Cognitive and Systems Neuroscience Group, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam Amsterdam, Netherlands.
Front Neural Circuits. 2012 Aug 17;6:52. doi: 10.3389/fncir.2012.00052. eCollection 2012.
Although the neocortex forms a distributed system comprised of several functional areas, its vertical columnar organization is largely conserved across areas and species, suggesting the existence of a canonical neocortical microcircuit. In order to elucidate the principles governing the organization of such a cortical diagram, a detailed understanding of the dynamics binding different types of cortical neurons into a coherent algorithm is essential. Within this complex circuitry, GABAergic interneurons, while forming approximately only 15-20% of all cortical neurons, appear critical in maintaining a dynamic balance between excitation and inhibition. Despite their importance, cortical GABAergic neurons have not been extensively studied in vivo and their precise role in shaping the local microcircuit sensory response still remains to be determined. Their paucity, combined with their molecular, anatomical, and physiological diversity, has made it difficult to even establish a consensual nomenclature. However, recent technological advances in microscopy and mouse genetics have fostered a renewed interest in neocortical interneurons by putting them within "visible" reach of experimenters. The anatomically well-defined whisker-to-barrel pathway of the rodent is particularly amenable to studies attempting to link cortical circuit dynamics to behavior. To each whisker corresponds a discrete cortical unit equivalent to a single column, specialized in the encoding and processing of the sensory information it receives. In this review, we will focus on the functional role that each subtype of supragranular GABAergic neuron embedded within such a single neocortical unit may play in shaping the dynamics of the local circuit during somatosensory integration.
尽管新皮层形成了由几个功能区域组成的分布式系统，但它的垂直柱状组织在不同区域和物种中基本保持一致，这表明存在一个规范的新皮层微电路。为了阐明支配这种皮层图组织的原则，详细了解将不同类型的皮层神经元绑定到一个连贯算法中的动力学是必不可少的。在这个复杂的电路中，GABA 能中间神经元虽然仅占所有皮层神经元的 15-20%左右，但在维持兴奋和抑制之间的动态平衡方面似乎至关重要。尽管它们很重要，但在体内对皮层 GABA 能神经元的研究还不够广泛，它们在塑造局部微电路感觉反应中的精确作用仍有待确定。它们的稀缺性，加上它们的分子、解剖和生理多样性，使得甚至建立一个共识性的命名法都变得困难。然而，显微镜和小鼠遗传学的最新技术进步，使实验者能够“看到”新皮层中间神经元，从而重新激发了人们对它们的兴趣。啮齿动物的解剖结构定义明确的胡须-桶状结构通路特别适合于试图将皮层电路动力学与行为联系起来的研究。每根胡须对应于一个离散的皮层单元，相当于单个柱体，专门用于编码和处理它所接收的感觉信息。在这篇综述中，我们将重点关注嵌入这种单个新皮层单元中的每个超颗粒 GABA 能神经元亚型在感觉整合过程中塑造局部电路动力学方面可能发挥的功能作用。
