Lei S, Xiao Z
Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2021 Jul 20;41(7):1079-1086. doi: 10.12122/j.issn.1673-4254.2021.07.17.
To study the response characteristics of the secondary auditory cortex (A2) to wriggling calls (WC) and the mechanism of response modulation in female mice.
We used patch-clamp and immunofluorescence labeling technique to mark and record the action potential and cell type of A2 neurons. Female C57 mice were stimulated with pure tone and white noise (control), 4.5 kHz, 9 kHz, or 13.5 kHz sound waves extracted from WC (single-frequency simulation group), the combinations of every two of the 3 single-frequency sound waves (two-tone frequency simulation group), or the combinations of 4.5 kHz+7.7 kHz+13.5 kHz and 4.5 kHz+9 kHz+13.5 kHz sound waves (three-frequency simulation group). The firing pattern, firing number, threshold, and latency of the action potential of the A2 neurons were recorded in response to the stimulations.
By comparison of the spikes elicited by different sound stimulations, we identified 3 types of neurons with different sensitivities to WC. The WC-sensitive neurons had a significantly greater number of spikes in response to WC than to other sounds and noise ( < 0.001). Comparison of the latency and threshold revealed significantly longer latencies of the WC-sensitive neurons and WC-insensitive neurons in response to WC stimulation than to pure tone stimulation (=0.002), but their latencies to WC and noise stimulation were similar (=0.093). The WC-sensitive neurons also had lower threshold to WC than to pure tone and noise stimulations (=0.02). Analysis of the firing patterns of action potentials showed that the WCsensitive neurons consisted mainly of parvalbumin interneurons. The results of immunofluorescence labeling indicated that inhibitory interneurons were present in the A2 neurons that responded to WC.
A2 contains 3 types of neurons with different sensitivities to WC. Among them, the WC-sensitive neurons is mainly PV neurons, whose response characteristics to different types of sounds can help to explain the mechanism of communication sound recognition and response modification in A2.
研究雌性小鼠次级听觉皮层(A2)对蠕动叫声(WC)的反应特性及反应调制机制。
采用膜片钳和免疫荧光标记技术标记并记录A2神经元的动作电位和细胞类型。用纯音和白噪声(对照组)、从WC中提取的4.5 kHz、9 kHz或13.5 kHz声波(单频模拟组)、3种单频声波中每两种的组合(双频模拟组)或4.5 kHz + 7.7 kHz + 13.5 kHz和4.5 kHz + 9 kHz + 13.5 kHz声波组合(三频模拟组)刺激雌性C57小鼠。记录A2神经元动作电位的发放模式、发放次数、阈值和潜伏期以响应这些刺激。
通过比较不同声音刺激引发的锋电位,我们鉴定出对WC具有不同敏感性的3种神经元类型。WC敏感神经元对WC产生的锋电位数量明显多于对其他声音和噪声产生的锋电位数量(<0.001)。潜伏期和阈值比较显示,WC敏感神经元和WC不敏感神经元对WC刺激的潜伏期明显长于对纯音刺激的潜伏期(=0.002),但它们对WC和噪声刺激的潜伏期相似(=0.093)。WC敏感神经元对WC的阈值也低于对纯音和噪声刺激的阈值(=0.02)。动作电位发放模式分析表明,WC敏感神经元主要由小白蛋白中间神经元组成。免疫荧光标记结果表明,对WC有反应的A2神经元中存在抑制性中间神经元。
A2包含对WC具有不同敏感性的3种神经元类型。其中,WC敏感神经元主要是小白蛋白神经元,其对不同类型声音的反应特性有助于解释A2中通讯声音识别和反应调制的机制。