| Budget Amount *help |
¥3,770,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥270,000)
Fiscal Year 2007: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2006: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2005: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Various spices of animals that build the nest at a fixed location show the homing behavior. Homing refers to the behavior to go back to the start point via the shortest path even after wandering away from the nest. The present research tried to find out the conditions the homing behavior appears and to elucidate the role of proprioceptive stimuli that is regarded as an important part of idiothetic information.
Under a condition where visual stimuli were controlled, rats reliably showed the homing behavior. Eight start boxes of the same appearance (home) were aligned along the perimeter of an arena that was surrounded by a curtain. Using one of the boxes as the day's home, rats were trained to go out to the arena, searched for a food pellet out of four cups in the arena, get the pellet, hold it in the mouth, and come back home. When the homing behavior was established and rats came back home directly with the food pellet in the mouth, rats were lesioned in the hippocampus. The lesion dis
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rupted the homing behavior. The lesioned rats could not find the home, and many of them ate the pellet in the arena.
At the next stage, rats were carried from their home to the food cup in a car manipulated by the experimenter (passive transportation procedure), and were released from the car in front of the food cup. With the passive transportation procedure, proprioceptive stimuli were unavailable. Therefore, it was expected to evaluate the role of the proprioceptive stimuli independent of other stimuli. However, rats went back directly to the released point, not to the home, after obtaining the food pellet. This experiment raised a question that the concept of the home the experimenter had in mind might not be appropriate. Further improvement in the experimental procedure will be required.
With the results of our research and other previous research, it has become clear that the hippocampus is involved in the homing behavior, and the hippocampus is important for not only the spatial recognition using allothetic information, but also path integration using idiothetic information. Less
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