References of "Salmon, Eric"
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See detailDissociation entre recollection et familiarité dans la maladie d’Alzheimer: Etude des bases cérébrales en imagerie par résonance magnétique fonctionnelle
Bastin, Christine ULg; Genon, Sarah ULg; Collette, Fabienne ULg et al

Conference (2012)

1. Matériels et méthodes. Les difficultés mnésiques des patients à un stade léger d’une maladie d’Alzheimer sont marquées par une atteinte sévère de la récupération consciente des informations dans leur ... [more ▼]

1. Matériels et méthodes. Les difficultés mnésiques des patients à un stade léger d’une maladie d’Alzheimer sont marquées par une atteinte sévère de la récupération consciente des informations dans leur contexte d’apprentissage (recollection). Par contre, la reconnaissance des informations sur base d’un sentiment de familiarité (savoir qu’une information a été rencontrée auparavant sans récupérer son contexte d’apprentissage) est relativement préservée (Dalla Barba, 1997; Rauchs et al., 2007). L’objectif de cette étude était de révéler les substrats cérébraux des processus de recollection et familiarité dans la maladie d’Alzheimer au moyen d’une tâche de mémoire associative analysée selon les principes de la Procédure de Dissociation des Processus (Jacoby, 1991). Pendant une acquisition en IRM fonctionnelle, 26 patients avec une maladie d’Alzheimer probable à un stade léger et 17 témoins âgés ont étudié des paires de mots, puis ont dû les reconnaître parmi des paires recombinées (deux mots vus mais pas ensemble) et des paires nouvelles. 2. Résultats. Les analyses comportementales ont indiqué que 10 patients Alzheimer avaient des indices de recollection nuls (AD-), tandis que 16 autres patients présentaient des processus de recollection résiduels (AD+) bien que significativement moins importants que les témoins. Par contre, le score estimant la contribution des processus de familiarité était équivalent dans les trois groupes. L’analyse de l’activité cérébrale a montré que, chez les patients AD+ comme chez les témoins, la recollection activait le cortex cingulaire postérieur. Cependant, cette région était fonctionnellement connectée à l’hippocampe, au cortex pariétal inférieur et au cortex préfrontal dorsolatéral uniquement chez les témoins. Par ailleurs, dans les trois groupes, la familiarité activait le sillon intrapariétal. 3. Conclusion. Cette étude montre un déficit sévère de recollection et une relative préservation de la familiarité chez des patients Alzheimer. Lorsque les patients possèdent des capacités résiduelles de recollection, celles-ci sont soutenues par le cortex cingulaire postérieur comme chez les personnes âgées saines. Cependant, une perturbation de la connectivité fonctionnelle entre le cortex cingulaire postérieur et des régions impliquées dans la mémoire relationnelle, les aspects subjectifs de la recollection et les processus de monitoring post-récupération suggère que la qualité de la recollection résiduelle des patients Alzheimer est dégradée. 4. Références. Dalla Barba, G. (1997). Recognition memory and recollective experience in Alzheimer's disease. Memory, 5, 657-672. Jacoby, L.L. (1991). A process dissociation framework: Separating automatic from intentional uses of memory. Journal of Memory and Language, 30, 513-541. Rauchs, G., Piolino, P., Mézenge, F., Landeau, B., Lalevée, C., Pélerin, A. et al. (2007). Autonoetic consciousness in Alzheimer's disease: Neuropsychological and PET findings using an episodic learning and recognition task. Neurobiology of Aging, 28, 1410-1420. [less ▲]

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See detailThe influence of cognitive reserve on inter-individual variability in resting-state cerebral metabolism in normal aging
Bastin, Christine ULg; Yakushev, Igor; Bahri, Mohamed Ali ULg et al

in Frontiers in Human Neuroscience (2012)

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See detailCognitive reserve impacts on inter-individual variability in resting-state cerebral metabolism in normal aging
Bastin, Christine ULg; Yakushev, Igor; Bahri, Mohamed Ali ULg et al

in NeuroImage (2012), 63

There is a great deal of heterogeneity in the impact of aging on cognition and cerebral functioning. One potential factor contributing to individual differences among the elders is the cognitive reserve ... [more ▼]

