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See detailMultifaceted Brain Networks Reconfiguration in Disorders of Consciousness Uncovered by Co-Activation Patterns
Di Perri, Carol ULiege; Amico, Enrico; Heine, Lizette ULiege et al

in Human Brain Mapping (in press)

Introduction: Given that recent research has shown that functional connectivity is not a static phenomenon, we aim to investigate the dynamic properties of the default mode network’s (DMN) connectivity in ... [more ▼]

Introduction: Given that recent research has shown that functional connectivity is not a static phenomenon, we aim to investigate the dynamic properties of the default mode network’s (DMN) connectivity in patients with disorders of consciousness. Methods: Resting-state fMRI volumes of a convenience sample of 17 patients in unresponsive wakefulness syndrome (UWS) and controls were reduced to a spatiotemporal point process by selecting critical time points in the posterior cingulate cortex (PCC). Spatial clustering was performed on the extracted PCC time frames to obtain 8 different co-activation patterns (CAPs). We investigated spatial connectivity patterns positively and negatively correlated with PCC using both CAPs and standard stationary method. We calculated CAPs occurrences and the total number of frames. Results: Compared to controls, patients showed (i) decreased within-network positive correlations and between-network negative correlations, (ii) emergence of “pathological” within-network negative correlations and between-network positive correlations (better defined with CAPs), and (iii) “pathological” increases in within-network positive correlations and between-network negative correlations (only detectable using CAPs). Patients showed decreased occurrence of DMN-like CAPs (1–2) compared to controls. No between-group differences were observed in the total number of frames Conclusion: CAPs reveal at a more fine-grained level the multifaceted spatial connectivity reconfiguration following the DMN disruption in UWS patients, which is more complex than previously thought and suggests alternative anatomical substrates for consciousness. BOLD fluctuations do not seem to differ between patients and controls, suggesting that BOLD response represents an intrinsic feature of the signal, and therefore that spatial configuration is more important for consciousness than BOLD activation itself. [less ▲]

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See detailIntensity and memory characteristics of near-death experiences
Martial, Charlotte ULiege; Charland-Verville, Vanessa ULiege; Cassol, Helena ULiege et al

in Consciousness & Cognition (in press)

Memories of Near-Death Experiences (NDEs) seem to be very detailed and stable over time. At present, there is still no satisfactory explanation for the NDEs’ rich phenomenology. Here we compared ... [more ▼]

Memories of Near-Death Experiences (NDEs) seem to be very detailed and stable over time. At present, there is still no satisfactory explanation for the NDEs’ rich phenomenology. Here we compared phenomenological characteristics of NDE memories with the reported experience’s intensity. We included 152 individuals with a self-reported “classical” NDE (i.e. occurring in life-threatening conditions). All participants completed a mailed questionnaire that included a measure of phenomenological characteristics of memories (the Memory Characteristics Questionnaire; MCQ) and a measure of NDE’s intensity (the Greyson NDE scale). Greyson NDE scale total score was positively correlated with MCQ total score, suggesting that participants who described more intense NDEs also reported more phenomenological memory characteristics of NDE. Using MCQ items, our study also showed that NDE’s intensity is associated in particular with sensory details, personal importance and reactivation frequency variables. [less ▲]

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See detailLes expériences de mort imminente: le point de vue des neurosciences
Martial, Charlotte ULiege

Conference (2017, September 27)

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See detailCorrigendum: Temporality of Features in Near-Death Experience Narratives
Martial, Charlotte ULiege; Cassol, Helena ULiege; Antonopoulos, Georgios ULiege et al

in Frontiers in Human Neuroscience (2017)

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See detailRôle des psychologues spécialisés en neuropsychologie auprès des patients en état de conscience altérée : état des lieux et perspectives
Wauquiez, Grégoire; Radiguer, François; Stephan, Julie et al

Poster (2017, June 02)

