Parallel Information Processing in Motor Systems: Intracerebral Recordings of Readiness Potential and CNV in Human Subjects

We performed intracerebral recordings of Readiness Potential (RP) and Contingent Negative Variation (CNV) with simple repetitive distal limb movement in candidates for epilepsy surgery. In 26 patients (in Paris), depth electrodes were located in various cortical structures; in eight patients (in Brno), in the basal ganglia and the cortex. RPs were displayed in the conteral primary motor cortex, conteral somato-sensory cortex, and bilaterally in the SMA and the caudal part of the anterior cingulate cortices. CNVs were recorded in the same cortical regiom as the RP, as well as in the ipsilateral primary motor cortex, and bilaterally in the premotor fronto-lateral, parietal superior, and middle temporal regions. In the basal ganglia, the RP was recorded in the putamen in six of seven patients, and in the head of the caudate nucleus and the pallidum in the only patient with electrodes in these recording sites. We suggest that our results are consistent with a long-lasting, simultaneous activation of cortical and subcortical structures, before and during self-paced and stimulus-triggered movements. The particular regiom that are simultaneously active may be determined by the task context

Vztahy mezi oscilacemi a jejich využití u adaptivní hluboké mozkové stimulace

Hluboká mozková stimulace (DBS) patří vedle dopaminergní léčby k nejvýznamnějším terapeutickým přístupům u Parkinsonovy nemoci (PN). Snaha potlačit některé limitace této terapie vede ke zvýšenému zájmu o přístupy jako je adaptivní DBS (aDBS). Stimulace s uzavřenou smyčkou řízená fluktuacemi výkonu v beta pásmu však nemusí být optimální pro všechny pacienty s PN. S cílem nalézt více senzitivní ukazatel než samotnou beta aktivitu byly analyzovány vztahy mezi jednotlivými oscilacemi v kontextu optimální stimulace subthalamického jádra (STN). Vztah fáze beta rytmu a amplitudy vysokofrekvenčních oscilací se jeví jako vhodný parametr pro cílení stimulace

On the Time Course of Synchronization Patterns of Neuronal Discharges in the Human Brain during Cognitive Tasks

Using intracerebral EEG recordings in a large cohort of human subjects, we investigate the time course of neural cross-talk during a simple cognitive task. Our results show that human brain dynamics undergo a characteristic sequence of synchronization patterns across different frequency bands following a visual oddball stimulus. In particular, an initial global reorganization in the delta and theta bands (2–8 Hz) is followed by gamma (20–95 Hz) and then beta band (12–20 Hz) synchrony

Smaller total and subregional cerebellar volumes in posttraumatic stress disorder:a mega-analysis by the ENIGMA-PGC PTSD workgroup

Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p -FDR &lt; 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.</p

Smaller total and subregional cerebellar volumes in posttraumatic stress disorder:a mega-analysis by the ENIGMA-PGC PTSD workgroup

Although the cerebellum contributes to higher-order cognitive and emotional functions relevant to posttraumatic stress disorder (PTSD), prior research on cerebellar volume in PTSD is scant, particularly when considering subregions that differentially map on to motor, cognitive, and affective functions. In a sample of 4215 adults (PTSD n = 1642; Control n = 2573) across 40 sites from the ENIGMA-PGC PTSD working group, we employed a new state-of-the-art deep-learning based approach for automatic cerebellar parcellation to obtain volumetric estimates for the total cerebellum and 28 subregions. Linear mixed effects models controlling for age, gender, intracranial volume, and site were used to compare cerebellum volumes in PTSD compared to healthy controls (88% trauma-exposed). PTSD was associated with significant grey and white matter reductions of the cerebellum. Compared to controls, people with PTSD demonstrated smaller total cerebellum volume, as well as reduced volume in subregions primarily within the posterior lobe (lobule VIIB, crus II), vermis (VI, VIII), flocculonodular lobe (lobule X), and corpus medullare (all p -FDR &lt; 0.05). Effects of PTSD on volume were consistent, and generally more robust, when examining symptom severity rather than diagnostic status. These findings implicate regionally specific cerebellar volumetric differences in the pathophysiology of PTSD. The cerebellum appears to play an important role in higher-order cognitive and emotional processes, far beyond its historical association with vestibulomotor function. Further examination of the cerebellum in trauma-related psychopathology will help to clarify how cerebellar structure and function may disrupt cognitive and affective processes at the center of translational models for PTSD.</p

