| Budget Amount *help |
¥35,670,000 (Direct Cost: ¥32,100,000、Indirect Cost: ¥3,570,000)
Fiscal Year 2002: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2001: ¥10,140,000 (Direct Cost: ¥7,800,000、Indirect Cost: ¥2,340,000)
Fiscal Year 2000: ¥20,200,000 (Direct Cost: ¥20,200,000)
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| Research Abstract |
We developed two confocal laser systems to image neuronal activities of behaving animals. The first system consists of a high-speed scanner built on an upright microscope. It can scan 500 frames per second but has a low signal-to-noise ratio to detect faint change in fluorescence signals. The second system is based on a conventional confocal laser system, but the scanning speed was improved to collect 10 full-frames to 500 line-frames every second. This confocal system has a higher signal-to-noise ratio to detect fluorescence change associated with synaptic inputs without averaging them. Using the system we observed the activities of reticulospinal neurons in the hindbrain of zebrafish larvae. Since the body and brain of larval zebrafish are transparent, the neuronal activities in vivo can be observed by calcium imaging of the neurons in the intact brain. Especially we succeeded in in vivo imaging of functional inhibitory networks on the Mauthner cell which is known to initiate fast escape response behavior of fish. It is the first report of imaging inhibitory synaptic action in intact animals. Finally we developed the optical system to observe neuronal activities of behaving animals. For this purpose, the high-speed video camera system was added to the laser-scan system to measure the fluorescence responses of neurons and behavioral responses of zebrafish simultaneously. The high-speed confocal laser scanning system associated with motion detector will help us to understand which and how central neurons contribute to controlling the simple behavior of animals.
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