Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Avenida General Flores, 2125 Montevideo, Uruguay.
J Exp Biol. 2013 Jul 1;216(Pt 13):2380-92. doi: 10.1242/jeb.082651.
This review deals with the question: what is the relationship between the properties of a neuron and the role that the neuron plays within a given neural circuit? Answering this kind of question requires collecting evidence from multiple neuron phenotypes and comparing the role of each type in circuits that perform well-defined computational tasks. The focus here is on the spherical neurons in the electrosensory lobe of the electric fish Gymnotus omarorum. They belong to the one-spike-onset phenotype expressed at the early stages of signal processing in various sensory modalities and diverse taxa. First, we refer to the one-spike neuron intrinsic properties, their foundation on a low-threshold K(+) conductance, and the potential roles of this phenotype in different circuits within a comparative framework. Second, we present a brief description of the active electric sense of weakly electric fish and the particularities of spherical one-spike-onset neurons in the electrosensory lobe of G. omarorum. Third, we introduce one of the specific tasks in which these neurons are involved: the trade-off between self- and allo-generated signals. Fourth, we discuss recent evidence indicating a still-undescribed role for the one-spike phenotype. This role deals with the blockage of the pathway after being activated by the self-generated electric organ discharge and how this blockage favors self-generated electrosensory information in the context of allo-generated interference. Based on comparative analysis we conclude that one-spike-onset neurons may play several functional roles in animal sensory behavior. There are specific adaptations of the neuron's 'response function' to the circuit and task. Conversely, the way in which a task is accomplished depends on the intrinsic properties of the neurons involved. In short, the role of a neuron within a circuit depends on the neuron and its functional context.
神经元的特性与其在特定神经回路中所扮演的角色之间存在什么关系？回答这类问题需要从多种神经元表型中收集证据，并比较每种类型在执行明确计算任务的回路中的作用。本文的重点是电鳗的电感觉叶中的球形神经元。它们属于在各种感觉模态和不同分类群中信号处理早期表达的单峰起始表型。首先，我们提到了单峰神经元的内在特性，它们建立在低阈值 K(+)电导的基础上，以及这种表型在比较框架内不同回路中的潜在作用。其次，我们简要描述了弱电鱼的主动电感觉以及 G. omarorum 电感觉叶中单峰起始神经元的特殊性。第三，我们介绍了这些神经元参与的特定任务之一：自我和异体信号之间的权衡。第四，我们讨论了最近的证据，表明单峰表型仍具有未被描述的作用。这种作用涉及到被自身产生的电器官放电激活后的通路阻断，以及在异体干扰的背景下，这种阻断如何有利于自身产生的电感觉信息。基于比较分析，我们得出结论，单峰起始神经元在动物感觉行为中可能发挥多种功能作用。神经元的“响应函数”存在针对特定回路和任务的特定适应性。相反，任务的完成方式取决于所涉及神经元的内在特性。简而言之，神经元在回路中的作用取决于神经元及其功能背景。
