One of the fundamental characteristics of the brain is its ability to pool information from different sensory modalities in order to facilitate the detection and identification of external events. This process of "multisensory integration" is continuously in operation and has profound influences on sensation, perception, and overt behavior. Its impact is evident in the facilitated detection, identification, and reaction to combinations of concordant cues from different modalities, and in the striking perceptual anomalies that occur when these cross-modal cues are discordant. Although the perceptual consequences of multisensory integration have been discussed by philosophers of science the time of ancient Greece, and have been explored in controlled studies during the modern era, our understanding of the basic neural principles by which it operates during normal behavior is surprisingly rudimentary.

A series of experiments is proposed here using the multisensory neuron in the superior colliculus (SC) to explore the neural processes that underlie this phenomenon. The initial aim is to determine the principles by which individual SC neurons integrate information from different sensory modalities (i.e., auditory and visual) by evaluating the multisensory products of systematic changes in the physical properties of those stimuli. These data will then be used to help understand how different levels of the neuraxis cooperate in producing this SC capacity, how this process is expressed during normal behavior, and whether the products of multisensory integration are immutable consequences of the physical properties of the stimuli encountered, or whether they can be substantially altered by the significance of those stimuli and/or the context in which they are encountered.

R01NS022543

1982-08-01

2007-04-30