Brain & Sound Lab, Department of Biomedicine, Basel University, 4056, Basel, Switzerland.
Sci Rep. 2019 Jul 3;9(1):9581. doi: 10.1038/s41598-019-45952-z.
In the rodent auditory system, the primary cortex is subdivided into two regions, both receiving direct inputs from the auditory thalamus: the primary auditory cortex (A1) and the anterior auditory field (AAF). Although neurons in the two regions display different response properties, like response latency, firing threshold or tuning bandwidth, it is still not clear whether they process sound in a distinct way. Using in vivo electrophysiological recordings in the mouse auditory cortex, we found that AAF neurons have significantly stronger responses to tone offset than A1 neurons. AAF neurons also display faster and more transient responses than A1 neurons. Additionally, offset responses in AAF - unlike in A1, increase with sound duration. Local field potential (LFP) and laminar analyses suggest that the differences in sound responses between these two primary cortices are both of subcortical and intracortical origin. These results emphasize the potentially critical role of AAF for temporal processing. Our study reveals a distinct role of two primary auditory cortices in tone processing and highlights the complexity of sound encoding at the cortical level.
在啮齿动物的听觉系统中，初级皮层分为两个区域，均接收来自听觉丘脑的直接输入：初级听觉皮层 (A1) 和前听觉场 (AAF)。尽管两个区域的神经元表现出不同的反应特性，如反应潜伏期、发放阈值或调谐带宽，但它们是否以不同的方式处理声音仍不清楚。我们在小鼠听觉皮层中进行了体内电生理记录，发现 AAF 神经元对音调结束的反应明显强于 A1 神经元。AAF 神经元的反应也比 A1 神经元更快、更短暂。此外，AAF 的结束反应（与 A1 不同）随声音持续时间增加而增加。局部场电位 (LFP) 和层分析表明，这两个初级皮层之间的声音反应差异既有皮质下起源，也有皮质内起源。这些结果强调了 AAF 对时间处理的潜在关键作用。我们的研究揭示了两个初级听觉皮层在音调处理中的不同作用，突出了皮质水平上声音编码的复杂性。
