An approach to identify the functional transduction and transmission of an activated pathway  

作　　者：WANG NingQian BO Lin ZHANG Fan TAN XiaoDong YANG XiaoLi XIAO ZhongJu 

机构地区：[1]Department of Physiology, School of Basic Medicine, Southern Medical University

出　　处：《Chinese Science Bulletin》2013年第11期1274-1284,共11页

基　　金：supported by the National Natural Science Foundation of China (31171059, 30930039 and 30970982);Program for Changjiang Scholars and Innovative Research Team in University (IRT1142)

摘　　要：In this study, we investigated the features of latency-amplitude (L-A) functions at different sound frequencies, using extracellular recording from auditory neurons in the central nucleus of the inferior colliculus (ICC) in mice. Isofrequency L-A functions from single neurons could be fit with a newly developed equation based on Pieron's law. The high degree of fitness indicates that the curvatures of all isofrequency L-A functions for a given neuron are similar, and that the difference between L-A functions is due to a shift in their positions in the coordinate system. When we normalized the L-A functions to match the position of the L-A function obtained at the neuronal characteristic frequency (CF), all isofrequency L-A functions from a given ICC neuron were highly superimposed. The similar shapes of the L-A functions at different frequencies may reflect the physical laws of sound being transferred into bioelectric signals. The position of a non-CF L-A function could be measured as the differences of the asymptotic L and A ( L and A) compared to the L-A function at a reference frequency such as the CF. The nerve fibers and synapses connecting to a neuron for acoustic information processing can be functionally simplified as a single "wire" (as the total length of nerve fibers) and "joint" (as the summated size/strength of synapses). The wire and joint mediate information transmission and transduction, respectively. Thus, L and A may be measurements of the total length of nerve fibers and the strength of summated synapses in the activated auditory pathway. L and A differed between frequency channels and neurons, suggesting that the differences of acoustic neuronal responses are always caused by activation of different pathways, and that the pathways that process sounds are diverse.In this study, we investigated the features of latency-amplitude （L-A） functions at different sound frequencies, using extracellular recording from auditory neurons in the central nucleus of the inferior colliculus （ICC） in mice. Isofrequency L-A functions from single neurons could be fit with a newly developed equation based on Pieron＇s law. The high degree of fitness indicates that the curvatures of all isofrequency L-A functions for a given neuron are similar, and that the difference between L-A functions is due to a shift in their positions in the coordinate system. When we normalized the L-A functions to match the position of the L-A function obtained at the neuronal characteristic frequency （CF）, all isofrequency L-A functions from a given ICC neuron were highly su- perimposed. The similar shapes of the L-A functions at different frequencies may reflect the physical laws of sound being trans- ferred into bioelectric signals. The position of a non-CF L-A function could be measured as the differences of the asymptotic L and A （△L and △A） compared to the L-A function at a reference frequency such as the CF. The nerve fibers and synapses connect- ing to a neuron for acoustic information processing can be functionally simplified as a single ＂wire＂ （as the total length of nerve fibers） and ＂joint＂ （as the summated size/strength of synapses）. The wire and joint mediate information transmission and trans- duction, respectively. Thus, △L and △A may be measurements of the total length of nerve fibers and the strength of summated synapses in the activated auditory pathway. △L and △A differed between frequency channels and neurons, suggesting that the dif- ferences of acoustic neuronal responses are always caused by activation of different pathways, and that the pathways that process sounds are diverse.

关 键 词：传输功能 转导 激活 听觉神经元 声音频率 神经纤维 细胞外记录 生物电信号 

分 类 号：R338[医药卫生—人体生理学]