Distinct Roles of SOM and VIP Interneurons during Cortical Up States.
Distinct Roles of SOM and VIP Interneurons during Cortical Up States.
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DOI：
10.3389/fncir.2016.00052
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发表时间：
2016
影响因子：
3.5
通讯作者：
Connors BW
中科院分区：
文献类型：
--
作者：
Neske GT;Connors BW
在皮质网络活动期间，锥体神经元之间的反复突触兴奋大致通过突触抑制来平衡，突触抑制是由大量的抑制性中间神经元提供的。不同中间神经元亚型对皮质网络活动期间抑制音调的相对贡献尚不清楚。我们之前表明，小鼠桶状皮层中的许多主要中间神经元亚型在 Up 状态下高度活跃；虽然快速放电 (FS)、小白蛋白 (PV) 阳性细胞是最活跃的中间神经元亚型，但许多非快速放电 (NFS)、PV 阴性中间神经元与邻近的锥体细胞一样活跃或更活跃。这表明 NFS 细胞可以在维持或调节 Up 状态中发挥作用。在这里，利用光遗传学技术，我们进一步剖析了两种主要 NFS、PV 阴性中间神经元亚型在 Up 状态下的功能作用：生长抑素 (SOM) 阳性细胞和血管活性肠肽 (VIP) 阳性细胞。我们发现，虽然当 SOM 细胞被光遗传学沉默时，Up 状态下锥体细胞的兴奋性显着增加，但 VIP 细胞在光遗传学沉默或激活时并不影响锥体细胞的兴奋性。尽管 VIP 细胞能够强烈抑制 SOM 细胞，但它们未能促成 Up 状态。我们认为 VIP 细胞对锥体细胞兴奋性的贡献可能随皮质状态的不同而变化。
During cortical network activity, recurrent synaptic excitation among pyramidal neurons is approximately balanced by synaptic inhibition, which is provided by a vast diversity of inhibitory interneurons. The relative contributions of different interneuron subtypes to inhibitory tone during cortical network activity is not well-understood. We previously showed that many of the major interneuron subtypes in mouse barrel cortex are highly active during Up states; while fast-spiking (FS), parvalbumin (PV)-positive cells were the most active interneuron subtype, many non-fast-spiking (NFS), PV-negative interneurons were as active or more active than neighboring pyramidal cells. This suggests that the NFS cells could play a role in maintaining or modulating Up states. Here, using optogenetic techniques, we further dissected the functional roles during Up states of two major NFS, PV-negative interneuron subtypes: somatostatin (SOM)-positive cells and vasoactive intestinal peptide (VIP)-positive cells. We found that while pyramidal cell excitability during Up states significantly increased when SOM cells were optogenetically silenced, VIP cells did not influence pyramidal cell excitability either upon optogenetic silencing or activation. VIP cells failed to contribute to Up states despite their ability to inhibit SOM cells strongly. We suggest that the contribution of VIP cells to the excitability of pyramidal cells may vary with cortical state.