Role of the corpus callosum in the development of a bimanual motor skill

Abstract

Normal adults quickly become highly skilled on a task of bimanual control of the movement of a pen on a vertical screen, described by Preilowski (1972) as an X‐Y plotter. When visual feedback is denied, the performance of highly practiced normal adults remains unchanged. In contrast, patients with surgical division of the anterior portion of the corpus callosum (Preilowski, 1972) or with callosal agensis (Jeeves, Silver, & Jacobson, in press) show marked deterioration of performance without visual feedback. Although groups of 10‐ and 20‐year‐olds performed as normal on Preilowski's task, a group of 6‐year‐olds performed more like acallosals. These results are seen as evidence of reduced functional efficiency of the corpus callosum before myelination is complete at age 10.