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.

下丘的中央核 (ICC) 整合有关声音不同特征的信息，然后将这些信息分发到丘脑皮质回路。然而，ICC 中缺乏明确的电路元件定义限制了我们对这些电路转换性质的理解。在这里，我们将基于病毒的遗传通路与电生理学和光遗传学方法相结合，以在蒙古沙鼠的 ICC 中识别一大群兴奋性、表达胆囊收缩素的丘脑投射神经元。我们表明这些神经元形成了一种独特的细胞类型，显示出均匀的形态和内在的放电特征，并专门为腹侧听觉丘脑提供强大的、空间受限的激发。体内，这些神经元始终表现出 V 形感受野特性，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 中这个原本均一的细胞群中得以维持，然后通过空间受限的丘脑亚域传递到皮层。