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See detailThe neural substrate of orientation working memory
Cornette, Luc; Dupont, Patrick; Salmon, Eric ULg et al

in Journal of Cognitive Neuroscience (2001), 13(6), 813-828

We have used positron emission tomography (PET) to identify the neural substrate of two major cognitive components of working memory (WM), maintenance and manipulation of a single elementary visual ... [more ▼]

We have used positron emission tomography (PET) to identify the neural substrate of two major cognitive components of working memory (WM), maintenance and manipulation of a single elementary visual attribute, i.e., the orientation of a grating presented in central vision. This approach allowed us to equate difficulty across tasks and prevented subjects from using verbal strategies or vestibular cues. Maintenance of orientations involved a distributed fronto-parietal network, that is, left and right lateral superior frontal sulcus (SFSl), bilateral ventrolateral prefrontal cortex (VLPFC), bilateral precuneus, and right superior parietal lobe (SPL). A more medial superior frontal sulcus region (SFSm) was identified as being instrumental in the manipulative operation of updating orientations retained in the WM. Functional connectivity analysis revealed that orientation WM relies on a coordinated interaction between frontal and parietal regions. In general, the current findings confirm the distinction between maintenance and manipulative processes, highlight the functional heterogeneity in the prefrontal cortex (PFC), and suggest a more dynamic view of WM as a process requiring the coordinated interaction of anatomically distinct brain areas. [less ▲]

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See detailNeural substrates of cognitive switching and inhibition in a face processing task.
Piguet, Camille; Sterpenich, Virginie; Desseilles, Martin ULg et al

in NeuroImage (2013), 82

We frequently need to change our current occupation, an operation requiring additional effortful cognitive demands. Switching from one task to another may involve two distinct processes: inhibition of the ... [more ▼]

We frequently need to change our current occupation, an operation requiring additional effortful cognitive demands. Switching from one task to another may involve two distinct processes: inhibition of the previously relevant task-set, and initiation of a new one. Here we tested whether these two processes are underpinned by separate neural substrates, and whether they differ depending on the nature of the task and the emotional content of stimuli. We used functional magnetic resonance imaging in healthy human volunteers who categorize emotional faces according to three different judgment rules (color, gender, or emotional expression). Our paradigm allowed us to separate neural activity associated with inhibition and switching based on the sequence of the tasks required on successive trials. We found that the bilateral medial superior parietal lobule and left intraparietal sulcus showed consistent activation during switching regardless of the task. On the other hand, no common region was activated (or suppressed) as a consequence of inhibition across all tasks. Rather, task-specific effects were observed in brain regions that were more activated when switching to a particular task but less activated after inhibition of the same task. In addition, compared to other conditions, the emotional task elicited a similar switching cost but lower inhibition cost, accompanied by selective decrease in the anterior cingulate cortex when returning to this task shortly after inhibiting it. These results demonstrate that switching relies on domain-general processes mediated by postero-medial parietal areas, engaged across all tasks, but also provide novel evidence that task inhibition produces domain-specific decreases as a function of particular task demands, with only the latter inhibition component being modulated by emotional information. [less ▲]

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See detailNeural substrates of cognitive switching and inhibition in a face processing task. Abstract Book of the conference .
Piguet, Camille; Sterpenich, Virginie; Desseilles, Martin ULg et al

Conference (2010, April)

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See detailNeural substrates of cognitive switching and inhibition in a face processing task. Abstract Book of the conference.
Piguet, Camille; Sterpenich, Virginie; Desseilles, Martin ULg et al

Conference (2010, January)

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See detailThe Neural Substrates of Memory Suppression: A fMRI Exploration of Directed Forgetting
Bastin, Christine ULg; Feyers, Dorothée ULg; Majerus, Steve ULg et al

in PLoS ONE (2012), 7(1), 29905

The directed forgetting paradigm is frequently used to determine the ability to voluntarily suppress information. However, little is known about brain areas associated with information to forget. The ... [more ▼]

The directed forgetting paradigm is frequently used to determine the ability to voluntarily suppress information. However, little is known about brain areas associated with information to forget. The present study used functional magnetic resonance imaging to determine brain activity during the encoding and retrieval phases of an item-method directed forgetting recognition task with neutral verbal material in order to apprehend all processing stages that information to forget and to remember undergoes. We hypothesized that regions supporting few selective processes, namely recollection and familiarity memory processes, working memory, inhibitory and selection processes should be differentially activated during the processing of to-be-remembered and to-be-forgotten items. Successful encoding and retrieval of items to remember engaged the entorhinal cortex, the hippocampus, the anterior medial prefrontal cortex, the left inferior parietal cortex, the posterior cingulate cortex and the precuneus; this set of regions is well known to support deep and associative encoding and retrieval processes in episodic memory. For items to forget, encoding was associated with higher activation in the right middle frontal and posterior parietal cortex, regions known to intervene in attentional control. Items to forget but nevertheless correctly recognized at retrieval yielded activation in the dorsomedial thalamus, associated with familiarity-based memory processes and in the posterior intraparietal sulcus and the anterior cingulate cortex, involved in attentional processes. [less ▲]

