Brain sensorimotor hand area functionality in acute stroke: insights from magnetoencephalography

Area of Science:

• Neuroscience
• Neurology
• Brain Plasticity

Background:

• Understanding post-stroke brain functional reorganization is crucial for insight into neuronal response to injury.
• Early adaptive mechanisms following ischemic stroke inform potential therapeutic strategies.

Purpose of the Study:

• To investigate functional brain readjustments in the acute phase after ischemic stroke.
• To explore neuronal adaptation and excitability changes in affected and unaffected hemispheres.

Main Methods:

• Magnetoencephalography (MEG) was used to record somatosensory-evoked fields (SEF) in 32 acute ischemic stroke patients.
• Analysis included latency, strength, and position of early cortical components (M20, M30), interhemispheric differences, and cross-correlations.
• Clinical severity was correlated with neurophysiological findings.

Main Results:

• No unusual neural recruitment observed, though some source displacement occurred.
• Stroke severity correlated with SEF source strengths, interhemispheric differences, and M30 latencies.
• Enhanced excitability was noted in the affected hemisphere (AH), often with preserved hand function.
• Larger lesions correlated with enhanced unaffected hemisphere (UH) excitability, suggesting abnormal transcallosal transmission and GABAergic function in AH.
• Some patients with spared BA2/parietal responses showed high hand functionality.

Conclusions:

• Early stroke phase reveals complex brain adaptation mechanisms involving interhemispheric interactions and excitability changes.
• Findings highlight the relationship between neurophysiological alterations, lesion characteristics, and clinical outcomes.
• Results provide a foundation for developing targeted therapeutic and rehabilitative interventions for stroke patients.