Block design performance following callosal sectioning. Observations on functional recovery

J. E. LeDoux, D. H. Wilson and M. S. Gazzaniga

A patient with complete surgical section of the corpus callosum was tested on a constructional task 17 months post-operatively. The left and right hands were separately tested under conditions of free visual exposure and lateralized visual field exposure. The results suggest that the typically observed improved performance of the right hand with increasing postoperative time is attributable to the acquisition of homolateral control over the right hand by the right hemisphere. The implications for left-right brain organization and the syndrome of constructional apraxia are considered.