【作者】 张季平；

【导师】 孙心德；

【作者基本信息】 华东师范大学 ， 2001， 博士

【摘要】 本报告以蝙蝠为实验动物，对听皮层和中脑下丘对听觉信息的频率和空间的编码进行了研究。本研究中，用电刺激结合双声抑制的方法，首次发现了听皮层在调制下丘听神经元兴奋性频率调谐曲线的同时，也伴随着对抑制性频率调谐曲线的调制，并提示，听皮层有可能通过改变下丘听神经元抑制区的大小来调制兴奋性频率调谐曲线。用电刺激结合微电泳的方法，首次用生理学的方法证实了听皮层调制下丘中央核听觉信息处理的一条神经通路，即听皮层发出下行兴奋性输入兴奋下丘外侧核，然后自下丘外侧核发出抑制性输入抑制下丘中央核，从而实现听皮层对下丘中央核听觉信息的调制。 在自由声场条件下，研究了声源方位对下丘听神经元频率调谐特性的影响。结果表明，声源方位对下丘听神经元频率调谐曲线的锐度、最低阈值有影响，多数神经元在记录部位同侧的频率调谐曲线的锐度比对侧大，最低阈值比对侧高。声源方位对大多数神经元的最佳频率无影响。声源方位对神经元频率调谐曲线影响的机制可能是抑制性和兴奋性输入的比例不同相互整合的结果。在下丘听神经元频率调谐方向敏感性的形成中，GABA能抑制有至关重要的作用。当声源方位由记录部位对侧移向同侧时，大多数神经元接受的GABA能抑制性输入的量增加，与兴奋性输入整合后，导致了频率调谐特性的方向性差异。 本研究首次提出了听皮层调制皮层下神经元方向性性信息的概念，并发现，下丘神经元频率调谐的方向敏感性的形成中，听皮层的下行调制有重要作用。听皮层的抑制性影响使大多数神经元在蝙蝠最敏感的声源方位C-40°的频率分辨能力明显提高，同时使C-40°和I-40°的最低阈值的差别进一步增大，提高了信噪比，提高下丘听神经元对声源方位和最佳频率的分辨能力。本研究还提示，听皮层对下丘神经元频率调谐的方向敏感性的调制，可能是通过改变神经元在不同声源方位的抑制区的大小实现的。 通过对幼年(出生后第四周)和成年蝙蝠下丘听神经元频率调谐的方向敏感性的比较，发现幼年蝙蝠频率调谐的方向敏感性比成年蝙蝠差，并认为可能是动物发育过程中，下丘的兴奋性和抑制性输入的整合也有一个发育的过程。 用声暴露结合免疫组织化学方法研究了鼠耳蝠脑干听觉系统Fos的表达， 博士后研究报告 听皮层和中后下丘对听觉信启、频率和金门编码的研究 厂中文摘要J 作者K4平 导师41·0总发现在脑干听核团耳蜗核、斜方体核、上橄榄核、外侧丘系的部分神经元为F。S阳性。在下丘、上主也有少量的阳性神经元。在脑桥核、脑千网状结构、小脑间置核，齿状核有少量的 FO S 阳性胞体。当一侧耳堵塞暴露时，FO S 阳性胞体的分布与为堵塞时基本一致，但双侧FOS阳性细胞呈非对称性分布。第一部分 大棕幅听皮层对中脑下丘听神经元频率调谐曲线的调制及调制及调制机制的研究第一章 听皮层对下丘听神经元兴奋性和抑制性频率调谐曲线的调制， Brain Research，1999 在自由声场条件下，用双声抑制的方法结合电刺激的方法研究了听皮层对下丘对下丘听神经元兴奋性和抑制性频率调谐曲线的调制。研究发现，听皮层对下丘的抑制性影响使兴奋性调谐曲线变窄，同时使抑制性频率调谐曲线不对称地扩大，听皮层的易化性影响与之相反。该发现支持了以前关于听觉系统中通过广泛的抑制作用来调制听觉信息处理的假说。第二章 大棕幅听皮层对中脑下丘听神经元频率调谐曲线的调制 科学通报， 2000 用双声刺激的方法和电刺激技术，进一步研究了在激活听皮层前后下丘听神经元兴奋性和抑制性频率调谐曲线的锐度、频率强度反应区域、最低阈值的协同变化．结果表明，听皮层的抑制性影响使下丘听神经元兴奋性频率调谐曲线的锐度增加、最低阈值升高、频率强度反应区域减小，同时使抑制性频率调谐曲线的锐度减小、最低阈值下降、频率强度反应区域增大．听皮层的易化性影响与之相反．在听皮层的抑制性影响中，兴奋性与抑制性频率调谐曲线的频率强度反应区域变化的百分数呈显著负相关．本研究结果提示，听皮层可能通过调制下丘听神经元的抑制性频率调谐曲线来提高下丘听神经元对频率信息的处理能力．第二部分 大棕幅听皮层对下丘神经元听觉信息调制的神经通路的研究第三章 一条自下丘外侧核到下丘中央核的听皮层下丘调制通路 3 L 博士后研究报告 听皮层和中历下立对听觉信息频率和空间编码的研究 厂中文摘要J 作十 张乔年 导师 孙·O总 本研究的目的为了证实我们在以前的报道中关于听皮层调制下丘听信息通路的假设：听皮层发出下行兴奋性输入至下丘外侧核，然后再由下丘外侧核发出抑制性输入至下丘中更多还原

