References of "Collette, Fabienne"
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See detailMetabolic correlates of clinical heterogeneity in questionable Alzheimer’s disease
Salmon, Eric ULg; Lekeu, Françoise ULg; Garraux, Gaëtan ULg et al

in Neurobiology of Aging (2008), 29

Thirty-four subjects with questionable Alzheimer's disease (QAD) were included in a 3-year prospective study and underwent neuropsychological testing and measurement of brain metabolism using FDG-PET at ... [more ▼]

Thirty-four subjects with questionable Alzheimer's disease (QAD) were included in a 3-year prospective study and underwent neuropsychological testing and measurement of brain metabolism using FDG-PET at entry. Seventeen patients (50%) did not convert to AD during the follow-up period. Compared to elderly controls of similar age, the cerebral activity of non-converters was reduced in the dorsolateral prefrontal cortex. Moreover, the variability of metabolism in the posterior cingulate cortex was related to their visuospatial memory performance, while disparity in parietal activity was related to their verbal memory performance. These results demonstrate the cerebral metabolic heterogeneity of patients with QAD. Initial functional images of converters showed that activity was already impaired in the posterior cingulate, lateral temporal cortex, anterior cingulate and orbitofrontal cortex. This metabolic pattern is consistent with a pre-dementia stage of AD, and highlights the fact that significant frontal metabolic involvement may be associated with impaired activity in posterior associative cortices in very early AD. [less ▲]

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See detailA Comparison of Unawareness in Frontotemporal Dementia and Alzheimer's Disease
Salmon, Eric ULg; Perani, Daniela; Collette, Fabienne ULg et al

in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(2), 176-9

BACKGROUND: Loss of insight is a core diagnostic feature of frontotemporal dementia (FTD) and anosognosia is frequently reported in Alzheimer's disease (AD). AIM: To compare unawareness (anosognosia) for ... [more ▼]

BACKGROUND: Loss of insight is a core diagnostic feature of frontotemporal dementia (FTD) and anosognosia is frequently reported in Alzheimer's disease (AD). AIM: To compare unawareness (anosognosia) for different symptoms, measured with a discrepancy score between patient's and caregiver's assessment, in AD and FTD. METHOD: In a prospective, multi-centre study, 123 patients with probable AD, selected according to the NINCDS-ADRDA procedure, were matched for age, sex, education, disease duration and dementia severity to patients with FTD (n = 41), selected according to international consensus criteria. A research complaint questionnaire was used to obtained patient's and caregiver's assessment concerning neuropsychological and behavioural symptoms. Data were compared in each group and between groups. Unawareness (measured by discrepancy scores) was compared between patients with AD and FTD. RESULTS: The caregivers generally assessed symptoms more severely than did patients, but both patient groups reported changes in affect (depressive mood or irritability) as their caregivers did. Unawareness was greater in patients with FTD than in patients with AD for language and executive difficulties, and for changes in behaviour and daily activities. CONCLUSION: The main finding is that unawareness was observed in both patients with FTD and patients with AD for most clinical domains. However, qualitative and quantitative differences showed that lack of awareness was greater in patients with FTD. [less ▲]

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See detailDirected forgetting and aging: the role of retrieval processes, processing speed, and proactive interference.
Hogge, Michaël; Adam, Stéphane ULg; Collette, Fabienne ULg

in Neuropsychology, Development, and Cognition. Section B, Aging, Neuropsychology and Cognition (2008), 15(4), 471-91

The directed forgetting effect obtained with the item method is supposed to depend on both selective rehearsal of to-be-remembered (TBR) items and attentional inhibition of to-be-forgotten (TBF) items. In ... [more ▼]

The directed forgetting effect obtained with the item method is supposed to depend on both selective rehearsal of to-be-remembered (TBR) items and attentional inhibition of to-be-forgotten (TBF) items. In this study, we investigated the locus of the directed forgetting deficit in older adults by exploring the influence of recollection and familiarity-based retrieval processes on age-related differences in directed forgetting. Moreover, we explored the influence of processing speed, short-term memory capacity, thought suppression tendencies, and sensitivity to proactive interference on performance. The results indicated that older adults' directed forgetting difficulties are due to decreased recollection of TBR items, associated with increased automatic retrieval of TBF items. Moreover, processing speed and proactive interference appeared to be responsible for the decreased recall of TBR items. [less ▲]