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See detailNeural substrates of phonological and lexicosemantic representations in Alzheimer's disease.
Peters, Frederic; Majerus, Steve ULg; Collette, Fabienne ULg et al

in Human Brain Mapping (2009), 30(1), 185-99

The language profile of patients suffering from Alzheimer's disease (AD) is characterized not only by lexicosemantic impairments but also by phonological deficits, as shown by an increasing number of ... [more ▼]

The language profile of patients suffering from Alzheimer's disease (AD) is characterized not only by lexicosemantic impairments but also by phonological deficits, as shown by an increasing number of neuropsychological studies. This study explored the functional neural correlates underlying phonological and lexicosemantic processing in AD. Using H(215)O PET functional brain imaging, a group of mild to moderate AD patients and a group of age-matched controls were asked to repeat four types of verbal stimuli: words, wordlike nonwords (WL+), non-wordlike nonwords (WL-) and simple vowels. The comparison between the different conditions allowed us to determine brain activation preferentially associated with lexicosemantic or phonological levels of language representations. When repeating words, AD patients showed decreased activity in the left temporo-parietal and inferior frontal regions relative to controls, consistent with distorted lexicosemantic representations. Brain activity was abnormally increased in the right superior temporal area during word repetition, a region more commonly associated with perceptual-phonological processing. During repetition of WL+ and WL- nonwords, AD patients showed decreased activity in the middle part of the superior temporal gyrus, presumably associated with sublexical phonological information; at the same time, AD patients showed larger activation than controls in the inferior temporal gyrus, typically associated with lexicosemantic levels of representation. Overall, the results suggest that AD patients use altered pathways to process phonological and lexicosemantic information, possibly related to a progressive loss of specialization of phonological and lexicosemantic neural networks. [less ▲]

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See detailNeural substrates of recollection and familiarity in Alzheimer’s disease
Genon, Sarah ULg; Salmon, Eric ULg; Collette, Fabienne ULg et al

in Proceedings of the 16th annual meeting of the Organization for Human Brain Mapping (2010)

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See detailNeural substrates of rumination tendency in non-depressed individuals.
Piguet, Camille; Desseilles, Martin ULg; Sterpenich, Virginie et al

in Biological psychology (2014), 103

The tendency to ruminate, experienced by both healthy individuals and depressed patients, can be quantified by the Ruminative Response Scale (RRS). We hypothesized that brain activity associated with ... [more ▼]

The tendency to ruminate, experienced by both healthy individuals and depressed patients, can be quantified by the Ruminative Response Scale (RRS). We hypothesized that brain activity associated with rumination tendency might not only occur at rest but also persist to some degree during a cognitive task. We correlated RRS with whole-brain fMRI data of 20 healthy subjects during rest and during a face categorization task with different levels of cognitive demands (easy or difficult conditions). Our results reveal that the more subjects tend to ruminate, the more they activate the left entorhinal region, both at rest and during the easy task condition, under low attentional demands. Conversely, lower tendency to ruminate correlates with greater activation of visual cortex during rest and activation of insula during the easy task condition. These results indicate a particular neural marker of the tendency to ruminate, corresponding to increased spontaneous activity in memory-related areas, presumably reflecting more internally driven trains of thoughts even during a concomitant task. Conversely, people who are not prone to ruminate show more externally driven activity. [less ▲]

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See detailThe neural substrates of the central executive: Exploration of the updating and shifting processes
Collette, Fabienne ULg; Van der Linden, Martial ULg; Delchambre, Marie et al

Conference (2002, September)

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See detailThe neural substrates of the central executive: Exploration of the updating and shifting processes
Collette, Fabienne ULg; Van der Linden, Martial ULg; Delchambre, Marie et al

Conference (2002, December)

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See detailNeural substrates of the tendency of individuals to ruminate. Abstract Book of the conference.
Piguet, Camille; Sterpenich, Virginie; Desseilles, Martin ULg et al

Conference (2010, May 27)

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See detailNeural substrates of the tendency of individuals to ruminate. Abstract Book of the congress.
Piguet, Camille; Sterpenich, Virginie; Desseilles, Martin ULg et al

Conference (2010, June 10)

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See detailNeurally adjusted ventilatory assist (NAVA) improves patient-ventilator interaction during non-invasive ventilation delivered by face mask
Piquilloud, L; Tassaux, D; Bialais, E et al

in Intensive Care Medicine (2012)

