Aberrant outputs of glutamatergic neurons in deep cerebellar nuclei mediate dystonic movements

Dystonia, characterized by repetitive twisting movements or abnormal postures, has been linked to the deep cerebellar nuclei (DCN). However, the specific roles of distinct neuronal populations within the DCN in driving dystonic behaviors remain unclear. This study explores the contributions of three distinct groups of DCN neurons in an animal model of paroxysmal dystonia harboring a mutation in the proline-rich transmembrane protein 2 (Prrt2) gene. We observed sustained calcium activity elevation across glutamatergic, glycinergic, and GABAergic inferior olive (IO)-projecting neurons within the DCN during episodes of dystonia in Prrt2-mutant mice. However, only the optogenetic activation of DCN glutamatergic neurons, but not glycinergic or GABAergic IO-projecting neurons, elicited dystonia-like behaviors in normal mice. Selective ablation of DCN glutamatergic neurons effectively eliminated aberrant cerebellar DCN outputs and alleviated dystonia attacks in both Prrt2-associated and kainic acid-induced dystonia mouse models. Collectively, our findings highlight the pivotal role of aberrant activation of DCN glutamatergic neurons in the neuropathological mechanisms underlying cerebellar-originated dystonia.