[Evaluation of compound action potential tuning curves from normal guinea pig cochleas]

Eighteen ears of normal guinea pigs were examined by means of compound action potential tuning curve (AP-TC) with different measure parameters. AP-TC was measured at pure-tone of various frequencies using simultaneous masking procedure by the electrodes on the round window. AP was evoked by filter click (2, 3, 4, 5, 6, 10 kHz) with an intensity 10, 30 and 50 dB above threshold. Masker level producing 30% reduction in AP amplitude was used. The results showed that AP-TC was more sharply as test frequency was elevated. It is corresponded well with the published results. No differences in tuning (i.e., the form of the curves and Q10 dB values) and thresholds were found between two different times for the same animal. In addition, the Q10 dB values of AP-TC were gradually reduced along with the elevate of the test stimuli intensity from 10 to 50 dB above threshold.