Neurons trapped in deep cerebellar nets: what deactivating the surface can do to the depths

Abstract

Despite recent evidences linking the cerebellum to relevant brain functions affected in addicts it is still being ignored in addiction research. Several studies unveiled its involvement in the development of pavlovian learning, acquisition and consolidation of emotional and cueinduced drug memories. Perineuronal nets (PNNs) are lattice-like structures made out of extracellular matrix components wrapped around special subsets of neurons. PNNs play a major role in stabilizing neuronal connections by reducing structural plasticity. It is known that this might be the underlying structural mechanism behind long-term memory storage; therefore PNNs would be significantly involved in the acquisition and expression of druginduced memories. In the present study we trained rats in cocaine-induced odor preference conditioning in order to acquire cue-induced drug-memories. Also, animals were lesioned with quinolinic acid in posterior cerebellum. We assessed neural activity and plasticity changes in deep cerebellar nuclei through cFos and PNN expression. Our results showed that the majority of neurons expressing strong PNNs in posterior interpositum displayed increased cFos activity.