蛙下丘频率调谐特性方向选择性的建模和仿真

MODELING AND SIMULATION OF DIRECTION SELECTIVITY OFFREQUENCY TUNING CHARACTERISTICS OF AUDITORY NEURONSIN THE INFERIOR COLLICULUS OF FROGS

基于Feng等人的神经电生理实验结果 ,建立了关于豹蛙(Ranapipien)半规隆凸 (torussemicircularis)核团神经元频率调谐特性方向选择性反应的模型 ,并在此基础上讨论了模型各个参数对模型方向性反应输出的影响。结果提示 :1)听觉系统两侧的相互抑制作用 -双耳抑制主要决定频率调谐特性的尖锐性随方向变化的特性 ;2)前级神经元对不同方位外界声源刺激具有不同强度平均脉冲发放率的特征则主要决定其最低阈值随方向变化的特性 ;3)模型半规隆凸神经元复杂的频率调谐曲线及其方向依赖性反应 ,其产生的主要原因既同双耳抑制有很大程度上的相关性 ,同时相对复杂的神经元相互之间的联系方式也是导致频率调谐曲线形状复杂化的因素。

Based on neural electro-physiological experiments, a model of directional selectivity of frequency tuning characteristics (DSFTC) of auditory neurons in torus semicircularis (TC) in leopard frogs was studied. Coincidence between experiment and simulation results supports the model. The roles of the parameters in the model played in the DSFTC were discussed, thus the possible underlying mechanism for DSFTC was displayed. The results suggest: 1. Binaural inhibition may play a crucial role in direction dependent Q-value of frequency tuning curve (FTC) of TC neurons; 2. The direction dependent threshold of FTC may mainly determined by the direction dependent discharging rate of the neurons in the auditory pathway before TC. 3. The production of complex FTC and its direction dependence are mainly caused by both binaural inhibition and complex connections between neurons.