Motor cortex excitability in acute cerebellar infarct

Area of Science:

• Neuroscience
• Neurology
• Rehabilitation Medicine

Background:

• Cerebellar infarcts are known to cause motor deficits.
• Limited evidence exists on motor cortex excitability changes post-cerebellar stroke.
• Understanding these changes is crucial for rehabilitation strategies.

Purpose of the Study:

• To investigate changes in motor cortex excitability after acute cerebellar infarct.
• To determine the functional relevance of these excitability changes.
• To explore the longitudinal course of cortical plasticity post-cerebellar stroke.

Main Methods:

• Paired-pulse transcranial magnetic stimulation (TMS) used to assess motor cortex excitability.
• Ten patients with acute unilateral cerebellar infarct studied longitudinally.
• Clinical assessments correlated with TMS findings over 12 months.

Main Results:

• Short-interval intracortical inhibition (SICI) significantly reduced in the contralateral motor cortex (contraM1) immediately post-stroke.
• SICI was also reduced in the ipsilateral motor cortex (ipsiM1) in patients with severe functional impairment.
• Reduced ipsiM1 SICI correlated with greater clinical impairment, suggesting functional relevance.

Conclusions:

• Acute cerebellar infarcts induce excitability abnormalities in both contra- and ipsilateral motor cortices.
• These changes are more pronounced in patients with severe functional impairment.
• Ipsilateral motor cortex changes may represent a functionally relevant plastic process to facilitate recovery.