VERNIER AND GRATING ACUITY IN ADULT HOODED RATS - THE INFLUENCE OF SEX

Although morphological sex differences are pervasive in the primary vi sual cortex of hooded rats, it is not known whether sex differences oc cur In vision in these rats. in this study, grating acuity was measure d in a forced-choice Y maze and a jumping stand in adult hooded rats, and vernier acuity thresholds were established in the jumping stand. W ith a criterion of 34 correct/50 trials, the: number of correct choice s for both sexes was high (1.0-1.6 cycles per degree [c/deg]) for spat ial gratings. Female rats made more correct identifications of the coa rse gratings (0.125 and 0.25 c/deg) than male rats, but no sex differe nces were found fur higher spatial frequencies. In contrast, male rats were better at detecting smaller vernier offsets in both the individu al criterion and group averages than female fats, and all of the: rats detected vernier misalignments at 34.1 min (equivalent to 1.75 c/deg) , which is above their grating acuity. Vernier acuity may mirror some sex differences in visual cortex anatomy.