Behavioral measurements of visual processing in adult male and female hooded rats: Do visual tasks reflect sex differences in visual cortex morphology?

Although anatomical sex differences are pervasive in the primary visual cortex of hooded rats, it is not known whether sex differences occur in vision in these animals. The purpose of this dissertation is to examine whether sex differences in morphology in the visual cortex of adult hooded rats influence vision in littermate pairs of male and female hooded rats. Three types of visual functions--grating acuity, vernier acuity, and motion parallax information--that are processed in the primary visual cortex were examined. Grating acuity was measured in a forced choice Y-maze and a jumping stand. Using a criterion of 34 correct/50 trials, grating acuity for both sexes was high (1.0-1.6 cycle/degree). Females made more correct identifications of the coarse gratings (0.125 and 0.25 c/deg) than males, but no sex differences were found for higher spatial frequencies. Vernier acuity thresholds were established in the jumping stand. In contrast to grating acuity, males were better at detecting smaller vernier offsets in both individual criterion and group averages than females. All of the rats were able to detect vernier misalignments (15.6 min of arc; 1.9 c/deg) above their level of grating acuity, and several subjects had vernier thresholds that exceeded the estimated Nyquist limit for hooded rats. In the third experiment, male and female rats, given a checkerboard distance cue in a fixed or movable position, were trained to jump up to 40cm from one elevated platform to another. There was no difference in the landing accuracy or in the number or size of head bobs that were generated to produce motion parallax information for distance estimation by male and female rats. Thus, there is evidence of sex differences in one visual function in rats that may mirror differences in the primary visual cortex.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Psychology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Seymoure, Penny

Contributors dc:contributor

• Juraska, Janice M.

• Psychology, Psychobiology
• Psychology, Developmental
• Psychology, Physiological

Statement dc:rights

• Copyright 1996 Seymoure, Penny

Language dc:language

eng

Identifier

(UMI)AAI9712436
9780591199932
AAI9712436

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/22014