Yelnik J
Research unit UMR679, Inserm, université Pierre-et-Marie-Curie, Salpêtrière Hospital, 47, boulevard de l'Hôpital, 75013 Paris, France.
Rev Neurol (Paris). 2008 Dec;164(12):969-76. doi: 10.1016/j.neurol.2008.04.019. Epub 2008 Jul 9.
Several models have been elaborated to describe the structure and function of the basal ganglia, but its different levels of architectural organization, macroscopic anatomy, connectivity, functional territorial subdivision and neuronal morphology have rarely been considered. In this review, I present some of these models and I analyze the functioning of the basal ganglia at the light of its architectural properties.
The basal ganglia form an important neuronal system, which interacts with the cerebral cortex through a complex series of loop circuits. While the morphological, electrophysiological and biochemical properties of this system are progressively known better and better, they have led to various interpretations from which different, sometimes contradictory, models have been constructed. The basal ganglia are often analyzed as homogeneous nuclei that communicate through excitatory or inhibitory connections, the so-called "box and arrows" models. Among them, the dual-, triple- and five circuit models are the most popular. Analysis of the "inside of the boxes" provides, however, important data such as the functional subdivision into three, motor, associative and limbic territories and the demonstration that integrative properties are a characteristic of the basal ganglia.
Considering these properties, the way cortical information is processed in the basal ganglia can be analyzed, which leads to modeling its organization and functioning. The striatum receives a compressed version of cortical information and transforms it through complex processes of activation/deactivation under a double dopaminergic and cholinergic control that enables behavioral reinforcement learning. The globus pallidus behaves as a keyboard on which various behavioral repertoires can be coded, from the simplest movement of a single joint to the most complex motor sequence involving the entire body and expressing an emotional content in a cognitive context. The role of the subthalamic nucleus must be considered at different scales. At the macroscopic scale, it works as a thermostat that regulates the level of execution of cortical commands. At a territorial scale, it can process separately motor, cognitive and emotional information. At the neuronal scale, it assures a much finer neuronal representation of cortical commands and can integrate motor, cognitive and emotional aspects. New experiments in both animal models and human clinical-research protocols are needed to demonstrate the neuronal mechanisms of these processes.
A model is proposed that considers how neural information is processed in the basal ganglia during the execution of motor, cognitive and emotional activities.
已经构建了多种模型来描述基底神经节的结构和功能，但很少有人考虑其不同层次的结构组织、宏观解剖结构、连接性、功能区域划分和神经元形态。在这篇综述中，我介绍了其中一些模型，并根据其结构特性分析了基底神经节的功能。
基底神经节构成一个重要的神经元系统，它通过一系列复杂的环路与大脑皮层相互作用。虽然对该系统的形态学、电生理学和生化特性的了解越来越深入，但这些特性引发了各种不同的解释，由此构建了不同的、有时甚至相互矛盾的模型。基底神经节常被分析为通过兴奋性或抑制性连接进行通信的同质核，即所谓的“方框箭头”模型。其中，双环路、三环路和五环路模型最为流行。然而，对“方框内部”的分析提供了重要数据，如功能划分为运动、联合和边缘三个区域，并证明整合特性是基底神经节的一个特征。
考虑到这些特性，可以分析基底神经节中皮质信息的处理方式，从而对其组织和功能进行建模。纹状体接收皮质信息的压缩版本，并在多巴胺能和胆碱能双重控制下，通过复杂的激活/失活过程对其进行转换，从而实现行为强化学习。苍白球就像一个键盘，可以对各种行为模式进行编码，从单个关节的最简单运动到涉及全身并在认知背景中表达情感内容的最复杂运动序列。底丘脑核的作用必须在不同尺度上加以考虑。在宏观尺度上，它就像一个恒温器，调节皮质指令的执行水平。在区域尺度上，它可以分别处理运动、认知和情感信息。在神经元尺度上，它确保对皮质指令进行更精细的神经元表征，并可以整合运动、认知和情感方面。需要在动物模型和人类临床研究方案中进行新的实验，以证明这些过程的神经元机制。
提出了一个模型，该模型考虑了在运动、认知和情感活动执行过程中基底神经节如何处理神经信息。
