| Abstract: | It was thought that simple finger movementsare commanded by the contralateral cerebral hemisphere. Dextroas digital movements mastered in thepostnatal period, however, may be preprogramed inone hemisphere only, that is, the dominant hemispherefor manual movements. The encoded signals aresent to the opposite hemisphere through a myriadcommissural fibers in the corpus callosum. Writing,drawing and paper cutting with scissors of eitherhand were tested in 46 normal subjects. Scissorscutting of both hands were basically similar in the46 subjects. Of the 38 right-handed persons whohad never written with the left hand previously, theideographs written and simple figures drawn withthe left hand for the first time were quite similarto those with the right hand. Four dextral illiteratescould only be tested on drawing. The simple figuresdrawn with either hand of these 4 persons, thoughrather poor, were very similar. Four left handedpersons had already learned to write with the righthand. In them the ideographs and drawings madewith the left hand were very close to those executedwith the right. It seems that the dextrous digitalmovements of both hands were under the c-ommand |
