海马CA1和CA3在离体完整海马自发同步性活动中起不同作用

发布时间：2018-06-26 22:34

本文选题：海马 + 自发活动　；参考：《华东师范大学》2017年硕士论文

【摘要】：海马是哺乳动物大脑边缘系统的重要组成部分,在学习和记忆、空间定位等功脑能中起到重要作用。目前普遍认为,海马功能的实现与海马神经元活动的同步性关系密切。对海马同步性活动的神经机制已有较多的研究,但这一问题尚待进一步明确。本论文采用幼年大鼠的离体全海马标本,对海马CA1同步性活动的海马内部环路机制进行了研究。在该离体全海马标本中,我们通过胞外场电位记录可观察到CA1内部活动具有高度同步性。接下来,我们从CA3侧开始,沿垂直于海马长轴方向切割开3/4的海马组织,在切割口两侧所记录的CA1场电位活动在1小时内仍然显著同步,维持在未作切割的完整海马组水平;然而其活动的同步不能长期维持,在3小时和5小时开展的记录中不能见到明显的同步性活动。另外,我们从海马CA1侧开始,沿垂直于海马长轴方向切割开3/4的海马组织,在切割口两侧记录CA1场电位,发现:切开1小时内CA1场电位的同步性活动消失;然而,在切开3小时后可观察到CA1活动的同步性得到明显恢复,至5小时同步性回到完整海马水平。为进一步观察从CA1方向切割海马后,CA1同步性从消失至恢复的过程,我们接下来采用双膜片钳的方法,观察CA1神经元之间的同步性活动,与场电位的实验结果类似:在切割两小时内所记录到的CA1细胞间的膜电位活动的同步性消失,4小时之后开展的记录可见同步性恢复到接近正常未切割的水平。本论文的研究显示:离体全海马CA1脑区的同步性依赖于CA1内部及CA3环路的完整性。并且,海马CA1内部部分连接的存在可以在短时间内维持CA1同步性活动,而其同步性的长期维持需要CA3输入的完整;同时,海马CA3完整的输入可以使得CA1内部连接断开时能逐步恢复CA1活动的同步。这些结果为进一步理解海马CA1同步性活动的环路机制提供了新的数据。
[Abstract]:Hippocampus is an important part of mammalian limbic system, which plays an important role in learning and memory, spatial localization and other functional brain functions. It is generally believed that the realization of hippocampal function is closely related to the synchronism of hippocampal neuron activity. The neural mechanism of hippocampal synchronous activity has been studied, but this problem needs to be further clarified. In this paper, the mechanism of hippocampal loop of hippocampal CA1 synchronous activity was studied using isolated hippocampal specimens of young rats. In this isolated hippocampal specimen, we observed that the internal activity of CA1 was highly synchronous by recording extracellular field potential. Next, we cut 3 / 4 of hippocampal tissue perpendicular to the hippocampal long axis from the CA3 side. The CA1 field potential activity recorded on both sides of the incisor was still significantly synchronized within 1 hour, and maintained at the level of intact hippocampal group without cutting. However, the synchronization of its activities can not be maintained for a long time, and no obvious synchronous activities can be observed in the records of 3 and 5 hours. In addition, we cut 3 / 4 of the hippocampal tissue perpendicular to the hippocampal long axis from the hippocampal CA1 side. We recorded CA1 field potentials on both sides of the incised orifice and found that the synchronous activity of CA1 field potentials disappeared within 1 hour of incision; however, It was observed that the synchronization of CA1 activity recovered significantly 3 hours after incision and returned to the intact hippocampal level at 5 hours. In order to further observe the process from disappearance to recovery of CA1 synchrony after hippocampal incising in the direction of CA1, we then used double patch clamp method to observe the synchronous activity between CA1 neurons. The results were similar to those of the field potential experiment: the synchronism of membrane potential activity between CA1 cells recorded within two hours of cutting was disappeared 4 hours later, and the synchronicity of the recording was restored to the normal level of uncleavage. The present study shows that the synchronism of the isolated hippocampal CA1 brain depends on the integrity of the CA 1 internal and CA 3 loop. Moreover, the existence of the internal partial connections in hippocampal CA1 can maintain the synchronous activity of CA1 for a short period of time, and the long-term maintenance of the synchronization requires the integrity of CA3 input. The complete input of hippocampal CA3 can gradually restore the synchronization of CA1 activity when the internal connection of CA1 is disconnected. These results provide new data for further understanding the loop mechanism of hippocampal CA1 synchronism.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q42

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