EEG correlates of hemispheric specialisation
EEG correlates of hemispheric specialisation
Previous studies using behavioural measures have reported differences between the two cerebral hemispheres in sustained attention. This was investigated in the work reported here using the frequency analysed EEG as a measure of the activation of the two hemispheres. EEG studies of hemisphere differences are critically reviewed,and the reported experiments were designed to overcome many of the limitations of these previous EEG studies.Stimuli consisted of sets of 4 digits presented sequentially (either visually or auditorily), and subjects were required to respond to those sets containing all odd digits. There were generally consistent effects in all the frequency bands used, showing lower EEG activity to be associated with stimuli containing more odd digits, i.e. showing greater arousal the more a stimulus resembled. the wanted signal. This effect was found to be greater for the left hemisphere EEG in some of the frequency bands included, hence implying greater left hemisphere involvement in task performance. This hemisphere difference was demonstrated to a greater extent with a modification of the basic task involving greater subject effort, but in all the experiments the hemisphere differences were small by comparison with overall bilateral effects of the task.No variations over time were found in the degree of laterality, and therefore these experiments offer no support for the previously reported variations in performance of the two hemispheres over time. Bilateral EEG changes over time were found, which were consistent with an overall decrease in arousal and a decrease in the effect of the stimuli during the 1 hour trials. No sex differences were found in the degree of laterality. Relationships between the EEG and performance, as indicated by reaction times and error rates, varied between the frequency bands used, and were not consistent between experiments.
University of Southampton
Shepherd, Richard
03272950-804a-47ce-8d66-afd07c747d1d
1980
Shepherd, Richard
03272950-804a-47ce-8d66-afd07c747d1d
Shepherd, Richard
(1980)
EEG correlates of hemispheric specialisation.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Previous studies using behavioural measures have reported differences between the two cerebral hemispheres in sustained attention. This was investigated in the work reported here using the frequency analysed EEG as a measure of the activation of the two hemispheres. EEG studies of hemisphere differences are critically reviewed,and the reported experiments were designed to overcome many of the limitations of these previous EEG studies.Stimuli consisted of sets of 4 digits presented sequentially (either visually or auditorily), and subjects were required to respond to those sets containing all odd digits. There were generally consistent effects in all the frequency bands used, showing lower EEG activity to be associated with stimuli containing more odd digits, i.e. showing greater arousal the more a stimulus resembled. the wanted signal. This effect was found to be greater for the left hemisphere EEG in some of the frequency bands included, hence implying greater left hemisphere involvement in task performance. This hemisphere difference was demonstrated to a greater extent with a modification of the basic task involving greater subject effort, but in all the experiments the hemisphere differences were small by comparison with overall bilateral effects of the task.No variations over time were found in the degree of laterality, and therefore these experiments offer no support for the previously reported variations in performance of the two hemispheres over time. Bilateral EEG changes over time were found, which were consistent with an overall decrease in arousal and a decrease in the effect of the stimuli during the 1 hour trials. No sex differences were found in the degree of laterality. Relationships between the EEG and performance, as indicated by reaction times and error rates, varied between the frequency bands used, and were not consistent between experiments.
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Published date: 1980
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Local EPrints ID: 463843
URI: http://eprints.soton.ac.uk/id/eprint/463843
PURE UUID: 09be8416-abfc-4e5e-8d06-fbd16420f77a
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Date deposited: 04 Jul 2022 20:57
Last modified: 04 Jul 2022 20:57
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Author:
Richard Shepherd
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