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See detailDissociation of perceptual and motor inhibitory processes in young and elderly participants using the Simon task.
Germain, Sophie ULg; Collette, Fabienne ULg

in Journal of the International Neuropsychological Society (2008), 14(6), 1014-21

Deficits in inhibitory abilities are frequently observed in normal aging. However, few studies have explored the generality of these deficits in a single group of participants. Here, we used an adaptation ... [more ▼]

Deficits in inhibitory abilities are frequently observed in normal aging. However, few studies have explored the generality of these deficits in a single group of participants. Here, we used an adaptation of the Simon task to differentially assess perceptual and motor inhibition using the same stimuli and task design and to determine whether these processes use separate or shared cognitive resources. We were interested in determining whether (1) normal aging is associated with the use of separate (as previously evidenced in young participants) or similar cognitive resources to perform perceptual and motor inhibition tasks; (2) older participants present a specific impairment in one of these two processes. Analyses of reaction times indicated that motor and perceptual inhibitory processes share some cognitive resources and both are impaired in normal aging. These results can be interpreted by considering that a dedifferentiation process is responsible for the inhibitory deficits presented by older participants. [less ▲]

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See detailSelf-reflection across time: cortical midline structures differentiate between present and past selves
D'Argembeau, Arnaud ULg; Feyers, Dorothée ULg; Majerus, Steve ULg et al

in Social Cognitive and Affective Neuroscience (2008), 3(3), 244-252

The processing of personal changes across time and the ability to differentiate between representations of present and past selves are crucial for developing a mature sense of identity. In this study, we ... [more ▼]

The processing of personal changes across time and the ability to differentiate between representations of present and past selves are crucial for developing a mature sense of identity. In this study, we explored the neural correlates of self-reflection across time using functional magnetic resonance imaging (fMRI). College undergraduates were asked to reflect on their own psychological characteristics and those of an intimate other, for both the present time period (i.e. at college) and a past time period (i.e. high school years) that involved significant personal changes. Cortical midline structures (CMS) were commonly recruited by the four reflective tasks (reflecting on the present self, past self, present other and past other), relative to a control condition (making valence judgments). More importantly, however, the degree of activity in CMS also varied significantly according to the target of reflection, with the ventral and dorsal medial prefrontal cortex and the posterior cingulate cortex being more recruited when reflecting on the present self than when reflecting on the past self or when reflecting on the other person. These findings suggest that CMS may contribute to differentiate between representations of present and past selves. [less ▲]

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See detailInterference and negative priming in normal aging and in mild Alzheimer’s disease
Hogge, Michaël; Salmon, Eric ULg; Collette, Fabienne ULg

in Psychologica Belgica (2008), 48(1), 1-23

Most studies that have administered interference and negative priming tasks to patients with Alzheimer’s disease (AD) and healthy elderly subjects have demonstrated inhibitory dysfunction in AD patients ... [more ▼]

Most studies that have administered interference and negative priming tasks to patients with Alzheimer’s disease (AD) and healthy elderly subjects have demonstrated inhibitory dysfunction in AD patients, and mixed results in the elderly. In the present study, we re-explored these two effects in these populations by administering two tasks that allow assessing interference and negative priming effects. Results on both tasks showed (1) the presence of an interference effect in AD and elderly adults, that can be explained by cognitive slowing in the case of elderly controls; (2) the preservation of negative priming abilities in the two groups. These surprising results for AD patients were interpreted by proposing that AD patients have a preserved ability to suppress the representation of a distracter, but specific inhibitory deficits when they have to resolve a selection conflict at the stage of response production (i.e. when competing stimuli have been fully processed). [less ▲]

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See detailRetrieval induced forgetting in normal aging
Hogge, Michaël; Adam, Stéphane ULg; Collette, Fabienne ULg

in Journal of Neuropsychology (2008), 2

The retrieval-induced forgetting (RIF) paradigm was used to assess the integrity of unintentional inhibitory functioning in normal aging. The paradigm was adapted to explore the RIF effect under ... [more ▼]

The retrieval-induced forgetting (RIF) paradigm was used to assess the integrity of unintentional inhibitory functioning in normal aging. The paradigm was adapted to explore the RIF effect under conditions that allow us to differentiate the contribution of intentional and automatic retrieval processes to performance. The results showed the presence of equivalent and significant RIF effects in young and older adults, for both the controlled and automatic retrieval performance. These results suggest that unintentional inhibitory processes are spared in normal aging, and confirm that RIF effect is independent of the kind of memory processes needed to perform the task. [less ▲]

