中介杏仁体影响听觉信息传递的神经元的鉴定

With the use of extracellularly electrophysiological recording method, this project researched the influence of the amygdaloid complex on the acoustic responses of thalamic and auditory cortical neurons induced by pure tone in 65 SD rats. The results demonstrated that amygdala stimulation could not only inhibit the acoustic response of the cortical neurons in AⅠarea, but also facilitate the acoustic response of other neurons in this area. The inhibitory effect includes decreasing the discharge rate of these neurons and enhancing the threshold of the acoustic responses, while the facilitatory effect represents increasing the acoustic responses and decreasing the threshold of these responses. Moreover amygdala stimulation could upgrade and narrow the tuning curves of auditory neurons in AⅠarea and increased their Q10 values. So the activity of amygdala can improve the capability of frequency selectivity of cortical neurons in AⅠarea, which maybe is the physiological significance of this effect. With the neuroanatomical method two nervous circuits involved of the said effect have been found. Oner is the amygdala-mediodorsal thalamic nucleus-auditory cortex pathway, the other is the direct projection from amygdala to auditory cortex. Furthermore by the multi-micropipette and microelectrophoresis methods it is proved that GABA is the right neurotransmitter which mediated the effect of the lateral amygdaloid nucleus on the auditory responses of the neurons in AⅠarea. And it is also resealed that the possible receptor is GABAA receptor. Additionally, with the method of neural tracing we have found the pyriform neurons of the lateral amygdaloid nucleus and the basalateral amygdaloid nucleus were involved in the modulation of amygdala on the auditory information, and the experimental results also shown that these pyriform neurons project to the layer Ⅲ and Ⅳ of auditory cortex.

以往实验证实，边缘系统调制内膝体上传听觉信息是经由杏仁-皮层-内膝体环路，并证明GABA能神经元参与了这一过程。本项目的主要目的是查明: 由皮层下行的这些纤维是否为GABA能的，它们是与内膝体听神经元直接发生联系或是经由GABA能中间神经元的中介。这一研究工作的完成将为阐明边缘系统调制听觉信息的机制提供重要的资料，并为听感觉系统外的结构参与整合提供重要的佐证。