Lesions of the prelimbic-infralimbic cortices in rats do not disrupt response selection processes but induce delay-dependent deficits: evidence for a role in working memory?
Effects of neurotoxic lesions of the prelimbic-infralimbic cortex (PL-IL) were examined in rats performing 2 conditional tasks. PL-IL-lesioned rats showed normal acquisition of a visuospatial conditional discrimination in a Y maze as well as a tone-light conditional discrimination in an operant chamber, indicating that the PL-IL is not necessary for response selection processes. When the working memory load was subsequently increased in the tone-light conditional discrimination, rats with PL-IL lesions showed a delay-dependent disruption of performance. This suggests a role of the PL-IL in some 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 the basis of previously acquired information.
Delatour
B
B
Laboratoire de Neurobiologie de l'Apprentissage, de la Mémoire et de la Communication, Université Paris-Sud, Orsay, France.
Gisquet-Verrier
P
P
D000818:Animals; D003216:Conditioning, Operant / Q000502:physiology*; D004193:Discrimination Learning / Q000502:physiology*; D018690:Excitatory Amino Acid Agonists; D007051:Ibotenic Acid; D008032:Limbic System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D017397:Prefrontal Cortex / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018690:Excitatory Amino Acid Agonists; D007051:Ibotenic Acid