References of "Collette, Fabienne"
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See detailSelf in Dementia
Antoine, Nicolas ULg; Genon, Sarah ULg; Bastin, Christine ULg et al

in Mishara; Corlett, P.; Fletcher, P. (Eds.) et al Phenomenological Neuropsychiatry, How Patient Experience Bridges Clinic with Clinical Neuroscience (in press)

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See detailThe neural bases of proactive and reactive control processes in normal aging
Manard, Marine ULg; François, Sarah ULg; Phillips, Christophe ULg et al

in Behavioural Brain Research (in press)

Introduction. Research on cognitive control suggests an age-related decline in proactive control abilities (anticipatory control), whereas reactive control (following conflict detection) seems to remain ... [more ▼]

Introduction. Research on cognitive control suggests an age-related decline in proactive control abilities (anticipatory control), whereas reactive control (following conflict detection) seems to remain intact. As proactive and reactive control abilities are associated with specific brain networks, this study investigated age-related effects on the neural substrates associated with each kind of control. Methods. In an event-related fMRI study, a modified version of the Stroop task was administered to groups of 20 young and 20 older healthy adults. Based on the theory of dual mechanisms of control, the Stroop task has been built to induce proactive or reactive control depending on task context. Results. Behavioral results (p < .05) indicated faster processing of interfering items in the mostly incongruent (MI) than the mostly congruent (MC) context in both young and older participants. fMRI results showed that reactive control is associated with increased activity in left frontal areas for older participants. For proactive control, decreased activity in the bilateral anterior cingulate cortex was associated with more activity in the right middle frontal gyrus in the older than the younger group. Conclusion. These observations support the hypothesis that aging affects the neural networks associated with reactive and proactive cognitive control differentially. These age-related changes are very similar to those observed in young adults with low dopamine availability, suggesting that a general mechanism (prefrontal dopamine availability) may modulate brain networks associated with various kinds of cognitive control. [less ▲]

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See detailRelating pessimistic memory predictions to Alzheimer’s disease brain structure
Genon, Sarah ULg; Simon, Jessica ULg; Bahri, Mohamed Ali ULg et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (in press)

Patients with Alzheimer’s disease (AD) show impairment of episodic memory and related metacognitive processes. The present study examined subjective metacognitive judgments preceding objective memory ... [more ▼]

Patients with Alzheimer’s disease (AD) show impairment of episodic memory and related metacognitive processes. The present study examined subjective metacognitive judgments preceding objective memory retrieval and investigated the neural correlates of pessimistic predictions for successfully retrieved memories in AD patients. AD patients and healthy older participants provided predictive judgements on their recognition performance before retrieval of famous (semantic) and recently learned (episodic) names. Correlations between grey matter volume (GMV) in T1 images and behavioural scores were examined with multivariate (PLS) and univariate (GLM) analyses in AD patients. AD patients showed a significant proportion of successful name recognition preceded by pessimistic prediction (Prediction_low_hits) in episodic memory. PLS revealed that behavioural pattern in AD patients was related with a mainly right lateralized pattern of GMV decrease including medial temporal lobe and posterior cingulate cortex, but also right ventrolateral prefrontal cortex (VLPFC). GLM further confirmed that pessimistic prediction negatively correlated with GMV in VLPFC. Thus, impaired monitoring processes (possibly influenced by inaccurate beliefs) allowing inferences about one’s own memory performance are primarily related to decrease GMV in VLPFC in AD patients. [less ▲]

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See detailThe influence of COMT on the neural substrates of short-term memory in normal aging
Manard, Marine ULg; Salmon, Eric ULg; Collette, Fabienne ULg

Conference (2016, September 02)

Working memory dopaminergic modulation is generally expressed in healthy aging by an advantage for carriers of the Met allele at behavioral and brain activity levels. However, most tasks used did not ... [more ▼]

Working memory dopaminergic modulation is generally expressed in healthy aging by an advantage for carriers of the Met allele at behavioral and brain activity levels. However, most tasks used did not allow to easily disentangle the contribution of maintenance and manipulation processes. We explored the effect of COMT genotype on the maintenance process using a Sternberg memory task varying the amount of information presented, in young and older homozygous carriers for the Val and Met alleles of the COMT gene. Although no clear behavioral difference was observed between groups, patterns of cerebral activity indicate difficulties for Met older individuals to maintain stable representations. These results will be discussed in terms of dopaminergic contribution to stability/flexibility of cognitive processes during aging. [less ▲]

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See detailAge-related changes in the modulation of attentional brain responses to sleep pressure at night
Schmidt, Christina ULg; Reichert, Carolin; Maire, Micheline et al

in Journal of Sleep Research (2016, September)