There is a great deal of heterogeneity in the impact of aging on cognition and cerebral functioning. One potential factor contributing to individual differences among the elders is the cognitive reserve, which designates the partial protection from the deleterious effects of aging that lifetime experience provides. Neuroimaging studies examining task-related activation in elderly people suggested that cognitive reserve takes the form of more efficient use of brain networks and/or greater ability to recruit alternative networks to compensate for age-related cerebral changes. In this multi-centre study, we examined the relationships between cognitive reserve, as measured by education and verbal intelligence, and cerebral metabolism at rest (FDG-PET) in a sample of 74 healthy older participants. Higher degree of education and verbal intelligence was associated with less metabolic activity in the right posterior temporoparietal cortex and the left anterior intraparietal sulcus. Functional connectivity analyses of resting-state fMRI images in a subset of 41 participants indicated that these regions belong to the default mode network and the dorsal attention network respectively. Lower metabolism in the temporoparietal cortex was also associated with better memory abilities. The findings provide evidence for an inverse relationship between cognitive reserve and resting-state activity in key regions of two functional networks respectively involved in internal mentation and goal-directed attention. [less ▲]

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See detailModulation of brain activity during a Stroop inhibitory task by the kind of cognitive control required
Grandjean, Julien ULg; D'Ostilio, Kevin ULg; Phillips, Christophe ULg et al

in PLoS ONE (2012), 7(7), 41513

This study used a proportion congruency manipulation in the Stroop task in order to investigate, at the behavioral and brain substrate levels, the predictions derived from the Dual Mechanisms of Control ... [more ▼]

This study used a proportion congruency manipulation in the Stroop task in order to investigate, at the behavioral and brain substrate levels, the predictions derived from the Dual Mechanisms of Control (DMC) account of two distinct modes of cognitive control depending on the task context. Three experimental conditions were created that varied the proportion congruency: mostly incongruent (MI), mostly congruent (MC), and mostly neutral (MN) contexts. A reactive control strategy, which corresponds to transient interference resolution processes after conflict detection, was expected for the rare conflicting stimuli in the MC context, and a proactive strategy, characterized by a sustained task-relevant focus prior to the occurrence of conflict, was expected in the MI context. Results at the behavioral level supported the proactive/reactive distinction, with the replication of the classic proportion congruent effect (i.e., less interference and facilitation effects in the MI context). fMRI data only partially supported our predictions. Whereas reactive control for incongruent trials in the MC context engaged the expected fronto-parietal network including dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex, proactive control in the MI context was not associated with any sustained lateral prefrontal cortex activations, contrary to our hypothesis. Surprisingly, incongruent trials in the MI context elicited transient activation in common with incongruent trials in the MC context, especially in DLPFC, superior parietal lobe, and insula. This lack of sustained activity in MI is discussed in reference to the possible involvement of item-specific rather than list-wide mechanisms of control in the implementation of a high task-relevant focus. [less ▲]

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See detailAttention Supports Verbal Short-Term Memory via Competition between Dorsal and Ventral Attention Networks.
Majerus, Steve ULg; Attout, Lucie ULg; D'Argembeau, Arnaud ULg et al

in Cerebral Cortex (2012), 22

Interactions between the neural correlates of short-term memory (STM) and attention have been actively studied in the visual STM domain but much less in the verbal STM domain. Here we show that the same ... [more ▼]

Interactions between the neural correlates of short-term memory (STM) and attention have been actively studied in the visual STM domain but much less in the verbal STM domain. Here we show that the same attention mechanisms that have been shown to shape the neural networks of visual STM also shape those of verbal STM. Based on previous research in visual STM, we contrasted the involvement of a dorsal attention network centered on the intraparietal sulcus supporting task-related attention and a ventral attention network centered on the temporoparietal junction supporting stimulus-related attention. We observed that, with increasing STM load, the dorsal attention network was activated while the ventral attention network was deactivated, especially during early maintenance. Importantly, activation in the ventral attention network increased in response to task-irrelevant stimuli briefly presented during the maintenance phase of the STM trials but only during low-load STM conditions, which were associated with the lowest levels of activity in the dorsal attention network during encoding and early maintenance. By demonstrating a trade-off between task-related and stimulus-related attention networks during verbal STM, this study highlights the dynamics of attentional processes involved in verbal STM. [less ▲]

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See detailMémoire associative dans le vieillissement normal : Effet de l’unification des associations
Simon, Jessica ULg; Collette, Fabienne ULg; Genon, Sarah ULg et al

in Proceedings of the XIIème Colloque International sur le Vieillissement Cognitif (2012)