Avec les progrès des techniques de soins intensifs et de réanimation, de nombreuses personnes survivent à des lésions cérébrales graves et peuvent notamment présenter dans les suites un état de conscience ... [more ▼]

Avec les progrès des techniques de soins intensifs et de réanimation, de nombreuses personnes survivent à des lésions cérébrales graves et peuvent notamment présenter dans les suites un état de conscience altérée. La création depuis les années 2000 d’unités spécialisées dites “Etats Végétatifs Chroniques / Etats Pauci-Relationnels” témoigne du développement de l’offre de soin dédiée à ces problématiques complexes. De plus en plus d’études scientifiques sont également publiées chaque année sur le sujet de l’évaluation et de la prise en charge de ces patients (ref1). La question du diagnostic d'état d'éveil non répondant ou d'état de conscience minimale constitue entre autres un enjeu majeur pour proposer à ces patients une stimulation adaptée (ref2). Néanmoins, ce domaine d’intervention paraît aujourd'hui encore modérément investi par les psychologues spécialisés en neuropsychologie, professionnels qui semblent pourtant à même d’y contribuer de manière pertinente de par leurs connaissances et leurs compétences (ref3). Où en sont les pratiques sur le terrain et quelles seraient les perspectives de développement à envisager ? Pour tenter de répondre à ces questions, nous avons diffusé une enquête en ligne à destination des neuropsychologues francophones (Belgique, France, Québec et Suisse) en vue de recueillir des données sur la formation, les activités et les attentes de nos collègues. En parallèle, nous avons réalisé une brève revue de la littérature scientifique sur le sujet et sollicité l’avis d’experts concernant les pratiques et spécificités des neuropsychologues auprès de ces patients. Nos premiers résultats mettent en avant 1°) qu’un nombre non négligeable de psychologues spécialisés en neuropsychologie travaillent auprès de patients en état de conscience altérée, 2°) qu'ils ont des connaissances et une pratique spécifique leur permettant d'apporter un réel bénéfice dans le diagnostic et la prise en charge interdisciplinaire de ces patients, et 3°) que le sujet des états de conscience altérée mériterait une place plus importante dans la formation initiale et continue des neuropsychologues afin de contribuer au développement d’une pratique de haut niveau auprès de ces patients tout à fait particuliers. Ces résultats nous feront discuter des questions de la formation initiale, des variétés de pratiques et de la perspective d’une enquête élargie aux pays non francophones. [less ▲]

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See detailMultimodal imaging analysis in Charles Bonnet Syndrome: a case report
Martial, Charlotte ULiege; Di Perri, Carol ULiege; Larroque, Stephen Karl ULiege et al

Poster (2017, June)

Charles Bonnet syndrome (CBS) is a rare condition characterized by visual impairment associated with complex visual hallucinations in psychologically normal elderly people. Previous studies have suggested ... [more ▼]

Charles Bonnet syndrome (CBS) is a rare condition characterized by visual impairment associated with complex visual hallucinations in psychologically normal elderly people. Previous studies have suggested that visual hallucinations may be caused by brain damage in the visual system. However, in the case of CBS, specific brain regions in the occipital cortex have not been clearly determined and functional neuroimaging remains relatively unexplored. To our knowledge, functional connectivity by means of resting-state magnetic resonance imaging (MRI) has never been investigated in patients with CBS. We here aimed to investigate structural imaging, brain metabolism and functional connectivity in a patient with CBS. Resting-state functional and structural MRI were acquired in an 85-year-old patient with CBS and 12 age- and gender-matched normally sighted controls. Cognitive functioning was measured by behavioral assessment. A seed-based resting state fMRI was performed to investigate the default mode network (DMN), the executive control network and the visual networks connectivity. A voxel-based morphometry (VBM) analysis was employed to investigate the grey matter volume. Cortical and subcortical grey matter thickness were further investigated. Finally, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was also acquired to observe regional glucose uptake by comparing standard uptake values (SUVs). Increased functional connectivity was found between the DMN and the temporo-occipital fusiform cortex, as well as between the secondary visual cortex and the left frontal cortex, in the CBS patient compared to controls. The patient also demonstrated increased functional connectivity between the primary visual cortex and the left supramarginal gyrus and between the associative visual cortex and the superior temporal gyrus/angular gyrus, as compared to controls. Decreased grey matter volume was observed in the lateral occipital cortex/angular gyrus in our patient as compared to controls. Diminished grey matter thickness values were observed in the lateral geniculate nucleus compared to healthy controls. FDG-PET results confirmed previous work and showed bilateral hypometabolism in the occipital cortex (mean SUV reduction of 5.36%, p<0.001). Our results suggest that structural alterations in visual system in CBS are associated with compensatory/adaptive changes in functional connectivity that involve regions known to support hallucinations of faces in CBS patients. We suggest that this functional connectivity reorganization following visual structural damage may contribute to visual hallucinations. These findings might shed light on the pathophysiology underlining this rare condition. [less ▲]

