Abstract
The e.e.g. was recorded from the left and right parietal and temporal regions of the scalps of 23 normal subjects while they were mentally at rest and then while they were executing tasks intended to engage, firstly, their dominant cerebral hemispheres, and secondly then their nondominant hemispheres. In each of the alpha and gamma frequency bands, 43 features of the e.e.g. expressed in terms of average power densities, coefficients of power density variation, coherencies and phases were calculated for each of the subjects. A method of separating the features which were related to the nature of the mental task from those which were related only to the mental workload represented by each of the tasks is presented. Of the features considered, many were found to be workload related, but only five, namely a power density variance, a right to left power ratio, an anterior to posterior phase angle and two coherency ratios, showed task-dependent behaviour. In this latter group, only two features point to the lateralisation of verbal and spatial cognitive processes to the dominant and nondominant cerebral hemispheres. The problem of the confounding of cerebral and mygenic effects and possible bias in the results owing to this effect is discussed.
Similar content being viewed by others
References
Annett, M. (1970) A classification of hand preference by association analysis.Brit. J. Psychol.,61, 303–321.
Beaumont, J. G., Mayes, A. R. andRugg, M. D. (1978) Asymmetry in EEG alpha coherence and power: effects of task and sex.Electroenceph. Clin. Neurophysiol.,45, 393–401.
Butler, S. R. andGlass, A. (1976) EEG correlates of cerebral dominance. InA. H. Riesen andR. F. Thompson (Eds.),Advances in Psychobiology, Vol. III, Wiley, New York, 219–272.
Cooper, B. E. (1969)Statistics for Experimentalists, Pergamon Press, 270–277.
Cornil, L. andGastaut, H. (1947) Etude eletroencephalographique de la dominance sensorielle d'une hemisphere cerebrale.Presse Med.,37, 421–422.
Doyle, J. C., Ornstein, R. andGalin, D. (1974) Lateral specialisation of cognitive mode: II EEG frequency analysis.Psychophysiol.,11, 567–578.
Galin, D. andOrnstein, R. (1972) Lateral specialisation of cognitive mode: an EEG study.Psychophysiol.,9, 412–418.
Galin, D., Johnstone, J. andHerron, J. (1978) Effects of task difficulty on EEG measures of cerebral engagement.Neurophyschologia,16, 461–472.
Galin, D. andOrnstein, R. E. (1973) Hemispheric specialisation and the duality of consciousness. In:Widroe, Harvey M. D. (Eds),Human Behavior and Brain Function, Charles C. Thomas, Springfield, Illinois.
Morgan, A. H., McDonald, P. J. andMacDonald, H. (1971) Diffrences in bilateral alpha activity as a function of experimental task with a note on lateral eye movements and hypnotisability.Neuropsychol.,9, 459–469.
Shaw, J. C., O'Connor, K. P. andOngley, C. (1977) The EEG as a measure of cerebral function organization.Brit. J. Psychiat.,130, 260–264.
Welch, P. D. (1967) The use of the fast fourier transform for the estimation of power spectra: a method based on time averaging over short modified periodograms.IEEE Trans. Audio and Electroacoustics,15, 70–73.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Koles, Z.J., Flor-Henry, P. Mental activity and the e.e.g.: Task and workload related effects. Med. Biol. Eng. Comput. 19, 185–194 (1981). https://doi.org/10.1007/BF02442714
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02442714