References of "Collette, Fabienne"
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See detailMemory Reactivation During Rapid Eye Movement (REM) Sleep Promotes Its Generalization and Integration in Cortical Stores
Sterpenich, Virginie; Schmidt, Christina ULg; Albouy, Genevièvre et al

in Sleep (2014), 37(6), 1061-1075

Memory reactivation appears to be a fundamental process in memory consolidation. Here, we tested the influence of memory reactivation during REM sleep on memory performance and brain responses at ... [more ▼]

Memory reactivation appears to be a fundamental process in memory consolidation. Here, we tested the influence of memory reactivation during REM sleep on memory performance and brain responses at retrieval in healthy human participants. Auditory cues were associated with pictures of faces during their encoding. These memory cues delivered during REM sleep enhanced subsequent accurate recollections but also false recognitions. These results suggest that reactivated memories interacted with semantically-related representations, and induced new creative associations, which subsequently reduced the distinction between new and previously encoded exemplars. Cues had no effect if presented during stage 2 sleep, or if they were not associated with faces during encoding. Functional MRI revealed that following exposure to conditioned cues during REM sleep, responses to faces during retrieval were enhanced both in a visual area and in a cortical region of multisensory (auditory-visual) convergence. These results show that reactivating memories during REM sleep enhances cortical responses during retrieval, suggesting the integration of recent memories within cortical circuits, favoring the generalization and schematization of the information. [less ▲]

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See detailMetabolic cerebral correlates of conjunctive and relational memory in Alzheimer's disease
Bastin, Christine ULg; Bahri, Mohamed Ali ULg; Collette, Fabienne ULg et al

Poster (2014)

Introduction. Memory deficits are the clinical hallmark of typical Alzheimer’s disease. The precise nature of these deficits however remains to be fully characterized. In this study, we investigated ... [more ▼]

Introduction. Memory deficits are the clinical hallmark of typical Alzheimer’s disease. The precise nature of these deficits however remains to be fully characterized. In this study, we investigated binding in long-term episodic memory. Relational binding processes in memory create an associative link between independent items or between items and context into episodic memories (Cohen et al., 1999). An alternative process, conjunctive binding, allows associations to be encoded as a united representation of features into a single entity (O'Reilly and Rudy, 2001; Mayes et al., 2007). The current study (1) assessed whether Alzheimer’s disease disrupt both conjunctive and relational memory, and (2) related patients’ memory performance to cerebral metabolism. Methods. Thirty patients with mild Alzheimer’s disease and 24 healthy older adults performed a source memory task where items were associated to a background color (Diana et al., 2008, 2010). In one condition, relational binding was promoted by the instruction to associate the item with another object of the same color as the background. In the other condition, color had to be integrated as an item feature (conjunctive binding). Patients’ brain metabolic activity at rest (FDG-PET) was analysed with spatio-temporal Partial Least Squares (McIntosh et al., 1996) in order to assess the relation of behavioral performance and activity in functional cerebral networks. Results. Alzheimer’s disease patients had an impaired capacity to remember item-color associations, with deficits in both relational and conjunctive memory. However, performance in the two kinds of associative memory varied independently across patients. Partial least square analyses revealed a significant pattern of metabolic activity that correlated specifically with each condition (accounting for 76.48 % of the covariance in the data; p< .05). More specifically, poor conjunctive memory was related to hypometabolism in an anterior temporal-posterior fusiform brain network, whereas relational memory correlated with metabolism in regions of the default mode network. Conclusions. These findings support the hypothesis of distinct neural systems specialized in different types of associative memory and point to heterogeneous profiles of memory alteration in Alzheimer’s disease as a function of damage to the respective neural networks. [less ▲]

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See detailA Partial Least Squares Analysis of the self reference effect in Alzheimer's disease: A reply to Irish
Genon, Sarah ULg; Bastin, Christine ULg; Angel, Lucie et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2014), 54

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See detailAge-related decline in cognitive control: the role of fluid intelligence and processing speed
Manard, Marine ULg; Carabin, Delphine; Jaspar, Mathieu ULg et al

in BMC Neuroscience (2014), 15(7),

Background Research on cognitive control suggests an age-related decline in proactive control abilities whereas reactive control seems to remain intact. However, the reason of the differential age effect ... [more ▼]

