Ito Masao
RIKEN Brain Science Institute, Wako, Saitama, Japan.
Prog Neurobiol. 2006 Feb-Apr;78(3-5):272-303. doi: 10.1016/j.pneurobio.2006.02.006.
Shortly after John Eccles completed his studies of synaptic inhibition in the spinal cord, for which he was awarded the 1963 Nobel Prize in physiology/medicine, he opened another chapter of neuroscience with his work on the cerebellum. From 1963 to 1967, Eccles and his colleagues in Canberra successfully dissected the complex neuronal circuitry in the cerebellar cortex. In the 1967 monograph, "The Cerebellum as a Neuronal Machine", he, in collaboration with Masao Ito and Janos Szentágothai, presented blue-print-like wiring diagrams of the cerebellar neuronal circuitry. These stimulated worldwide discussions and experimentation on the potential operational mechanisms of the circuitry and spurred theoreticians to develop relevant network models of the machinelike function of the cerebellum. In following decades, the neuronal machine concept of the cerebellum was strengthened by additional knowledge of the modular organization of its structure and memory mechanism, the latter in the form of synaptic plasticity, in particular, long-term depression. Moreover, several types of motor control were established as model systems representing learning mechanisms of the cerebellum. More recently, both the quantitative preciseness of cerebellar analyses and overall knowledge about the cerebellum have advanced considerably at the cellular and molecular levels of analysis. Cerebellar circuitry now includes Lugaro cells and unipolar brush cells as additional unique elements. Other new revelations include the operation of the complex glomerulus structure, intricate signal transduction for synaptic plasticity, silent synapses, irregularity of spike discharges, temporal fidelity of synaptic activation, rhythm generators, a Golgi cell clock circuit, and sensory or motor representation by mossy fibers and climbing fibers. Furthermore, it has become evident that the cerebellum has cognitive functions, and probably also emotion, as well as better-known motor and autonomic functions. Further cerebellar research is required for full understanding of the cerebellum as a broad learning machine for neural control of these functions.
约翰·埃克尔斯完成了他关于脊髓突触抑制的研究（他因此获得了1963年诺贝尔生理学/医学奖）后不久，便开启了神经科学的另一篇章——他对小脑展开了研究。1963年至1967年期间，埃克尔斯和他在堪培拉的同事成功剖析了小脑皮质中复杂的神经元回路。在1967年出版的专著《作为神经元机器的小脑》中，他与伊藤正雄和雅诺什· Szentágothai合作，展示了类似蓝图的小脑神经元回路接线图。这些接线图引发了全球范围内关于该回路潜在运作机制的讨论和实验，并促使理论家们开发出与小脑机器样功能相关的网络模型。在接下来的几十年里，小脑的神经元机器概念因对其结构模块化组织和记忆机制（后者以突触可塑性的形式，尤其是长时程抑制）的更多了解而得到强化。此外，几种类型的运动控制被确立为代表小脑学习机制的模型系统。最近，在细胞和分子分析层面，小脑分析的定量精确性以及对小脑的整体认识都有了显著进展。小脑回路现在包括卢加罗细胞和单极刷细胞作为额外的独特元素。其他新发现包括复杂肾小球结构的运作、突触可塑性的复杂信号转导、沉默突触、尖峰放电的不规则性、突触激活的时间保真度、节律发生器、高尔基细胞时钟回路，以及苔藓纤维和攀缘纤维的感觉或运动表征。此外，很明显小脑具有认知功能，可能还具有情感功能，以及更为人熟知的运动和自主功能。要全面理解小脑作为这些功能神经控制的广泛学习机器，还需要进一步开展小脑研究。
