Effect of visual experience on the habituation of orienting behavior.

Orienting behavior elicited by novel visual and auditory stimuli was examined in light-reared (LR) and dark-reared (DR) rats at 30, 60, 90, or 120 days of age. Orienting behavior was assessed by examining the rat's ability to interrupt ongoing licking and perform appropriate head and postural adjustments when apparently moving or stationary light displays or tones were presented. When the lights were first presented to the LR and DR rats, their orienting behavior did not differ at any of the ages examined. However, age and visual experience did influence habituation and recovery of orienting with changes in the light display. The older DR rats habituated with fewer repeated presentations of the light displays than their LR counterparts and did not recover orienting as effectively to all the subsequent changes of the light displays. The younger LR and DR rats did not differ reliably. These results are discussed with regard to the nature of the habituation process for rodents and the relation between visual experience and habituation of attentional responses.