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See detailAssociative memory in normal aging: The effect of unitization
Simon, Jessica ULg; Collette, Fabienne ULg; Genon, Sarah ULg et al

in Proceedings of the first joint meeting of the Belgian Association for Psychological Sciences (BAPS) and the Sociedad Española de Psicología Experimental (SEPEX) (2012)

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See detailThe role of the salience of fluency in recognition memory in Alzheimer’s disease
Bastin, Christine ULg; Salmon, Eric ULg; Willems, Sylvie ULg

in Proceedings of the First joint meeting of the Belgian Association for Psychological Sciences (BAPS) and the Sociedad Española de Psicología Experimental (SEPEX) (2012)

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See detailDissociation entre recollection et familiarité dans la maladie d'Alzheimer : Etude des bases cérébrales en imagerie par résonance magnétique fonctionnelle.
Bastin, Christine ULg; Genon, Sarah ULg; Collette, Fabienne ULg et al

in Proceedings of the 11th Reunion Francophone sur la Maladie d’Alzheimer et les Syndromes Apparentés (2012)

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See detailFrontal and posterior cingulate metabolic impairment in the behavioural variant of frontotemporal dementia with impaired autonoetic consciousness
Bastin, Christine ULg; Feyers, Dorothée ULg; Souchay, Céline et al

in Human Brain Mapping (2012), 33

Although memory dysfunction is not a prominent feature of the behavioural variant of frontotemporal dementia (bv-FTD), there is evidence of specific deficits of episodic memory in these patients. They ... [more ▼]

Although memory dysfunction is not a prominent feature of the behavioural variant of frontotemporal dementia (bv-FTD), there is evidence of specific deficits of episodic memory in these patients. They also have problems monitoring their memory performance. The objective of the present study was to explore the ability to consciously retrieve own encoding of the context of events (autonoetic consciousness) and the ability to monitor memory performance using feeling-of-knowing (FOK) in bv-FTD. Analyses of the patients’ cerebral metabolism (FDG-PET) allowed an examination of whether impaired episodic memory in bv-FTD is associated with the frontal dysfunction characteristic of the pathology or a dysfunction of memory-specific regions pertaining to Papez’s circuit. Data were obtained from 8 bv-FTD patients and 26 healthy controls. Autonoetic consciousness was evaluated by Remember responses during the recognition memory phase of the FOK experiment. As a group, bv-FTD patients demonstrated a decline in autonoetic consciousness and FOK accuracy at the chance level. While memory monitoring was impaired in most (7) patients, 4 bv-FTD participants had individual impairment of autonoetic consciousness. They specifically showed reduced metabolism in the anterior medial prefrontal cortex, the left dorsolateral prefrontal cortex (near the superior frontal sulcus), parietal regions and the posterior cingulate cortex. These findings were tentatively interpreted by considering the role of the metabolically impaired brain regions in self-referential processes, suggesting that the bv-FTD patients’ problem consciously retrieving episodic memories may stem at least partly from deficient access to and maintenance/use of information about the self. [less ▲]

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See detailLes troubles cognitifs associés au vieillissement normal
Collette, Fabienne ULg; Salmon, Eric ULg; Audiffren, Michel

in Audiffren, Michel; François, Pierre-Henri (Eds.) Créativité, Motivation et Vieillissement. Les science cognitives en débat. (2012)

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See detailPerceptual and motor abilities in normal aging and Alzheimer’s disease: a preliminary study
Stawarczyk, David ULg; Grandjean, Julien ULg; Salmon, Eric ULg et al

in Archives of Gerontology & Geriatrics (2012), 54

Deficits in inhibitory abilities are frequently observed in normal aging and Alzheimer disease (AD). However, few studies have explored the generality of these deficits in a single group of participants ... [more ▼]

Deficits in inhibitory abilities are frequently observed in normal aging and Alzheimer disease (AD). However, few studies have explored the generality of these deficits in a single group of participants. A battery of tasks assessing perceptual and motor inhibitory functioning was administered to young and older healthy participants (Study 1), as well as to mild Alzheimer patients (Study 2). Results did not agree with a selective impairment of motor or perceptual inhibition in either AD or normal aging but rather suggest that a decrease in cognitive resources available in working memory could explain inhibitory performance both in normal aging and AD. [less ▲]

