1. School of Life Sciences, Central China Normal University, Wuhan 430079, China 2. Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, the Chinese Academy of Sciences, Beijing 100080, China 3. Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
To study the basic properties of neuron response to sound stimulation in the inferior colliculus of Rhinolophus pusillus, one kind of CF/FM (constant frequency/frequency modulated) bats, single unit was recorded with microelectrode under free field stimulation conditions. The results from 110 recorded neurons showed that there were five different types of discharge patterns in the inferior colliculus, including phasic (54.5%), tonic (25.5%), sustained (7.3%), chopper (7.3%), and pauser (5.4%). Ranges of recording depth, best frequency (BF), minimum threshold (MT) and response latency at 10 dB above MT of these neurons were 208-1 855 μm (829.0±328.1 μm), 16.7-75.6 kHz (38.9±15.7 kHz), 5-74 dB SPL (34.7±13.6 dB SPL) and 5.0-27.5 ms (15.2±3.9 ms), respectively. BFs of neurons increased with the increase of recording depth (r=0.9578, P<0.001). The V-shaped FTCs of 54 neurons were obtained and divided into two types, i. e. single peak and double peak. The most (69.2%, 36/52) of FTCs were wider (Q 10-dB value<5) and the few (30.8%, 16/52) were narrower (Q 10-dB value>5). Moreover, FTCs with double peaks were with milder slope in low-frequency limb and steeper in highfrequency limb and their Q 10-dB values are 1.95, 8 and 2.89, 6.51. There are three kinds of rateintensity functions in 34 neuron including monotonic, non-monotonic and saturated. In combination with our previous observation of Pipistrellus abramus, the differences of acoustic response properties of the neurons and their behavioral significance were analyzed and discussed.