Semantic hyperpriming in schizophrenic patients: increased facilitation or impaired inhibition in semantic association processing?

International audiencePrevious studies analyzing semantic priming in schizophrenic patients have reported conflicting results. In the present study, we explored semantic priming in a sample of schizophrenic patients with mild thought disorders. We wondered if distinct cognitive processes, such as facilitation and/or inhibition, underlie semantic hyperpriming and are variously impaired in schizophrenic patients. Using a lexical decision task, we evaluated semantic priming in 15 schizophrenic patients (DSM-IV) with mild thought disorders and 15 healthy controls matched for sex, age, and education level. The task was designed to divide semantic priming into two additive components, namely facilitation effect and inhibition effect. One-sample t-tests were performed to investigate differences in semantic priming, facilitation, and inhibition within each group. ANOVAs were performed to compare the effects of semantic priming, facilitation, and inhibition between groups. Patients displayed greater semantic priming than controls (i.e., hyperpriming), but this was not due to increased facilitation in processing semantically related pairs. On the contrary, hyperpriming was the result of prolonged response time to process semantically unrelated pairs, corresponding to a requirement to inhibit unrelated information. We demonstrated semantic hyperpriming in stabilized schizophrenic patients with mild severity of symptoms. Thus, semantic hyperpriming may be an intrinsic feature of schizophrenia that is not related to the clinical state of patients. Semantic hyperpriming was due to an inhibition effect involved in processing semantically unrelated information not to increased facilitatory effect for related pairs

Insight et neuro-imagerie : l’apport de l’étude des réseaux du repos

International audienceL'insight, dans le cadre de la psychiatrie, est un phénomène complexe impliquant la conscience de souffrir d'une maladie mentale, de la nécessité d'un traitement, mais aussi l'attribution d'une cause aux différents symptômes et événements de vie. L'insight semble être fréquemment altéré chez les sujets schizophrènes, entraînant une péjoration majeure du pronostic. Plusieurs modèles théoriques postulent un lien entre l'altération de l'insight et certains dysfonctionnements neurocognitifs en lien avec les fonctions exécutives et autobiographiques. Depuis une dizaine d'années, de nombreux travaux sont consacrés à un réseau particulier : le Réseau du Mode par Défaut. Ce réseau semble être le support de l'activité mentale spontanée d'un sujet au repos. Plus particulièrement, son activation semble être liée aux pensées ayant trait à la conscience de soi. Dans le cadre d'une étude en Imagerie par Résonance Magnétique fonctionnelle, nous avons mis en évidence plusieurs altérations de ce réseau chez les patients, certaines spécifiquement liées aux capacités d'insight. À la lumière de ces résultats, nous proposons un nouveau modèle de l'altération de l'insight chez les patients schizophrènes

Resting-State Brain Organization Revealed by Functional Covariance Networks

BACKGROUND: Brain network studies using techniques of intrinsic connectivity network based on fMRI time series (TS-ICN) and structural covariance network (SCN) have mapped out functional and structural organization of human brain at respective time scales. However, there lacks a meso-time-scale network to bridge the ICN and SCN and get insights of brain functional organization. METHODOLOGY AND PRINCIPAL FINDINGS: We proposed a functional covariance network (FCN) method by measuring the covariance of amplitude of low-frequency fluctuations (ALFF) in BOLD signals across subjects, and compared the patterns of ALFF-FCNs with the TS-ICNs and SCNs by mapping the brain networks of default network, task-positive network and sensory networks. We demonstrated large overlap among FCNs, ICNs and SCNs and modular nature in FCNs and ICNs by using conjunctional analysis. Most interestingly, FCN analysis showed a network dichotomy consisting of anti-correlated high-level cognitive system and low-level perceptive system, which is a novel finding different from the ICN dichotomy consisting of the default-mode network and the task-positive network. CONCLUSION: The current study proposed an ALFF-FCN approach to measure the interregional correlation of brain activity responding to short periods of state, and revealed novel organization patterns of resting-state brain activity from an intermediate time scale

Altered Effective Connectivity Network of the Amygdala in Social Anxiety Disorder: A Resting-State fMRI Study

