Some brain mechanisms for auditory scene analysis.

Abstract

Detection and discrimination of sounds in complex auditory environments is facilitated by knowledge of the locations of sound sources and by spatial separation of signals and maskers. In studies of the spatial sensitivity of auditory cortical neurons in anesthetized cats, we find that location‐dependent variation in temporal spike patterns can signal sound‐source locations throughout up to 360 deg of space. In awake cats, spatial receptive fields can be similarly broad, although cortical neurons show a greater diversity of temporal patterns than is seen in anesthetized conditions. Our recent results demonstrate that spatial tuning tends to sharpen when a cat is engaged in an auditory task, compared to idle conditions, and that tuning can sharpen even further when the task involves sound localization. In human psychophysical studies, spatial hearing permits perceptual “stream segregation” of multiple temporally interleaved sequences of sounds. In parallel studies of the auditory cortex in anesthetized cats...