| Project/Area Number |
12640667
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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 | Kyushu Institute of Technology |
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Principal Investigator |
MATSUMOTO Nobuyoshi Kyushu Institute of Technology, Graduate School of Life Science and Systems Engineering, Professor, 生命体工学研究科, 教授 (80029545)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAGAWA Hideki Kyushu Institute of Technology, Graduate School of Life Science and Systems Engineering, Associate Professor, 生命体工学研究科, 助教授 (80212083)
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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 |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2000: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | optic tectum / simultaneous multiunit recording / retinal ganglion cell / frog / looming stimulation / collision avoidance behavior / receptive field / visual information processing |
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| Research Abstract |
It has been well known that a retinotopic map is represented in the frog optic tectum. This suggests that spatial distribution of spike activity in the tectum is dynamically changed in response to movement of retinal image. In this study, by using multielectrode arrays, we examined spatiotemporal pattern of physiologically characterized retinal ganglion cell's and tectal neuron's activity to a black square expanding in looming fashion and with constant velocity.
The two types of computer generated stimuli with various optical parameters were presented to right eye of the frog, Ranacatesbeiana. Microelectrode arrays, arranged in a geometric 5 x 5 grid were inserted into the left optic tectum in MS222 anesthetized animals, and neuronal activity across retinotectal map was measured.
This experiment revealed neuronal activity expanding across the optic tectum in the manner particular to time course of expansion of retinal image. It showed that, as for looming stimulation, temporal pattern of presynaptic activity is quite different between the center of expansion and peripheral sites. The former showed sustained activity in early stage of expansion, while the latter showed transient activity during rapid expansion. On the other hand, as for expansion with constant velocity, the neuronal activity was transient in both sites. The similar spatiotemporal pattern of activity were observed in both R1/2 and R3 retinal ganglion cells. These results suggest that early sustained activity in the center of expansion and subsequent transient activity in peripheral region are essential for elicitation of frog escape behavior to looming stimulation. Furthermore, in the deep tectal layers, putative looming sensitive neurons were found, which have extremely wide receptive field and show strict tuning to collision course.
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