The amygdala is often found to be abnormally recruited in social anxiety disorder (SAD) patients. The question whether amygdala activation is primarily abnormal and affects other brain systems or whether it responds “normally” to an abnormal pattern of information conveyed by other brain structures remained unanswered. To address this question, we investigated a network of effective connectivity associated with the amygdala using Granger causality analysis on resting-state functional MRI data of 22 SAD patients and 21 healthy controls (HC). Implications of abnormal effective connectivity and clinical severity were investigated using the Liebowitz Social Anxiety Scale (LSAS). Decreased influence from inferior temporal gyrus (ITG) to amygdala was found in SAD, while bidirectional influences between amygdala and visual cortices were increased compared to HCs. Clinical relevance of decreased effective connectivity from ITG to amygdala was suggested by a negative correlation of LSAS avoidance scores and the value of Granger causality. Our study is the first to reveal a network of abnormal effective connectivity of core structures in SAD. This is in support of a disregulation in predescribed modules involved in affect control. The amygdala is placed in a central position of dysfunction characterized both by decreased regulatory influence of orbitofrontal cortex and increased crosstalk with visual cortex. The model which is proposed based on our results lends neurobiological support towards cognitive models considering disinhibition and an attentional bias towards negative stimuli as a core feature of the disorder

Neuroimaging the consciousness of self: Review, and conceptual-methodological framework

We review neuroimaging research investigating self-referential processing (SRP), that is, how we respond to stimuli that reference ourselves, prefaced by a lexical-thematic analysis of words indicative of “self-feelings”. We consider SRP as occurring verbally (V-SRP) and non-verbally (NV-SRP), both in the controlled, “top-down” form of introspective and interoceptive tasks, respectively, as well as in the “bottom-up” spontaneous or automatic form of “mind wandering” and “body wandering” that occurs during resting state. Our review leads us to outline a conceptual and methodological framework for future SRP research that we briefly apply toward understanding certain psychological and neurological disorders symptomatically associated with abnormal SRP. Our discussion is partly guided by William James’ original writings on the consciousness of self

Mind wandering and task-focused attention: ERP correlates

Previous studies looking at how Mind Wandering (MW) impacts performance in distinct Focused Attention (FA) systems, using the Attention Network Task (ANT), showed that the presence of pure MW thoughts did not impact the overall performance of ANT (alert, orienting and conflict) performance. However, it still remains unclear if the lack of interference of MW in the ANT, reported at the behavioral level, has a neurophysiological correspondence. We hypothesize that a distinct cortical processing may be required to meet attentional demands during MW. The objective of the present study was to test if, given similar levels of ANT performance, individuals predominantly focusing on MW or FA show distinct cortical processing. Thirty-three healthy participants underwent an EEG high-density acquisition while they were performing the ANT. MW was assessed following the ANT using an adapted version of the Resting State Questionnaire (ReSQ). The following ERP's were analyzed: pN1, pP1, P1, N1, pN, and P3. At the behavioral level, participants were slower and less accurate when responding to incongruent than to congruent targets (conflict effect), benefiting from the presentation of the double (alerting effect) and spatial (orienting effect) cues. Consistent with the behavioral data, ERP's waves were discriminative of distinct attentional effects. However, these results remained true irrespective of the MW condition, suggesting that MW imposed no additional cortical demand in alert, orienting, and conflict attention tasks.Acknowledgements Óscar F. Gonçalves was funded by the Brazilian National Counsel for Scientific and Technological Development (CNPq) as a Special Visiting Researcher of the Science Without Borders program (401143/2014-7). Paulo S Boggio was funded by a CNPq researcher fellowship (311641/2015-6). Olivia Morgan Lapenta and Tatiana Conde were supported by two postdoctoral grants from CNPq (150249/2017-9 and 152358/2016-1). Sandra Carvalho was funded by the Portuguese Foundation for Science and Technology (FCT) with the grant IF/00091/2015. Gabriel Rêgo was supported by a PhD grant from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP-2015/18713-9). This work was partially supported by FEDER funds through the Programa Operacional Factores de Competitividade – COMPETE and by national funds through FCT – Fundação para a Ciência e a Tecnologia (P2020-PTDC/MHC-PCN/3950/2014).info:eu-repo/semantics/publishedVersio

Sommeil et schizophrénie (une revue des données actuelles)

CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF

Repérage précoce des prodromes de manie par le patient et ses proches, rôle de l'entourage dans la prise en charge (à propos d'une étude exploratoire)

CAEN-BU Médecine pharmacie (141182102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Le psychotraumatisme (de la dissociation à la prise en charge en hypnothérapie)

CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF