Applications de la neurophysiologie cognitive et de la stimulation cerebrale non invasive a l’etude du langage.

Les potentiels liés aux événements (ERP) sont une méthode d'évaluation et de cartographie du cerveau qui nous permet de comprendre la dynamique temporelle du traitement de l'information, fournissant aux neurosciences un outil précieux pour examiner le traitement du langage chez les enfants et les adultes, ainsi que dans les troubles cérébraux où il y a un certain trouble du langage. Son utilisation nous permet de comprendre avec précision les marqueurs cérébraux impliqués dans des aspects aussi importants que l'acquisition ou l'intégration du langage et les inadéquations sémantiques et syntaxiques. D'autre part, l'utilisation des techniques de stimulation cérébrale non invasives représente une véritable révolution dans l'étude du langage, non seulement parce que nous disposons d'un outil puissant pour l'évaluation des réseaux cérébraux qui le facilitent ou l'inhibent, mais aussi parce qu'elle nous permet d'améliorer ou de corriger de manière substantielle l'apprentissage et les performances dans les tests de lecture et de compréhension ou de mémoire, tant dans les populations saines que dans les traitements de réadaptation dans les populations cliniques.Los potenciales relacionados con eventos(ERP) son un método de evaluación y de mapeo cerebral que permite entender la dinámica temporal del procesamiento de la información, dotando a la neurociencia de una herramienta de gran valor para escudriñar el procesamiento del lenguaje en niños y adultos, así como en trastornos cerebrales. Su uso está permitiendo comprender con precisión aquellos marcadores cerebrales involucrados en aspectos tan importantes como la adquisición del lenguaje o la integración y los desajustes semánticos y sintácticos. Por otra parte, el empleo de técnicas de estimulación cerebral no invasivasestá suponiendo una auténtica revolución en el estudio del lenguaje; es una potente herramienta para la evaluación de aquellas redes cerebrales que lo facilitan o lo inhiben y permite mejorar o corregir sustancialmente el aprendizaje y el rendimiento en pruebas de lectura y comprensión o recuerdo, tanto en población sana como en tratamientos rehabilitadores en población clínica.Event-Related Potentials (ERP) is a method of brain assessment and mapping that allows understanding the temporal dynamics of information processing, providing neuroscience with a valuable tool for studying language processing in children and adults, as well as brain disorders associated to language disorders. It improves the understanding of those brain markers involved in aspects as language acquisition or how the semantic and syntactic level cooperate. On the other hand, the use of non-invasive brain stimulation techniques is representing a revolution in the study of language: it is a powerful tool for the evaluation of brain networks and it allows us to improve or correct learning and performance in reading and comprehension or memory tests, both in healthy and clinical populations

Neuroimaging and serum biomarkers of neurodegeneration and neuroplasticity in Parkinson’s disease patients treated by intermittent theta-burst stimulation over the bilateral primary motor area: a randomized, double-blind, sham-controlled, crossover trial study

Background and objectives: Intermittent theta-burst stimulation (iTBS) is a patterned form of excitatory transcranial magnetic stimulation that has yielded encouraging results as an adjunctive therapeutic option to alleviate the emergence of clinical deficits in Parkinson’s disease (PD) patients. Although it has been demonstrated that iTBS influences dopamine-dependent corticostriatal plasticity, little research has examined the neurobiological mechanisms underlying iTBS-induced clinical enhancement. Here, our primary goal is to verify whether iTBS bilaterally delivered over the primary motor cortex (M1) is effective as an add-on treatment at reducing scores for both motor functional impairment and nonmotor symptoms in PD. We hypothesize that these clinical improvements following bilateral M1-iTBS could be driven by endogenous dopamine release, which may rebalance cortical excitability and restore compensatory striatal volume changes, resulting in increased striato-cortico-cerebellar functional connectivity and positively impacting neuroglia and neuroplasticity. Methods: A total of 24 PD patients will be assessed in a randomized, double-blind, sham-controlled crossover study involving the application of iTBS over the bilateral M1 (M1 iTBS). Patients on medication will be randomly assigned to receive real iTBS or control (sham) stimulation and will undergo 5 consecutive sessions (5 days) of iTBS over the bilateral M1 separated by a 3-month washout period. Motor evaluation will be performed at different follow-up visits along with a comprehensive neurocognitive assessment; evaluation of M1 excitability; combined structural magnetic resonance imaging (MRI), resting-state electroencephalography and functional MRI; and serum biomarker quantification of neuroaxonal damage, astrocytic reactivity, and neural plasticity prior to and after iTBS. Discussion: The findings of this study will help to clarify the efficiency of M1 iTBS for the treatment of PD and further provide specific neurobiological insights into improvements in motor and nonmotor symptoms in these patients. This novel project aims to yield more detailed structural and functional brain evaluations than previous studies while using a noninvasive approach, with the potential to identify prognostic neuroprotective biomarkers and elucidate the structural and functional mechanisms of M1 iTBS-induced plasticity in the cortico-basal ganglia circuitry. Our approach may significantly optimize neuromodulation paradigms to ensure state-of-the-art and scalable rehabilitative treatment to alleviate motor and nonmotor symptoms of PD.17 páginas

