Dynamics of magnetic cortico-cortical responses evoked by single-pulse electrical stimulation.

Objective: Intracranial single-pulse electrical stimulation (SPES) can elicit cortico-cortical evoked potentials. Their investigation with intracranial EEG is biased by the limited number and selected location of electrodes, which could be circumvented by simultaneous non-invasive whole-scalp recording. This study aimed at investigating the ability of magnetoencephalography (MEG) to characterize cortico-cortical evoked fields (CCEFs) and effective connectivity between the epileptogenic zone (EZ) and non-epileptogenic zone (i.

A novel, robust, and portable platform for magnetoencephalography using optically-pumped magnetometers.

Magnetoencephalography (MEG) measures brain function via assessment of magnetic fields generated by neural currents. Conventional MEG uses superconducting sensors, which place significant limitations on performance, practicality, and deployment; however, the field has been revolutionised in recent years by the introduction of optically-pumped magnetometers (OPMs). OPMs enable measurement of the MEG signal without cryogenics, and consequently the conception of "OPM-MEG" systems which ostensibly allow increased sensitivity and resolution, lifespan compliance, free subject movement, and lower cost.

Spectrotemporal cortical dynamics and semantic control during sentence completion.

Objective: To investigate cortical oscillations during a sentence completion task (SC) using magnetoencephalography (MEG), focusing on the semantic control network (SCN), its leftward asymmetry, and the effects of semantic control load.

Methods: Twenty right-handed adults underwent MEG while performing SC, consisting of low cloze (LC: multiple responses) and high cloze (HC: single response) stimuli. Spectrotemporal power modulations as event-related synchronizations (ERS) and desynchronizations (ERD) were analyzed: first, at the whole-brain level; second, in key SCN regions, posterior middle/inferior temporal gyri (pMTG/ITG) and inferior frontal gyri (IFG), under different semantic control loads.

A Novel, Robust, and Portable Platform for Magnetoencephalography using Optically Pumped Magnetometers.

Magnetoencephalography (MEG) measures brain function via assessment of magnetic fields generated by neural currents. Conventional MEG uses superconducting sensors, which place significant limitations on performance, practicality, and deployment; however, the field has been revolutionised in recent years by the introduction of optically-pumped-magnetometers (OPMs). OPMs enable measurement of the MEG signal without cryogenics, and consequently the conception of 'OPM-MEG' systems which ostensibly allow increased sensitivity and resolution, lifespan compliance, free subject movement, and lower cost.

Motor learning- and consolidation-related resting state fast and slow brain dynamics across wake and sleep.

Motor skills dynamically evolve during practice and after training. Using magnetoencephalography, we investigated the neural dynamics underpinning motor learning and its consolidation in relation to sleep during resting-state periods after the end of learning (boost window, within 30 min) and at delayed time scales (silent 4 h and next day 24 h windows) with intermediate daytime sleep or wakefulness. Resting-state neural dynamics were investigated at fast (sub-second) and slower (supra-second) timescales using Hidden Markov modelling (HMM) and functional connectivity (FC), respectively, and their relationship to motor performance.

Subclinical epileptiform activity in the Alzheimer continuum: association with disease, cognition and detection method.

Background: Epileptic seizures are an established comorbidity of Alzheimer's disease (AD). Subclinical epileptiform activity (SEA) as detected by 24-h electroencephalography (EEG) or magneto-encephalography (MEG) has been reported in temporal regions of clinically diagnosed AD patients. Although epileptic activity in AD probably arises in the mesial temporal lobe, electrical activity within this region might not propagate to EEG scalp electrodes and could remain undetected by standard EEG.

Towards the automated detection of interictal epileptiform discharges with magnetoencephalography.

Background: The analysis of clinical magnetoencephalography (MEG) in patients with epilepsy traditionally relies on visual identification of interictal epileptiform discharges (IEDs), which is time consuming and dependent on subjective criteria.

New Method: Here, we explore the ability of Independent Components Analysis (ICA) and Hidden Markov Modeling (HMM) to automatically detect and localize IEDs. We tested our pipelines on resting-state MEG recordings from 10 school-aged children with (multi)focal epilepsy.

Tri-axial rubidium and helium optically pumped magnetometers for on-scalp magnetoencephalography recording of interictal epileptiform discharges: a case study.

Cryogenic magnetoencephalography (MEG) enhances the presurgical assessment of refractory focal epilepsy (RFE). Optically pumped magnetometers (OPMs) are cryogen-free sensors that enable on-scalp MEG recordings. Here, we investigate the application of tri-axial OPMs [Rb (Rb-OPM) and He gas (He-OPM)] for the detection of interictal epileptiform discharges (IEDs).

Speech-derived haptic stimulation enhances speech recognition in a multi-talker background.

