Cerebral hemispheres and selective attention

The present paper is intended to discuss critically the integration model of the functional interhemispheric relation that has become dominant in neuropsychology with the development, in the last two decades, of split-brain studies.While the split-brain research has undoubtedly produced new experimental methodologies, the current theorizing in this area has been contrastingly conservative. The present paper examines some of its basic assumptions, in particular that the corpus callosum is an association pathway devoted to interhemispheric transmission of information, and that the disconnected cerebral hemispheres function in a parallel way. It is shown that these assumptions have only low consistency both with split-brain behavior and with the normal organization of the fore-brain connectivity.In the early seventies, theoretical novelty has emerged from another research field with Kinsbourne's interpretation of laterality effects in normal man. His concept of asymmetrical hemispheric arousal is shown to be supported, with some reservations, by evidence in this field. But this dynamical concept has a more general value and there are signs that current ideas about the functional relation between the cerebral hemispheres are presently deeply transformed.