References of "Peigneux, Philippe"
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See detailPartially Segregated Neural Networks for Spatial and Contextual Memory in Virtual Navigation
Rauchs, G.; Orban, Pierre ULg; Balteau, Evelyne ULg et al

in Hippocampus (2008), 18(5), 503-518

Finding our way in a previously learned, ecologically valid environment concurrently involves spatial and contextual cognitive operations. The former process accesses a cognitive map representing the ... [more ▼]

Finding our way in a previously learned, ecologically valid environment concurrently involves spatial and contextual cognitive operations. The former process accesses a cognitive map representing the spatial interactions between all paths in the environment. The latter accesses stored associations between landmark objects and their milieu. Here, we aimed at dissociating their neural basis in the context of memory-based virtual navigation. To do so, subjects freely explored a virtual town for 1 h, then were scanned using fMRI while retrieving their way between two locations, under four navigation conditions designed to probe separately or jointly the spatial and contextual memory components. Besides prominent commonalities found in a large hippocampo-neocortical network classically involved in topographical navigation, results yield evidence for a partial dissociation between the brain areas supporting spatial and contextual components of memory-based navigation. Performance-related analyses indicate that hippocampal activity mostly supports the spatial component, whereas parahippocampal activity primarily supports the contextual component. Additionally, the recruitment of contextual memory during navigation was associated with higher frontal, posterior parietal and lateral temporal activity. These results provide evidence for a partial segregation of the neural substrates of two crucial memory components in human navigation, whose combined involvement eventually leads to efficient navigation behavior within a learned environment. (c) 2008 Wiley-Liss, Inc. [less ▲]

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See detailOwl or lark? Stroop-related cerebral activity is modulated by time of day and chronotype
Schmidt, Christina ULg; Collette, Fabienne ULg; Sterpenich, Virginie et al

in Journal of Sleep Research (2008), 17(Suppl. 1),

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See detailChronotype-dependent performance modulation according to time of day : a functional neuroimaging approach
Schmidt, Christina ULg; Collette, Fabienne ULg; Sterpenich, Virginie et al

in NeuroImage (2008), 41(Suppl. 1),

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See detailSleep modulates the neural substrates of both spatial and contextual memory consolidation
Rauchs, G; Orban, P; Schmidt, Christina ULg et al

in PLoS ONE (2008), 3(8), 2949

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See detailPerception of pain in the minimally conscious state with PET activation: an observational study.
Boly, Mélanie ULg; Faymonville, Marie-Elisabeth ULg; Schnakers, Caroline et al

in Lancet Neurology (2008), 7(11), 1013-20

BACKGROUND: Patients in a minimally conscious state (MCS) show restricted self or environment awareness but are unable to communicate consistently and reliably. Therefore, better understanding of cerebral ... [more ▼]

BACKGROUND: Patients in a minimally conscious state (MCS) show restricted self or environment awareness but are unable to communicate consistently and reliably. Therefore, better understanding of cerebral noxious processing in these patients is of clinical, therapeutic, and ethical relevance. METHODS: We studied brain activation induced by bilateral electrical stimulation of the median nerve in five patients in MCS (aged 18-74 years) compared with 15 controls (19-64 years) and 15 patients (19-75 years) in a persistent vegetative state (PVS) with (15)O-radiolabelled water PET. By way of psychophysiological interaction analysis, we also investigated the functional connectivity of the primary somatosensory cortex (S1) in patients and controls. Patients in MCS were scanned 57 (SD 33) days after admission, and patients in PVS 36 (9) days after admission. Stimulation intensities were 8.6 (SD 6.7) mA in patients in MCS, 7.4 (5.9) mA in controls, and 14.2 (8.7) mA in patients in PVS. Significant results were thresholded at p values of less than 0.05 and corrected for multiple comparisons. FINDINGS: In patients in MCS and in controls, noxious stimulation activated the thalamus, S1, and the secondary somatosensory or insular, frontoparietal, and anterior cingulate cortices (known as the pain matrix). No area was less activated in the patients in MCS than in the controls. All areas of the cortical pain matrix showed greater activation in patients in MCS than in those in PVS. Finally, in contrast with patients in PVS, those in MCS had preserved functional connectivity between S1 and a widespread cortical network that includes the frontoparietal associative cortices. INTERPRETATION: Cerebral correlates of pain processing are found in a similar network in controls and patients in MCS but are much more widespread than in patients in PVS. These findings might be objective evidence of a potential pain perception capacity in patients in MCS, which supports the idea that these patients need analgesic treatment. [less ▲]

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See detailConsciousness and cerebral baseline activity fluctuations
Boly, Mélanie ULg; Phillips, Christophe ULg; Balteau, Evelyne ULg et al

in Human Brain Mapping (2008), 29

The origin of within-subject variability in perceptual experiments is poorly understood. We here review evidence that baseline brain activity in the areas involved in sensory perception predict subsequent ... [more ▼]

