Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Contingent Negative Variation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,423 records · Page 79Linked to original sources
PubMed1987

Two-level CNV and extrication wave in human brain.

In this experiment, the paradigm of CNV is changed, with two warning stimuli presented and the key press for discrimination exchanged in order to reject the motor factor in CNV. The main results are: Second level of CNV is increased, an extrication wave is discovered. Various hypotheses about CNV are discussed, proposing that the psychological factor in CNV is not a unitary one, but the increase of the mental load which is synthetically composed of many psychological factors.

Adult↗
PubMed1986

Electrophysiological evidence for right frontal lobe dominance in spatial visuomotor learning.

Slow negative potential shifts were recorded together with the error made in motor performance when two different groups of 14 students tracked visual stimuli with their right hand. Various visuomotor tasks were compared. A tracking task (T) in which subjects had to track the stimulus directly, showed no decrease of error in motor performance during the experiment. In a distorted tracking task (DT) a continuous horizontal distortion of the visual feedback had to be compensated. The additional demands of this task required visuomotor learning. Another learning condition was a mirrored-tracking task (horizontally inverted tracking, hIT), i.e. an elementary function, such as the concept of changing left and right was interposed between perception and action. In addition, subjects performed a no-tracking control task (NT) in which they started the visual stimulus without tracking it. A slow negative potential shift was associated with the visuomotor performance (TP: tracking potential). In the learning tasks (DT and hIT) this negativity was significantly enhanced over the anterior midline and in hIT frontally and precentrally over both hemispheres. Comparing hIT and T for every subject, the enhancement of the tracking potential in hIT was correlated with the success in motor learning in frontomedial and bilaterally in frontolateral recordings (r = 0.81-0.88). However, comparing DT and T, such a correlation was only found in frontomedial and right frontolateral electrodes (r = 0.5-0.61), but not at the left frontolateral electrode. These experiments are consistent with previous findings and give further neurophysiological evidence for frontal lobe activity in visuomotor learning. The hemispherical asymmetry is discussed in respect to hemispherical specialization (right frontal lobe dominance in spatial visuomotor learning).

Contingent Negative Variation↗
PubMed1986

The influence of concentration and relaxation on the EEG power spectra during a CNV paradigm.

EEG segments of 1 sec duration, beginning 1 sec before the imperative stimulus were analysed by Fast Fourier Transformation in a CNV paradigm with interstimulus intervals (ISI) of different durations (1, 3, 5 sec) and with constant (K1, K3, K5) and randomized (R1, R3, R5) ISI presentation. In the alpha band, there were found differences in the power spectra between the constant and the longer randomized (R3, R5) ISI conditions, the latter having a slower center frequency, a smaller radius of gyration and a higher kurtosis. This describes a sharper alpha line of slower frequency in the R3 and the R5 ISI condition, due to pronounced synchronisation of alpha activity. It is discussed as an expression of increased relaxation and reduced concentration. In the theta band, differences appeared between the short ISI conditions (K1, R1) and the longer ones.

Adult↗
PubMedDate not supplied

[Electrophysiologic aspects of infantile autism].

Since the first description of infantile autism by Kanner, many physiopathological hypotheses have been suggested to explain this syndrome. In order to confirm these hypotheses, a lot of biological technics have been used among which the cerebral electroencephalography plays a leading part. The authors describe the main electroencephalographical technics used in autistic children. For each sort of examination, the physiopathological contribution has been studied. Then, these electrophysiological data have been confronted with neuroanatomical hypotheses (temporal, frontal, mesencephalic functional troubles) or neurobiochemical hypotheses (dysfunctioning of the corresponding dopaminergic systems).

Autistic Disorder↗
PubMedDate not supplied

Application of a portable microprocessor-based system for electrophysiological field testing of neurotoxicity.

A portable microprocessor-based system designated PEARL II has been developed for neurotoxicity testing in human populations. PEARL II provides a flexible and powerful data acquisition capability to record sensory evoked potentials (auditory, visual and somatosensory), event-related slow potentials (CNV, P300) and behavioral measures. PEARL II has been mounted in a mobile laboratory to facilitate field testing. Data obtained in pediatric lead studies are provided for illustration.

Brain Stem↗
PubMedDate not supplied

EEG spectrum analysis techniques applied to the problem of psi phenomena.

Electroencephalographic techniques were used to study unusual sensory capabilities. One S, the "sender," of a pair of Ss was stimulated with 10 sec duration trains of flicker at 6 or 16 fps, randomly interspersed with periods of no flicker. EEGs were recorded from another S, the "receiver," to determine if EEG driving or alpha block would be evident on trials when the sender was stimulated, compared to when the sender was not stimulated. Differential alpha block on control and stimulus trials was observed reliably in one receiver, indicating some information transfer. The S's overt indications of which stimulus occurred were not different from what would be expected by chance. The physical parameters by which the EEG effect was mediated were not determined.

Alpha Rhythm↗