Motor imagery after subcortical stroke: a functional magnetic resonance imaging study

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Motor Control

Background:

• Motor network activation in subcortical stroke recovery varies with task.
• The impact on motor imagery (MI) remains unclear.

Purpose of the Study:

• To assess motor imagery (MI) activation using functional MRI in recovered subcortical stroke patients.
• To contrast MI with motor execution in these patients.

Main Methods:

• Functional MRI was used to study 20 recovered subcortical stroke patients and 17 controls.
• Participants performed motor execution and motor imagery (MI) of a finger-thumb sequence.
• Brain activation in primary motor cortex (BA4a, 4p), premotor, and supplementary motor areas was analyzed.

Main Results:

• Motor execution activation in the affected hand was similar to controls.
• Motor imagery (MI) activation was largely similar, but with key differences in BA4a and dorsal premotor cortex.
• Reduced lateralization in BA4p and a positive correlation between ipsilesional BA4p activation and motor performance were observed.

Conclusions:

• The motor system, including ipsilesional BA4, is activated during MI in recovered subcortical stroke patients.
• MI-related activation patterns show disorganization proportional to residual motor impairment.
• Motor system components upstream of execution are differentially affected by stroke and may be targets for rehabilitation.