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See detailValuing One's Self: Medial Prefrontal Involvement in Epistemic and Emotive Investments in Self-views.
D'Argembeau, Arnaud ULg; Jedidi, Haroun ULg; Balteau, Evelyne ULg et al

in Cerebral Cortex (2012), 22

Recent neuroimaging research has revealed that the medial prefrontal cortex (MPFC) is consistently engaged when people form mental representations of themselves. However, the precise function of this ... [more ▼]

Recent neuroimaging research has revealed that the medial prefrontal cortex (MPFC) is consistently engaged when people form mental representations of themselves. However, the precise function of this region in self-representation is not yet fully understood. Here, we investigate whether the MPFC contributes to epistemic and emotive investments in self-views, which are essential components of the self-concept that stabilize self-views and shape how one feels about oneself. Using functional magnetic resonance imaging, we show that the level of activity in the MPFC when people think about their personal traits (by judging trait adjectives for self-descriptiveness) depends on their investments in the particular self-view under consideration, as assessed by postscan rating scales. Furthermore, different forms of investments are associated with partly distinct medial prefrontal areas: a region of the dorsal MPFC is uniquely related to the degree of certainty with which a particular self-view is held (one's epistemic investment), whereas a region of the ventral MPFC responds specifically to the importance attached to this self-view (one's emotive investment). These findings provide new insight into the role of the MPFC in self-representation and suggest that the ventral MPFC confers degrees of value upon the particular conception of the self that people construct at a given moment. [less ▲]

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See detailThe neural basis of semantic and episodic forms of self-knowledge: insights from functional neuroimaging
D'Argembeau, Arnaud ULg; Salmon, Eric ULg

in Lopez-Larrea, Carlos (Ed.) Sensing in nature (2012)

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See detailAging effect on recollection and familiarity processes
Collette, Fabienne ULg; Angel, Lucie; Bastin, Christine ULg et al

Scientific conference (2011, December 22)

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See detailDiagnostic de la maladie d’Alzheimer: étude comparative du pouvoir discriminant de différentes tâches de mémoire épisodique
Grotz, Catherine; Adam, Stéphane ULg; Teunisse, J-P. et al

Poster (2011, December 02)

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See detailViability for the Siemens Ecat HR+ of the new stability test of PET scanners elaborated by the Belgian Hospital Physicist Association
Nguyen, Daniel ULg; Dalemans, Christophe; Bahri, Mohamed Ali ULg et al

in European Journal of Nuclear Medicine and Molecular Imaging (2011, October), 38(S2), 174

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See detailPerformance evaluation of the General Electric eXplore CT 120 micro-CT using the vmCT phantom.
Bahri, Mohamed Ali ULg; Warnock, Geoffrey ULg; Plenevaux, Alain ULg et al

in Nuclear Instruments & Methods in Physics Research Section A (2011), 648

The eXplore CT 120 is the latest generation micro-CT from General Electric. It is equipped with a high power tube and a flat panel detector. It allows high resolution and high contrast fast CT scanning of ... [more ▼]

The eXplore CT 120 is the latest generation micro-CT from General Electric. It is equipped with a high power tube and a flat panel detector. It allows high resolution and high contrast fast CT scanning of small animals. The aim of this study was to compare the performance of the eXplore CT 120 with the one of the eXplore Ultra, its predecessor for which the methodology using the vmCT phantom was already described [1]. The phantom was imaged using typical rat (fast scan or F) or mouse (in vivo bone scan or H) scanning protocols. With the slanted edge method, a 10% modulation transfer function (MTF) was observed at 4.4 (F) and 3.9-4.4 (H) mm-1 corresponding to 114 μm resolution. A fairly larger MTF was obtained with the coil method with the MTF for the thinnest coil (3.3 mm-1 ) equal to 0.32 (F) and 0.34 (H). The geometric accuracy was better than 0.3%. There was a highly linear (R2 > 0.999) relationship between measured and expected CT numbers for both the CT number accuracy and linearity sections of the phantom. A cupping effect was clearly seen on the uniform slices and the uniformity-to-noise ratio ranged from 0.52 (F) to 0.89 (H). The air CT number depended on the amount of polycarbonate surrounding the area where it was measured: a difference as high as approximately 200 HU was observed. This hindered the calibration of this scanner in HU. This is likely due to the absence of corrections for beam hardening and scatter in the reconstruction software. However in view of the high linearity of the system, the implementation of these corrections would allow a good quality calibration of the scanner in HU. In conclusion, the eXplore CT 120 achieved a better spatial resolution than the eXplore Ultra (based on previously reported specifications) and future software developments to include beam hardening and scatter corrections will make the new generation CT scanner even more promising. [less ▲]

