Transcallosal inhibition in chronic subcortical stroke

Area of Science:

• Neuroscience
• Motor Control
• Stroke Rehabilitation

Background:

• Chronic stroke survivors often exhibit motor deficits.
• Increased interhemispheric inhibition (IHI) is observed in the lesioned hemisphere during paretic hand movements.

Purpose of the Study:

• To investigate if abnormal IHI also affects movements of the non-paretic hand in chronic subcortical stroke patients.
• To compare IHI during paretic and non-paretic hand movements.

Main Methods:

• Studied IHI during voluntary index finger movements in chronic subcortical stroke patients.
• Utilized a simple reaction time paradigm.
• Measured IHI targeting the contralateral primary motor cortex ((c)M1) for both paretic and non-paretic hands.

Main Results:

• Non-paretic hand movements showed decreased IHI, transitioning to facilitation near movement onset, similar to controls.
• Paretic hand movements exhibited significantly deeper premovement IHI compared to the non-paretic hand.
• Abnormal IHI persisted throughout premovement timings for the paretic hand.

Conclusions:

• Chronic subcortical stroke is associated with deeper premovement IHI during paretic hand movements.
• This heightened IHI may contribute to motor control deficits observed in stroke patients.
• Findings highlight potential therapeutic targets for improving motor function after stroke.