Representation of sound location in the primate brain
Knowing where things are in space is essential to our existence. The visual, auditory, and cutaneous senses all contribute to the perception of stimulus location, but they acquire spatial information in radically different ways. Positional information is literally built into the neural wiring for vision and touch: stimuli at different positions in the environment activate receptors at different positions on the retina or on the body surface. In contrast, the topographic organization of the cochlea produces a map for the frequency content of a sound, not its direction. Sound source position must be inferred from the direction-dependent filtering of the sound by the external ear (spectral cues) and from differences in sound arrival time and pressure level (or intensity) across the two ears (binaural difference cues).