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See detailTemporality of Features in Near-Death Experience Narratives
Martial, Charlotte ULiege; Cassol, Helena ULiege; Antonopoulos, Georgios ULiege et al

in Frontiers in Human Neuroscience (2017)

Background: After an occurrence of a Near-Death Experience (NDE), Near- Death Experiencers (NDErs) usually report extremely rich and detailed narratives. Phenomenologically, a NDE can be described as a ... [more ▼]

Background: After an occurrence of a Near-Death Experience (NDE), Near- Death Experiencers (NDErs) usually report extremely rich and detailed narratives. Phenomenologically, a NDE can be described as a set of distinguishable features. Some authors have proposed regular patterns of NDEs, however, the actual temporality sequence of NDE core features remains a little explored area. Objectives: The aim of the present study was to investigate the frequency distribution of these features (globally and according to the position of features in narratives) as well as the most frequently reported temporality sequences of features. Methods: We collected 154 French freely expressed written NDE narratives (i.e., Greyson NDE scale total score 7/32). A text analysis was conducted on all narratives in order to infer temporal ordering and frequency distribution of NDE features. Results: Our analyses highlighted the following most frequently reported sequence of consecutive NDE features: Out-of-Body Experience, Experiencing a tunnel, Seeing a bright light, Feeling of peace. Yet, this sequence was encountered in a very limited number of NDErs. Conclusion: These findings may suggest that NDEs temporality sequences can vary across NDErs. Exploring associations and relationships among features encountered during NDEs may complete the rigorous definition and scientific comprehension of the phenomenon. [less ▲]

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See detailIs oral feeding compatible with an unresponsive wakefulness syndrome?
MELOTTE, Evelyne ULiege; MAUDOUX, Audrey ULiege; DELHALLE, Sabrina ULiege et al

Conference (2017, May)

INTRODUCTION AND AIMS Vegetative state/Unresponsive wakefulness syndrome (VS/UWS) is defined by the presence of eye-opening and the absence of awareness and voluntary movement (Laureys et al., 2010). VS ... [more ▼]

