Effect of Reverberation on Directional Sensitivity of Auditory Neurons: Central and Peripheral Factors

In reverberant environments, acoustic reflections interfere with the direct sound arriving at a listener’s ears, distorting the binaural cues for sound localization. Using virtual auditory space simulation techniques, we investigated the effects of reverberation on the directional rate responses of single neurons in the inferior colliculus (IC) of unanesthetized rabbits. We find that reverberation degrades the directional sensitivity of single neurons, although the amount of degradation depends on the characteristic frequency (CF) and the type of binaural cues available. To investigate the extent to which these midbrain results reflect peripheral processing of the monaural input signals, we extracted directional information from spike trains recorded from auditory nerve (AN) in anesthetized cat for the same VAS stimuli. Our results suggest that the frequency-dependent degradation in ITD-based directional sensitivity in reverberation originates in the auditory periphery.