Interaurally phase/time sensitive cells in the cat inferior colliculus

Abstract

Using dichotically presented sinusoids, the response of many low‐frequency cells in the inferior colliculus (IC) will vary cyclically as a function of the interaural delay. Furthermore, the interval between peaks of this cyclic pattern equals the period of the stimulating frequency, indicating that these neurons are sensitive to changes in interaural phase created by the delays. This is further demonstrated by the use of binaural beat stimuli which yield results similar to those obtained by the interaural delay method. Most IC neurons show an equal amplitude symmetrical cyclic response independent of the magnitude or sign of the interaural delay and rate or direction of interaural phase change. However, we have encountered a sizeable number of cells that are sensitive to the above parameters as well as to the stimulus features such as off‐time and interaural intensity differences. These results have been helpful in developing a computer simulated model of a binaural cell. Recently, we have extended our studies to high‐frequency IC neurons and have found that under appropriate stimulus conditions they are sensitive to changes in interaural delay in a manner similar to their low‐frequency counterparts.