The caudate nucleus and acquisition of win-shift radial-maze behavior: Effect of exposure to the reinforcer during maze adaptation

Abstract

Rats with lesions of the caudate nucleus or sham lesions were trained on a win-shift radial-maze task following one of two types of maze-adaptation trials. In one adaptation condition, rats were allowed to obtain food from maze arms on an unlimited basis for 5 min on 2 consecutive days prior to the start of win-shift food trials. In this maze-adaptation condition, rats with lesions of the caudate nucleus exhibited a transient impairment in the acquisition of win-shift behavior. In a second maze-adaptation condition, different groups of caudate or sham rats were allowed to explore an empty maze for 5 min on 2 consecutive days prior to the start of win-shift food trials. In this maze-adaptation condition, caudate rats were not impaired in the acquisition of win-shift behavior. The role of reinforcers may be one difference in the operating principles that distinguish between caudate-nucleus and hippocampal memory systems.