Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 8089033

Event-related desynchronization (ERD) during visual processing.

G Pfurtscheller·C Neuper·W Mohl
View original source ↗Export metadata ↓

Abstract

Event-related desynchronization (ERD) is the short-lasting attenuation or blocking of rhythms within the alpha (beta) band. ERD is found during but also before visual stimulation. Two different types of ERD can be differentiated: one short-lasting, localized to occipital areas and involving upper alpha components; the other longer lasting, more widespread, most prominent over parietal areas and maximal for lower alpha components. The former most likely reflects primary visual processing and feature extraction, the latter is more related to cognitive processing and mechanisms of attention.

Explore related subjects

Alpha RhythmBrain MappingCognitionCortical SynchronizationEvoked Potentials, VisualHumansMental ProcessesPhotic StimulationVisual PerceptionJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G Pfurtscheller, C Neuper, W Mohl. 1994. Event-related desynchronization (ERD) during visual processing.. https://doi.org/10.1016/0167-8760(89)90041-x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1995

Event-related potentials and alpha synchronization in preadolescent boys at risk for psychoactive substance use.

Numerous studies have evaluated event-related potentials (ERPs) as biological indicators of the liability for alcoholism. This study extends that approach by investigating ERPs in boys at risk for other substance use disorders. Prepubertal (10-12 years) sons of fathers diagnosed with psychoactive substance dependence (n = 28) were compared to matched sons of nonaffected fathers (n = 26) on an auditory ERP oddball task. Multivariate analyses of variance applied to peak amplitude and latency measures indicated small to moderate between-groups differences at midline or parietal sites: N2 and P3 amplitude; P2, N2, P3, and Nc latency. This replicated P3 amplitude findings in alcoholism-risk studies, though the effect size was moderate. Analysis of event-related alpha power indicated significantly longer latency of alpha synchronization and oscillations of desynchronization in boys at risk. The alpha power findings were statistically the more robust of the measures applied. The role of neurocognitive factors in determining liability for substance use disorders is discussed.

Alpha Rhythm↗
PubMed1995

Sleep, its subjective perception, and daytime performance in insomniacs with a pattern of alpha sleep.

Intrusion of alpha activity, an electroencephalographic (EEG) pattern typical for wakefulness, into sleep stages has repeatedly been described and investigated in various populations. Some studies suggested that it is a less deep and restorative sleep, but others did not support this interpretation. The present study was carried out to collect ample data on neurophysiology and subjective experience of sleep and on daytime cognitive performance to clarify this point. A sample of 128 primary insomniacs was investigated with polysomnography (PSG) that was submitted to a computerized, automatic analysis of alpha activity during sleep. It yielded two groups of 64 Ss each with a normal, that is, nonalpha sleep EEG and with alpha-sleep, respectively. Contrasting the two groups for PSG showed that alpha sleep Ss had significantly more stage 4 and a (nonsignificant) tendency for more awakenings. Subjectively, they largely underestimated intermittent wake time and consequently overestimated sleep duration by 50 min. The performance test battery showed a difference in one test only, that is, a better short-term memory function by alpha sleep Ss. In conclusion, there was no result supporting the assumption that alpha sleep is less restorative, but a significant lack of perception of intermittent awakenings during night sleep by alpha sleep Ss was found. The authors propose an explanation and point to the implications this misperception might have for the clinician.

Alpha Rhythm↗
PubMed1995

Operant (biofeedback) control of left-right frontal alpha power differences: potential neurotherapy for affective disorders.

Two experiments were done with subjects from a paid pool of undergraduates. In each study, there were five 1-hour sessions on each of 5 days: (1) Baseline: Rewards given for randomly selected 20% of the 700-ms sequential epochs; mean and SD of baseline power differences determined. 2) Exploration: Subjects were rewarded when right minus left alpha differences in an epoch were greater than the baseline mean plus about .85 SD (p = .20); subjects told to discover how to generate rewards. (3)-(5). Training: Subjects were paid (over and above the $8/h flat rate) in proportion to their hit rates. In the first study (in which active filters passed 8-12 Hz activity, and the rectified, integrated amplitude was utilized), 6 of 8 subjects met learning criteria (a significant difference between baseline and training scores). In the second study (in which on-line FFTs were used to extract alpha power), 3 of 5 subjects met learning criteria.

Alpha Rhythm↗