Network mechanisms in rapid-onset dystonia-parkinsonism.

Rapid-onset dystonia-parkinsonism (RDP) is a rare neurological disorder caused by mutations in the ATP1A3 gene. Symptoms are characterized by a dystonia-parkinsonism. Recently, experimental studies have shown that the pathophysiology of the disease is based on a combined dysfunction of the cerebellum (CB) and basal ganglia (BG) and that blocking their interaction can alleviate the symptoms. The underlying network mechanisms have not been studied so far. Our aim was to characterize neuronal network activity in the BG and CB and motor cortex in the ouabain model of RDP by site-specific infusion of ouabain. Rats were chronically infused with ouabain either in the CB, striatum (STR) or at both places simultaneously. Motor behavior was scored using published rating systems. Parallel in vivo recordings of local field potentials (LFP) from M1, deep cerebellar nuclei (DCN) and substantia nigra reticulata (SNr) were performed. Data were compared to untreated controls. Ouabain infusion into the cerebellum produced severe dystonia that was associated with increased high-frequency gamma oscillations in the DCNs, which were subsequently transmitted to the BG and M1. Striatal infusion led to parkinsonism and elevated beta-oscillations in SNr that were transmitted to the CB and M1. The simultaneous application of STRs and CB with ouabain resulted in dystonia-parkinsonism and increased beta oscillations in BG, CB, and M1. We demonstrate that symptom-specific beta and gamma oscillations can be transmitted between the BG and CB, which is likely to be very important for the understanding of disease mechanisms.