Spiking in auditory cortex following thalamic stimulation is dominated by cortical network activity.
Spiking in auditory cortex following thalamic stimulation is dominated by cortical network activity.
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DOI：
10.3389/fnsys.2014.00170
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发表时间：
2014
影响因子：
3
通讯作者：
Banks MI
中科院分区：
文献类型：
--
作者：
Krause BM;Raz A;Uhlrich DJ;Smith PH;Banks MI
感觉皮层网络的状态可以对神经反应和感知产生深远的影响。在啮齿类动物的听觉皮层中，据报道感觉反应发生在网络事件的背景下，类似于短暂的UP状态，其产生尖峰的“包”并且与同步的突触输入相关联（Mackellier等人，; Hromadka等人，Luczak等人，）。然而，基于视觉和体感皮层数据的传统模型预测，感觉丘脑皮层（TC）上行通路依次激活第4层（L4）、L2/3和L5层的细胞。这两种时空活动模式之间的关系尚不清楚。在这里，我们使用钙成像和电生理记录在小鼠听觉TC脑切片调查层状反应模式的刺激TC传入。我们发现，虽然单突触驱动的尖峰响应TC传入发生，绝大多数的尖峰发射TC刺激后发生在短暂的UP状态和L4>L2/3>L5激活序列的背景之外。具体而言，在整个层2-6中观察到具有类似的lavelance的单突触阈下TC响应，推测是通过位于L3和L4中的树突状突起上的突触。然而，单突触尖峰是罕见的，主要发生在L4和L5非锥体细胞。相比之下，在短暂的，TC诱导的UP状态，尖峰密集，主要发生在锥体细胞。这些网络事件总是涉及颗粒下层，而参与颗粒上层是可变的。在UP状态下，颗粒下和颗粒上细胞之间的棘波潜伏期相当。这些数据是一致的模型，其中激活的听觉皮层，特别是颗粒上层，取决于内部产生的网络事件，代表一个非线性放大过程，启动颗粒下细胞和前馈抑制细胞的严格监管。
The state of the sensory cortical network can have a profound impact on neural responses and perception. In rodent auditory cortex, sensory responses are reported to occur in the context of network events, similar to brief UP states, that produce “packets” of spikes and are associated with synchronized synaptic input (Bathellier et al.,; Hromadka et al.,; Luczak et al.,). However, traditional models based on data from visual and somatosensory cortex predict that ascending sensory thalamocortical (TC) pathways sequentially activate cells in layers 4 (L4), L2/3, and L5. The relationship between these two spatio-temporal activity patterns is unclear. Here, we used calcium imaging and electrophysiological recordings in murine auditory TC brain slices to investigate the laminar response pattern to stimulation of TC afferents. We show that although monosynaptically driven spiking in response to TC afferents occurs, the vast majority of spikes fired following TC stimulation occurs during brief UP states and outside the context of the L4>L2/3>L5 activation sequence. Specifically, monosynaptic subthreshold TC responses with similar latencies were observed throughout layers 2–6, presumably via synapses onto dendritic processes located in L3 and L4. However, monosynaptic spiking was rare, and occurred primarily in L4 and L5 non-pyramidal cells. By contrast, during brief, TC-induced UP states, spiking was dense and occurred primarily in pyramidal cells. These network events always involved infragranular layers, whereas involvement of supragranular layers was variable. During UP states, spike latencies were comparable between infragranular and supragranular cells. These data are consistent with a model in which activation of auditory cortex, especially supragranular layers, depends on internally generated network events that represent a non-linear amplification process, are initiated by infragranular cells and tightly regulated by feed-forward inhibitory cells.