Speech understanding, while effortless in quiet conditions, is challenging in noisy environments. Previous studies have revealed that a feasible approach to supplement speech-in-noise (SiN) perception consists in presenting speech-derived signals as haptic input. In the current study, we investigated whether the presentation of a vibrotactile signal derived from the speech temporal envelope can improve SiN intelligibility in a multi-talker background for untrained, normal-hearing listeners.

From cryogenic to on-scalp magnetoencephalography for the evaluation of paediatric epilepsy.

Magnetoencephalography (MEG) is a neurophysiological technique based on the detection of brain magnetic fields. Whole-head MEG systems typically house a few hundred sensors requiring cryogenic cooling in a rigid one-size-fits-all (commonly adult-sized) helmet to keep a thermal insulation space. This leads to an increased brain-to-sensor distance in children, because of their smaller head circumference, and decreased signal-to-noise ratio.

Anodal Cerebellar Transcranial Direct Current Stimulation Reduces Motor and Cognitive Symptoms in Friedreich's Ataxia: A Randomized, Sham-Controlled Trial.

Background: Friedreich Ataxia is the most common recessive ataxia with only one therapeutic drug approved solely in the United States.

Objective: The aim of this work was to investigate whether anodal cerebellar transcranial direct current stimulation (ctDCS) reduces ataxic and cognitive symptoms in individuals with Friedreich's ataxia (FRDA) and to assess the effects of ctDCS on the activity of the secondary somatosensory (SII) cortex.

Methods: We performed a single-blind, randomized, sham-controlled, crossover trial with anodal ctDCS (5 days/week for 1 week, 20 min/day, density current: 0.

Functional identification of language-responsive channels in individual participants in MEG investigations.

Making meaningful inferences about the functional architecture of the language system requires the ability to refer to the same neural units across individuals and studies. Traditional brain imaging approaches align and average brains together in a common space. However, lateral frontal and temporal cortex, where the language system resides, is characterized by high structural and functional inter-individual variability.

Diagnostic and therapeutic approaches in refractory insular epilepsy.

Due to heterogenous seizure semiology and poor contribution of scalp electroencephalography (EEG) signals, insular epilepsy requires use of the appropriate diagnostic tools for its diagnosis and characterization. The deep location of the insula also presents surgical challenges. The aim of this article is to review the current diagnostic and therapeutic tools and their contribution to the management of insular epilepsy.

Neurodevelopmental oscillatory basis of speech processing in noise.

Humans' extraordinary ability to understand speech in noise relies on multiple processes that develop with age. Using magnetoencephalography (MEG), we characterize the underlying neuromaturational basis by quantifying how cortical oscillations in 144 participants (aged 5-27 years) track phrasal and syllabic structures in connected speech mixed with different types of noise. While the extraction of prosodic cues from clear speech was stable during development, its maintenance in a multi-talker background matured rapidly up to age 9 and was associated with speech comprehension.

Cortical tracking of lexical speech units in a multi-talker background is immature in school-aged children.

Children have more difficulty perceiving speech in noise than adults. Whether this difficulty relates to an immature processing of prosodic or linguistic elements of the attended speech is still unclear. To address the impact of noise on linguistic processing per se, we assessed how babble noise impacts the cortical tracking of intelligible speech devoid of prosody in school-aged children and adults.

Atypical procedural learning skills in children with Developmental Coordination Disorder.

We investigated the procedural learning deficit hypothesis in Developmental Coordination Disorder (DCD) while controlling for global performance such as slower reaction times (RTs) and variability. Procedural (sequence) learning was assessed in 31 children with DCD and 31 age-matched typically developing (TD) children through a serial reaction time task (SRTT). Sequential and random trial conditions were intermixed within five training epochs.

Impact of Human Immunodeficiency Virus and Recreational Drugs on Cognitive Functions.

Background: This prospective study characterizes the structural and metabolic cerebral correlates of cognitive impairments found in a preclinical setting that considers the lifestyle of young European men exposed to human immunodeficiency virus (HIV), including recreational drugs.

Methods: Simultaneous structural brain magnetic resonance imaging (MRI) and positron emission tomography using [18F]-fluorodeoxyglucose (FDG-PET) were acquired on a hybrid PET-MRI system in 23 asymptomatic young men having sex with men with HIV (HIVMSM; mean age, 33.6 years [range, 23-60 years]; normal CD4+ cell count, undetectable viral load).

Cognitive, perceptual, and motor profiles of school-aged children with developmental coordination disorder.

Developmental coordination disorder (DCD) is a heterogeneous condition. Besides motor impairments, children with DCD often exhibit poor visual perceptual skills and executive functions. This study aimed to characterize the motor, perceptual, and cognitive profiles of children with DCD at the group level and in terms of subtypes.