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OPTICAL RECORDING OF SOUND-INDUCED DYNAMIC ACTIVITIES IN THE AUDITORY CORTEX

听觉皮层声诱发动态活动的光学记录

基本信息

批准号：
08680924
负责人：
HORIKAWA Junsei
金额：
$ 1.54万
依托单位：
TOKYO MEDICAL AND DENTAL UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08680924/
关键词：
Auditory cortex Neural dynamics Optical recording Frequency modulation Two-tone stimulation Step-wise frequency change Guinea pigs GABAergic inhibition 聴覚皮質

项目摘要

Using an optical recording method with a 12 x 12-channel photodiode array and a voltage-sensitive dye (RH795), dynamic activities of neurons in anterior (A : primary) and dorsocaudal (DC) fields of the guinea pig auditory cortex were recorded under anesthetized condition (Nembutal 30 mg/kg, doroperidol 0.3 mg/kg/h and pentazocine 1.1 mg/kg/h). For sound stimulation, pure tones, frequency-modulated (FM) sounds, sounds with step-wise frequency changes (SF) and sequential two tones were presented to the ear contralateral to the recording side.The response to a pure-tone appeared as a band (isofrequency band) in both fields A and DC.The response was dynamic : the active spot moved ventrally or dorsally along the isofrequency band. The responses to SF sounds were the sequential activation of the isofrequency bands corresponding to the frequencies of the components in the SF sounds. Each response was similar to those to pure tones. The active spot in response to FM sounds moved obliquely crossing the isofrequency bands. When the direction of the frequency sweep was changed, the active spot moved in the opposite direction. No cortical area specifically responding to the FM sounds was found.The responses to sequenial two tones showed that inhibition between and within isofrequency bands occurs after the excitatory responses. When bicuculline, a GABA_A antagonist, was applied to the auditory cortex, the excitatory response to a pure tone was spread widely beyond the isofrequency band. This spread was prevented by further application of an NMDA antaonist.These results indicate that sounds were represented by dynamic neural acivities in the auditory cortex and these activities were created by excitatory and inhibitory interactions between isofrequency bands. A network model to simulate these results was proposed.

用12 × 12通道光电二极管阵列和电压敏感染料（RH 795）的光学记录方法，在麻醉条件下（Nembutal 30 mg/kg，doroperidol 0.3 mg/kg/h和pentazocine 1.1 mg/kg/h）记录豚鼠听皮层前（A：初级）和背尾（DC）区神经元的动态活动。在声刺激时，将纯音、调频（FM）声、步进频率变化（SF）声和连续双音声分别刺激对侧耳，对纯音声的反应在A场和DC场中均表现为一条带（Isobacter band），其反应是动态的：活动点沿Isobacter band向腹侧或背侧沿着移动。对SF音的反应是对应于SF音中成分频率的等时带的顺序激活。每个反应都与纯音相似。对FM声响应的活动点斜向移动穿过等离子体带。当频率扫描的方向改变时，活动光斑向相反方向移动。对连续两个音调的反应表明，在兴奋性反应之后，在同调带之间和同调带内出现抑制。当GABA_A拮抗剂荷包牡丹碱作用于听皮层时，纯音引起的兴奋性反应扩散到等电位带以外。进一步应用NMDA antaonist.These结果表明，声音是由听觉皮层的动态神经活动，这些活动是由兴奋和抑制的相互作用的isoblasts带。提出了一个网络模型来模拟这些结果。