1992 Fiscal Year Final Research Report Summary
Central control mechanisms of motor patterns by multimodal inputs.
| Project/Area Number |
02454024
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
ICHIKAWA Toshio Kyushu Univ.Fac.Sci. Associate professor, 理学部, 助教授 (50136420)
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| Co-Investigator(Kenkyū-buntansha) |
TOH Yoshihiro Kyushu Univ.Fac.Sci. Professor, 理学部, 教授 (60037265)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Motor pattern / Escape behavior / Neural circuit / Cockroach / Ocellar system / Signal procerssing / Mechanoreceptors / Photoreceptors |
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| Research Abstract |
Morphological and physiological properties of multimodal interneurons modulating the motor patterns of locomotion in the American cockroach Periplaneta americana have been examined. A cerebral local interneuron integrated signals from various mechanoreceptors on the cerci, antennae and legs and from photoreceptors in the compound eyes and ocelli. Activation of this small neuron produced excitatory postsynaptic potentials (EPSPs) in the large second-order ocellar neurons which receive input from photoreceptors. Pharmacological and immunohistochemical experiments suggested that this neuron was GABAergic. Eight types of descending interneurons were identified. Most descendingneurons responded with a train of spikes to a puff of wind to the cerci and antennae. Four types of neurons shows an inhibition of spike discharges in response to illumination of either of two ocelli or both, while remaining four showed little response to the ocellar illumination. Some neurons were characterized by their strong responses to a spot of light moving in front of the compound eyes. Electrical stimulation of a particular descending interneurons caused EPSPs in a thoracic interneurons and a few spikes in some motoneurons innervating leg muscles. There were many thoracic interneurons which were excited by cercal stimulation and inhibited by ocellar illumination. Major information signaled by various interneurons examined in the present study appears to concern wind and tactile stimuli, because such stimuli usually produced a train of spikes in the neurons. However, such a strong response was often effectively suppressed by illumination of the ocelli. It is supposed that various external and internal mechanoreceptors are continuously stimulated during locomotion, which would evoke spikes in many interneurons, and changes in ocellar light conditions would modulate their spike discharges. This may result in course control by ocellar light condition during escape locomotion.
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