菲菊头蝠的下丘神经元基本声反应特性
Basic Properties of Neuron Response to Sound Stimulation in the Inferior Colliculus of Rhinolophus pusillus
-
摘要: 自由声场刺激条件下，采用单单位胞外微电极记录方法，研究了一种未被研究过的恒频/调频(CF/FM)蝙蝠——菲菊头蝠(Rhinolophus pusillus)的下丘神经元基本声反应特性，其结果发现，在所得的110个下丘神经元中，发放类型包括相位型(54.5%)、紧张型(25.5%)、持续型(7.3%)、梳齿型(7.3%)和暂停型(5.4%)等5种类型。记录深度在208～1 855(829.0±328.1)μm之间，最佳频率在16.7～75.6(38.9±15.7)kHz之间，最小阈值在5～74(34.7±13.6)dB SPL之间，阈上10 dB SPL潜伏期在5.0～27.5(15.2±3.9)ms之间。最佳频率随记录深度的增加而增大(r=0.957 8，P<0.001)；记录的54个频率调谐曲线(FTCs)均为开放型，其中52个为单峰型，2个为双峰型。52个单峰型FTC的Q10-dB值介于1.56～31.61之间，并且大部分是狭窄型(Q 10-dB值>5)，占69.2%(36/52)，少部分为宽阔型(Q 10-dB值<5)，占30.8%(16/52)。2个双峰型神经元FTC在低频处为宽阔型，高频处为狭窄型，Q 10-dB值分别为1.95、8和2.89、6.51。共获得34个神经元的强度－发放率函数(RIFs)，可分为单调型、非单调型和饱和型。结合先前所研究的FM蝙蝠——普通伏翼蝠(Pipistrellus abramus)下丘神经元的基本声反应特性，比较分析了CF/FM蝙蝠与FM蝙蝠下丘神经元的声反应差异及其行为学意义。Abstract: 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.
下载: