Effects of checkerboard pattern stimulation on evoked cortical responses in relation to check size and visual field

Abstract

Cortical evoked responses to checkerboard stimulation were studied as a function of check size and visual field. Stimuli were presented to the upper, central, and lower parts of the retina. Regardless of check size, largest potentials were obtained to lower-field stimulation; central-field stimulation yielded intermediate responses; upper-field stimulation produced the smallest responses. Maximal responses were obtained to intermediate check sizes during lower-field stimulation and to the smallest checks during upper-field stimulation. The results suggest that the cortical visual system is more responsive to patterned stimuli appearing in the lower viewing field than in the upper, but that the system may be relatively more sensitive to smaller objects appearing in the upper field. © 1970, Psychonomic Journals, Inc.. All rights reserved.