EFFECTS OF AN ELECTROLYTIC LESION OF THE PRELIMBIC AREA ON ANXIETY-RELATED AND COGNITIVE TASKS IN THE RAT

The aim of this paper was to study the role of the prelimbic area of r ats in response selection. A bilateral electrolytic lesion was made in the prelimbic area. The rats were tested in the Morris water-maze, th e conditioned shock-prod burying test, the elevated plus-maze, a modif ied open held test, and the step-through passive avoidance test. In th e water-maze during initial acquisition, the latency times of the lesi oned rats were not different from those of the controls, but they foun d the platform faster than the sham-operated rats after the platform w as placed in a new position. The lesion did not affect performance in the shock-prod burying test. In the elevated plus-maze the lesioned ra ts were more active than the sham-operated rats and spent more time on the open arms. In the open held there was no difference between lesio ned and sham-operated rats with regard to distance travelled or the ti me spent near the object in the center of the open held. In the passiv e avoidance test the lesioned rats had a shorter latency time to enter the shock compartment during the retention trial than the sham-operat ed rats did. The results were discussed in relation to those of simila r studies. The extent and precise localisation of the lesion seems to be crucial for the outcome: lesions confined to the prelimbic area may have the opposite effects of larger lesions. Furthermore, it may well be that the prelimbic area is only involved in processing of stimuli of a specific sensory modality, as made probable by the results of dif ferent conditioned reinforcement tasks. Finally, it was stated that we still lack a hypothesis about the precise role of the prelimbic area in response selections.