Differential Signaling to Subplate Neurons by Spatially Specific Silent Synapses in Developing Auditory Cortex
Differential Signaling to Subplate Neurons by Spatially Specific Silent Synapses in Developing Auditory Cortex
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DOI：
10.1523/jneurosci.0233-14.2014
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发表时间：
2014-06-25
影响因子：
5.3
通讯作者：
Kanold, Patrick O.
中科院分区：
文献类型：
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作者：
Meng, Xiangying;Kao, Joseph P. Y.;Kanold, Patrick O.
板下神经元（SPN）形成大脑皮层中最早成熟的回路之一，对皮层发育至关重要。除了丘脑输入之外，SPN 的子集在出生后第二周还从发育中的皮质板接收兴奋性 AMPAR 介导的输入。功能性沉默（非 AMPAR 介导的）兴奋性突触在发育过程中存在于多个系统中，并且此类输入的存在可以先于 AMPAR 介导的突触的出现。由于 SPN 接收来自不同皮质层的突触前细胞的输入，因此我们研究了 AMPAR 介导的沉默突触是否可能起源于不同的皮质层。我们在出生后 2 周内对小鼠听觉皮层的急性丘脑皮层切片进行激光扫描光刺激，以研究 SPN 上沉默突触的空间起源。我们发现来自皮质板的沉默突触存在于 SPN 上，并且它们起源于与功能性（AMPAR 介导的）突触不同的皮质位置。此外，我们发现 SPN 可以根据沉默和 AMPAR 介导的连接的空间模式进行分类。由于 SPN 可以在年轻时通过丘脑输入激活，因此年轻时不同的皮质神经元群体能够根据 SPN 的激活状态向 SPN 发出信号。因为在发育过程中皮质内回路是自发活动的，所以我们的结果表明 SPN 可能会将丘脑的上行输入与自发产生的皮质活动模式整合起来。总之，我们的结果表明 SPN 是正在发育的皮质内回路的一个组成部分，因此可以塑造丘脑皮质连接。
Subplate neurons (SPNs) form one of the earliest maturing circuits in the cerebral cortex and are crucial to cortical development. In addition to thalamic inputs, subsets of SPNs receive excitatory AMPAR-mediated inputs from the developing cortical plate in the second postnatal week. Functionally silent (non-AMPAR-mediated) excitatory synapses exist in several systems during development, and the existence of such inputs can precede the appearance of AMPAR-mediated synapses. Because SPNs receive inputs from presynaptic cells in different cortical layers, we investigated whether AMPAR-mediated and silent synapses might originate in different layers. We used laser-scanning photostimulation in acute thalamocortical slices of mouse auditory cortex during the first 2 postnatal weeks to study the spatial origin of silent synapses onto SPNs. We find that silent synapses from the cortical plate are present on SPNs and that they originate from different cortical locations than functional (AMPAR-mediated) synapses. Moreover, we find that SPNs can be categorized based on the spatial pattern of silent and AMPAR-mediated connections. Because SPNs can be activated at young ages by thalamic inputs, distinct populations of cortical neurons at young ages have the ability to signal to SPNs depending on the activation state of SPNs. Because during development intracortical circuits are spontaneously active, our results suggest that SPNs might integrate ascending input from the thalamus with spontaneously generated cortical activity patterns. Together, our results suggest that SPNs are an integral part of the developing intracortical circuitry and thereby can sculpt thalamocortical connections.