Lee L T, Bullock T H
Neurobiology Unit, University of California, San Diego, La Jolla.
Brain Behav Evol. 1990;35(5):278-90. doi: 10.1159/000115874.
The responses of cerebellar units following electrical stimulation applied to the area dorsalis centralis (Dc) of the telencephalon were studied in the siluroid teleost Ictalurus nebulosus. Two kinds of units are distinguished on physiological criteria, identified as Purkinje and eurydendroid cells (the efferent neurons of the cerebellum in teleosts equivalent to cells of the deep nuclei in other vertebrates). A high proportion of both kinds of units in the corpus cerebelli are sensitive to such stimulation. Each kind of unit shows several consistent response types. Purkinje cells fire simple spikes spontaneously at the rate of 8-50 spikes/s and respond to a single shock to Dc with an initial latency of 34-64 ms. The response can be one of the following types: (1) inhibition alone, with a duration of 0.3-1.5 s; (2) initial inhibition for 0.04-0.2 s, followed by postinhibitory rebound, or (3) initial excitation followed by inhibition which may or may not be followed by a late excitation. It is suggested that the initial excitation and the initial inhibition reflect the activation of mossy fiber-granule cell-Purkinje cell circuitry and mossy fiber-granule cell-inhibitory interneuron-Purkinje cell circuitry, respectively. Indirect evidence suggests the involvement of climbing fibers, but their characteristic complex spikes are rarely seen. Changing the stimulation sites within Dc does not appear to change the response pattern but may alter the threshold intensities, latencies and amplitudes. Changing stimulation frequency has complex effects depending on the response type. Purkinje cells responding with initial excitation are located along the lateral edges and along the midline of the corpus cerebelli; units responding with initial inhibition are more often found in an intermediate zone. This suggests three sagittal bands on each side. The contralateral cerebellum has a relative excess of Purkinje cells with initially inhibitory response. Putative eurydendroid cells show either initial excitation or a pattern of inhibition, excitation, inhibition. The initial latency is longer than in Purkinje cells. The contralateral cerebellum has a relative excess of eurydendroid cells with initially excitatory response. The high proportion of units that respond to Dc stimulation, their complex dynamics, diverse response types and compartmentalization point to the importance of the cerebrocerebellar influence in teleosts. Principal differences from mammals are the much longer latencies and less differentiation according to place of stimulation in the cerebrum.
在鲶形硬骨鱼云斑鮰中，研究了对端脑背侧中央区（Dc）施加电刺激后小脑神经元的反应。根据生理标准区分出两种神经元，分别鉴定为浦肯野细胞和广树突细胞（硬骨鱼中小脑的传出神经元，相当于其他脊椎动物深核中的细胞）。小脑本体中这两种神经元的很大一部分对这种刺激敏感。每种神经元都表现出几种一致的反应类型。浦肯野细胞以8 - 50次/秒的速率自发发放简单锋电位，对Dc的单次电击以34 - 64毫秒的初始潜伏期做出反应。反应可能是以下类型之一：（1）仅抑制，持续时间为0.3 - 1.5秒；（2）初始抑制0.04 - 0.2秒，随后是抑制后反弹，或（3）初始兴奋后接着抑制，抑制后可能有也可能没有晚期兴奋。有人认为，初始兴奋和初始抑制分别反映了苔藓纤维 - 颗粒细胞 - 浦肯野细胞回路以及苔藓纤维 - 颗粒细胞 - 抑制性中间神经元 - 浦肯野细胞回路的激活。间接证据表明有攀缘纤维参与，但很少见到它们典型的复合锋电位。改变Dc内的刺激部位似乎不会改变反应模式，但可能会改变阈值强度、潜伏期和幅度。改变刺激频率根据反应类型有复杂的影响。以初始兴奋做出反应的浦肯野细胞位于小脑本体的外侧边缘和中线；以初始抑制做出反应的神经元更常出现在中间区域。这表明每侧有三个矢状带。对侧小脑相对有更多具有初始抑制反应的浦肯野细胞。假定的广树突细胞表现出初始兴奋或抑制、兴奋、抑制的模式。初始潜伏期比浦肯野细胞长。对侧小脑相对有更多具有初始兴奋反应的广树突细胞。对Dc刺激有反应的神经元比例高、其复杂的动力学、多样的反应类型和分区表明脑 - 小脑影响在硬骨鱼中的重要性。与哺乳动物的主要区别在于潜伏期长得多，并且根据大脑中刺激部位的分化程度较低。