Neuroimaging-based classification of PTSD using data-driven computational approaches: A multisite big data study from the ENIGMA-PGC PTSD consortium

Background: Recent advances in data-driven computational approaches have been helpful in devising tools to objectively diagnose psychiatric disorders. However, current machine learning studies limited to small homogeneous samples, different methodologies, and different imaging collection protocols, limit the ability to directly compare and generalize their results. Here we aimed to classify individuals with PTSD versus controls and assess the generalizability using a large heterogeneous brain datasets from the ENIGMA-PGC PTSD Working group. Methods: We analyzed brain MRI data from 3,477 structural-MRI; 2,495 resting state-fMRI; and 1,952 diffusion-MRI. First, we identified the brain features that best distinguish individuals with PTSD from controls using traditional machine learning methods. Second, we assessed the utility of the denoising variational autoencoder (DVAE) and evaluated its classification performance. Third, we assessed the generalizability and reproducibility of both models using leave-one-site-out cross-validation procedure for each modality. Results: We found lower performance in classifying PTSD vs. controls with data from over 20 sites (60 % test AUC for s-MRI, 59 % for rs-fMRI and 56 % for D-MRI), as compared to other studies run on single-site data. The performance increased when classifying PTSD from HC without trauma history in each modality (75 % AUC). The classification performance remained intact when applying the DVAE framework, which reduced the number of features. Finally, we found that the DVAE framework achieved better generalization to unseen datasets compared with the traditional machine learning frameworks, albeit performance was slightly above chance. Conclusion: These results have the potential to provide a baseline classification performance for PTSD when using large scale neuroimaging datasets. Our findings show that the control group used can heavily affect classification performance. The DVAE framework provided better generalizability for the multi-site data. This may be more significant in clinical practice since the neuroimaging-based diagnostic DVAE classification models are much less site-specific, rendering them more generalizable

Modification of Brain Functional Connectivity in Adolescent Thoracic Idiopathic Scoliosis by Lower Extremities Position

The involvement of the brain motor system in idiopathic scoliosis remains unclear. In this paper, we question whether the functional connectivity (FC) of the central motor circuitry is abnormal in adolescent idiopathic scoliosis (AIS) and whether it can be modified by flexion of the lower extremities. Functional magnetic resonance imaging (fMRI) in 18 patients with a right thoracic idiopathic curve greater than 30&deg; (mean angle 49.4&deg;, mean age 15.3 years, 4 males) and 22 healthy controls (mean age 18.2 years, 4 males) was explored using a 3T MR scanner. We measured their resting-state fMRI: (a) with extended lower extremities; (b) with semiflexion of the left lower extremity and extended right lower extremity, with hip abduction. Decreased FC between the secondary motor area (SMA) and postcentral cortex, pallidum and cuneus, postcentral gyrus and cerebellum, putamen and temporal lateral neocortex was observed in AIS. This pathological connectivity was reversed by lower extremity semiflexion. The FC between cortical and subcortical motor structures is significantly decreased in AIS. The decreased FC of the SMA, basal ganglia, cuneus (a hub structure), and cerebellum indicates the functional impairment of structures involved in regulating muscular tone. FC impairment in patients with AIS appears to be a reaction to the pathological condition. This pathological pattern flexibly reacts to changes in the positioning of the lower extremities, showing that the functional impairment of brain motor circuitry in AIS is reversible. We suggest that the reactivity of cerebral activity leading to brain activity normalization could be used for a rehabilitation program for patients with AIS