Studies on Cerebellar Mechanisms Underlying Fish Swimming

1. 本研究绘制了金鱼的脑图谱，用于标记特定脑结构上的神经元。在小脑体（CC）和小脑瓣膜（VC）注射神经元示踪剂，以确定小脑传出神经元的靶脑区。通过注射CC和内侧VC，在对侧间脑、中脑、髓质和同侧VC中发现了小脑神经元的轴突末梢，包括躯干肌肉或鳍控制游泳的运动中枢。在CC基底部注射示踪剂，发现硬骨鱼的正常传出神经元eurydendriroid细胞分布在浦肯野细胞层周围。第一次描述细胞有少量粗大的初生树突，扩展在体的副矢状面上，分布于细胞的分子层和颗粒层。免疫细胞化学首次在硬骨鱼中证实浦肯野细胞是gaba能细胞，而泛舟树突细胞不是。我们开发了一种方法，通过使用电极和安装在头部的运算放大器来记录游泳鱼的小脑神经元的电活动。根据所记录的动作电位的形状，我们成功地识别了小脑神经元。期望在本研究的基础上，对硬骨鱼的小脑功能进行更深入的研究。

1. A brain atlas of the goldfish was made for mapping labeled neurons on specific brain structures in this study.2. To identify target brain regions of efferent cerebellar neurons, a neuronal tracer was injected into the corpus cerebelli (CC) and the valvula cerebelli (VC). By injection to CC and medial VC, axon terminals of the cerebellar neurons were found in the contralateral diencephalons, midbrain and medulla, and the ipsilateral VC, including locomotive centers for controlling swimming by either the trunk muscles or the fin.3. Tracer injection into the basal part of CC demonstrated that eurydendroid cells, proper efferent neurons of the teleost fish, were distributed around the Purkinje cell layer. It is the first description that the cells have a few thick primary dendrites expanding on the parasagittal planes of the body and are distributed in the molecular and the granular cell layers.4. It was demonstrated inmunocytochemically for the first time in teleosts that the Purkinje cells are GABAergic and eurydendroid cells are not.5. We developed a method to record electrical activities of cerebellar neurons from swimming fish by using electrodes and an operational amplifier mounted on the head. On the shape of action potentials recorded, we identified cerebellar neurons successfully.6. It is expected to augment the knowledge of cerebellar functions of teleosts by advanced studies based on the present study.