Work on the neurophysiology of feature-based selective attention has almost exclusively been focused within a single sensory modality. Yet in the real world relevant objects are often specified in more than sense, and this likely results in selectively attending to inputs across multiple sensory systems. Clearly a full understanding of selective attention processes requires that the neurophysiology of selective attention be studies under conditions in which subjects are attending to related features across sensory systems. The primary aim of this proposal is to apply the high temporal resolution of electrophysiological recordings with the fine spatial resolution of functional magnetic resonance imaging, under identical task conditions, in order to characterize both the time course and neuroanatomical substrates of cross-sensory selective attention mechanisms in relation to the vast literature on uni-sensory selective attention. Importantly, this work will be extended to schizophrenia patients, to characterize the neurophysiology of selective attention deficits in this population. A variation of the selective attention paradigm of Hillyard (1973) will be used. Ultimately, findings on the neurophysiology of cross-sensory selective attention will provide a more complete picture of attentional processes, and add to the basis for understanding attentional dysfunction in patients with schizophrenia.
