Dynamic rewiring of neural circuits in the motor cortex in mouse models of Parkinson's disease

Using in vivo imaging, the authors explore how dopamine loss in Parkinson’s disease mouse models affects synaptic plasticity in motor cortex. They find that dopamine D1 and D2 receptor signaling distinctly regulates dendritic spine dynamics and that dopamine loss results in atypical synaptic adaptations. These mechanisms may contribute to impaired motor performance in Parkinson's disease. Dynamic adaptations in synaptic plasticity are critical for learning new motor skills and maintaining memory throughout life, which rapidly decline with Parkinson's disease (PD). Plasticity in the motor cortex is important for acquisition and maintenance of motor skills, but how the loss of dopamine in PD leads to disrupted structural and functional plasticity in the motor cortex is not well understood. Here we used mouse models of PD and two-photon imaging to show that dopamine depletion resulted in structural changes in the motor cortex. We further discovered that dopamine D1 and D2 receptor signaling selectively and distinctly regulated these aberrant changes in structural and functional plasticity. Our findings suggest that both D1 and D2 receptor signaling regulate motor cortex plasticity, and loss of dopamine results in atypical synaptic adaptations that may contribute to the impairment of motor performance and motor memory observed in PD.