INTRODUCTION AND AIMS Vegetative state/Unresponsive wakefulness syndrome (VS/UWS) is defined by the presence of eye-opening and the absence of awareness and voluntary movement (Laureys et al., 2010). VS/UWS patients classically receive hydration and nutrition through an enteral feeding tube. We present the cases of two patients that were diagnosed as VS/UWS but were able to resume oral feeding. It is however unclear if the presence of oral feeding is compatible with the diagnosis of VS/UWS or if this observation should lead to a modification of the diagnosis. METHODS AND RESULTS We retrospectively reviewed the clinical information of 65 VS/UWS patients (aged 45±12; range 16-85 years) evaluated at the CHU hospital of Liege searching for mention of oral feeding. VS/UWS diagnosis was made after repeated behavioral assessments using the standardized Coma Recovery Scale–Revised (CRS-R, (Teasdale & Jennet, 1974)) in association with complementary evaluations using neuroimaging techniques. Of the 65 VS/UWS patients, two could resume oral feeding (3%). One could achieve full oral feeding (mixed texture and liquid) and the other had oral feeding (liquid and semi-liquid) in addition to gastrostomy feeding. Neuroimaging evaluations showed in both patients a massive decrease in the spontaneous brain activity and its functional connectivity (using functional magnetic resonance imaging), bilateral cerebral cortex hypometabolism (fronto- parietal associative areas, posterior parietal areas, cingulate cortices, precuneus) and preserved metabolism in the brainstem and cerebellum (using positron emission tomography). CONCLUSIONS Oral feeding is rare in VS/UWS patients (3% in our cohort). Based on neuroimaging results, this behaviour does not seem to be incompatible with the diagnosis of VS/UWS but the neuromecanistic root, which allows this behavior, still needs to be elucidate. This study also emphasizes the importance of systematic swallowing evaluation in patients with altered state of consciousness regardless of their level of consciousness. Moreover, tactile oro-facial stimulation, manual therapy, taste stimulation and therapeutic feeding can be another “gateway” to interact with these patients and improve their quality of life. [less ▲]

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See detailClinical sub-categorization of minimally conscious state according to resting functional connectivity
Aubinet, Charlène ULiege; Heine, Lizette ULiege; Martial, Charlotte ULiege et al

Conference (2017, March 31)

Introduction: Patients in a minimally conscious state (MCS) have been subcategorized in MCS plus and MCS minus, respectively with and without command following capacity. Here we aim to characterize ... [more ▼]

Introduction: Patients in a minimally conscious state (MCS) have been subcategorized in MCS plus and MCS minus, respectively with and without command following capacity. Here we aim to characterize differences in MCS plus as compared to MCS minus by means of functional connectivity (FC). Method: Resting state functional magnetic resonance imagery (fMRI) was acquired in 292 MCS patients and a seed-based analysis was conducted on a convenience sample of 19 MCS patients (10 MCS plus and 9 MCS minus) and 35 healthy controls. We investigated the left and right frontoparietal networks (FPN), the auditory network and the default mode network (DMN). We employed a ROI-to-ROI analysis to investigate the inter-hemispheric connectivity and we investigated inter-group differences in grey and white matter volume by means of voxel-based morphometry. Results: We found a higher FC in MCS plus as compared to MCS minus in the left FPN, specifically between the left dorso-lateral prefrontal cortex and the left temporo-occipital fusiform cortex (TOFC). The FC of auditory network, right FPN and DMN, inter-hemispheric connectivity and structure of grey and white matter did not show differences between patients groups. Discussion: Our results suggest that the clinical sub-categorization of MCS is sustained by FC differences in a language-related executive control network. MCS plus and MCS minus patients are not differentiated by networks involved in auditory processing, perception of surroundings and internal thoughts, nor by differences in inter-hemispheric connectivity and in morphology. [less ▲]

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See detailNear-death experiences: recent findings
Martial, Charlotte ULiege

Conference (2017, March)

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See detailCan science explain consciousness? Lessons from coma and related states
Martial, Charlotte ULiege

Conference (2017, March)

Understanding consciousness remains one of the greatest mysteries for science to solve. How do our brains work? How can we know if some patients in coma have any consciousness left and how could we ... [more ▼]

