize across the brain and partly play out differently for distinct tracts. We used diffusion-tensor imaging and structural equation modeling to investigate this issue in a sample of 260 adults aged 60-87 years. Mean fractional anisotropy and mean diffusivity of seven white matter tracts in each hemisphere were quantified. Results showed good fit of a model positing that individual differences in white matter microstructure are structured according to tracts. A general factor, although accounting for variance in the measures, did not adequately represent the individual differences. This indicates the presence of a substantial amount of tract-specific individual differences in white matter microstructure. In addition, individual differences are to a varying degree shared between tracts, indicating that general factors also affect white matter microstructure. Age-related differences in white matter microstructure were present for all tracts. Correlations among tract factors did not generally increase as a function of age, suggesting that aging is not a process with homogenous effects on white matter microstructure across the brain. These findings highlight the need for future research to examine whether relations between white matter microstructure and diverse outcomes are specific or general.

  • 5. Ossewaarde, Lindsey
    et al.
    van Wingen, Guido A.
    Rijpkema, Mark
    Bäckström, Torbjörn
    Umeå universitet, Medicinska fakulteten, Institutionen för klinisk vetenskap, Obstetrik och gynekologi.
    Hermans, Erno J.
    Fernandez, Guillen
    Menstrual cycle-related changes in amygdala morphology are associated with changes in stress sensitivity2013Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 34, nr 5, s. 1187-1193Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Premenstrual increases in negative mood are thought to arise from changes in gonadal hormone levels, presumably by influencing mood regulation and stress sensitivity. The amygdala plays a major role in this context, and animal studies suggest that gonadal hormones influence its morphology. Here, we investigated whether amygdala morphology changes over the menstrual cycle and whether this change explains differences in stress sensitivity. Twenty-eight young healthy women were investigated once during the premenstrual phase and once during the late follicular phase. T1-weighted anatomical images of the brain were acquired using magnetic resonance imaging and analyzed with optimized voxel-based morphometry. To measure mood regulation and stress sensitivity, negative affect was assessed after viewing strongly aversive as well as neutral movie clips. Our results show increased gray matter volume in the dorsal part of the left amygdala during the premenstrual phase when compared with the late follicular phase. This volume increase was positively correlated with the premenstrual increase in stress-induced negative affect. This is the first study showing structural plasticity of the amygdala in humans at the macroscopic level that is associated with both endogenous gonadal hormone fluctuations and stress sensitivity. These results correspond with animal findings of gonadal hormone-mediated neural plasticity in the amygdala and have implications for understanding the pathogenesis of specific mood disorders associated with hormonal fluctuations. Hum Brain Mapp, 2013. (c) 2011 Wiley Periodicals, Inc.

  • 6.
    Persson, Jonas
    et al.
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Karolinska Inst, ARC, S-11330 Stockholm, Sweden; Stockholm Univ, S-11330 Stockholm, Sweden; Stockholm Univ, Dept Psychol, S-11330 Stockholm, Sweden.
    Rieckmann, Anna
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Massachusetts Gen Hosp, Athinoula A Martinos Ctr Biomed Imaging, Charlestown, MA USA.
    Kalpouzos, Grégoria
    Fischer, Håkan
    Bäckman, Lars
    Influences of a DRD2 polymorphism on updating of long-term memory representations and caudate BOLD activity: magnification in aging2015Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 36, nr 4, s. 1325-1334Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A number of genetic polymorphisms are related to individual differences in cognitive performance. Striatal dopamine (DA) functions, associated with cognitive performance, are linked to the TaqIA polymorphism of the DRD2/ANKK1 gene. In humans, presence of an A1 allele of the DRD2/ANKK1-TaqIA polymorphism is related to reduced density of striatal DA D2 receptors. The resource-modulation hypothesis assumes that aging-related losses of neurochemical and structural brain resources modulate the extent to which genetic variations affect cognitive functioning. Here, we tested this hypothesis using functional MRI during long-term memory (LTM) updating in younger and older carriers and noncarriers of the A1-allele of the TaqIa polymorphism. We demonstrate that older A1-carriers have worse memory performance, specifically during LTM updating, compared to noncarriers. Moreover, A1-carriers exhibited less blood oxygen level-dependent (BOLD) activation in left caudate nucleus, a region critical to updating. This effect was only seen in older adults, suggesting magnification of genetic effects on functional brain activity in aging. Further, a positive relationship between caudate BOLD activation and updating performance among non-A1 carriers indicated that caudate activation was behaviorally relevant. These results demonstrate a link between the DRD2/ANKK1-TaqIA polymorphism and neurocognitive deficits related to LTM updating, and provide novel evidence that this effect is magnified in aging. Hum Brain Mapp 36:1325-1334, 2015.

  • 7.
    Rieckmann, Anna
    et al.
    Umeå universitet, Medicinska fakulteten, Institutionen för strålningsvetenskaper, Diagnostisk radiologi.
    Hedden, Trey
    Younger, Alayna P
    Sperling, Reisa A
    Johnson, Keith A
    Buckner, Randy L
    Dopamine transporter availability in clinically normal aging is associated with individual differences in white matter integrity2016Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 37, nr 2, s. 621-631Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aging-related differences in white matter integrity, the presence of amyloid plaques, and density of biomarkers indicative of dopamine functions can be detected and quantified with in vivo human imaging. The primary aim of the present study was to investigate whether these imaging-based measures constitute independent imaging biomarkers in older adults, which would speak to the hypothesis that the aging brain is characterized by multiple independent neurobiological cascades. We assessed MRI-based markers of white matter integrity and PET-based marker of dopamine transporter density and amyloid deposition in the same set of 53 clinically normal individuals (age 65-87). A multiple regression analysis demonstrated that dopamine transporter availability is predicted by white matter integrity, which was detectable even after controlling for chronological age. Further post-hoc exploration revealed that dopamine transporter availability was further associated with systolic blood pressure, mirroring the established association between cardiovascular health and white matter integrity. Dopamine transporter availability was not associated with the presence of amyloid burden. Neurobiological correlates of dopamine transporter measures in aging are therefore likely unrelated to Alzheimer's disease but are aligned with white matter integrity and cardiovascular risk. More generally, these results suggest that two common imaging markers of the aging brain that are typically investigated separately do not reflect independent neurobiological processes.

  • 8. Zuo, Nianming
    et al.
    Salami, Alireza
    Umeå universitet, Medicinska fakulteten, Umeå centrum för funktionell hjärnavbildning (UFBI). Umeå universitet, Medicinska fakulteten, Institutionen för integrativ medicinsk biologi (IMB). Umeå universitet, Medicinska fakulteten, Wallenberg centrum för molekylär medicin vid Umeå universitet (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 loads2019Inngår i: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 40, nr 9, s. 2800-2812Artikkel i tidsskrift (Fagfellevurdert)
    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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