CAJ | 학술논문

尽管昆明小鼠下丘神经元对纯音的反应已有深入研究,但其对调频声的反应情况却未见报道.本研究在自由声场条件下,采用单单位细胞外记录方法,观察了昆明小鼠下丘神经元对调频声刺激的反应情况.根据神经元对调频声及纯音反应的阈值差异,所记录的99个下丘神经元可分为三种类型:对调频声刺激反应的阈值低于纯音的为Ⅰ型(57/99,57.6%),二者阈值相当的为Ⅱ型(12/99,12.1%),而纯音阈值低于调频声的为Ⅲ型(30/99,30.3%).与Ⅲ型神经元相比,Ⅰ型神经元具有较低的CF和Q20dB(P＜0.05 和 P＜0.001)和较高的RB20dB(P＜0.05).通过分析下丘神经元对上、下扫时发放数的差异,发现有36个(36/99,36.4%)神经元表现出方向选择性,其中22个(22/99,22.2%)为上扫敏感,其余14个(14/99,14.2%)为下扫敏感,且上扫敏感性神经元比下扫敏感性神经元在Ⅰ、Ⅱ和Ⅲ型神经元中有更广的分布范围.通过比较发现,Ⅰ型神经元和方向选择性神经元的特征频率都非常集中地分布在10 kHz-20 kHz范围内(77.2%和83.3%).此外,对其中24个神经元采取了不同调制速度的调频声刺激,大多数(15/24,62.5%)神经元对快调频声反应最为敏感,并且随着调制速度的升高,方向选择性神经元的比例有下降趋势(45.8% vs 41.7% vs 33.3%).上述结果提示,昆明小鼠下丘神经元能有效处理调频声刺激,且具有方向选择性的调频声在昆明小鼠的声通讯中占有重要地位.
진관곤명소서하구신경원대순음적반응이유심입연구,단기대조빈성적반응정황각미견보도.본연구재자유성장조건하,채용단단위세포외기록방법,관찰료곤명소서하구신경원대조빈성자격적반응정황.근거신경원대조빈성급순음반응적역치차이,소기록적99개하구신경원가분위삼충류형:대조빈성자격반응적역치저우순음적위Ⅰ형(57/99,57.6%),이자역치상당적위Ⅱ형(12/99,12.1%),이순음역치저우조빈성적위Ⅲ형(30/99,30.3%).여Ⅲ형신경원상비,Ⅰ형신경원구유교저적CF화Q20dB(P＜0.05 화 P＜0.001)화교고적RB20dB(P＜0.05).통과분석하구신경원대상、하소시발방수적차이,발현유36개(36/99,36.4%)신경원표현출방향선택성,기중22개(22/99,22.2%)위상소민감,기여14개(14/99,14.2%)위하소민감,차상소민감성신경원비하소민감성신경원재Ⅰ、Ⅱ화Ⅲ형신경원중유경엄적분포범위.통과비교발현,Ⅰ형신경원화방향선택성신경원적특정빈솔도비상집중지분포재10 kHz-20 kHz범위내(77.2%화83.3%).차외,대기중24개신경원채취료불동조제속도적조빈성자격,대다수(15/24,62.5%)신경원대쾌조빈성반응최위민감,병차수착조제속도적승고,방향선택성신경원적비례유하강추세(45.8% vs 41.7% vs 33.3%).상술결과제시,곤명소서하구신경원능유효처리조빈성자격,차구유방향선택성적조빈성재곤명소서적성통신중점유중요지위.
Very few studies have been performed on the inferior colliculus (IC) by using frequency modulated (FM) stimulus though its acoustical response properties have been investigated by using pure tone in the Kunming mouse (Mus musculus, Km). In the present paper, the responses of IC neurons to FM stimulus in the free-field conditions were examined. The main results were as follow: 1) according to the difference in the MT for pure tone and FM stimuli, the 99 IC neurons recorded were classified into three types; type Ⅰ neurons (57/99, 57.58%) were characterized by the lower MTs for the FM stimuli than for pure tone stimuli, while type Ⅲ neurons (30/99, 30.30%) were characterized by the lower MTs for the pure tone stimuli; a small fraction of neurons (type Ⅱ,12/99, 12.12%) exhibited no change of the MT when both types of stimuli were presented; 2) comparison of type A with type C neurons, we found that the former had lower characteristics frequencies (CFs) and Q20dB (P＜0.05 and P＜0.001, respectively) but higher frequency response bandwidth at 20 dB above the MT (RB20dB, P＜0.05); 3) 36 IC neurons (36/99, 36.36%) were direction selective and among them 61.11% (22/36) were up-selective and 38.89% (14/36) were down-selective neurons; up-selective neurons had a wider distribution across type Ⅰ, Ⅱ, and Ⅲ neurons than down-selective neurons; 4)the CFs of type Ⅰ and direction selective neurons had densest distribution over the range of 10 kHz-20 kHz (77.19% and 83.33%, respectively); 5) among the 24 recorded neurons responding to 3 different modulation rates, most of them (15/24, 62.50%) were more sensitive to rapid FM stimuli; the proportion of the direction selective neurons decreased with the increasing modulation rates (45.83% vs 41.77% vs 33.33%). Our data suggest that IC neurons of Km mouse could process FM stimuli effectively. FM sounds may play a significant role in acoustic communication in the Km mouse.