References of "Collette, Fabienne"
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See detailSeasonal variation in human executive brain responses
Meyer, Christelle ULg; Jaspar, Mathieu ULg; Muto, Vincenzo ULg et al

Poster (2014)

It is well established that cognition shows daily fluctuations with changes in circadian phase and sleep pressure. The physiological impact of season changes, which is well characterized in animals ... [more ▼]

It is well established that cognition shows daily fluctuations with changes in circadian phase and sleep pressure. The physiological impact of season changes, which is well characterized in animals, remains largely unexplored in human. Here we investigated the impact of seasonal variation on human cognitive brain function. This cross-sectional study,conducted in Liège (Belgium),spanned from May 2010 to October 2011. Following 8h in-lab baseline night of sleep, 30 volunteers (age 20.9+1.5; 15F)spent 42h awake under constant routine conditions(<5lux, semi-recumbent position, no time-cues). After12h recovery night, they underwent15minfMRI recording while performing a working memory 3-back task (3b) and a letter detection 0-back task (0b). Thus, fMRI data were acquired when volunteers had been in isolation under controlled conditionsfor 63h. Executive brain responses were isolated by subtracting 0b activity from 3b responses (3b>0b).Analysis tested seasonal influence on executive brain responses at the random effects level, using a phasoranalysis across the year.Inferences were conducted at p<0.05, after correction for multiple comparisons over a priori small volume of interest. Significanteffects of season on executive responses were detected inmiddle frontal and frontopolarregions, insula, and thalamus, with a maximum response at the end of summer and a minimum response at the end of winter.These brain areas are key regions for executive control and alertness. These results constitute the first demonstration that seasonality directly impacts on human cognitive brain functions. [less ▲]

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

in Frontiers in Human Neuroscience (2014)

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See detailThe impact of aging and hearing status on verbal working memory
Verhaegen, Clémence ULg; Collette, Fabienne ULg; Majerus, Steve ULg

in Neuropsychology, Development, and Cognition. Section B, Aging, Neuropsychology and Cognition (2014), 21(4), 464-482

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See detailCognitive and neuroimaging evidence of impaired interaction between Self and memory in Alzheimer’s disease
Genon, Sarah ULg; Bahri, Mohamed Ali ULg; Collette, Fabienne ULg et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2014), 51

In human cognition, self and memory processes strongly interact, as evidenced by the memory advantage for self-referential materials (Self Reference Effect (SRE) and Self Reference Recollection Effect ... [more ▼]

In human cognition, self and memory processes strongly interact, as evidenced by the memory advantage for self-referential materials (Self Reference Effect (SRE) and Self Reference Recollection Effect (SRRE)). The current study examined this interaction at the behavioural level and its neural correlates in patients with Alzheimer’s disease (AD). Healthy older controls (HC) and AD patients performed trait-adjectives judgements either for self-relevance or for other-relevance (encoding phase). In a first experiment, the encoding and subsequent yes-no recognition phases were administrated in an MRI scanner. Brain activation as measured by fMRI was examined during self-relevance judgements and anatomical images were used to search for correlation between the memory advantage for self-related items and grey matter density (GMD). In a second experiment, participants described the retrieval experience that had driven their recognition decisions (familiarity vs. recollective experience). The behavioural results revealed that the SRE and SRRE were impaired in AD patients compared to HC participants. Furthermore, verbal reports revealed that the retrieval of self-related information was preferentially associated with the retrieval of contextual details, such as source memory in the HC participants, but less so in the AD patients. Our imaging findings revealed that both groups activated the medial prefrontal cortex (MPFC) at encoding during self-relevance judgments. However, the variable and limited memory advantage for self-related information was associated with GMD in the lateral prefrontal cortex in the AD patients, a region supporting high-order processes linking self and memory. These findings suggest that even if AD patients engage MPFC during self-referential judgments, the retrieval of self-related memories is qualitatively and quantitatively impaired in relation with altered high-order processes in the lateral PFC. [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 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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