Interaural phase coding in auditory midbrain: influence of dynamic stimulus features

A laterally located sound source stimulates the two ears at slightly different times, generating interaural phase disparities (IPDs) that are used for sound localization. Under natural conditions, such interaural cues are likely to be constantly changing, or dynamic. In the inferior colliculus of gerbils and cats, the nonlinearities in the coding of dynamic interaural phase cues are demonstrated. Responses to ecologically realistic phase cues are more reflective of the change of IPD than of the absolute IPDs over which that change occurs. This observation is inconsistent with the established view that directional information is coded in terms of absolute IPD.