The effect of cortico-spinal tract damage on primary sensorimotor cortex activation after rehabilitation therapy

Recently, it was shown that patients have different functional activation patterns within affected primary sensorimotor cortex (SMC) after intensive rehabilitation therapy. This individual difference was supposed to depend on the integrity of the cortico-spinal fibres from the primary motor cortex. In this study, we considered whether patients with different fMRI activation patterns after intensive rehabilitation therapy suffered from different cortico-spinal fibre lesions. To comprehend this circumstance a lesion subtraction analysis was used. To verify these results with the use of transcranial magnetic stimulation motor evoked potentials was also derived. Patients were treated after a modified version of constraint-induced movement therapy (modCIMT; 3 h daily for 4 weeks). Increased and decreased SMC activation showed similar individual patterns as described previously. These activation differences depend on the integrity of the cortico-spinal tract, which was measured via lesion subtraction analysis between patient groups, and was supported by affected motor evoked potentials.