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Neural mechanism of habituation of crayfish escape behavior

小龙虾逃逸行为习惯化的神经机制

基本信息

批准号：
12640657
负责人：
NAGAYAMA Toshiki
金额：
$ 2.24万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640657/
关键词：
crayfish escape behavior learning memory habituation retention LG synapse アナリカザリガニ

项目摘要

(1) The retention time of the habituation of crayfish escape behavior is depended upon the frequency of applied stimulus (ISI). With a short ISI, crayfish habituate readily but recover quickly. With a long ISI, crayfish habituate slowly and the retention time is depended upon the post-habituation rest in the crayfish. If a period of the rest is short, LGs can give rise to spike. By contrast, if crayfish take a rest for an hour, stimulation fails to give rise to spike in the LGs. (2) LGs are activated by mono- and disynaptic pathways from mechanosensory afferents. A short letency EPSP is called as α component and longer latency EPSP as β component. The depression of EPSPs was different in each term retaining habituation. In a short-term retaining habituation, only EPSP of longer latency is decreased in amplitude, while both short and longer latency EPSPs are decreased in a long-term retaining habituation. Zucker (1971) has proposed that short-term retaining habituation is depended upon the decline in the chemical synaptic transmission between afferents and ascending interneurones but I found no interneurones showed the decline of EPSP amplitude in response to repetitive stimulation that introduces habituation of LGs. (3) Longer latency EPSPs of LG is decreased in amplitute under bath application of d-tubocurarine. These EPSPs are discriminated into two phases, and fast phase of the EPSP is diminished almost completely while later EPSP is only gradually decreased. Hyperpolarization of LG increases EPSP in the later part of α component. Some sensory afferents make direct chemically mediated synaptic connections with LG, and synaptic depression between these affferents and LG mediates habituation of LGs.

(1)螯虾逃避行为的适应化持续时间与刺激频率有关。在短暂的ISI下，小龙虾很容易适应，但很快就会恢复。随着ISI的增加，螯虾适应缓慢，其停留时间取决于适应后的休息时间。如果休息时间较短，LG可能会引起尖峰。相反，如果小龙虾休息一个小时，刺激不会引起LGs的尖峰。(2)LG通过来自机械感觉传入的单突触和双突触通路激活。短潜伏期的EPSP称为α成分，长潜伏期的EPSP称为β成分。在保持习惯的各个阶段，EPSP的抑制程度不同。在短期保持习惯中，只有较长潜伏期的EPSP的振幅降低，而在长期保持习惯中，短潜伏期和较长潜伏期的EPSP都降低。Zucker（1971）提出短期保持性习惯化依赖于传入神经元和上行中间神经元之间化学突触传递的下降，但我没有发现中间神经元对引入LGs习惯化的重复刺激的EPSP振幅下降。(3)长潜伏期的LG EPSPs在d-筒箭毒碱浴下的振幅降低。这些EPSP被分为两个阶段，快相EPSP几乎完全消失，而晚相EPSP只是逐渐减少。LG超极化使α成分后段EPSP增加。一些感觉传入与LG直接进行化学介导的突触连接，并且这些传入与LG之间的突触抑制介导LG的习惯化。