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See detailAge-related differences in the dynamics of cortical excitability and cognitive inhibition during prolongedwakefulness
Gaggioni, Giulia ULg; Chelllappa, S.; Ly, J. et al

Conference (2016, September)

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See detailLocal modulation of human brain responses by circadian rhythmicity and sleep debt
Muto, Vincenzo ULg; Jaspar, Mathieu ULg; Meyer, Christelle et al

in Science (2016), 351(6300),

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See detailEffects of aging on task- and stimulus-related cerebral attention networks
Kurth, Sophie ULg; Majerus, Steve ULg; Bastin, Christine ULg et al

in Neurobiology of Aging (2016), 44

Interactions between a dorsal attention (DAN) and a ventral attention cerebral network (VAN) have been reported in young participants during attention or short term memory (STM) tasks. Since it remains an ... [more ▼]

Interactions between a dorsal attention (DAN) and a ventral attention cerebral network (VAN) have been reported in young participants during attention or short term memory (STM) tasks. Since it remains an under-investigated question, age effects on DAN and VAN activity and their functional balance were explored during performance of a STM task. Older and young groups showed similar behavioral patterns of results. At the cerebral level, DAN activation increased as a function of increasing STM load in both groups, suggesting preserved activity in DAN during healthy aging. Age-related over-recruitment in regions of the DAN in the higher task load raised the question of compensation attempt versus less efficient use of neural resources in older adults. Lesser decrease of VAN activation with increasing load and decreased stimulus-driven activation in the VAN, especially in the higher load, in older participants suggested age-related reduced response in the VAN. However, functional connectivity measures showed that VAN was still functionally connected to the DAN in older participants. [less ▲]

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See detailThe influence of COMT on the neural substrates of short-term memory in normal aging
Collette, Fabienne ULg; Manard, Marine ULg; Salmon, Eric ULg

Conference (2016, July 21)

Working memory dopaminergic modulation is generally expressed in healthy aging by an advantage for carriers of the Met allele at behavioral and brain activity levels. However, most tasks used did not ... [more ▼]

Working memory dopaminergic modulation is generally expressed in healthy aging by an advantage for carriers of the Met allele at behavioral and brain activity levels. However, most tasks used did not allow to easily disentangle the contribution of maintenance and manipulation processes. We explored the effect of COMT genotype on the maintenance process using a Sternberg memory task varying the amount of information presented, in young and older homozygous carriers for the Val and Met alleles of the COMT gene. Although no clear behavioral difference was observed between groups, patterns of cerebral activity indicate difficulties for Met older individuals to maintain stable representations. These results will be discussed in terms of dopaminergic contribution to stability/flexibility of cognitive processes during aging. [less ▲]

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See detailDisrupted interaction between self and memory in patients with Alzheimer’s disease
Genon, Sarah ULg; Salmon, Eric ULg; Collette, Fabienne ULg et al

Conference (2016, July)

In humans, self and memory processes interact as evidenced by the self reference (SRE) and self reference recollection effects (SRRE). However, in patients with Alzheimer’s disease (AD), this relationship ... [more ▼]

In humans, self and memory processes interact as evidenced by the self reference (SRE) and self reference recollection effects (SRRE). However, in patients with Alzheimer’s disease (AD), this relationship can be disrupted. This was evidenced by impaired SRE and SRRE in AD for recognition of adjectives previously judged for self-relevance, as well as recall of names of people previously linked to the self. For both materials, a qualitative impairment of the recollective experience for the self-related items was also observed in AD. A neuroimaging approach suggested that reduced SRE is related to decreased grey matter volume in the lateral prefrontal cortex (lPFC). Thus, retrieval of recent self-related memories is impaired in relation to altered high-order processes in lPFC in AD. [less ▲]

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See detailSeasonal variation in human COGNITIVE brain responses
Meyer, Christelle; Muto, Vincenzo ULg; Jaspar, Mathieu ULg et al

Poster (2016, June)

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See detailSubstrats neuronaux de l'encodage non réussi dans le vieillissement
François, Sarah ULg; Angel, Lucie; Salmon, Eric ULg et al

Conference (2016, May 27)

Objectifs En utilisant l'IRM fonctionnelle, nous nous sommes intéressés à l'effet de l'âge sur les substrats neuronaux de l'encodage non réussi – l'activation à l'encodage pour les items oubliés par la ... [more ▼]