PURPOSE: To determine if, compared to pressure support (PS), neurally adjusted ventilatory assist (NAVA) reduces patient-ventilator asynchrony in intensive care patients undergoing noninvasive ventilation ... [more ▼]

PURPOSE: To determine if, compared to pressure support (PS), neurally adjusted ventilatory assist (NAVA) reduces patient-ventilator asynchrony in intensive care patients undergoing noninvasive ventilation with an oronasal face mask. METHODS: In this prospective interventional study we compared patient-ventilator synchrony between PS (with ventilator settings determined by the clinician) and NAVA (with the level set so as to obtain the same maximal airway pressure as in PS). Two 20-min recordings of airway pressure, flow and electrical activity of the diaphragm during PS and NAVA were acquired in a randomized order. Trigger delay (T(d)), the patient's neural inspiratory time (T(in)), ventilator pressurization duration (T(iv)), inspiratory time in excess (T(iex)), number of asynchrony events per minute and asynchrony index (AI) were determined. RESULTS: The study included 13 patients, six with COPD, and two with mixed pulmonary disease. T(d) was reduced with NAVA: median 35 ms (IQR 31-53 ms) versus 181 ms (122-208 ms); p = 0.0002. NAVA reduced both premature and delayed cyclings in the majority of patients, but not the median T(iex) value. The total number of asynchrony events tended to be reduced with NAVA: 1.0 events/min (0.5-3.1 events/min) versus 4.4 events/min (0.9-12.1 events/min); p = 0.08. AI was lower with NAVA: 4.9 % (2.5-10.5 %) versus 15.8 % (5.5-49.6 %); p = 0.03. During NAVA, there were no ineffective efforts, or late or premature cyclings. PaO(2) and PaCO(2) were not different between ventilatory modes. CONCLUSION: Compared to PS, NAVA improved patient ventilator synchrony during noninvasive ventilation by reducing T(d) and AI. Moreover, with NAVA, ineffective efforts, and late and premature cyclings were absent. [less ▲]

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See detailNeurally Adjusted Ventilatory Assist (NAVA) improves the matching of diaphragmatic electrical activity and tidal volume in comparison to pressure support (PS)
Piquilloud, L; Chiew, YS; Bialais, E et al

in Intensive Care Medicine (2011), 37 (Suppl 1)

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See detailNeuregulin signaling regulates neural precursor growth and the generation of oligodendrocytes in vitro
Calaora, Viviane; Rogister, Bernard ULg; Bismuth, Karen et al

in Journal of Neuroscience (2001), 21

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See detailNeuregulin-1 modulates the differentiation of neural stem cells in vitro trough an interaction with the Swi/Snf complex.
Pirotte, Dorothée ULg; Wislet, Sabine ULg; cloes, J. M. et al

in Molecular & Cellular Neuroscience [=MCN] (2010)

The neuregulin-1 (Nrg-1) gene is translated into several protein isoforms, which are either secreted or membrane-anchored. In vitro, neural stem cells (NSC) express mainly the cystein-rich-domain NRG (CRD ... [more ▼]

The neuregulin-1 (Nrg-1) gene is translated into several protein isoforms, which are either secreted or membrane-anchored. In vitro, neural stem cells (NSC) express mainly the cystein-rich-domain NRG (CRD-NRG) isoform, a membrane-anchored type III form. This isoform exhibits a cystein-rich-domain, which constitutes a second transmembrane domain and can be cleaved to release both a signaling EGF-containing domain (ECD) at the cell surface and an intracellular domain (ICD). The main goal of this paper was to determine the exact role of ECD and ICD in NSC survival and differentiation. Using an siRNA approach, we demonstrated that CRD-NRG inhibition was followed by a decrease in NSC proliferation and of neuronal or oligodendroglial differentiation. Overexpression of ICD but not ECD was followed by a decrease in NSC proliferation and an increase in neuronal and oligodendroglial differentiation. Moreover, we showed that ICD physically interacted in cultured NSC with BRM and BAF57, two members of the Swi/Snf remodeling complex, and that ICD stimulation of neuronal cell differentiation is dependent on the presence of BAF57. [less ▲]

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See detailNeuro-imagerie des conduites suicidaires
Desseilles, Martin ULg

Scientific conference (2012, November 08)

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See detailNeuro-imagerie des conduites suicidaires.
Desseilles, Martin ULg

Scientific conference (2011, October 13)

Detailed reference viewed: 8 (0 ULg)
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See detailNeuro-imagerie et biomarqueurs dans les démences corticales
Salmon, Eric ULg; Collette, Fabienne ULg; Bastin, Christine ULg

in Amieva, Hélène; Belliard, Serge; Salmon, Eric (Eds.) Les démences : Aspects cliniques, neuropsychologiques, physiopathologiques et thérapeutiques (2014)

Detailed reference viewed: 21 (0 ULg)