| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
It has been made clear that the insect brains containe small amounts of neurons(30, 000 to 40, 000)relatively, however many kinds of insect display distinct behaviors as mating ones. Adult insects have the deutocerebrum, protocerebrum and tritocerebrum etc. in the brain. Especialy, the protocerebrum as a higher functional region does not be analyzed physiologically and morphologically. GeneraIly, there are one pair of mushroom body in the region. In this study, silkworm moth and american cockroach were used. The mushroom body of cockroach developed more better than those of other species. The large calyces and long storks were observed in staining preparation of the cockroach brainThe mushroom body was re-constructed by three dimensional construction method. lidth of the calyx was 350um ; height 400um ; length of stork 390um ; width of stork 110um ; length of alpha-lobe was 390um. And its volume occupied in the brain was about 12% in both sex. Value of the surface area was about 1.6mm^
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2. The Kenyon cell was 5 to 7um in diameter and the cell body was occupied with large nucleus. Many synapses were observed in the calyces, and many axons(ca. 90, 000)run downward into the stork in parallel to each. The diameter 'of the axon was 0.2-0.4um. To record responses to pheromone(peripranon A and B), 115 neurons in the protocerebrum were tested by microelectrode extra- or intracellularly. But Kenyon cells did not responded remarkably. On the other hand, protocerebral neurons(LPL neurons in the ventral side of the mushroom body)of silkworm moth responded well with long excitatory pattern of impulse to sex pheromone. These impulse responses continued for about 1 min with high frequency after ceasing of stimulus. It was cleared that these descending impulses arrive to the thoracic ganglion, and then they initiate wing fluttering through the thoracic motor neurons. It is seemed that the protocerebral neurons have important roles as command neurons for mating behavior in the silkworm moth. Less
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