THE DISCONNECTION SYNDROME - BASIC FINDINGS REAFFIRMED

Recent challenges to the traditional view of the disconnection syndrom e have been based primarily on evidence of information shared between the hemispheres in commissurotomy patients L.B. and N.G. of the West C oast series. In order to evaluate the generality of these claims, pati ents J.W., V.P. and D.R. were tested using a series of experiments whi ch replicated and extended some of the experiments carried out in the West Coast series. Using comparisons of numerical identity and value a s the model tasks, we found no indication that the separated hemispher es of J.W. or D.R. could share information on any of the tasks they pe rformed. V.P., who has spared callosal fibres and has shown highly spe cific transfer in previous investigations, performed above chance (60% ) in one out of three between field conditions. Together the data fail to support the claims that split-brain patients show evidence of unif ied cognitive functioning particularly for more abstract, nonperceptua l tasks. The data are consistent with the traditional view of the corp us callosum as the primary interhemispheric pathway by which sensory a nd high-level cognitive integration is achieved.