References of "Maquet, Pierre"
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See detailIntrinsic brain activity in altered states of consciousness: how conscious is the default mode of brain function?
Boly, Mélanie ULg; Phillips, Christophe ULg; Tshibanda, Luaba ULg et al

in Annals of the New York Academy of Sciences (2008), 1129

Spontaneous brain activity has recently received increasing interest in the neuroimaging community. However, the value of resting-state studies to a better understanding of brain-behavior relationships ... [more ▼]

Spontaneous brain activity has recently received increasing interest in the neuroimaging community. However, the value of resting-state studies to a better understanding of brain-behavior relationships has been challenged. That altered states of consciousness are a privileged way to study the relationships between spontaneous brain activity and behavior is proposed, and common resting-state brain activity features observed in various states of altered consciousness are reviewed. Early positron emission tomography studies showed that states of extremely low or high brain activity are often associated with unconsciousness. However, this relationship is not absolute, and the precise link between global brain metabolism and awareness remains yet difficult to assert. In contrast, voxel-based analyses identified a systematic impairment of associative frontoparieto-cingulate areas in altered states of consciousness, such as sleep, anesthesia, coma, vegetative state, epileptic loss of consciousness, and somnambulism. In parallel, recent functional magnetic resonance imaging studies have identified structured patterns of slow neuronal oscillations in the resting human brain. Similar coherent blood oxygen level-dependent (BOLD) systemwide patterns can also be found, in particular in the default-mode network, in several states of unconsciousness, such as coma, anesthesia, and slow-wave sleep. The latter results suggest that slow coherent spontaneous BOLD fluctuations cannot be exclusively a reflection of conscious mental activity, but may reflect default brain connectivity shaping brain areas of most likely interactions in a way that transcends levels of consciousness, and whose functional significance remains largely in the dark. [less ▲]

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See detailBrain function in physiologically, pharmacologically, and pathologically altered states of consciousness
Boveroux, Pierre ULg; Bonhomme, Vincent ULg; Vanhaudenhuyse, Audrey ULg et al

in International Anesthesiology Clinics (2008), 46(3), 131-146

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See detailOffline processing of memories induced by perceptual visual learning during subsequent wakefulness and sleep: A behavioral study.
Matarazzo, Luca ULg; Franko, Edit; Maquet, Pierre ULg et al

in Journal of Vision (2008), 8(4), 71-9

To further characterize perceptual memory consolidation during sleep, we used a coarse orientation discrimination task in which participants had to discriminate the orientation of orthogonal gratings ... [more ▼]

To further characterize perceptual memory consolidation during sleep, we used a coarse orientation discrimination task in which participants had to discriminate the orientation of orthogonal gratings occluded by increasing levels of noise. In a first study (N = 11), we showed that the learning effect in this task is retinotopic (position-specific) and orientation specific. In a second experiment, we assessed the effect of nocturnal sleep, as opposed to the effect of time, on perceptual learning. A first group of participants was trained in the morning, tested in the evening and retested the next morning (morning-evening-morning, MEM, N = 11); a second group was trained in the evening, tested the next morning, and retested in the evening (evening-morning-evening; EME; N = 12). Between training and testing, EME subjects improved significantly more (after a night of sleep) than MEM subjects (after 12 waking hours). Similarly, between test and retest, performance of MEM subjects (after a full night of sleep) improved significantly more than in EME subjects (after 12 further waking hours). These results suggest a beneficial effect of sleep on coarse orientation discrimination. Further studies are needed to characterize the neural correlates of this perceptual learning and the offline consolidation of perceptual memory. [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 detailWhen thoughts become action: An fMRI paradigm to study volitional brain activity in non-communicative brain injured patients
Boly, Mélanie ULg; Coleman, M. R.; Davis, M. H. et al

in NeuroImage (2007), 36(3), 979-992

The assessment of voluntary behavior in non-communicative brain injured patients is often challenging due to the existence of profound motor impairment. In the absence of a full understanding of the ... [more ▼]

The assessment of voluntary behavior in non-communicative brain injured patients is often challenging due to the existence of profound motor impairment. In the absence of a full understanding of the neural correlates of consciousness, even a normal activation in response to passive sensory stimulation cannot be considered as proof of the presence of awareness in these patients. In contrast, predicted activation in response to the instruction to perform a mental imagery task would provide evidence of voluntary task-dependent brain activity, and hence of consciousness, in non-communicative patients. However, no data yet exist to indicate which imagery instructions would yield reliable single subject activation. The aim of the present study was to establish such a paradigm in healthy volunteers. Two exploratory experiments evaluated the reproducibility of individual brain activation elicited by four distinct mental imagery tasks. The two most robust mental imagery tasks were found to be spatial navigation and motor imagery. In a third experiment, where these two tasks were directly compared, differentiation of each task from one another and from rest periods was assessed blindly using a priori criteria and was correct for every volunteer. The spatial navigation and motor imagery tasks described here permit the identification of volitional brain activation at the single subject level, without a motor response. Volunteer as well as patient data [Owen, A. M., Coleman, M.R., Boly, M., Davis, M.H., Laureys, S., Pickard J.D., 2006. Detecting awareness in the vegetative state. Science 313, 1402] strongly suggest that this' paradigm may provide a method for assessing the presence of volitional brain activity, and thus of consciousness, in non-communicative brain-injured patients. (c) 2007 Elsevier Inc. All rights reserved. [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 detailActive brain processes during human quiescent sleep: an EEG/fMRI study of non-REM slow oscillations
Dang-Vu, T.; Schabus, M.; Desseilles, Martin ULg et al

in Journal of Neurology (2007, May), 254(Suppl. 3), 50

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See detailfMRI study of hypnosis-induced analgesia
Boly, Mélanie ULg; Balteau, Evelyne ULg; Schnakers, Caroline ULg et al

in Journal of Neurology (2007, May), 254(Suppl. 3), 38-39

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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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See detailFASST - fMRI Artefact rejection and Sleep Scoring Toolbox
Phillips, Christophe ULg; Schrouff, Jessica ULg; Coppieters, Dorothée ULg et al

