Effect of stimulus orientation on the latency and amplitude of the VEP

VEPs were recorded using 5.0 c/deg square wave gratings presented at vertical and oblique (45 deg) orientations and phase-alternated at two rates, 6 alternations/sec and 12 alternations/sec. In agreement with previous reports, VEP amplitude was smaller for obliquely oriented gratings than for vertically oriented gratings at both alternation rates. Unlike previous studies, however, the authors found that VEP latency was longer for obliquely oriented gratings at the slower (6/sec) alternation rate.