Search results for "electrophysiology"

Co-activation and tension-regulating phenomena during isokinetic knee extension in sedentary and highly skilled humans.

1996

The aim of this study was to examine isokinetic torque produced by highly skilled (HS) and sedentary (S) human subjects, during knee extension, during maximal voluntary and superimposed electrical activation. To verify the level of activation of agonist (vastus lateralis, VL, and vastus medialis, VM) and antagonist muscles (semi-tendineous, ST), during maximal voluntary activation, their myo-electrical activities were detected and quantified as root mean square (rms) amplitude. Ten HS and ten S subjects performed voluntary and superimposed isometric actions and isokinetic knee extensions at 14 angular velocities (from -120 to 300 degrees*s(-1)). The rms amplitude of each muscle was normaliz…

Visuospatial attention shifts by gaze and arrow cues: an ERP study.

2007

Orienting of visual attention can be automatically triggered not only by illumination changes occurring in the visual periphery but also by centrally presented gaze and arrow cues. We investigated whether the automatic shifts of visuospatial attention triggered by centrally displayed gaze and arrow cues rely on the same neural systems. To this end we measured event-related potentials (ERPs) time-locked to the cue and target onsets while the participants (n=17) performed a spatial cuing task. In the task, the participants detected and responded to laterally presented targets preceded by centrally presented, non-predictive, gaze or arrow cues. Manual reaction times and target-triggered ERP da…

Electrophysiological signatures of masked transposition priming in a same-different task: Evidence with strings of letters vs. pseudoletters

2012

Research on masked transposed-letter priming (i.e., jugde-JUDGE triggers a faster response than jupte-JUDGE) has become a key phenomenon to reveal how the brain encodes letter position. Recent behavioural evidence suggests that the mechanism responsible for position coding in a masked priming procedure works with familiar "object" identities (e.g., letters, digits, symbols) but not with unfamiliar object identities (e.g., pseudoletters). Here we used event-related potentials (ERPs) to explore the time course of masked transposition priming of letters vs. pseudoletters in a cue-target same-different matching task. Target stimuli were preceded by a masked prime that could be: (i) identical to…

Amplitude envelope correlation detects coupling among incoherent brain signals.

2000

Event-related potentials (ERPs) to changes in the visual environment were recorded in rabbits. In the oddball condition, infrequently presented (deviant) stimuli occurred in a series of frequently presented (standard) stimuli. In the deviant-alone condition, standards were omitted. ERPs to oddball-deviants differed from those to standards in all recording sites (cerebellar cortex, visual cortex, dentate gyrus). No corresponding differences were found between ERPs to deviants in the oddball condition and those in the deviant-alone condition. However, because ERPs to deviants in the deviant-alone condition and those to standards did not differ either, ERPs to stimulus changes in the oddball c…

Cutaneous Recording and Stimulation of Muscles Using Organic Electronic Textiles

2016

International audience; Electronic textiles are an emerging field providing novel and non-intrusive solutions for healthcare. Conducting polymer-coated textiles enable a new generation of fully organic surface electrodes for electrophysiological evaluations. Textile electrodes are able to assess high quality muscular monitoring and to perform transcutaneous electrical stimulation.

Anxiety, Stress, and Contingent Negative Variation Reconsidered

1984

Functional properties of the brain during sleep under subchronic zopiclone administration in man.

1994

Zopiclone, a non-benzodiazepine, has been shown to be efficient in the treatment of transient, short-term or chronic sleep disorders. Apart from its hypnotic effects zopiclone has anxiolytic, anticonvulsant and myorelaxant properties and is therefore hardly distinguishable from benzodiazepines. Dependence liability and discontinuation effects have been reported to be less pronounced. Therefore zopiclone seems to be a hypnotic drug which may cause fewer side effects than conventional benzodiazepines. From the electrophysiological point of view one requires from a hypnotic drug the induction of a physiological sleep pattern as well as no alterations of information processing by the brain. The…

Electrophysiological parameters as biomarkers for psychiatry: Intra-individual variability and influencing factors.

2017

Combined EEG and MEG analysis of early somatosensory evoked activity in children and adolescents with focal epilepsies

2006

Abstract Objective The study aimed to evaluate differences between EEG and MEG analysis of early somatosensory evoked activity in patients with focal epilepsies in localizing eloquent areas of the somatosensory cortex. Methods Twenty-five patients (12 male, 13 female; age 4–25 years, mean 11.7 years) were included. Syndromes were classified as symptomatic in 17, idiopathic in 2 and cryptogenic in 6 cases. 10 patients presented with malformations of cortical development (MCD). 122 channel MEG and simultaneous 33-channel EEG were recorded during tactile stimulation of the thumb (sampling rate 769 Hz, band-pass 0.3–260 Hz). Forty-four hemispheres were analyzed. Hemispheres were classified as t…

Bottom-up influences on working memory: behavioral and electrophysiological distraction varies with distractor strength.

2004

Abstract. The present study investigates bottom-up effects serving the optimal balance between focusing attention on relevant information and distractibility by potentially significant events outside the focus of attention. We tested whether distraction, indicated by behavioral and event-related brain potential (ERP) measures, varies with the strength of task-irrelevant deviances. Twenty subjects performed a tone-duration discrimination task (200 or 400 ms sinusoidal tones presented equiprobably). The stimuli were presented with frequent standard (p = 0.84; 1000 Hz) or infrequent deviant (p = 0.16) pitch. These task-irrelevant pitch changes consisted in a frequency increase/decrease of 1%,…