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See detailModulating effect of COMT genotype on the brain regions underlying inhibition
Jaspar, Mathieu ULg; Grandjean, Julien ULg; Salmon, Eric ULg et al

Poster (2011, June 26)

Introduction Catechol-O-methytransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex (Männistö & Kaakkola, 1999). Actually, a transition of ... [more ▼]

Introduction Catechol-O-methytransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex (Männistö & Kaakkola, 1999). Actually, a transition of guanine to adenine at codon 158 of the COMT gene results in a valine to methionine substitution (Lotta & al., 1995). This phenomenon leads to different COMT genotypes, each associated with a different COMT enzymatic activity (Weinshilboum, & al., 1999). A large number of studies reported an effect of COMT on executive functioning. However, most of them used multi-determined executive tasks (e.g., Barnett & al., 2007). We are interested here to determine the effect of COMT Val158Met genotype on the activity of frontal and parietal areas (Nee & al., 2007; Laird & al., 2005) underlying the specific executive process of inhibition. Methods Procedure In an event-related fMRI experiment, a modified form of the Stroop task was administered to 44 young adults (age range: 18-30) separated into three groups according to their COMT Val158Met genotype: 15 homozygous val/val (VV), 14 homozygous met/met (MM) and 15 heterozygotes val/met (VM) carriers. The Stroop task consisted in the presentation of color words printed in various ink colors (e.g the word blue written in red). Subjects were instructed to name of ink color as fast and accurately as possible by avoiding to read the word. In this version of the Stroop task, three different contexts were created (data not showed here): (1) a congruent context (MC) with a majority of facilitator items (IC), (2) a non-congruent context (MI) with mainly interfering items (II), (3) a neutral context (MN) with mainly neutral items (IN, series of %%% written in different colors). MRI acquisition, data analysis Functional MRI time series were acquired on a 3T head-only scanner operated with the standard transmit-receive quadrature head coil. Multislice T2*-weighted functional images were acquired with a gradient-echo echo-planar imaging sequence using axial slice orientation and covering the whole brain (32 slices, FoV = 220x220 mm², voxel size 3.4x3.4x3 mm³, 30% interslice gap, matrix size 64x64x32, TR = 2130 ms, TE = 40 ms, FA = 90°). Structural images were obtained using a high resolution T1-weighted sequence (3D MDEFT [Deichmann & al., (2004)] ; TR = 7.92 ms, TE = 2.4 ms, TI = 910 ms, FA = 15°, FoV = 256 x 224 x 176 mm³, 1 mm isotropic spatial resolution). Preprocessing and statistical analyses were performed with SPM8 (p<.001 uncorrected). Results Behavioral results indicated the presence of a general interference effect (II – IN items) for reaction time (F(1,41) = 292,44 ; p < 0,001) but no significant difference in interference between the three groups (F(2,41) = 0,27; p = 0,76). FMRI results revealed that interference effect [(MI_II-MI_IN) + (MC_II-MC_IN) + (MN_II-MN_IN)] observed in our three groups is mainly associated with cerebral activity in frontal and parietal areas. Moreover, group comparisons indicates that this effect is associated with increased medial frontal and precentral gyrus activity in VV and VM groups by comparison with MM group, but also in the superior temporal gyrus and in the thalamus in the VM by comparison to MM . Conversely, no supplementary brain area was observed for the comparison of the MM to the two other groups. Conclusions The fronto-parietal brain network associated with interference resolution observed here is consistent with prior reports (Nee & al., 2007; Laird & al., 2005). Moreover, results showed activity in different brain areas according to the COMT genotype. Indeed, a similar behavioral performance is associated to the recruitment of supplementary areas in the carriers of the val allele. This observation, paralleling with the lower COMT enzymatic activity and, thus, the higher cortical dopamine level in met/met individuals, confirms our expectation of a COMT Val158Met genotype modulation of the brain regions underlying inhibition efficiency. [less ▲]

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