STIMULUS LEVEL OF DICHOTICALLY PRESENTED TONES AND CAT SUPERIOR OLIVE S-SEGMENT CELL DISCHARGE

Knowledge of the frequency of the stimulus and existing interaural intensity differences are inadequate for predicting S segment cell discharge rates. The stimulus level, re threshold, of dichotically delivered tones must also be known. At low stimulus levels the most active population of S segment cells consists of cells whose CFs are tuned to the frequency of the stimulus tone. As stimulus levels of dichotically delivered tones increase above threshold, cells with CFs not tuned to the stimulus frequency, tend to discharge at rates higher than these of the cells initially responsive at low levels. The higher the stimulus level, the greater the discrepancy in frequency between the CFs of the most active cell population and the stimulus. Thus, the locus of maximum activity within the S segment is dependent not only on the frequency of the dichotically delivered stimulus tone but also on its stimulus level. © 1969, Acoustical Society of America. All rights reserved.