Background Research on cognitive control suggests an age-related decline in proactive control abilities whereas reactive control seems to remain intact. However, the reason of the differential age effect on cognitive control efficiency is still unclear. This study investigated the potential influence of fluid intelligence and processing speed on the selective age-related decline in proactive control. Eighty young and 80 healthy older adults were included in this study. The participants were submitted to a working memory recognition paradigm, assessing proactive and reactive cognitive control by manipulating the interference level across items. Results Repeated measures ANOVAs and hierarchical linear regressions indicated that the ability to appropriately use cognitive control processes during aging seems to be at least partially affected by the amount of available cognitive resources (assessed by fluid intelligence and processing speed abilities). Conclusions This study highlights the potential role of cognitive resources on the selective age-related decline in proactive control, suggesting the importance of a more exhaustive approach considering the confounding variables during cognitive control assessment. [less ▲]

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See detailModulating effect of COMT genotype on the brain regions underlying proactive control process during inhibition
Jaspar, Mathieu ULg; Genon, Sarah ULg; Muto, Vincenzo ULg et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2014), 50

Introduction. Genetic variability related to the catechol-O-methyltransferase (COMT) gene (Val158Met polymorphism) has received increasing attention as a possible modulator of cognitive control functions ... [more ▼]

Introduction. Genetic variability related to the catechol-O-methyltransferase (COMT) gene (Val158Met polymorphism) has received increasing attention as a possible modulator of cognitive control functions. Methods. In an event-related fMRI study, a modified version of the Stroop task was administered to three groups of 15 young adults according to their COMT Val158Met genotype [Val/Val (VV), Val/Met (VM) and Met/Met (MM)]. Based on the theory of dual mechanisms of control (Braver, et al., 2007), the Stroop task has been built to induce proactive or reactive control processes according to the task context. Results. Behavioral results did not show any significant group differences for reaction times but Val allele carriers individuals are less accurate in the processing of incongruent items. fMRI results revealed that proactive control is specifically associated with increased activity in the anterior cingulate cortex (ACC) in carriers of the Met allele, while increased activity is observed in the middle frontal gyrus (MFG) in carriers of the Val allele. Conclusion. These observations, in keeping with a higher cortical dopamine level in MM individuals, support the hypothesis of a COMT Val158Met genotype modulation of the brain regions underlying proactive control, especially in frontal areas as suggested by Braver et al. [less ▲]

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See detailLa contribution des lobes frontaux au fonctionnement exécutif
Collette, Fabienne ULg

Conference (2014)

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See detailLes modifications du fonctionnement exécutif dans le vieillissement normal
Collette, Fabienne ULg; Salmon, Eric ULg

in Psychologie Française (2014), 59(1), 41-58

Il est maintenu bien reconnu que le vieillissement cognitif est associé à une diminution des capacités exécutives. Toutefois, si des déficits sont effectivement observés au sein des différentes fonctions ... [more ▼]

Il est maintenu bien reconnu que le vieillissement cognitif est associé à une diminution des capacités exécutives. Toutefois, si des déficits sont effectivement observés au sein des différentes fonctions, des dissociations entre performances préservées/altérées ont également été observées au sein de chacune. Dans cette revue de question, nous détaillerons les effets du vieillissement dans les fonctions de mise à jour, flexibilité, inhibition et coordination de tâches doubles, ainsi que les modifications au sein des réseaux cérébraux associés à ces processus. Nous discuterons également l'influence des capacités attentionnelles, des ressources en mémoire de travail et de certaines caractéristiques génétiques sur ces modifications. [less ▲]

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See detailPLS analysis of fMRI data on cognitive processes
Bahri, Mohamed Ali ULg; Genon, Sarah ULg; Bastin, Christine ULg et al

Conference (2013, December 12)

Cognitive processes like memory and self-referential are known to be underlined by extended neural networks. To study these complex processes, multivariate methods appear as the methods of the first ... [more ▼]

Cognitive processes like memory and self-referential are known to be underlined by extended neural networks. To study these complex processes, multivariate methods appear as the methods of the first choice since they take into account the functional integration. Partial Least Square (PLS) was used to study neural networks related to memory and self-referential processing in Alzheimer’s disease patients (AD) and two examples were presented. In the first one, we investigated the metabolic correlates of two forms of memory (conjunctive and relational memory performances) in AD. PLS identified two different brain networks highlighting correlations of the two types of memory and the glucose metabolism. In the second example, we assessed brain regions engaged during self-referential processing of information in AD patients during a task related fMRI study. PLS identified a wide brain network showing the effect of self- vs. other-referential processing. In contrast to univariate methods, PLS showed to be suitable for the study of cognitive processes. [less ▲]

