Ipsilateral Motor Pathway Confirmed by Brain Mapping in a Patient with Traumatic Brain Injury: A case report

ABSTRACT

The aim of this study is to investigate the mechanism of motor recovery using both functional Magnetic Resonance Imaging (fMRI) and Transcranial Magnetic Stimulation (TMS) in a patient with hemorrhagic contusion on the right basal ganglia area. Functional MRI showed that the left primary sensorimotor cortex and the supplementary motor area were activated when the right fingers performed the flexion-extension exercise. On the other hand, the bilateral primary sensorimotor cortex and the left premotor area were activated with the excerise of left hand. Brain mapping for both abductor pollicis brevis muscles (APB) using TMS revealed that ipsilateral motor evoked potentials (MEPs) were obtained at left APB. Ipsilateral MEPs of left APB showed delayed latency and lower amplitude compared to that of right APB when stimulated at the left motor cortex. We concluded that ipsilateral motor pathway from undamaged motor cortex seems to contribute to the motor recovery in this patient and combining TMS with fMRI may provide a powerful tool for investigating the mechanism of motor recovery.