fMRI Demonstrates Diaschisis in the Extrastriate Visual Cortex

Abstract

Background and Purpose— Diaschisis may play a critical role in motor recovery, but in other cortical networks its role is unclear. Some visual system regions, such as the fusiform gyri, depend on intact striate regulation for their function. We evaluated visual cortical diaschisis by serial functional magnetic resonance imaging. Methods— Using a high-level visual activation task, we studied patients with visual system stroke by functional magnetic resonance imaging within 10 days and at 6 months. Their activation data were compared with those of age-appropriate healthy control subjects. Results— Three patients were studied. In the short term, patients displayed absent or significantly reduced activation in ventral extrastriate sites. All displayed a restitution of activation to these sites at 6 months. Conclusions— Functional magnetic resonance imaging revealed evidence of ipsilesional cortical diaschisis within ventral extrastriate sites. Diaschisis may play an underrecognized role in visual recovery after stroke.