Sex differences in averaged visual evoked potentials during food intake in rats

Averaged visual evoked potentials (AVEP's) were recorded in unrestrained male and female rats during alert wakefulness (baseline condition), feeding and drinking. The rats had been deprived of food and water for 23 hr prior to testing. Peak-to-peak amplitude of the AVEP's was measured between the slow negative and the preceding positive component. Under baseline conditions females had higher amplitude AVEP's than males. It is suggested that sex differences in adrenal steroid secretion could account for this observation. During feeding and drinking, AVEP's increased significantly in amplitude in both sexes, and high-voltage, slow EEG activity was observed to appear in most animals. During feeding, these increases in AVEO amplitude were significantly larger in males than in females. These findings support recent views on sex differences in the regulation of feeding behavior.