Understanding consciousness remains one of the greatest mysteries for science to solve. How do our brains work? How can we know if some patients in coma have any consciousness left and how could we communicate with them? What are near-death experiences? What is brain death? What happens in our brains during dreaming, hypnosis or meditation? At present, nobody understands how matter (our trillions of neural connections) becomes perception and thought. We will here briefly review some neurological facts on consciousness and impaired consciousness. Thanks to recent advances in (neuroimaging) technology, the mapping of conscious perception and cognition in health (e.g., conscious waking, sleep, dreaming, hypnosis, meditation, sleepwalking and anesthesia) and in disease (e.g., coma, near-death, “vegetative” state, seizures, hallucinations etc) is providing exiting new insights into the functional neuroanatomy of human consciousness. Our perception of the outside world (sensory awareness; what we see, hear, etc.) and our awareness of an inner world (self-awareness; the little "voice" inside that "speaks" to ourselves) seemingly depend on two separate networks we could recently identify. Philosophers might argue that the subjective aspect of the mind will never be sufficiently accounted for by the objective methods of reductionistic science. We here prefer a more pragmatic approach and remain naively optimistic that technological advances might ultimately lead to an understanding of the neural substrate of human consciousness. [less ▲]

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See detailApplication of Qualitative Thematic Analysis to Near-Death Experiences
Cassol, Helena ULiege; Pétré, Benoît ULiege; Degrange, Sophie ULiege et al

Poster (2017, February 01)

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See detailCharacterization of minimally conscious state minus and plus according to resting functional connectivity
Aubinet, Charlène ULiege; Heine, Lizette; Martial, Charlotte ULiege et al

Scientific conference (2017, February 01)

The minimally conscious state (MCS) has been sub-categorized in MCS plus and MCS minus, i.e. respectively with and without command following capacity. Here we aimed at characterizing differences in MCS ... [more ▼]

The minimally conscious state (MCS) has been sub-categorized in MCS plus and MCS minus, i.e. respectively with and without command following capacity. Here we aimed at characterizing differences in MCS plus as compared to MCS minus by means of functional connectivity (FC). Resting state functional magnetic resonance imagery (fMRI) was acquired in 292 MCS patients and a seed-based analysis was conducted on a convenience sample of 19 MCS patients (10 MCS plus and 9 MCS minus) and 35 healthy controls. We investigated the left and right frontoparietal networks (FPN), the auditory network and the default mode network (DMN). We employed a ROI-to-ROI analysis and a voxel-based morphometry in order to investigate the inter-hemispheric connectivity and the grey and white matter volume, respectively. A significantly higher FC was found in MCS plus as compared to MCS minus in the left FPN, specifically between the left dorso-lateral prefrontal cortex and the left temporo-occipital fusiform cortex (TOFC). The FC of auditory network, right FPN and DMN, inter-hemispheric connectivity and structure of grey and white matter did not show differences between patients groups. The clinical sub-categorization of MCS is therefore sustained by FC differences in a language-related executive control network. These patient groups are not differentiated by networks involved in auditory processing, perception of surroundings and internal thoughts, nor by differences in inter-hemispheric connectivity and in morphology. [less ▲]

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See detailNear-death experiences: actual considerations.
Charland-Verville, Vanessa ULiege; Martial, Charlotte ULiege; Cassol, Helena ULiege et al

in Schnakers, Caroline; Laureys, Steven (Eds.) Coma and Disorders of Consciousness, Second Edition (2017)

The notion that death represents a passing to an afterlife, where we are reunited with loved ones and live eternally in a utopian paradise, is common in the anecdotal reports of people who have ... [more ▼]

The notion that death represents a passing to an afterlife, where we are reunited with loved ones and live eternally in a utopian paradise, is common in the anecdotal reports of people who have encountered a “near-death experience” (NDE). These experiences are usually portrayed as being extremely pleasant including features such as a feeling of peacefulness, the vision of a dark tunnel leading to a brilliant light, the sensation of leaving the body, or the experience of a life review. NDEs are increasingly being reported as a clearly identifiable physiological and psychological reality of clinical and scientific significance. The definition and causes of the phenomenon as well as the identification of NDE experiencers are still matters of debate. The phenomenon has been thoroughly portrayed by the media, but the science of NDEs is rather recent and still lacking of rigorous experimental data and reproducible controlled experiments. It seems that the most appropriate theories to explain the phenomenon tend to integrate both psychological and neurobiological mechanisms. The paradoxical dissociation between the richness and intensity of the memory, probably occurring during a moment of brain dysfunction, offers a unique opportunity to better understand the neural correlates of consciousness. In this chapter, we will attempt to describe NDEs and the methods to identify them. We will also briefly discuss the NDE experiencers’ characteristics. We will then address the main current explicative models and the science of NDEs. [less ▲]

