The locus coeruleus is a complex and differentiated neuromodulatory system
The locus coeruleus is a complex and differentiated neuromodulatory system
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DOI：
10.1101/109710
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发表时间：
2017-02
期刊：
影响因子：
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通讯作者：
Nelson K. Totah;Ricardo M. Neves;S. Panzeri;N. Logothetis;O. Eschenko
中科院分区：
文献类型：
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作者：
Nelson K. Totah;Ricardo M. Neves;S. Panzeri;N. Logothetis;O. Eschenko
了解去甲肾上腺素能蓝斑(LC)对前脑的神经调节作用是认知科学和系统神经科学的基础。长期以来，单个LC神经元的弥漫性投射和它们的同步峰电位一直被认为是去甲肾上腺素能神经调节的全球性特征。然而，普遍提到的潜在的全球神经调节的“同步性”，从未在大量人群中被评估过，也没有与投射靶标特异性相关。在这里，我们同时记录了大鼠LC中多达52个单一单位(总共3164个单位对)，并通过刺激15个前脑部位来表征投射。棘波计数的相关性很低，令人惊讶的是，只有13%的成对棘波序列具有同步的自发放电。值得注意的是，即使是有害的感官刺激也没有激活整个群体，在每次试验中只在大约16%的单位中唤起了同步反应。我们还发现了新的次慢(0.01-1赫兹)的LC单位峰值波动，这种波动在整个人群中是不同步的。少数人可能通过缝隙连接同步，偏向于限制性(非全局)前脑投射模式。最后，我们描述了两种不同类型的LC单个单位的波形形状、同步化倾向以及与皮质的相互作用。这些细胞类型形成了结构精细的群体。我们的发现表明，LC传递高度复杂、不同的、潜在靶点特异性的神经调节信号。
Understanding the forebrain neuromodulation by the noradrenergic locus coeruleus (LC) is fundamental for cognitive and systems neuroscience. The diffuse projections of individual LC neurons and presumably their synchronous spiking have long been perceived as features of the global nature of noradrenergic neuromodulation. Yet, the commonly referenced “synchrony” underlying global neuromodulation, has never been assessed in a large population, nor has it been related to projection target specificity. Here, we recorded up to 52 single units simultaneously (3164 unit pairs in total) in rat LC and characterized projections by stimulating 15 forebrain sites. Spike count correlations were low and, surprisingly, only 13% of pairwise spike trains had synchronized spontaneous discharge. Notably, even noxious sensory stimulation did not activate the entire population, only evoking synchronized responses in ~16% of units on each trial. We also identified novel infra-slow (0.01-1 Hz) fluctuations of LC unit spiking that were asynchronous across the population. A minority, synchronized possibly by gap junctions, was biased toward restricted (non-global) forebrain projection patterns. Finally, we characterized two types of LC single units differing by waveform shape, propensity for synchronization, and interactions with cortex. These cell types formed finely-structured ensembles. Our findings suggest that the LC conveys a highly complex, differentiated, and potentially target-specific neuromodulatory signal.