Decoupling of motor cortex to movement in Parkinson's dyskinesia rescued by sub-anaesthetic ketamine.
Brain : a journal of neurology June 3, 2025 Abhilasha Vishwanath, Mitchell J Bartlett, Torsten Falk et al. 8 citations
In a rat model of Parkinson's disease and levodopa-induced dyskinesia (LID), correlations between movement, gamma-band activity, and single-unit firing in primary motor cortex were high under control conditions but decreased considerably after levodopa administration, suggesting the motor cortex becomes functionally decoupled from ongoing movements during LID. This decoupling occurred in both dopamine-depleted and non-depleted hemispheres. Ketamine (20 mg/kg) disrupted finely tuned gamma oscillations, reduced LID, and moderately increased single-unit correlations with movement, but did not enhance gamma-band correlations with movement. Ketamine also reorganized cell-pair firing-rate correlations, inducing a distinct neural ensemble state in LID animals. The findings suggest the motor cortex does not directly trigger specific dyskinetic movements but may permit aberrant movements to emerge in downstream circuits.