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Abstract：
Mouse auditory cortex is composed of six sub-fields: primary auditory field (AI), secondary auditory field (AII), anterior auditory field (AAF), insular auditory field (IAF), ultrasonic field (UF) and dorsoposterior field (DP). Previous studies have examined thalamo-cortical connections in the mice auditory system and learned that AI, AAF, and IAF receive inputs from the ventral division of the medial geniculate body (MGB). However, the functional and thalamo-cortical connections between nonprimary auditory cortex (AII, UF, and DP) is unclear. In this study, we examined the locations of neurons projecting to these three cortical sub-fields in the MGB, and addressed the question whether these cortical sub-fields receive inputs from different subsets of MGB neurons or common. To examine the distributions of projecting neurons in the MGB, retrograde tracers were injected into the AII, UF, DP, after identifying these areas by the method of Optical Imaging. Our results indicated that neuron cells which in ventral part of dorsal MGB (MGd) and that of ventral MGB (MGv) projecting to UF and AII with less overlap. And DP only received neuron projecting from MGd. Interestingly, these three cortical areas received input from distinct part of MGd and MGv in an independent manner. Based on our foundings these three auditory cortical sub-fields in mice may independently process auditory information.
摘要：
小鼠听觉皮层由六个子场组成：初级听觉场（AI），次级听觉场（AII），前听视野(AAF),岛状听觉场（IAF），超声场（UF）和背后场（DP）。先前的研究已经检查了小鼠听觉系统中的丘脑-皮层连接，并了解到AI，AAF,和IAF从内侧膝状体（MGB）的腹侧分区接收输入。然而,非初级听觉皮层之间的功能和丘脑-皮层连接(AII，UF,和DP）不清楚。在这项研究中,我们检查了投射到MGB中这三个皮层子场的神经元的位置，并解决了这些皮质子场是否从MGB神经元的不同子集或公共接收输入的问题。为了检查MGB中投射神经元的分布，逆行示踪剂被注入AII，UF,DP,通过光学成像的方法识别这些区域。我们的结果表明，背侧MGB（MGd）和腹侧MGB（MGv）腹侧部分的神经元细胞向UF和AII突出的重叠较少。而DP只接收从MGd投射的神经元。有趣的是,这三个皮质区域以独立的方式从MGd和MGv的不同部分接收输入。基于我们的发现,小鼠中的这三个听觉皮层子场可以独立地处理听觉信息。
