A micro-stimulation study on the supraspinal descending neurons underlying fish swimming.

1.通过增加鳃冲洗管等修改，重建了用于大鼠的立体定向装置，使其可用于小鱼。用100muA，8msec， 100Hz或更低的负矩形电流微刺激鲤鱼整个中脑区域。以近阈值电流刺激纵向内侧束核（Nfl）、纵向内侧束核（flm）和结膜臂时，游泳运动表现正常。将兴奋性氨基酸l -谷氨酸溶液微注射到Nfl附近。在大多数情况下，尾巴向同侧移动。在两个Nfls的中间部位注射诱导对称尾搏。注核胶无游泳现象。4 .同侧nfl单侧标记神经元膜上HRP注射。这些结果证实，是Nfl神经元通过同侧的膜发送信号激活脊髓中的中央模式发生器。当一侧的Nfl或膜被电损伤破坏时，鱼不能使用同一侧的轴向肌肉。橡胶核或结膜讨论支的破坏导致成对鱼鳍的异常运动。作为研究的下一步，我必须检查每个Nfl神经元与脊髓中片段模式生成器之间的关系，网络的结构以及大脑高级区域对中脑运动区域的控制。

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.