1988 Fiscal Year Final Research Report Summary
Functional significance of the parallel circuits of local nonspiking interneurons in crayfish motor systems
| Project/Area Number |
61480016
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
動物発生・生理学
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| Research Institution | Hokkaido University |
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Principal Investigator |
HISADA Mituhiko Hokkaido University Faculty of Science, 理学部, 教授 (70000768)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAO Takashi Hokkaido University, 実験生物センター, 助手 (70113595)
TAKAHATA Masakazu Hokkaido University Faculty of Science, 理学部, 助手 (10111147)
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| Project Period (FY) |
1986 – 1988
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| Keywords | crayfish / local nonspiking interneurons / parallel circuit / motor control system / central nervous system / 神経行動学 |
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| Research Abstract |
Functional roles of the parallel circuits of local nonspiking interneurons have been studied in the crayfish motor systems.
(1) Equilibrium reflex The motoneuron activity during the uropod equilibrium reflex has been shown to be controlled by a set of local nonspiking interneurons. Some part of the descending statocyst information was transmitted to the motoneurons through these interneurons which also received excitatory input from the abdominal posture system. This observation indicates that the postural facilitation of the uropod equilibrium response is based on the synaptic interaction in the nonspiking interneurons.
(2) Avoidance reaction When a mechanical stimulus is applied to the uropod, the animal displays an avoidance reaction which changes during the growth. The sensory information is transmitted to the motoneurons through a set of nonspiking interneurons organized in parallel. Individual interneurons make facilitatory, disinhibitory, disfacilitatory of inhibitory connection t
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o motoneurons. The final output seems to be determined by the balance of these circuit operation, and that the behavioral change is based on the change in that balance.
(3) Abdominal posture movement A set of nonspiking interneurons were identified which were organized in parallel and controlled the activity of abdominal postural motoneurons. These interneurons inhibited the activity of slow extensor inhibitors and slow flexor excitors on both sides of the 4th abdominal ganglion, However, they had no effect on extensor excitors and flexor inhibitors. We concluded that these interneurons worked in ensuring the abdominal extension movement to occur by inhibiting the antagonistic flexion movement.
The results indicate that the parallel circuits of local nonspiking interneurons are neuronal modulators of behavior. Further study is needed to examine the possibility that these interneurons are the site for other higher-order functions of the central nervous system such as learning and motivation. Less
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