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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 (in press)

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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 detailCognitive and neuroimaging evidence of impaired interaction between Self and memory in Alzheimer’s disease.
Genon, Sarah ULg; Genon, Sarah ULg; Bahri, Mohamed Ali 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 detailDifferential effects of aging on the neural correlates of recollection and familiarity
Angel, Lucie; Bastin, Christine ULg; Genon, Sarah ULg et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2013), 49

The present experiment aimed to investigate age differences in the neural correlates of familiarity and recollection, while keeping performance similar across age groups by varying task difficulty. Twenty ... [more ▼]

The present experiment aimed to investigate age differences in the neural correlates of familiarity and recollection, while keeping performance similar across age groups by varying task difficulty. Twenty young and twenty older adults performed an episodic memory task in an event-related fMRI design. At encoding, participants were presented with pictures, either once or twice. Then, they performed a recognition task, with a Remember/Know paradigm. A similar performance was observed for the two groups in the Easy condition for recollection and in the Hard condition for familiarity. Imaging data revealed the classic recollection-related and familiarity-related networks, common to young and older groups. In addition, we observed that some activity related to recollection (left frontal, left temporal, left parietal cortices and left parahippocampus) and familiarity (bilateral anterior cingulate, right frontal gyrus and left superior temporal gyrus) was reduced in older compared to young adults. However, for recollection processes only, older adults additionally recruited the right precuneus, possibly to successfully compensate for their difficulties, as suggested by a positive correlation between recollection and precuneus activity. [less ▲]

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See detailItem familiarity and controlled associative retrieval in Alzheimer's disease: An fMRI study
Genon, Sarah ULg; Collette, Fabienne ULg; Feyers, Dorothée ULg et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2013), 49

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See detailThe neural correlates of recollection and familiarity during aging
Angel, Lucie; Bastin, Christine ULg; Genon, Sarah ULg et al

in Journal of Psychophysiology (2013), 27(Suppl 1), 48

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See detailThe neural correlates of recollection and familiarity during aging
Angel, Lucie; Bastin, Christine ULg; Genon, Sarah ULg et al

Poster (2013)

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See detailCONTROLLED AND AUTOMATIC MEMORY RETRIEVAL IN ALZHEIMER’S DISEASE
Bastin, Christine ULg; Genon, Sarah ULg; Willems, Sylvie ULg et al

in Proceedings of the 8th Panhellenic Interdisciplinary Conference of Alzheimer's Disease and Related Disorders (2013)

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See detailEnhancing the salience of fluency improves recognition memory performance in mild Alzheimer’s disease
Bastin, Christine ULg; Willems, Sylvie ULg; Genon, Sarah ULg et al

in Journal of Alzheimer's Disease [=JAD] (2013), 33

Recognition memory can rely on recollection (recall of the details from the encoding episode) and familiarity (feeling that some information is old without any recollection). In Alzheimer’s disease (AD ... [more ▼]

Recognition memory can rely on recollection (recall of the details from the encoding episode) and familiarity (feeling that some information is old without any recollection). In Alzheimer’s disease (AD), whereas there is a clear deficit of recollection, the evidence regarding familiarity is mixed, with some studies showing preserved familiarity and others reporting impairment. The current study examined whether recognition memory performance can be improved in AD when the use of familiarity is facilitated by the salience of processing fluency due to an earlier encounter with the information. Fifteen AD patients and 16 healthy controls performed a verbal recognition memory task where the salience of fluency was manipulated by means of letters overlap. Studied and unstudied words were constituted of either two separate sets of letters (no-overlap condition, high fluency salience) or the same set of letters (overlap condition, low fluency salience). The results showed that, although performance was globally poorer in AD patients than in the controls, both groups performed significantly better in the no-overlap condition than in the overlap condition. This suggests that AD patients benefited as much as the controls from the salience of fluency. [less ▲]

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See detailVerbal learning in Alzheimer’s disease and mild cognitive impairment:fine-grained acquisition and short-delay consolidation performance and neural correlates
Genon, Sarah ULg; Collette, Fabienne ULg; Moulin, Chris et al

in Neurobiology of Aging (2013), 34

The aim of this study was to examine correlations between acquisition and short-delay consolidation and brain metabolism at rest measured by fluorodeoxyglucose positron emission tomography (FDG-PET) in 44 ... [more ▼]

The aim of this study was to examine correlations between acquisition and short-delay consolidation and brain metabolism at rest measured by fluorodeoxyglucose positron emission tomography (FDG-PET) in 44 Alzheimer’s disease (AD) patients, 16 patients with mild cognitive impairment (MCI) who progressed to dementia (MCI-AD), 15 MCI patients who remained stable (MCI-S, 4–8 years of follow-up), and 20 healthy older participants. Acquisition and short-delay consolidation were calculated respectively as mean gained (MG) and lost (ML) access to items of the California Verbal Learning Task. MG performance suggests that acquisition is impaired in AD patients even at predementia stage (MCI-AD). ML performance suggests that short-delay consolidation is deficient only in confirmed AD patients. Variations in acquisition performance in control participants are related to metabolic activity in the anterior parietal cortex, an area supporting task-positive attentional processes. In contrast, the acquisition deficit is related to decreased activity in the lateral temporal cortex, an area supporting semantic processes, in patients at an early stage of AD and is related to metabolic activity in the hippocampus, an area supporting associative processes, in confirmed AD patients. [less ▲]

