|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1994 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1993 : ¥1,800,000 (Direct Cost : ¥1,800,000)
1.A stereotaxic apparatus for the rat was reconstructed to be usable for small fish by some modifications such as an addition of a gill-irrigating tube.
2.The whole mid-brain region of the carp was micro-stimulated with negative rectangular current of 100muA,8msec, 100Hz, or lower. Swimming movement appeared normal was elicited by a stimulation with near threshold currents to the nucleus fasciculus longitudinalis medialis (Nfl), the fasciculus longitudinalis medialis (flm), and the brachium conjunctivum.
3.Solution of an excitatory aminoacid, L-glutamate was micro-injected into the vicinity of Nfl. Tail movements beating toward the ipsilateral side were elicited in the most case. Symmetrical tail beats were induced by injections to the middle place of the both Nfls. No swimming occurred by injection to the nucleus ruber.
4.HRP injections to flm of the one side labeled neurons in ipsilateral Nfl.
5.These results confirm that it is Nfl neurons that send an signal activating the central pattern generators in the spinal cord through flm of the ipsilateral side.
6.When Nfl or flm of the one side was destroved by an electric lesion, the fish could not use the axial muscles of the same side. Destruction of the nucleus ruber or the decussatio branchium conjunctivum caused abnormal movements in paired fins.
7.As the next step of the investigation, I must examine relationships between each Nfl neuron and segmental pattern generators in the cord, architecture of the network and the control of the midbrain locomotor region by higher brain regions.