Functional abnormalities in the cerebello-thalamic pathways in an animal model of dystonia
Dystonia is often associated with functional alterations in the cerebello-thalamic pathways, which have been proposed to contribute to the disorder by propagating pathological firing patterns to the forebrain. Here, we examined the function of the cerebello-thalamic pathways in a model of DYT25 dystonia, mice carrying a heterozygous invalidation of Gnal gene which notably disrupts striatal function, exhibiting dystonic movements and postures following systemic or striatal administration of oxotremorine. Theta-burst optogenetic stimulations of the cerebellar nuclei evoked a potentiation of the responses to cerebellar stimulations in the thalamus and motor cortex in WT mice, without evident motor function disruption. In contrast, theta burst stimulations evoked a depression of these responses only in dystonia-manifesting Gnal+/- mice after oxotremorine administration, decreased the disabling dystonia attacks, and increased normal active wake behaviour in Gnal+/- mice. The cerebellum could thus offer a gateway for a corrective treatment of motor impairments in dystonia including striatal dysfunction. One sentence summaryA mouse model of DYT25 dystonia, carrying a Gnal mutation disrupting striatal neurotransmission, exhibits anomalous cerebello-thalamic plasticity in the non-manifesting state, but theta-burst cerebellar stimulations during cholinergic-induced dystonia depress the cerebello-thalamic transmission and reduce the severity of the motor symptoms.