Neural mechanism of habituation of crayfish escape behavior
| Project/Area Number |
12640657
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
動物生理・代謝
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
NAGAYAMA Toshiki Hokkaido Univ., Grad. Sch. Sci., Associate Prof., 大学院・理学研究科, 助教授 (80218031)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | crayfish / escape behavior / learning / memory / habituation / retention / LG / synapse / アナリカザリガニ |
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| Research Abstract |
(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.
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Report
(3 results)
Research Products
(9 results)