Objectifs En utilisant l'IRM fonctionnelle, nous nous sommes intéressés à l'effet de l'âge sur les substrats neuronaux de l'encodage non réussi – l'activation à l'encodage pour les items oubliés par la suite. Méthodologie Dans un scanner IRM, nous avons soumis des volontaires (20 jeunes et 19 âgés) à une tâche de mémoire épisodique avec consignes d'encodage incident. Durant celle-ci, des dessins d'objets en noir et blanc leur étaient présentés. Il leur était demandé d'effectuer un jugement de taille sur ces objets. Ensuite, toujours dans le scanner, les objets de la phase d'encodage ainsi que de nouveaux objets leurs étaient présentés afin d'évaluer leur reconnaissance de ceux-ci. Pour ce faire, les volontaires effectuaient un jugement de Recollection/Familiarité/Nouveauté. Résultats Les résultats comportementaux montrent une recollection altérée mais une familiarité préservée chez nos volontaires âgés. L'analyse des résultats IRM a été effectuée selon un design évènementiel (SPM8), dans lequel nous avons comparé les aires cérébrales activées à l'encodage pour les items qui n'ont pas été reconnus ultérieurement et pour ceux qui ont donné lieu à un jugement de recollection (p<.001 non-corrigé). Dans les deux groupes, un pattern d'activation correspondant au réseau du mode par défaut (RMD). Chez les volontaires âgés, les résultats ont également mis en évidence une activation supplémentaire du réseau attentionnel fronto-pariétal. Ensuite, le contraste entre les activations pour les items qui n'ont pas été reconnus ultérieurement et ceux qui ont donné lieu à un jugement de familiarité a aussi mis en évidence des régions du RMD, mais dans une moindre mesure. En effet, les activités communes aux deux groupes d'âge n'ont montré qu'une activation du précuneus. Discussion Comparé à la recollection, l'oubli d'informations semble associé, à l'encodage, à un recrutement accru du RMD qui pourrait refléter une incapacité à mettre en place des processus d'encodage efficaces, à la fois chez les jeunes adultes et les adultes plus âgés. De plus, l'activation supplémentaire du réseau fronto-pariétal chez ces derniers pourrait indiquer un fonctionnement moins différencié des réseaux cérébraux associés à l'encodage en mémoire. Lorsque l'on compare l'oubli d'informations à la familiarité, l'activation moindre du RMD pourrait suggérer qu'un certain niveau d'activation du RMD (et donc la présence de pensées étrangères à la tâche) n'empêche pas forcément toute reconnaissance sur base d'un sentiment de familiarité. [less ▲]

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See detailSubstrats cérébraux du contrôle proactif et réactif dans le vieillissement non pathologique
Manard, Marine ULg; François, Sarah ULg; Salmon, Eric ULg et al

Poster (2016, May 27)

Les recherches sur le contrôle cognitif proposent l’apparition d’un déclin lié à l’âge dans les capacités de contrôle proactif (forme anticipatoire de contrôle comportemental) alors que le contrôle ... [more ▼]

Les recherches sur le contrôle cognitif proposent l’apparition d’un déclin lié à l’âge dans les capacités de contrôle proactif (forme anticipatoire de contrôle comportemental) alors que le contrôle réactif (forme réactionnelle à la détection d’un conflit) semble rester intact [1]. Ces deux formes de contrôle ont été associées à des aires cérébrales différentes [2], cependant peu d’études ont étudié les effets de l’âge sur les régions cérébrales sous-tendant chacun de ces deux types de contrôle. Pour ce faire, une version adaptée de la tâche de Stroop a été administrée à 16 jeunes (18-30 ans) et 16 adultes (60-75 ans) en IRM fonctionnelle. Cette version de la tâche variait la quantité d’items interférents, permettant la création de trois contextes (Mostly Congruent « MC », Mostly Incongruent « MI » et Neutre) favorisant respectivement la mise en place des deux types de contrôle (réactif = congruent / proactif = incongruent). Les analyses ont été réalisées avec SPM8 (p<.001 non-corrigé). Les résultats comportementaux révèlent un traitement plus rapide de l’interférence dans le contexte « MI » que « MC » pour les jeunes adultes uniquement. Au niveau cérébral, le traitement de l’interférence en MI semble associé à une diminution d’activité (surtout à droite) dans les régions frontales et temporales chez les volontaires âgés par rapport aux plus jeunes, alors qu’en MC, les âgés montrent une augmentation d’activité bilatérale au niveau frontal. Ainsi, les résultats comportementaux montrent que les adultes âgés semblent avoir plus de difficultés à implémenter un contrôle proactif (associé à une diminution d’activité) que les jeunes dans les régions sous-tendant la performance à cette tâche. Cependant, le recrutement supplémentaire de régions frontales observé lors du contexte MC postulé pour favoriser le contrôle réactif, suggère la présence de mécanismes de compensation. Pour conclure, le vieillissement semble affecter de manière différentielle l’activité des régions cérébrales sous-tendant les différents types de contrôle. [less ▲]

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See detailThe influence of COMT single nucleotide polymorphism (rs4680) on the neural substrates of working memory representations maintenance in healthy aging
Manard, Marine ULg; François, Sarah ULg; Bahri, Mohamed Ali ULg et al