Software (2007)

"FASST" stands for "fMRI Artefact rejection and Sleep Scoring Toolbox". This M/EEG toolbox is developed by researchers from the Cyclotron Research Centre, University of Li ege, Belgium, with the financial ... [more ▼]

"FASST" stands for "fMRI Artefact rejection and Sleep Scoring Toolbox". This M/EEG toolbox is developed by researchers from the Cyclotron Research Centre, University of Li ege, Belgium, with the financial support of the Fonds de la Recherche Scienti que-FNRS, the Queen Elizabeth's funding, and the University of Li ege. On Dr. Pierre Maquet's impulse we started writing these tools to analyze our sleep EEG-fMRI data and tackle four crucial issues: * Continuous M/EEG. Long multi-channel recording of M/EEG data can be enormous. These data are cumbersome to handle as it usually involves displaying, exploring, comparing, chunking, appending data sets, etc. * EEG-fMRI. When recording EEG and fMRI data simultaneously, the EEG signal acquired contains, on top of the usual neural and ocular activity, artefacts induced by the gradient switching and high static eld of an MR scanner. The rejection of theses artefacts is not easy especially when dealing with brain spontaneous activity. * Scoring M/EEG. Reviewing and scoring continuous M/EEG recordings, such as is common with sleep recordings, is a tedious task as the scorer has to manually browse through the entire data set and give a \score" to each time-window displayed. * Waves detection. Continuous and triggerless recordings of M/EEG data show specifi c wave patterns, characteristic of the subject's state (e.g., sleep spindles or slow waves). Their automatic detection is thus important to assess those states. [less ▲]

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See detailWavelength-dependent modulation of brain responses to a working memory task by daytime light exposure
Vandewalle, Gilles ULg; Gais, S.; Schabus, Manuel ULg et al

in Cerebral Cortex (2007), 17(12), 2788-2795

In addition to classical visual effects, light elicits nonvisual brain responses, which profoundly influence physiology and behavior. These effects are mediated in part by melanopsin-expressing light ... [more ▼]

In addition to classical visual effects, light elicits nonvisual brain responses, which profoundly influence physiology and behavior. These effects are mediated in part by melanopsin-expressing light-sensitive ganglion cells that, in contrast to the classical photopic system that is maximally sensitive to green light (550 nm), is very sensitive to blue light (470-480 nm). At present, there is no evidence that blue light exposure is effective in modulating nonvisual brain activity related to complex cognitive tasks. Using functional magnetic resonance imaging, we show that, while participants perform an auditory working memory task, a short (18 min) daytime exposure to blue (470 nm) or green (550 nm) monochromatic light (3 x 10(13) photons/cm(2)/s) differentially modulates regional brain responses. Blue light typically enhanced brain responses or at least prevented the decline otherwise observed following green light exposure in frontal and parietal cortices implicated in working memory, and in the thalamus involved in the modulation of cognition by arousal. Our results imply that monochromatic light can affect cognitive functions almost instantaneously and suggest that these effects are mediated by a melanopsin-based photoreceptor system. [less ▲]

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See detailEffects of attention on emotional face processing in depression : a functional MRI study
Desseilles, Martin; Maquet, Pierre ULg; Dang Vu, Thien Thanh et al

Poster (2007)

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See detailSleep deprivation on the post-encoding night modifies the neural correlates of retrieval of emotional memories 6 months later
Sterpenich, Virginie ULg; Albouy, Geneviève ULg; Darsaud, Annabelle et al

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

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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 detailEvaluation comportementale et par neuroimagerie fonctionnelle des patients en état végétatif
Vanhaudenhuyse, Audrey ULg; Schnakers, Caroline ULg; Boly, Mélanie ULg et al

in Revue Médicale de Liège (2007), 62 Spec No

Currently, there remains a high rate of misdiagnosis of the vegetative state. This should incite clinicians to use the most sensitive "coma scales" to detect signs of consciousness in these patients. The ... [more ▼]

Currently, there remains a high rate of misdiagnosis of the vegetative state. This should incite clinicians to use the most sensitive "coma scales" to detect signs of consciousness in these patients. The gold standard remains the Glasgow Coma Scale (GCS, Teasdale and Jennet, 1974), with the Glasgow Liege Scale (GLS, Born, 1988) adding standardized assessment of brainstem reflexes. New sensible behavioral assessment tools for use in the acute neurocritical care setting include the Full Outline of UnResponsiveness (FOUR, Wijdicks et al., 2005). The Coma Recovery Scale-Revised (CRS-R, Giacino and Kalmar, 2004) specifically tests the diagnostic criteria differentiating vegetative from minimally conscious patients. Detecting signs of consciousness also depends on the employed methodology. We showed that for the assesment of the presence of visual pursuit, using a moving mirror is better suited than using a moving object or person. The clinical diagnosis can be confirmed by cerebral positron emission tomography studies objectively quantifying residual metabolic activity in vegetative and minimally conscious patients. Ongoing studies evaluate the prognostic value of functional magnetic resonance imaging studies in these challenging patient populations. [less ▲]

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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 detailNeuroimaging of REM sleep and dreaming
Dang Vu, Thien Thanh ULg; Schabus, Manuel; Desseilles, Martin ULg et al

in McNamara, Patrick; Barrett, Deirdre (Eds.) The New Science of Dreaming (2007)

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