Premium
Lateral Specialization of Cognitive Mode: II. EEG Frequency Analysis
Author(s) -
Doyle Joseph C.,
Ornstein Robert,
Galin David
Publication year - 1974
Publication title -
psychophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.661
H-Index - 156
eISSN - 1469-8986
pISSN - 0048-5772
DOI - 10.1111/j.1469-8986.1974.tb01116.x
Subject(s) - psychology , electroencephalography , cognition , asymmetry , lateralization of brain function , alpha (finance) , task (project management) , cognitive psychology , elementary cognitive task , audiology , developmental psychology , neuroscience , physics , psychometrics , medicine , construct validity , management , quantum mechanics , economics
This study reports a frequency analysis of hemispheric EEG asymmetries in normal subjects performing cognitive tasks. Language and arithmetic tasks were expected to engage primarily the left hemisphere; spatial and musical tasks were expected to engage primarily the right hemisphere. Both motor and non‐motor tasks were used, e.g. writing a letter and composing a letter mentally. Recordings from temporal leads (T 3 ,T 4 ) and parietal leads (P 3 ,P 4 ) referred to the vertex C z were subjected to discrete Fourier transforms; ratios of power from homologous leads (T 4 /T 3 , P 4 /P 3 ) were computed in conventional frequency bands. These ratios (right/left) are significantly higher in verbal and arithmetic tasks than in spatial tasks primarily in the alpha band; the beta and theta bands show this effect less consistently. The delta band shows no such systematic effect of cognitive mode. Considering the alpha band alone reveals a task dependence of the asymmetry 2–5 times greater than we reported earlier for whole band power (1–35 Hz). Whenever a significant task dependence of asymmetry appears in any band, it is in the same direction: the hemisphere primarily engaged in the cognitive activity develops proportionately less power. The requirement of motor output increases the task dependence of alpha asymmetry and lowers alpha power levels.