Accession Number : ADA139797

Title :   Brain Responses and Information Processing IV. Investigations of Hemispheric Asymmetry in Event Related Potentials and Performance during Discrimination of Line Orientation, Color, Shape and under Visual Masking.

Descriptive Note : Final rept. 1 Oct 79-30 Sep 83,


Personal Author(s) : Andreassi,J L ; Juszczak,N M

PDF Url : ADA139797

Report Date : 30 Nov 1983

Pagination or Media Count : 84

Abstract : The research completed over the last twelve months has included a number of studies concerned with evoked cortical potential correlates of visual stimulus processing in humans. The first experiment was conducted in order to replicate an earlier finding in which the amplitude of a relatively late positive component of the event related potential (ERP), known as the P3, was larger to a line orientation that required a 'yes' response than one that required a 'no'. The angular difference between the two lines was only 5 degrees. Another purpose was to assess the reliability of the better right hemisphere performance found with male subjects in the line orientation discrimination task used. In a second experiment, we examined the possibility of hemispheric asymmetry in response to two different colors (red and blue). The two hemispheres responded in essentially the same manner to the two colors. However, an interesting finding was the larger ERPs of both left and right hemispheres to the color blue, especially with central visual field stimulation. A third experiment was directed at the determination of whether the right hemisphere would be more sensitive to visual masking than the left, especially with a metacontrast paradigm which is dependent on spatial factors to produce the masking effect. A fourth experiment was performed to determine the relative responsivity of the two hemispheres to verbal (letter) and spatial (geometric form) stimuli.

Descriptors :   *Brain, *Information processing, *Psychophysiology, Response(Biology), Visual perception, Humans, Stimuli, Males, Females, Discrimination, Orientation(Direction), Scoring, Vision, Masking, Sensitivity

Subject Categories : Psychology

Distribution Statement : APPROVED FOR PUBLIC RELEASE