Variations in attentional bias of the disconnected cerebral hemispheres

Abstract

The research presented in this paper investigates differences in the hemispheric control of attention. In particular, the contribution of environmental as well as egocentric co-ordinates to the speed of responses to attended visual stimuli is considered. Five patients with complete section of the corpus callosum were tested under conditions that allow hemispheric sensitivity to environmental and egocentric co-ordinates to be examined separately. We conclude that each hemisphere can direct attention in the contraversive direction in both egocentric and environmental co-ordinate space. Additionally, right-hemisphere dominance for maintenance of alertness is supported. These results are discussed in the context of neurophysiological data and current theories of attention.