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See detailFalse memory susceptibility in coma survivors with and without a near-death experience
Martial, Charlotte ULiege; Charland-Verville, Vanessa ULiege; Dehon, Hedwige ULiege et al

in Psychological Research (2017)

It has been postulated that memories of neardeath experiences (NDEs) could be (at least in part) reconstructions based on experiencers’ (NDErs) previous knowledge and could be built as a result of the ... [more ▼]

It has been postulated that memories of neardeath experiences (NDEs) could be (at least in part) reconstructions based on experiencers’ (NDErs) previous knowledge and could be built as a result of the individual’s attempt to interpret the confusing experience. From the point of view of the experiencer, NDE memories are perceived as being unrivalled memories due to its associated rich phenomenology. However, the scientific literature devoted to the cognitive functioning of NDErs in general, and their memory performance in particular, is rather limited. This study examined NDErs’ susceptibility to false memories using the Deese–Roediger–McDermott (DRM) paradigm. We included 20 NDErs who reported having had their experience in the context of a life-threatening event (Greyson NDE scale total score ≥7/32) and 20 volunteers (matched for age, gender, education level, and time since brain insult) who reported a life-threatening event but without a NDE. Both groups were presented with DRM lists for a recall task during which they were asked to assign “Remember/Know/Guess” judgements to any recalled response. In addition, they were later asked to complete a post-recall test designed to obtain estimates of activation and monitoring of critical lures. Results demonstrated that NDErs and volunteers were equally likely to produce false memories, but that NDErs recalled them more frequently associated with compelling illusory recollection. Of particular interest, analyses of activation and monitoring estimates suggest that NDErs and volunteers groups were equally likely to think of critical lures, but source monitoring was less successful in NDErs compared to volunteers. [less ▲]

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See detailPrevalence of coma-recovery scale-revised signs of consciousness in patients in minimally conscious state
Wannez, Sarah ULiege; Gosseries, Olivia ULiege; Azzolini, Deborah et al

in Neuropsychological Rehabilitation (2017)

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See detailObjective assessment of visual pursuit in patients with disorders of consciousness: an exploratory study.
Wannez, Sarah ULiege; Hoyoux, Thomas; Langohr, Thomas et al

in Journal of Neurology (2017)

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See detailTracking dynamic interactions between structural and functional connectivity: a TMS/EEG-dMRI study
Amico, Enrico; Bodart, Olivier ULiege; Rosanova, Mario et al

in Brain connectivity (2017)

Transcranial magnetic stimulation (TMS) in combination with neuroimaging techniques allows to measure the effects of a direct perturbation of the brain. When coupled to high density electroencephalography ... [more ▼]

Transcranial magnetic stimulation (TMS) in combination with neuroimaging techniques allows to measure the effects of a direct perturbation of the brain. When coupled to high density electroencephalography (TMS/hd-EEG), TMS pulses revealed electrophysiological signatures of different cortical modules in health and disease. However, the neural underpinnings of these signatures remain unclear. Here, by applying multimodal analyses of cortical response to TMS recordings and diffusion magnetic resonance imaging (dMRI) tractography, we investigated the relationship between functional and structural features of different cortical modules in a cohort of awake healthy volunteers. For each subject we computed directed functional connectivity interactions between cortical areas from the source reconstructed TMS/hd- EEG recordings and correlated them with the correspondent structural connectivity matrix extracted from dMRI tractography, in three different frequency bands (alpha, beta, gamma) and two sites of stimulation (left precuneus and left premotor). Each stimulated area appeared to mainly respond to TMS by being functionally elicited in specific frequency bands, i.e. beta for precuneus and gamma for premotor. We also observed a temporary decrease in the whole-brain correlation between directed functional connectivity and structural connectivity after TMS in all frequency bands. Notably, when focusing on the stimulated areas only, we found that the structurefunction correlation significantly increases over time in the premotor area contralateral to TMS. Our study points out the importance of taking into account the major role played by different cortical oscillations when investigating the mechanisms for integration and segregation of information in the human brain. [less ▲]

