小鼠听觉丘脑后内侧核的声音反应特性

Acoustic response characteristics of posterior intralaminar nucleus of auditory thalamus in mice

目的探究成年VGluT2-Cre转基因小鼠非丘系听觉丘脑后内侧核(posterior intralaminar nucleus,PIN)对不同声音刺激的反应特性。方法2017年10月至2018年10月30只8~12周龄成年雄性VGluT2-Cre转基因小鼠为研究对象,通过定位注射特异性AAV-hSyn-DIO-GCaMP6m病毒转染PIN,采用光纤记录钙离子敏感蛋白荧光信号的方法,分别记录PIN群体神经元对不同给声方式的10 kHz纯音和白噪声的反应幅值。利用Matlab软件编写相应的数据处理程序,进行统计分析。结果共12只小鼠光纤准确定位到PIN上方且病毒成功转染并表达良好,声刺激时采集的信号数据均来自于PIN。在持续3 s的给声刺激中,白噪声产生的信号幅值优于10 kHz纯音,差异有统计学意义(n=6,t=2.404,P=0.037 1)。在连续3次或连续5次短促给声(白噪声或10 kHz纯音)刺激中,连续3次短促刺激的跟随性均优于续5次短促刺激,且10 kHz纯音连续3次短促声刺激产生的信号幅值衰减速度比连续5次短促声更快,差异具有统计学意义(n=6, t=2.748 P=0.033 4)。无论白噪声还是10 kHz纯音刺激,PIN对连续3次短促给声的响应度均比连续5次短促给声要好,而持续3 s给声的响应度介于二者之间。结论在相同给声强度下,成年VGluT2-Cre转基因小鼠PIN对白噪声的反应要好于纯音,对重复的10 kHz纯音的衰减比白噪声更快,适应性更强。PIN对噪声的响应度高于纯音。

Objective To study the response characteristics of the posterior intralaminar nucleus (PIN) of auditory thalamus in VGluT2-Cre transgenic adult mice when exposed to white noise and 10K pure tone stimulation. Methods All adult male Vglut2-Cre mice (8-12 weeks) were used in this study between Oct, 2017 and Oct, 2018. Using the calcium signal fiber photometry method, optic fiber was employed to locate on PIN by injecting AAV-hSyn-DIO-GCaMP6m virus, and thereafter, the activity of the target cluster neurons during different acoustic stimuli was recorded. Matlab was used for data processing and statistical analysis. Results (1)In both white noise and 10 kHz pure tone as a continuous three-second stimulation, the peak amplitude of calcium signal activity generated in PIN by white noise was superior to that of pure tone, the statistic result showed significantly difference (n=6, t=2.404, P=0.037 1).(2)In addition, when white noise and 10K pure tone played as consecutive 3 or 5 pips within three-second stimulation, the stimulus-following ability in a consecutive 3 pulses play within 3 seconds was far better than a consecutive 5 pips play within 3 seconds (in both white noise and 10 kHz pure tone), yet consecutive 3 pips play showed greater signal attenuation speed than that in consecutive 5 pips play, the statistic result showed significantly difference (n=6, t=2.748 P=0.033 4).(3)Regardless of the intra-group comparisons between white noise and 10 kHz pure tone stimulation, PIN showed better signal response in a consecutive 3 pips play than consecutive 5 pips play or a continuous three-second stimulation. When came to the statistical analysis, the acoustic response degree of a continuous three-second stimulation was an intermediate between two others, both consecutive 3 or 5 pips play showed significantly difference. Conclusions The results suggest that under the same acoustic intensity, VGluT2-Cre transgenic adult mice′s PIN shows greater signal response in white noise than pure tone. PIN shows greater signal attenuation to repetition play of 10 kHz pure tone, which implies PIN shows stronger adaptation to 10 kHz pure tone than to white noise. Lastly, PIN is more responsive to a complex sound information (white noise) than to simple sound information (pure tone).