Auditory Cortex Lesion and Sound Lateralization: Interaural Time Difference Versus the Interaural Intensity Difference

Abstract

Sound localization in the horizontal plane primarily depends on the interaural time difference (ITD) and interaural intensity difference (HD). Single-unit techniques have shown that binaural neurons in the auditory cortex of cats (6, 7) are sensitive to the ITD or IID. If identical sounds with the ITD or IID are presented to both ears through earphones, the sound images are lateralized to the side receiving the earlier, or louder, stimulus within the head. The perceptual effects are therefore termed sound lateralization rather than sound localization. In free-field, these two cues are combined with spectral cues provided by the outer ears to characterize the origin of a sound source.

The material in this chapter was excerpted from: Yamada K., Kaga K, uno A, Shindo M (1995) Sound lateralization in patients with lesions including the auditory cortex: comparison of interaural time difference (ITD) discrimination and interaural intensity difference (IID) discrimination. Hear Res 101:173–180, 1995; Yamada K, Kaga K, Uno A, Shindo M (1997) Comparison of interaural time and intensity difference discrimination in patients with temporal lobe lesions. Acta Otolaryngol Suppl 532:135–137.