关键词: 普氏蹄蝠, 下丘, 听觉诱发电位, on-off 反应

Abstract: We investigated the responses of neuron groups in the inferior colliculus of Pratt’s leaf-nosed bat (Hipposideros pratti),during 500 -4 000 μm recording depth,to constant frequency components of three harmonics (CF1 - CF3 ),using auditory evoked potential combined with the computer averaging technique. The results showed that evoked potential waves included 2 -4 peaks under the given stimuli,and all exhibited on-off responses below the 1 000 μm recording depth. With increasing recording depth,the amplitudes of on-responses all reached maximum at 3 000 μm and then decreased(P <0.001),while the latencies decreased linearly (P < 0. 001);the off-responses triggered by CF2 had the largest amplitudes, while the amplitudes of off-responses evoked by CF1 and CF3 were smaller. The off-responses of CF2 (P <0.001)had linearly decreasing latencies,but the CF1 (P > 0. 05)and CF3 (P >0. 05)had no such linear change with the increased recording depth. The results reveal there were unanimous tendency of neuron groups’processing on-responses, indicating that the processing of the acoustic signals related to behavior may have complex interactions among frequency layers;and off-responses were sensitive to the frequency near the dominant frequency, suggesting that they may play a role in Doppler shift,capturing the fluttering of insects or communication of constant frequency-frequency modulation bats.

Key words: Auditory evoked potentials, Hipposideros pratti, Inferior colliculus, On-off response