2002 Fiscal Year Final Research Report Summary
Central compensation of an insect behavior and a plasticity of microbrain system
| Project/Area Number |
11168220
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas (A)
|
| Allocation Type | Single-year Grants |
|---|
| Review Section |
Biological Sciences
|
|---|
| Research Institution | Ehime University |
|---|
Principal Investigator |
KANOU Masamichi Ehime University, Faculty of Science, Associate Professor, 理学部, 助教授 (80183276)
|
|---|
| Project Period (FY) |
1999 – 2001
|
| Keywords | microbrain / cricket / air current sense / cercus / escape behavior / giant interneuron / compensation |
|---|
| Research Abstract |
The rearing condition necessary for behavioral compensation after sensory deprivation was investigated in the cricket Gryllus bimaculatus. The unilaterally cereal ablated cricket was reared in a glass vial with a slightly larger diameter than the body length of the cricket. After two weeks of rearing in the vial, the air-puff-evoked escape behavior of the cricket was investigated. The response rate (relative occurrence of the escape behavior after a standard air puff) obtained was identical with that of crickets reared in a large cage. On the other hand, unlike crickets reared in a large cage, the distorted escape directional property of the cricket reared in the vial was not compensated at all. Control experiments proved that the restraint in the vial did not affect the motor system, and the air motion from environments was not essential for the compensational recovery of the escape direction. Therefore, the ablated crickets required spontaneous walking in order to compensate the directionality of their escape. A self-generated wind caused by spontaneous walking appears necessary for the crickets to realize the defect of their sensory system and to compensate the related escape behavior. A hypothesis for the compensation mechanism based on the Efference copy signal is proposed, I.e., the Efference copy signal is likely to be used for the estimation of a GI response in intact crickets. In order to ascertain the hypothesis, descending neural pathways that may carry the efference copy of walking were investigated. When the cricket walked fast, the frequency of the bursting was large and vice versa. Therefore, the velocity of walking was encoded into the frequency of the bursting. Furthermore, the angle of turn was encoded into the difference of the burst numbers of descending neurons running in the right and the left connectives. These results suggest that the descending neurons carry the Efference copy signal as was suggested in our hypothesis.
|
