Cortico-Cerebellar Connectivity Underlying Motor Control in Chronic Poststroke Individuals

Area of Science:

• Neuroscience
• Cerebro-cerebellar interactions
• Stroke rehabilitation

Background:

• Stroke-induced sensorimotor cortex damage reduces cerebellar metabolism, impairing motor rehabilitation outcomes.
• Understanding movement-related cerebellar physiology and cortico-cerebellar coherence (CCC) post-stroke is vital for developing new neuromodulatory techniques.
• Previous research has lacked thorough investigation into human cerebellar electrophysiology and cortico-cerebellar connectivity after stroke.

Purpose of the Study:

• To investigate the excitability and interaction between the ipsilesional cortex and the cerebellar dentate nucleus (DN) in chronic post-stroke individuals.
• To explore the relationship between cortico-cerebellar coherence (CCC) and motor impairment levels during a visuo-motor task.
• To assess the feasibility of targeting the cerebello-thalamo-cortical pathway for upper limb motor rehabilitation.

Main Methods:

• Conducted a first-in-human phase I trial of deep brain stimulation of the cerebellar dentate nucleus (DN).
• Collected invasive DN recordings and scalp electroencephalography (EEG) in stroke participants during a visuo-motor tracking task.
• Analyzed event-related oscillations and cortico-cerebellar coherence (CCC) in the low beta band.

Main Results:

• Significant correlation in event-related oscillations between ipsilesional cortex and DN at movement onset in the low beta band.
• Moderately and severely impaired participants showed desynchronization and synchronization, respectively, in the low beta band.
• Significant CCC was observed in the low beta band during the isometric hold period, critical for task accuracy.

Conclusions:

• A strong coupling exists between the ipsilesional sensorimotor cortex and the cerebellar dentate nucleus in the low beta band during motor control.
• This coupling is present across all levels of motor impairment post-stroke.
• Findings encourage the exploration of the cerebello-thalamo-cortical pathway, specifically electrical stimulation of the DN, as a promising neuromodulation target for promoting upper limb motor rehabilitation.