On-BF和Off-BF频率激活的抑制性突触输入共同锐化小鼠下丘神经元的频率调谐：在体细胞内记录

发布时间：2018-07-11 17:45

本文选题：下丘神经元 + on-BF频率　；参考：《华中师范大学》2014年硕士论文

【摘要】：频率是声信号的参数之一,它在传递声音信息方面起着重要作用,频率调谐(frequency tuning)成为听觉神经元的一种重要功能。通过比较外周和中枢听觉神经元频率调谐曲线(frequency tuning curve, FTC)的形状,发现中枢听觉神经元具有更强的对频率的调谐和分析的能力。由于缺乏来自兴奋性和抑制性突触输入之间相互整合在锐化频率调谐方面的作用的直接实验证据,使得锐化频率调谐的机制仍不完全清楚。因而,我们在本研究中采用在体细胞内记录的方法,探讨了由on-BF (on best frequency)和偏离BF,即off-BF (off best frequency)频率激活的抑制在锐化小鼠下丘(inferior colliculus, IC)神经元频率调谐方面的作用。从31只由戊巴比妥钠(Nembutal,0.02mL/g b.wt.)麻醉的成年健康的昆明小鼠(Mus musculus, Km) IC上总共获得了87个声敏感神经元,这些神经元的记录深度(μm)和最佳频率(kHz)的范围分别为633-1950(1368.4±364.1)、7-47(22.3±10.9)。通过对其中53个神经元的频率调谐进行分析,它们可以被分成2种类型,一种类型是在兴奋性频率调谐曲线(excitatory frequency tuning curves, EFTC)低频边或/和高频边带有侧抑制区(lateral inhibitory area, LIA)的神经元(n=25),另一种类型则是在EFTC的高、低频边均不具有LIA的神经元(n=28)。在双声刺激条件下,由on-BF和off-BF所激活的抑制均能锐化这些神经元的FTC。另外,对于28个不具有LIA的神经元,它们频率调谐的锐化主要依赖于on-BF频率激活的抑制,或许还有来自IC下某个听觉中枢的侧抑制(lateral inhibition, LI)的参与。通过比较由on-BF和off-BF所激活的两种抑制锐化频率调谐的程度,统计学分析发现两种抑制在锐化的程度上存在有显著的差别(p0.05)。这些结果提示由on-BF和off-BF频率所激活的抑制性突触输入共同锐化下丘神经元的频率调谐。
[Abstract]:Frequency is one of the parameters of acoustic signal, which plays an important role in transmitting sound information. Frequency tuning (frequency tuning) becomes an important function of auditory neurons. By comparing the shape of frequency tuning curves of peripheral and central auditory neurons, it is found that central auditory neurons have stronger ability of frequency tuning and analysis. Due to the lack of direct experimental evidence from the integration of excitatory and inhibitory synaptic inputs in sharpening frequency tuning, the mechanism of sharpening frequency tuning is still unclear. In this study, we investigated the effects of on-BF (on best frequency) and off-BF (off best frequency) frequency activation on the frequency tuning of (inferior colliculus, IC neurons in sharpened mouse inferior colliculus by means of somatic recording. Nembutala (0.02mL / g b 路wt.) A total of 87 acoustic-sensitive neurons were obtained in anesthetized adult healthy Kunming mice (Ms) IC. The recording depth (渭 m) and optimal frequency (kHz) of these neurons ranged from 633-1950 (1368.4 卤364.1) to 47 (22.3 卤10.9), respectively. By analyzing the frequency tuning of 53 of these neurons, they can be divided into two types. One type is the neurons with LIA-25 on the low-frequency or / and high-frequency edge of the excitatory frequency tuning curve (excitatory frequency tuning curves,), and the other is the neuron with no LIA-LIA on the high side of the excitatory frequency tuning curve (excitatory frequency tuning curves,). The inhibition activated by on-BF and off-BF can sharpen the FTC of these neurons under the condition of double acoustic stimulation. In addition, for 28 neurons without LIA, the sharpening of their frequency tuning mainly depends on the inhibition of on-BF frequency activation, and maybe the lateral inhibition of (lateral inhibition, Li from an auditory center under IC. By comparing the tuning degree of sharpening frequencies activated by on-BF and off-BF, it was found that there was a significant difference in sharpening degree between the two kinds of inhibition (p0.05). These results suggest that inhibitory synaptic inputs activated by on-BF and off-BF frequencies jointly sharpen the frequency tuning of inferior colliculus neurons.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：Q421

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