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See detailLa maladie d'Alzheimer
Collette, Fabienne ULg; Feyers, Dorothée ULg; Bastin, Christine ULg

in Dujardin, Kathy; Lemaire, Patrick (Eds.) Neuropsychologie du vieillissement normal et pathologique (2008)

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See detailLes troubles des fonctions exécutives
Collette, Fabienne ULg

in Laterre, E. C. (Ed.) Sémiologie des maladies nerveuses (2008)

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See detailA Time to Think: Circadian Rhythms in Human Cognition
Schmidt, Christina ULg; Collette, Fabienne ULg; Cajochen, Christian et al

in Cognitive Neuropsychology (2007), 24(7), 755-89

Although peaks and troughs in cognitive performance characterize our daily functioning, time-of-day fluctuations remain marginally considered in the domain of cognitive psychology and neuropsychology ... [more ▼]

Although peaks and troughs in cognitive performance characterize our daily functioning, time-of-day fluctuations remain marginally considered in the domain of cognitive psychology and neuropsychology. Here, we attempt to summarize studies looking at the effects of sleep pressure, circadian variations, and chronotype on cognitive functioning in healthy subjects. The picture that emerges from this assessment is that beyond physiological variables, time-of-day modulations affect performance on a wide range of cognitive tasks measuring attentional capacities, executive functioning, and memory. These performance fluctuations are also contingent upon the chronotype, which reflects interindividual differences in circadian preference, and particularly upon the synchronicity between the individuals' peak periods of circadian arousal and the time of the day at which testing occurs. In themselves, these conclusions should direct both the clinician's and the researcher's attention towards the utmost importance to account for time-of-day parameters when assessing cognitive performance in patients and healthy volunteers. [less ▲]

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See detailComparison of inhibitory functioning in mild Alzheimer's disease and frontotemporal dementia
Collette, Fabienne ULg; Amieva, Hélène; Adam, Stéphane ULg et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2007), 43(7), 866-874

Executive dysfunction is frequently reported in Alzheimer's disease (AD) and the frontal variant of frontotemporal dementia (FTD). More specifically, inhibitory dysfunction is observed early in AD and ... [more ▼]

Executive dysfunction is frequently reported in Alzheimer's disease (AD) and the frontal variant of frontotemporal dementia (FTD). More specifically, inhibitory dysfunction is observed early in AD and inhibitory deficits are also prominent in patients with FTD. However, few studies have simultaneously explored and compared inhibitory abilities in both degenerative diseases. Consequently, the aim of this study was to compare verbal and motor inhibitory processes in the initial stages of AD and the frontal variant of FTD. Stroop and Go/No-go tasks were administered. The results demonstrate that, on the Go/No-go task, AD and FTD patients do not produce more errors than control subjects. However, both groups are impaired on the Stroop task (mainly with regard to the error score) but do not differ from each other. These results indicate that AD and FTD patients do not present a general impairment of their inhibitory abilities. Moreover, these two kinds of dementia present similar quantitative and qualitative inhibitory impairments on the two tasks, although their patterns of structural and functional cerebral impairments are known to be different. The presence of similar inhibitory deficits despite very different patterns of brain damage is in agreement with the hypothesis that inhibitory dysfunction in the two groups of patients depends on a disconnection process between anterior and posterior cerebral areas, rather than on the presence of focal metabolism decreases in different regions. [less ▲]

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See detailExploration of the neuronal substrates of Directed Forgetting with fMRI.
Feyers, Dorothée ULg; Hogge, Michaël; Salmon, Eric ULg et al

Conference (2007, June 26)

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See detailExploration of the neuronal substrates of Directed Forgetting with fMRI
Feyers, Dorothée ULg; Hogge, Michaël; Salmon, Eric ULg et al

Conference (2007, June 01)

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See detailDistinct regions of the medial prefrontal cortex are associated with self-referential processing and perspective taking
D'Argembeau, Arnaud ULg; Ruby, Perinne; Collette, Fabienne ULg et al

in Journal of Cognitive Neuroscience (2007), 19(6), 935-944

The medial prefrontal cortex (MPFC) appears to play a prominent role in two fundamental aspects of social cognition, that is, self-referential processing and perspective taking. However, it is currently ... [more ▼]

