Abstract

Evidence from studies requiring the recognition and discrimination of facial and letter stimuli suggests that the right and left cerebral hemispheres are more sensitive to low and high spatial frequencies, respectively. More direct tests requiring the detection of simple sinusoidal gratings have yielded inconclusive findings with some supporting hemispheric asymmetries and others failing to do so. These studies using sinusoidal gratings have used small n terms of 2 or 3, have not controlled eye movements, and in some cases have confounded hemiretina with hemispheric stimulation. Therefore, in the present study we investigated hemispheric and hemiretinal sensitivity to a low (0.8-cycle/deg) and a high (8.7-cycles/deg) spatial frequency grating in 8 observers. To minimize eye movements, the gratings were randomly presented for 100 ms, 1.4 deg from a central fixation in the right, left, upper, or lower visual fields. The right and left eye of each observer was tested during each of two sessions using a criterion-free spatial forced choice procedure. No evidence for asymmetric sensitivity to either spatial frequency was found between the right and left visual fields or for the nasal and temporal hemiretina.

© 1987 Optical Society of America