The origin of within-subject variability in perceptual experiments is poorly understood. We here review evidence that baseline brain activity in the areas involved in sensory perception predict subsequent variations in sensory awareness. We place these findings in light of recent findings on the architecture of spontaneous BOLD fluctuations in the awake human brain, and discuss the possible origins of the observed baseline brain activity fluctuations. [less ▲]

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See detailBoth the hippocampus and striatum are involved in consolidation of motor sequence memory.
Albouy, Geneviève ULg; Sterpenich, Virginie ULg; Balteau, Evelyne ULg et al

in Neuron (2008), 58(2), 261-72

Functional magnetic resonance imaging (fMRI) was used to investigate the cerebral correlates of motor sequence memory consolidation. Participants were scanned while training on an implicit oculomotor ... [more ▼]

Functional magnetic resonance imaging (fMRI) was used to investigate the cerebral correlates of motor sequence memory consolidation. Participants were scanned while training on an implicit oculomotor sequence learning task and during a single testing session taking place 30 min, 5 hr, or 24 hr later. During training, responses observed in hippocampus and striatum were linearly related to the gain in performance observed overnight, but not over the day. Responses in both structures were significantly larger at 24 hr than at 30 min or 5 hr. Additionally, the competitive interaction observed between these structures during training became cooperative overnight. These results stress the importance of both hippocampus and striatum in procedural memory consolidation. Responses in these areas during training seem to condition the overnight memory processing that is associated with a change in their functional interactions. These results show that both structures interact during motor sequence consolidation to optimize subsequent behavior. [less ▲]

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See detailMesurer la douleur chez le patient non communicant.
Chatelle, Camille ULg; Vanhaudenhuyse, Audrey ULg; Mergam, Anne-Nora ULg et al

in Revue Médicale de Liège (2008), 63(5-6), 429-37

Pain is a subjective experience. Its assessment is based on the subject's direct verbal report. This method of assessment is, however, impossible in patients who cannot communicate their feelings. In this ... [more ▼]

Pain is a subjective experience. Its assessment is based on the subject's direct verbal report. This method of assessment is, however, impossible in patients who cannot communicate their feelings. In this context, indirect measurements such as behavioral observations or physiological measurements are needed. To facilitate the assessment of pain in non-communicative patients, numerous standardized behavioral scales have been developed. The aim of this review is to discuss the main validated pain scales employed in end-stage dementia, newborn and preverbal children, and severely brain damaged patients with a disorder of consciousness such as coma, the vegetative state or the minimally conscious state. [less ▲]

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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 detailBaseline brain activity fluctuations predict somatosensory perception in humans
Boly, Mélanie ULg; Balteau, Evelyne ULg; Schnakers, Caroline ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (2007), 104(29), 12187-12192

In perceptual experiments, within-individual fluctuations in perception are observed across multiple presentations of the same stimuli, a phenomenon that remains only partially understood. Here, by means ... [more ▼]

In perceptual experiments, within-individual fluctuations in perception are observed across multiple presentations of the same stimuli, a phenomenon that remains only partially understood. Here, by means of thulium-yttrium/aluminum- garnet laser and event-related functional MRI, we tested whether variability in perception of identical stimuli relates to differences in prestimulus, baseline brain activity. Results indicate a positive relationship between conscious perception of low-intensity somatosensory stimuli and immediately preceding levels of baseline activity in medial thalamus and the lateral frontoparietal network, respectively, which are thought to relate to vigilance and "external monitoring." Conversely, there was a negative correlation between subsequent reporting of conscious perception and baseline activity in a set of regions encompassing posterior cingulate/ precuneus and temporoparietal cortices, possibly relating to introspection and self-oriented processes. At nociceptive levels of stimulation, pain-intensity ratings positively correlated with baseline fluctuations in anterior cingulate cortex in an area known to be involved in the affective dimension of pain. These results suggest that baseline brain-activity fluctuations may profoundly modify our conscious perception of the external world. [less ▲]

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See detailCerebral asymmetries in sleep-dependent processes of memory consolidation
Peigneux, Philippe ULg; Schmitz, Remy; Willems, Sylvie ULg

in Learning & Memory (2007), 14(6), 400-406

Preference for previously seen, unfamiliar objects reflects a memory bias on affective judgment, known as the "mere exposure effect" (MEE). Here, we investigated the effect of time, post-exposure sleep ... [more ▼]

