Neural Mechanisms of Binaural Processing in the Auditory Brainstem

Spatial hearing, and more specifically the ability to localize sounds in space, is one of the most studied and best understood aspects of hearing. Because there is no coding of acoustic space at the receptor organ, physiological sensitivity to spatial aspects of sounds first emerges in the central nervous system. Much progress has been made in the identification and characterization of the circuits in the auditory brainstem that create sensitivity to binaural and monaural cues toward acoustic space. We review the progress over the past third of a century, with a focus on the mammalian brainstem and on the anatomy and cellular physiology underlying the physiological tuning of monaural and binaural circuits to acoustic cues toward spatial hearing. In addition to examining the detailed mechanisms involved in the processing of the three main spatial cues, we also review the integration of these cues and their use toward behavior.