Lesions of the prelimbic-infralimbic cortices in rats do not disrupt response selection processes but induce delay-dependent deficits: Evidence for arole in working memory?

Effects of neurotoxic lesions of the prelimbic-infralimbic cortex (PL-IL) w ere examined in rats performing 2 conditional tasks. PL-IL-lesioned rats sh owed normal acquisition of a visuospatial conditional discrimination in a Y maze as well as a tone-light conditional discrimination in an operant cham ber, indicating that the PL-IL is not necessary for response selection proc esses. When the working memory load was subsequently increased in the tone- light conditional discrimination, rats with PL-IL lesions showed a delay-de pendent disruption of performance. This suggests a role of the PL-IL in som e working memory processes. However, the present results, considered along with previous studies, suggest that the PL-IL does not seem to be directly involved in the processes necessary to maintain specific items over a delay period but rather in the planning of forthcoming behavioral responses on t he basis of previously acquired information.