Activating Lobule VI PC(TH+)-Med Pathway in Cerebellum Blocks the Acquisition of Methamphetamine Conditioned Place Preference in Mice.

Cerebellum has been implicated in drug addiction; however, its underlying cellular populations and neuronal circuitry remain largely unknown. In the current study, we identified a neural pathway from tyrosine hydroxylase (TH)-positive Purkinje cells (PC(TH+)) in cerebellar lobule VI to calcium/calmodulin-dependent protein kinase II (CaMKII)-positive glutamatergic neurons in the medial cerebellar nucleus (Med(CaMKII)), forming the lobule VI PC(TH+)-Med(CaMKII) pathway in male mice. In naive male mice, inhibition of PC(TH+) neurons activated Med neurons. During conditioned place preference (CPP) training, exposure to methamphetamine (METH) inhibited lobule VI PC(TH+) neurons while excited Med(CaMKII) neurons in mice. Silencing Med(CaMKII) using a tetanus toxin light chain (tettox) suppressed the acquisition of METH CPP in mice but resulted in motor coordination deficits in naive mice. In contrast, activating lobule VI PC(TH+) terminals within Med inhibited the activity of Med neurons and subsequently blocked the acquisition of METH CPP in mice without affecting motor coordination, locomotor activity, and sucrose reinforcements in naive mice. Our findings identified a novel lobule VI PC(TH+)-Med(CaMKII) pathway within the cerebellum and explored its role in mediating the acquisition of METH-preferred behaviors.