Department of Neuroscience and Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712-0248.
Department of Neuroscience and Center for Learning and Memory, The University of Texas at Austin, Austin, TX 78712-0248
Proc Natl Acad Sci U S A. 2021 Mar 9;118(10). doi: 10.1073/pnas.2007724118.
The central nucleus of the inferior colliculus (ICC) integrates information about different features of sound and then distributes this information to thalamocortical circuits. However, the lack of clear definitions of circuit elements in the ICC has limited our understanding of the nature of these circuit transformations. Here, we combine virus-based genetic access with electrophysiological and optogenetic approaches to identify a large family of excitatory, cholecystokinin-expressing thalamic projection neurons in the ICC of the Mongolian gerbil. We show that these neurons form a distinct cell type, displaying uniform morphology and intrinsic firing features, and provide powerful, spatially restricted excitation exclusively to the ventral auditory thalamus. In vivo, these neurons consistently exhibit V-shaped receptive field properties but strikingly diverse temporal responses to sound. Our results indicate that temporal response diversity is maintained within this population of otherwise uniform cells in the ICC and then relayed to cortex through spatially restricted thalamic subdomains.
下丘中央核（ICC）整合了有关声音不同特征的信息，然后将这些信息分配到丘脑皮质回路。然而，由于 ICC 中电路元件缺乏明确的定义，限制了我们对这些电路转换性质的理解。在这里，我们结合基于病毒的遗传方法与电生理和光遗传学方法，在蒙古沙鼠的 ICC 中鉴定出一大类兴奋性、胆囊收缩素表达的丘脑投射神经元。我们表明，这些神经元形成了一个独特的细胞类型，具有统一的形态和内在的放电特征，并专门提供强大的、空间限制的兴奋性，仅传递到腹侧听觉丘脑。在体内，这些神经元始终表现出 V 形的感受野特性，但对声音的时间响应却截然不同。我们的结果表明，时间响应多样性在 ICC 中这个细胞群体内得以维持，然后通过空间限制的丘脑亚区传递到皮层。
