|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1997 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1996 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1995 : ¥1,500,000 (Direct Cost : ¥1,500,000)
Directional sensitivities and intensity-response relations of 6 types of air current sensitive giant interneurons (GIs 8-1,9-1,9-2,9-3,10-2 and 10-3) of the cricket, Gryllus bimaculatus, were confirmed. These response properties of each GI were formed by an excitatory and inhibitory connections between cercal sensory filiform hairs with particular directionalities. GIs 8-1,9-1 and 9-2 in the unilaterally cercal ablated adult crickets showed functional compensation 21 days after the ablation. Those compensations were direction dependent, i.e.some of the compensational changes were observed only when the stimulus was applied from particular directions. Compensational recoveries after the unilateral cercal ablation was also investigated during the postembryonic development. The degree of the change was dependent on the duration of the sensory deprivation to some extent.
The wind-evoked escape behavior was investigated by using a quantitatively controlled short duration air current stimulus (air-puff). To the standard air-puff stimulus (3.0m/s in peak velocity), normal adult crickets showed 50-60% response rate and the direction of the escape was almost 180ﾟopposite from the stimulus source. After the unilateral cercal ablation, the response rate became small and the orientation of the escape became incorrect. However, both response rate and escape direction showed compensational changes. The response rate showed significant recovery about 6 days after the ablation. On the other hand, 14 days were necessary for the recovery of the escape orientation. Information processing for the response rate and for the behavioral orientation are likely being progressed in defferent neural pathways.