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See detailInfluence of circadian rhythm and PER3 genotype on executive discriminative ability under sleep deprivation during a constant routine
Jaspar, Mathieu ULg; Meyer, Christelle ULg; Muto, Vincenzo ULg et al

Conference (2013, August 12)

Maintaining optimal performance during a working memory task requires not only to detect target items but also to discard fillers. Following signal detection theory, the ability to discriminate target ... [more ▼]

Maintaining optimal performance during a working memory task requires not only to detect target items but also to discard fillers. Following signal detection theory, the ability to discriminate target from non-target stimuli is estimated by d prime (d'). Here we assessed whether d' was modulated by the oscillating circadian signal during a 42-hour constant routine while participants performed 13 sessions of auditory 3-back task. We also tested whether the individual vulnerability to sleep loss predicted by the PERIOD3 gene polymorphism would influence this cognitive modulation imposed by sleep/wake regulation. From a sample of about 400 screened volunteers, thirty-five healthy young volunteers (age 19-26; 17 females) were recruited based on the PER3 polymorphism (twelve 5/5 and twenty-three 4/4 homozygotes). A linear mixed model tested on d’ the effect of circadian rhythmicity (based on melatonin level) and PER3 polymorphism. Given that 3back sessions were not administered at equidistant points, we used ranges to center each individual performance on dim light melatonin onset (DLMO). Analyses on d’ showed an effect of circadian oscillation (F(12,302) = 16.05, p< 0.0001), but also an interaction between gene and circadian oscillation (F(12,302)=1,88, p = 0.0362). This interaction was mainly characterized by a worst d’ in PER35/5subjects in the range covering a period between 21 and 23 hours after the DLMO (W=47; p = 0.0426). These results showed that circadian rhythm influence the discriminative ability under constant routine condition. Interestingly, we observed a better performance in PER34/4in the phase preceding the DLMO, but only in situation of high sleep pressure. Those results show that discriminative ability is differently affect by sleep homeostasis in PER3 polymorphism at the same circadian phase. We interpret this as a bigger vulnerability to sleep loss in PER35/5individuals in the period just before the wake maintenance zone. [less ▲]

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See detailDo fluid intelligence and executive functioning protect from age-related decline in cognitive control?
Manard, Marine ULg; Lorant, Caroline ULg; Collette, Fabienne ULg

Poster (2013, July)

Age-related studies on cognitive control suggest a decline in proactive control whereas reactive control remains intact (Braver, Gray, & Burgess, 2007). This study was designed to investigate the ... [more ▼]

Age-related studies on cognitive control suggest a decline in proactive control whereas reactive control remains intact (Braver, Gray, & Burgess, 2007). This study was designed to investigate the potential influence of fluid intelligence (Raven’s Advanced Progressive Matrices) and general executive functioning (Executive composite score from executive assessment) on cognitive control abilities during normal aging. Cognitive control was assessed using a computerized version of the Stroop paradigm in which proactive and reactive control processes were pseudo randomly engaged by varying the amount of interference across the task. Thirteen young and 27 older adults were included in this study. In the whole sample, results confirmed a significant age-related decline in proactive control. However, when older adults were divided in high- and low fluid intelligence subgroups, only older adults with low fluid intelligence showed a significant decline in proactive control compared to younger adults and this difference disappeared for older adults with high fluid intelligence level. When older adults were distinguished according to high and low executive capacities, the analysis revealed that, compared to the young ones, older adults with low executive functioning showed a general cognitive control decline (proactive and reactive processes). However, differences disappeared when young adults were compared to older adults with a high executive functioning. Accuracy results suggested that older adults have a slower but spared access to goal-representations that are necessary to correctly manage interference. So, this study confirmed the previous results obtained by Braver et al. (2007), but also suggest an influence of fluid intelligence and executive resources that seems important to take into account to investigate age-related decline in reactive and proactive cognitive control processes. [less ▲]

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See detailBrain metabolic dysfunction in Capgras syndrome during Alzheimer’s disease: a positron emission tomography study
Jedidi, Haroun ULg; Daury, Noémy; Cappa, Rémi et al

Poster (2013, June)

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