The world surrounds us with an immense variety of sounds, colors, textures, and odors. In everyday life we need to receive and interpret this information to help us plan and adopt appropriate behaviors. Perception is the first phase of this interaction with the world. It progresses from initial encoding of data in a number of specialized sensory end organs for the different modalities (vision, hearing, taste, touch, and smell) through various stages of processing in subcortical and cortical structures in the brain, stages that elaborate, [Page 633]focus, interpret, and ultimately integrate this information to provide us with what we regard as our experience of the world.

Given the complexities of perceptual processing and the wide range of neural structures involved, it is not surprising to find ...