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See detailMapping the functional connectome traits of levels of consciousness
Amico, Enrico; Marinazzo, Daniele; Di Perri, Carol ULiege et al

in NeuroImage (2017)

Examining task-free functional connectivity (FC) in the human brain offers insights on how spontaneous integration and segregation of information relate to human cognition, and how this organization may ... [more ▼]

Examining task-free functional connectivity (FC) in the human brain offers insights on how spontaneous integration and segregation of information relate to human cognition, and how this organization may be altered in different conditions, and neurological disorders. This is particularly relevant for patients in disorders of consciousness (DOC) following severe acquired brain damage and coma, one of the most devastating conditions in modern medical care. We present a novel data-driven methodology, connICA, which implements Independent Component Analysis (ICA) for the extraction of robust independent FC patterns (FC-traits) from a set of individual functional connectomes, without imposing any a priori data stratification into groups. We here apply connICA to investigate associations between network-traits derived from task-free FC and cognitive features that define levels of consciousness. Three main independent FC-traits were identified and linked to consciousness-related clinical features. The first one represents the functional configuration of an "awake resting" brain, and is associated to the level of arousal. The second FC-trait reflects the disconnection of the visual and sensory-motor connectivity patterns and relates to the ability of communicating with the external environment. The third FC-trait isolates the connectivity pattern encompassing the fronto-parietal and the default-mode network areas as well as the interaction between left and right hemisphere, which are also associated to the awareness of the self and its surroundings. Each FC-trait represents a distinct functional process with a role in the degradation of conscious states in functional brain networks, shedding further light on the functional subcircuits that get disrupted in severe brain-damage. [less ▲]

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See detailFunctional Connectivity Substrates for tDCS Response in Minimally Conscious State Patients
Cavaliere, Carlo ULiege; Aiello, Marco; Di Perri, Carol ULiege et al

in Frontiers in Cellular Neuroscience (2016)

Transcranial direct current stimulation (tDCS) is a non-invasive technique recently employed in disorders of consciousness, and determining a transitory recovery of signs of consciousness in almost half ... [more ▼]

Transcranial direct current stimulation (tDCS) is a non-invasive technique recently employed in disorders of consciousness, and determining a transitory recovery of signs of consciousness in almost half of minimally conscious state (MCS) patients. Although the rising evidences about its possible role in the treatment of many neurological and psychiatric conditions exist, no evidences exist about brain functional connectivity substrates underlying tDCS response. We retrospectively evaluated resting state functional Magnetic Resonance Imaging (fMRI) of 16 sub-acute and chronic MCS patients (6 tDCS responders) who successively received a single left dorsolateral prefrontal cortex (DLPFC) tDCS in a double-blind randomized cross-over trial. A seed-based approach for regions of left extrinsic control network (ECN) and default-mode network (DMN) was performed. tDCS responders showed an increased left intra-network connectivity for regions co-activated with left DLPFC, and significantly with left inferior frontal gyrus. Non-responders (NR) MCS patients showed an increased connectivity between left DLPFC and midline cortical structures, including anterior cingulate cortex and precuneus. Our findings suggest that a prior high connectivity with regions belonging to ECN can facilitate transitory recovery of consciousness in a subgroup of MCS patients that underwent tDCS treatment. Therefore, resting state-fMRI could be very valuable in detecting the neuronal conditions necessary for tDCS to improve behavior in MCS. [less ▲]

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