Multisensory integration of audio-visual inputs in normal subjects and neglect patients

Neurophysiological studies have shown in animals that a sudden sound enhanced perceptual processing of subsequent visual stimuli. In the present chapter we explored the possibility that such enhancement also exists in humans and can be explained through crossmodal integration effects, whereby the interaction occurs at the level of bimodal neurons. Normal subjects and RBD patients were required to detect visual stimuli in a unimodal visual condition or in crossmodal audio-visual conditions. The spatial and the temporal proximity of multisensory stimuli were systematically varied. An enhancement of the visual percetion was found when the audiovisual stimuli followed a rather clear spatial and temporal rule, governing multisensory integration at the neuronal level.