Poster (2016, May 10)

The COMT val108/158met polymorphism was associated to the dopaminergic modulation in the brain, and therefore stimulated research on its influence for cognitive functioning and particularly working memory ... [more ▼]

The COMT val108/158met polymorphism was associated to the dopaminergic modulation in the brain, and therefore stimulated research on its influence for cognitive functioning and particularly working memory. First, a general advantage of carrying the met allele was reported. However, many studies used tasks that did not allow efficiently assessing the contribution of manipulation and maintenance processes in working memory, leading to divergent results, in both young and older populations, resulting in debates about the exact phenotypic effect of the COMT polymorphism. Using fMRI, this study was designed to assess the potential effect of the COMT polymorphism on age-related differences in working memory representations maintenance abilities (Sternberg paradigm). Partial Least Squares method was used to determine the brain-behavior correlations at low, intermediate, and high cognitive demands among young and older groups, homozygous for the val or for the met allele. First, young val/val showed some disadvantages at brain and behavioral level compared to their m/m counterparts. However, in older adults subgroups, the m/m participants tended to show greater age-related difference (when compared to younger adults with similar genotype), suggesting an advantage in carrying the val allele when dopamine signaling is not at optimal efficiency (optimal: young/middle adulthood vs suboptimal: childhood or older ages). These results will be discussed in regard to compensating theories and dopaminergic models accounting for the potential effect of COMT polymorphism on stability/flexibility abilities. [less ▲]

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See detailAge-related modulations in cognitive functions and its cerebral underpinnings
Collette, Fabienne ULg

Scientific conference (2016, March 29)

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See detailThe impact of dopaminergic genes on inhibitory processes and cognitive control.
Jaspar, Mathieu ULg; Muto, Vincenzo ULg; Meyer, Christelle et al

Poster (2016, March 18)

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See detailModulating effect of COMT genotype on brain areas underlying cognitive control processes
Collette, Fabienne ULg; Jaspar, Mathieu ULg

Conference (2016, March 18)

Catechol-O-methyltransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex. A large number of studies reported an effect on executive ... [more ▼]

Catechol-O-methyltransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex. A large number of studies reported an effect on executive functioning of COMT genotype, each genotype being associated with a different COMT enzymatic activity. In this talk, I will present some of our studies that explored the neural substrates of inhibitory processes according to COMT genotype. These studies showed that COMT genotype modulates the brain-level implementation of proactive and reactive inhibitory control processes. We will discuss how individual differences related to DA-mediated signaling can differently influence inhibition in function of the form of cognitive control required by the task, but also regarding the specific inhibitory mechanism induced by the task. [less ▲]

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See detailNeural bases of subsequent forgetting in young and older adults
François, Sarah ULg; Angel, Lucie; Salmon, Eric ULg et al

Poster (2016, March 17)

Objectives Using functional MRI, we looked into the age-related difference in the neural underpinnings of subsequent forgetting - cerebral activation at encoding for items that are later forgotten ... [more ▼]

Objectives Using functional MRI, we looked into the age-related difference in the neural underpinnings of subsequent forgetting - cerebral activation at encoding for items that are later forgotten. Methods In an MRI scanner, during an incidental encoding phase, participants (20 young and 19 older adults) were presented with black-and-white drawings of objects. They were instructed to perform a size judgement on the depicted objects. Then, still in the scanner, the volunteers' memory for the objects was tested by showing them pictures shown previously along with new ones and asking them to make a Remember/Know/New judgement. Results Behaviourally, older participants showed decreased recollection, but intact familiarity at recognition. In an event-related design (SPM8), we compared cerebral areas activated at encoding for items subsequently forgotten compared to those leading to recollection (p<.001 uncorrected). In both groups, a pattern of activation consistent with the default-mode network (DMN) was found. Furthermore, results pointed out to additional activations in the frontoparietal control network in older adults. Also, contrasting activations for items subsequently forgotten with those leading to familiarity revealed activations in DMN areas. In young adults, these activations were limited to the posterior cingulate cortex. Conclusions The forgetting of information appears to be associated with a higher recruitment of the DMN, which might reflect disengagement from encoding-supportive processes, both in young and older participants. Moreover, the additional fronto-parietal activity found in the older group could indicate that their failure to recollect the pictures was related to inefficient encoding mechanisms, in addition to disengagement from the task. [less ▲]

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See detailSeasonality in human cognitive brain responses
Meyer, Christelle ULg; Muto, Vincenzo ULg; Jaspar, Mathieu ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (2016)

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See detailSuccessful episodic memory encoding in ageing: an fMRI study
François, Sarah ULg; Angel, Lucie; Salmon, Eric ULg et al

Poster (2016, January 25)

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