Double decussated ipsilateral corticospinal tract in schizencephaly.

We report a patient with left hemiparesis because of schizencephaly affecting the right precentral gyrus and describe a double decussated ipsilateral corticospinal tract detected using the multimodal brain mapping technique. In this patient, we could observe that the unaffected primary motor cortex (M1) controls both hands by functional magnetic resonance imaging and motor-evoked potential study. We were also able to visualize the corticospinal tract originating from the unaffected M1 that passed through the internal capsule and cerebral peduncle on the same side. It then crossed over twice at the brain stem level to go down to the ipsilateral spinal cord. These findings show a unique pattern of brain reorganization in the recovery from early brain injury.