Preference for previously seen, unfamiliar objects reflects a memory bias on affective judgment, known as the "mere exposure effect" (MEE). Here, we investigated the effect of time, post-exposure sleep, and the brain hemisphere solicited on preference generalization toward objects viewed in different perspectives. When presented in the right visual field (RVF), which promotes preferential processing in the left hemisphere, same and mirrored exemplars were preferred immediately after exposure. MEE generalized to much dissimilar views after three nights of sleep. Conversely, object presentation in the left visual field (LVF), promoting right hemisphere processing, elicited a MEE for same views immediately after exposure, then for mirror views after sleep. Most importantly, sleep deprivation during the first post-exposure night, although followed by two recovery nights, extinguished MEE for all views in the LVF but not in the RVF. Besides demonstrating that post-exposure time and sleep facilitate the generalization process by which we integrate various representations of an object, our results suggest that mostly in the right hemisphere, sleep may be mandatory to consolidate the memory bias underlying affective preference. These interhemispheric differences tentatively call for a reappraisal of the role of cerebral asymmetries in wake- and sleep-dependent processes of memory consolidation. [less ▲]

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See detailCerebral resting state fluctuations predict somatosensory perception
Boly, Mélanie ULg; Balteau, Evelyne ULg; Schnakers, Caroline ULg et al

in Journal of Neurology (2007, May), 254(Suppl. 3), 42

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See detailThe Role of Sleep in Motor Memory Consolidation assessed by fMRI and MEG
Albouy, Geneviève ULg; Sterpenich, Virginie ULg; Darsaud, Annabelle et al

in Journal of Neuroscience (2007), 27(Suppl. 1),

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See detailTherapeutic use of high-frequency repetitive transcranial magnetic stimulation in stroke.
Hotermans, Christophe; Peigneux, Philippe ULg; Moonen, Gustave ULg et al

in Stroke (2007), 38(2), 253254

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See detailSleep transforms the cerebral trace of declarative memories
Gais, Steffen; Albouy, Geneviève ULg; Boly, Mélanie ULg et al

in Proceedings of the National Academy of Sciences of the United States of America (2007), 104(47), 18778-18783

After encoding, memory traces are initially fragile and have to be reinforced to become permanent. The initial steps of this process occur at a cellular level within minutes or hours. Besides this rapid ... [more ▼]

After encoding, memory traces are initially fragile and have to be reinforced to become permanent. The initial steps of this process occur at a cellular level within minutes or hours. Besides this rapid synaptic consolidation, systems consolidation occurs within a time frame of days to years. For declarative memory, the latter is presumed to rely on an interaction between different brain regions, in particular the hippocampus and the medial prefrontal cortex (mPFC). Specifically, sleep has been proposed to provide a setting that supports such systems consolidation processes, leading to a transfer and perhaps transformation of memories. Using functional MRI, we show that postlearning sleep enhances hippocampal responses during recall of word pairs 48 h after learning, indicating intrahippocampal memory processing during sleep. At the same time, sleep induces a memory-related functional connectivity between the hippocampus and the mPFC. Six months after learning, memories activated the mPFC more strongly when they were encoded before sleep, showing that sleep leads to long-lasting changes in the representation of memories on a systems level. [less ▲]

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See detailTask-related interaction between basal ganglia and cortical dopamine release.
Garraux, Gaëtan ULg; Peigneux, Philippe ULg; Carson, Richard E et al

in Journal of Neuroscience (2007), 27(52), 14434-41

Dopamine (DA) is a powerful neuromodulator for a wide variety of behaviors. Considerable evidence accumulated from rodent and monkey experiments over the last two decades suggests that DA activity in the ... [more ▼]

Dopamine (DA) is a powerful neuromodulator for a wide variety of behaviors. Considerable evidence accumulated from rodent and monkey experiments over the last two decades suggests that DA activity in the frontal cortex is reciprocally linked to that in functionally related basal ganglia (BG) structures. However, the functional importance of this in humans is still unknown. To address this issue, we measured endogenous DA release using positron emission tomography in 15 healthy subjects as they practiced the first training session of a finger sequence learning task. Significant results were observed not only in striatal areas but also in extrastriatal "motor" regions, bilaterally. Faster learning was specifically coupled to lower DA release in the sensorimotor part of the globus pallidus pars interna (GPi) contralateral to the moving hand, which was paralleled by a higher increase in DA levels in the pre-supplementary motor area (pre-SMA). This finding provides original evidence supporting a motor-learning-related interaction between DA release in left GPi and pre-SMA, a mechanism that may also apply to other anatomically and functionally interconnected BG and frontal cortical areas as a function of behavior. [less ▲]

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See detailThe role of sleep in motor memory consolidation assessed by fMRI
Albouy, Geneviève ULg; Sterpenich, Virginie ULg; Darsaud, A. et al

in Journal of Sleep Research (2006, September), 15(Suppl. 1), 189

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