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 high-frequency limb and their Q
10-dB values are 1.95, 8 and 2.89, 6.51. There are three kinds of rate-intensity 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.