The medial prefrontal cortex (MPFC) appears to play a prominent role in two fundamental aspects of social cognition, that is, self-referential processing and perspective taking. However, it is currently unclear whether the same or different regions of the MPFC mediate these two interdependent processes. This functional magnetic resonance imaging study sought to clarify the issue by manipulating both dimensions in a factorial design. Participants judged the extent to which trait adjectives described their own personality (e.g., 'Are you sociable?') or the personality of a close friend (e.g., 'Is Caroline sociable?') and were also asked to put themselves in the place of their friend (i.e., to take a third-person perspective) and estimate how this person would judge the adjectives, with the target of the judgments again being either the self (e.g., 'According to Caroline, are you sociable?') or the other person (e.g., 'According to Caroline, is she sociable?'). We found that self-referential processing (i.e., judgments targeting the self vs. the other person) yielded activation in the ventral and dorsal anterior MPFC, whereas perspective taking (i.e., adopting the other person's perspective, rather than one's own, when making judgments) resulted in activation in the posterior dorsal MPFC; the interaction between the two dimensions yielded activation in the left dorsal MPFC. These findings show that self-referential processing and perspective taking recruit distinct regions of the MPFC and suggest that the left dorsal MPFC may be involved in decoupling one's own from other people's perspectives on the self. [less ▲]

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See detailExploration des substrats cérébraux du fonctionnement exécutif
Collette, Fabienne ULg

Scientific conference (2007, May 29)

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See detailSocial mind representation: Where does it fail in frontotemporal dementia?
Ruby, P.; Schmidt, Christina ULg; Hogge, Michaël et al

in Journal of Cognitive Neuroscience (2007), 19(4), 671-683

We aimed at investigating social disability and its cerebral correlates in frontotemporal dementia (FTD). To do so, we contrasted answers of patients with early-stage FTD and of their relatives on ... [more ▼]

We aimed at investigating social disability and its cerebral correlates in frontotemporal dementia (FTD). To do so, we contrasted answers of patients with early-stage FTD and of their relatives on personality trait judgment and on behavior prediction in social and emotional situations. Such contrasts were compared to control contrasts calculated with answers of matched controls tested with their relatives. in addition, brain metabolism was measured in patients with positron emission tomography and the [F-18]fluorodeoxyglucose method. Patients turned out to be as accurate as controls in describing their relative's personality, but they failed to predict their relative's behavior in social and emotional circumstances. Concerning the self, patients were impaired both in Current personality assessment and in prediction of their own behavior. Those two self-evaluation measures did not correlate. Only patients' anosognosia for social behavioral disability was found to be related to decreased metabolic activity in the left temporal pole. Such results suggest that anosognosia for social disability in FTD originates in impaired processing of emotional autobiographical information, leading to a self-representation that does not match current behavior. Moreover, we propose that perspective-taking disability participates in anosognosia, preventing patients from correcting their inaccurate self-representation based on their relative's perspective. [less ▲]

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See detailAdministrateur central et fonctions exécutives
Collette, Fabienne ULg

Conference (2007, March 27)

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See detailShort-term memory and the left intraparietal sulcus: Focus of attention? Further evidence from a face short-term memory paradigm
Majerus, Steve ULg; Bastin, Christine ULg; Poncelet, Martine ULg et al

in NeuroImage (2007), 35(1), 353-367

This study explored the validity of an attentional account for the involvement of the left intraparietal sulcus (IPS) in visual STM tasks. This account considers that during STM tasks, the IPS acts as an ... [more ▼]

This study explored the validity of an attentional account for the involvement of the left intraparietal sulcus (IPS) in visual STM tasks. This account considers that during STM tasks, the IPS acts as an attentional modulator, maintaining activation in long-term memory networks that underlie the initial perception and processing of the specific information to be retained. In a recognition STM paradigm, we presented sequences of unfamiliar faces and instructed the participants to remember different types of information: either the identity of the faces or their order of presentation. We hypothesized that, if the left IPS acts as an attentional modulator, it should be active in both conditions, but connected to different neural networks specialized in serial order or face identity processing. Our results showed that the left IPS was activated during both order and identity encoding conditions, but for different reasons. During order encoding, the left IPS showed functional connectivity with order processing areas in the right IPS, bilateral premotor and cerebellar cortices, reproducing earlier results obtained in a verbal STM experiment. During identity encoding, the left IPS showed preferential functional connectivity with right temporal, inferior parietal and medial frontal areas involved in detailed face processing. These results not only support an attentional account of left IPS involvement in visual STM, but given their similarity with previous results obtained for a verbal STM task, they further highlight the importance of the left IPS as an attentional modulator in a variety of STM tasks. [less ▲]

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