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See detailExploration of the neurocognitive mecanisms of memory awareness in Alzheimer’s disease (AD).
Genon, Sarah ULg

Scientific conference (2012, December 17)

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See detailItem familiarity and controlled associative retrieval in Alzheimer’s disease: an fMRI study.
Genon, Sarah ULg; Collette, Fabienne ULg; Feyers, Dorothée ULg et al

in Proceedings of the Amsterdam Memory Slam 2012 (2012, August 30)

Alzheimer’s disease (AD) is characterised by altered recollection function, with impaired controlled retrieval of associations. In contrast, familiarity-based memory for individual items may sometimes be ... [more ▼]

Alzheimer’s disease (AD) is characterised by altered recollection function, with impaired controlled retrieval of associations. In contrast, familiarity-based memory for individual items may sometimes be preserved in early stages of the disease. This is the first study that directly examines whole brain regional activity engaged during one core aspect of the recollection function: associative controlled episodic retrieval (CER), contrasted to item familiarity in AD patients. Cerebral activity related to associative CER and item familiarity in AD patients and healthy controls (HC) was measured with functional magnetic resonance imaging during a word-pair recognition task to which the process dissociation procedure was applied. Some patients had null CER estimates (AD-), whereas others did show some CER abilities (AD+) although significantly less than HC. In contrast, familiarity estimates were equivalent in the three groups. In AD+ like in controls, associative CER activated the inferior precuneus/posterior cingulate cortex (PCC). However, during associative CER, functional connection between this region and the hippocampus, the inferior parietal and the dorsolateral prefrontal cortex was significantly higher in HC than in AD+. In the three groups, item familiarity was related to activation along the intraparietal sulcus (IPS). In conclusion, whereas the preserved automatic detection of an old item (without retrieval of accurate word association) is related to a parietal activation centred on the IPS, the inferior precuneus/PCC supports associative CER ability in AD patients as in HC. However, AD patients have deficient functional connectivity during associative CER suggesting that residual recollection function in these patients might be impoverished by lack of some recollection-related aspects such as autonoetic quality, episodic details and verification. [less ▲]

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See detailMétamémoire pour des informations épisodiques et sémantiques dans la maladie d’Alzheimer.
Simon, Jessica ULg; Bastin, Christine ULg; Collette, Fabienne ULg et al

in Proceedings of the "XIIème Colloque International sur le Vieillissement Cognitif" (2012, June 25)

Quelques études ont examiné la précision du jugement concernant leur propre mémoire chez des patients présentant une maladie d’Alzheimer (MA) à l’aide de la procédure « Feeling-of-Knowing » (FOK). Dans ... [more ▼]

Quelques études ont examiné la précision du jugement concernant leur propre mémoire chez des patients présentant une maladie d’Alzheimer (MA) à l’aide de la procédure « Feeling-of-Knowing » (FOK). Dans cette procédure, le participant est invité à prédire sa capacité à reconnaître parmi des distracteurs l’item qu’il n’est pas parvenu à rappeler avant de passer à la phase de reconnaissance. Chez les patients en début de MA, la précision du jugement semble préservée lorsque la tâche implique la mémoire sémantique mais apparaît altérée lorsque la tâche implique la mémoire épisodique (Perrotin & Insingrini, 2010). Il existerait donc une dissociation dans la précision du jugement métacognitif chez les patients avec MA débutante entre les domaines épisodique et sémantique. Cependant, cette hypothèse n’a jamais été examinée au sein d’une même tâche. Dans cette étude, nous avons administré une version adaptée du FOK à 23 patients avec MA débutante et 17 sujets de contrôle. Les participants voyaient des visages de personnes dont ils avaient dû étudier le nom auparavant (items épisodiques) et des visages de personnes célèbres (items sémantiques). Pour chaque visage, les participants devaient indiquer la probabilité qu’ils reconnaissent le nom de la personne sur une échelle qualitative à 4 points (« Aucune chance », « Faible chance », « Forte chance », « Je le connais (rappel) ») puis reconnaître le nom parmi 3 distracteurs. La précision des jugements a été évaluée à l’aide du score de Hamann. Une ANOVA a révélé un effet significatif d’interaction entre le groupe et le domaine mnésique (P = .05), la moindre précision du jugement en mémoire épisodique étant exacerbée chez les patients avec MA. Cette étude renforce donc l’hypothèse selon laquelle il existe une dissociation entre les domaines épisodique et sémantique dans la capacité métacognitive des patients avec MA débutante. Perrotin, A. & Insingrini, M. (2010). La métamémoire et sa fonction de monitoring dans le vieillissement normal et dans la maladie d’Alzheimer. Revue de Neurospsychologie Neurosciences cognitives et cliniques, 2(4), 299-309. [less ▲]