Predicting Neuropsychological Impairment in Relapsing Remitting Multiple Sclerosis: The Role of Clinical Measures, Treatment, and Neuropsychiatry Symptoms

Objective: This retrospective observational study aimed to define neuropsychological impairment (NI) profiles and determine the influence of clinical, demographic, and neuropsychiatric measures in specific cognitive domains in a cohort of relapsing-remitting multiple sclerosis (RRMS) patients. Methods: Ninety-one RRMS patients underwent a neurological examination and a brief neuropsychological assessment. Patients were classified according to the disease-modifying therapies (DMTs) received (platform or high-efficacy). Differences between groups and multiple regression analyses were performed to determine the predictive value of the assessed measures in cognitive performance. Results: More than two-thirds of the patients showed NI. Specifically, mild to moderate NI was presented in approximately half of the participants. Paced Auditory Serial Addition Test (PASAT-3) and Symbol Digit Modalities Test (SDMT) were the most frequently impaired cognitive tests (45.3% and 41.3%, respectively) followed by phonemic verbal fluency (PVF) (27.8%). Expanded Disability Status Scale (EDSS), age, depressive symptoms, and disease duration were the best predictors of SDMT (R2 = .34; p < .01), whereas disease duration, EDSS, and anxiety-state levels predicted PASAT-3 (R2 = .33, p < .01). Educational level, age, EDSS, and depressive symptoms demonstrated the strongest association with PVF (R2 = .31, p < .01). Conclusions: Our results indicated a significant prevalence of NI in RRMS patients that was not dependent on the DMT type. In addition to the meaningful working memory (PASAT-3) and information processing speed (SDMT) impairments found, PVF deficits may also be an important marker of cognitive impairment in RRMS patients. This study supports the relevance of standard clinical measures and reinforces the importance of quantifying clinical and neuropsychiatric symptoms to predict subsequent cognitive performance on a similar multiple sclerosis phenotype and disease stage.36(4):475-484. doi: 10.1093/arclin/acaa088

Nucleus Accumbens Stimulation Modulates Inhibitory Control by Right Prefrontal Cortex Activation in Obsessive-Compulsive Disorder

Inhibitory control is considered a compromised cognitive function in obsessive-compulsive (OCD) patients and likely linked to corticostriatal circuitry disturbances. Here, 9 refractory OCD patients treated with deep brain stimulation (DBS) were evaluated to address the dynamic modulations of large-scale cortical network activity involved in inhibitory control after nucleus accumbens (NAc) stimulation and their relationship with cortical thickness. A comparison of DBS "On/Off" states showed that patients committed fewer errors and exhibited increased intraindividual reaction time variability, resulting in improved goal maintenance abilities and proactive inhibitory control. Visual P3 event-related potentials showed increased amplitudes during Go/NoGo performance. Go and NoGo responses increased cortical activation mainly over the right inferior frontal gyrus and medial frontal gyrus, respectively. Moreover, increased cortical activation in these areas was equally associated with a higher cortical thickness within the prefrontal cortex. These results highlight the critical role of NAc DBS for preferentially modulating the neuronal activity underlying sustained speed responses and inhibitory control in OCD patients and show that it is triggered by reorganizing brain functions to the right prefrontal regions, which may depend on the underlying cortical thinning. Our findings provide updated structural and functional evidence that supports critical dopaminergic-mediated frontal-striatal network interactions in OCD.31(5):2742-2758. doi: 10.1093/cercor/bhaa39