Somatotopic organization of motor fibers in the corona radiata in monoparetic patients with small subcortical infarct.

BACKGROUND AND PURPOSE

The somatotopic organization of the corticospinal fibers is of importance because it is related to certain stroke syndromes. Although it has been suggested that motor fibers are somatotopically arranged in the corona radiata, the evidence is still insufficient in human.

METHODS

The relative anteroposterior and mediolateral location of the lesions was measured on T2-weighted MRI in 28 patients who developed isolated motor deficit limited to the arm, leg, or bulbofacial muscles after a small corona radiata infarct.

RESULTS

The location of the lesions associated with bulbofacial, arm, and leg paresis showed anterolateral-to-posteromedial distribution.

CONCLUSIONS

The results suggest that motor fibers subserving the bulbofacial, arm, and leg muscles are somatotopically arranged at the level of the corona radiata.