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See detailSelf-appraisal and medial prefrontal activation in early stage Alzheimer’s disease
Genon, Sarah ULg; Collette, Fabienne ULg; Angel, Lucie et al

Poster (2012, June 12)

Introduction Self-referential processing in healthy subjects is related to activation within cortical midline structures, such as the medial prefrontal cortex (MPFC) and the posterior cingulate cortex ... [more ▼]

Introduction Self-referential processing in healthy subjects is related to activation within cortical midline structures, such as the medial prefrontal cortex (MPFC) and the posterior cingulate cortex (PCC; Northoff et al., 2006). Little is know about the engagement of these structures during self-referential processing at different stages of Alzheimer’s disease (AD). The PCC and the MPFC have been found to be activated during a self-appraisal task of adjectives in patients at very early stage of the disease (patients with Mild Cognitive Impairment, MCI; Ries et al., 2006). In contrast, in a similar task, Ruby et al. (2009) have found that mild demented patients activated the dorsal part of the MPFC (DMPFC) to a lesser extent than healthy controls (HC). Ruby et al. did not assess depression symptoms in their patients. Yet, MPFC activations have been found to be modified during self-referential processing in depressed participants (Lemogne et al., 2012). Therefore, in this study, we examined brain correlates of self-appraisal processing in AD patients when controlling for depressive symptoms. Methods Twenty-two mild AD patients and 22 HC matched on age, level of education and gender (respectively: 76±5y; 11±3y; 12M10F) to the AD patients (respectively: 76±7y; 11±3y; 11M11F) were recruited. To control for dementia severity and depression, the participants were administrated the Mattis Dementia Rating (MDR) and the Geriatric Depression Scale (GDS). A self-appraisal task intermixed with a recognition task was administered in an fMRI experimentation. In the self-appraisal task, the participants saw adjectives and had to indicate if the trait describes them (Self-condition; SC) or the King Albert II (for men)/the Queen Fabiola (for women; Other-condition; OC). The adjectives were presented in blocks of 6 items. Participants performed 9 runs consisting in one block of SC and one block of OC followed by a recognition phase where participants were presented with the 12 adjectives that they had just previously seen randomly mixed with 12 new adjectives. They were asked to indicate for each adjective whether they had seen it in the previous task. Statistical analyses focused on the self-appraisal task. Brain activations related to the self appraisal process were isolated in each participant by subtracting brain activation related to OC items from brain activation related to SC items. Then at the group level, we examined differences between groups (HC>AD and AD>HC) and a conjunction analysis examined brain activations that were common to both groups. Preprocessing and statistical analyses were performed with SPM8 (p<.001 uncorrected with a-priori hypotheses). Results GDS scores were similar in AD (3±3) and HC (3±3; T(42) = .1; P=.9) groups. No region was found to be significantly more activated during self-appraisal process in HC than in AD and vice versa when performing direct statistical comparison. Moreover, a conjunction analysis revealed that the VMPFC was the only region commonly activated in AD and HC during self-appraisal process (Punc<.001). Conclusions Our results revealed that AD patients engaged the ventral part of the MPFC to a similar extent than HC during self-appraisal judgements. These results and the results found in patients with MCI by Ries et al. (2006) suggest that at initial stages of AD, patients engaged self-related regions when they performed judgements about themselves as HC do. The divergence with the findings by Ruby et al. (2009) may be related either to the fact that they did not controlled for depressive symptoms or to the fact that their patients showed on average lower scores at the MDR (124) than our patients (127). One can assume that engagement of the self-related regions during self-appraisal judgements in the AD patients depends on the severity of the dementia and/or depressive symptoms. In conclusion, MPFC may be engaged during self-referential processing in very mild AD patients without depressive symptoms. References: Lemogne, C., Delaveau, P., Freton, M., Guionnet, S. & Fossati, P. (2012). Medial prefrontal cortex and the self in major depression. Journal of Affective Disorders, 136, 1-11. Ries, M. L., Schmitz, T.W., Kawahara, T.N., Torgerson, B.M., Trivedi, M.A. & Johnson, S.C. (2006). Task-dependent posterior cingulated activation in mild cognitive impairment. NeuroImage, 29, 485-492. Ruby, P., Collette, F., D’Argembeau, A., Péters, F., Degueldre, C., Balteau, E., Luxen, A., Maquet, P. & Salmon, E. (2009). Perspective taking to assess self-personality: What’s modified in Alzheimer’s disease ? Neurobiology of Aging, 30(10), 1637-1651. [less ▲]

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