【Abstract】 Frequency and spatial coding of auditory information in auditory cortex and inferior colliculus was studied in this research. We found that AC stimulation narrowed the excitatory FTCs and asymmetrically expanded the lateral inhibitory FTCs of corticofugally inhibited ICc neurons. The opposite results were observed for excitatory and inhibitory FTCs of corticofugally facilitated ICc neurons. Corticofugal inhibition increased sharpness, minimum threshold, and decreased the frequency-intensity response area of EFTCs, at the same time it decreased the sharpness, minimum threshold but increased the frequency-intensity response area of IFTCs. The opposite results were observed for EFTCs and IFTCs of corticofugally facilitated inferior collicular neurons. During corticofugal inhibition, the percent change of frequency-intensity response area of EFTCs had significant correlation with the percent change of that of IFTCs. These data suggest that cortical neurons are likely to improve frequency information processing of inferior collicular neurons by modulation of IFTCs. We also demonstrated that one corticofugai pathway is that auditory cortex sends excitatory inputs to ICX and then sends inhibitory inputs to ICC from ICX.Under free field sound stimulation conditions, we studied the sound direction effect on frequency tuning curves of inferior collicular (IC) neurons. This study showed that the MT and sharpness of frequency tuning curves increased as the sound direction changed from contralateral to ipsilateral azimuthal angles. It suggests that sound direction effect on frequency tuning may be through the complex interplay between the excitatory and inhibitory inputs. The application of GABA(A) antagonist, bicuculline, lowered all MTs but the application did not abolish direction-dependent variation in MT. In contrast, although application of bicuculline essentially had no effect on the BFs of IC neurons, it differentially broadened neurons FTCs at different azimuths abolishing the direction-dependent sharpening of frequency tuning. These data indicate that GABAergic inhibition makes an important contribution to the direction-dependent frequency tuning of most IC neurons. Corticofugal modulation of the excitatory and inhibitory FTCs of most IC neurons was more pronounced at one sound direction than the other. Sound direction effects on frequency tuning characteristics may undergo a postnatal development due to the development of excitation and inhibition integration.In this study, we also examined the Sound stimulation activates C-Fos expression in auditoryCorticofugal regulation of excitatory and inhibitory frequency tuning curves of bat inferior collicular neurons Brain Res 1999 Sep ll;841(l-2): 184-188Corticofugal regulation of excitatory and inhibitory frequency tuning curves (FTCs) of neurons in the central nucleus of bat inferior colliculus (ICc) was studied by electrical stimulation of the primary auditory cortex (AC stimulation) under free field stimulation conditions using a two-tone inhibition paradigm. AC stimulation narrowed the excitatory FTCs and asymmetrically expanded the lateral inhibitory FTCs of corticofugally inhibited ICc neurons. The opposite results were observed for excitatory and inhibitory FTCs of corticofugally facilitated ICc neurons. These data support previous reports that corticofugal systems work together with widespread lateral inhibition to regulate subcortical frequency processing.Corticofugal Modulation of Frequency Tuning of Inferior Collicular Neurons in Big Brown Bat, Eptesicus Fuse us Chinese Science Bulletin, 2000In order to explore the possible mechanism of corticofugal modulation of excitatory frequency tuning curves (EFTCs) of midbrain neurons, we examine the change of sharpness, frequency-intensity response area, minimum threshold of both EFTCs and inhibitory frequency tuning curves (IFTCs) of inferior coliicular neurons during corticofugal modulation using two-tone inhibition paradigm and micro-electrical stimulation technique. Our data showed that更多还原