Plasticity in the infralimbic cortex after a lesion of the dorsal posterior cerebellum: an inhibitory pathway for drug-dependent memories

Abstract

Addiction could be considered the result of pathological learning. Drug-associated cues become strong conditioned stimuli that create drug-related memories which promote drug seeking leading to relapse. Both, the striatumcortico-limbic circuitry and the cerebellum store information about reinforcing stimuli and their related cues, sharing widespread connections. Previous studies from the lab showed that both, the IL and the cerebellum exhibit hallmark signatures of drug-induced memories, changes in c- Fos expression and in PNNs. Moreover, the deactivation of the infralimbic cortex (IL) promote preference towards cocaine-associated cues, and expressed increased c-Fos+ neurons, and stronger PNNs in Golgi neurons in the apex of lobule VIII of the cerebellum. In the present study, we managed the effect of a permanent lesion of the lobule VIII vermis of the cerebellum on cocaine-induced odour preference conditioning and plasticity changes in the IL. We aimed to elucidate whether the plasticity changes of drug-induced memories observed in the cerebellum can also be found in the IL. Our results showed that a permanent lesion of the lobule VIII in the vermis promotes preference towards cocaine-associated cues, an increased number of c-Fos+ neurons, and a reduction in the number of infralimbic neurons that expressed a PNN, but no differences were found between groups related to average intensity of the matrix expression. It seems that the IL cortex and vermis are part of a functional and structural network for inhibitory effects on the acquisition of these drug-dependent preference memories.