Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA.
Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA.
Cell Rep. 2017 Aug 22;20(8):1844-1854. doi: 10.1016/j.celrep.2017.07.079.
Many studies have explored how neuromodulators affect synaptic function, yet little is known about how they modify computations at the microcircuit level. In the dorsal cochlear nucleus (DCN), a region that integrates auditory and multisensory inputs from two distinct pathways, serotonin (5-HT) enhances excitability of principal cells, predicting a generalized reduction in sensory thresholds. Surprisingly, we found that when looked at from the circuit level, 5-HT enhances signaling only from the multisensory input, while decreasing input from auditory fibers. This effect is only partially explained by an action on auditory nerve terminals. Rather, 5-HT biases processing for one input pathway by simultaneously enhancing excitability in the principal cell and in a pathway-specific feed-forward inhibitory interneuron. Thus, by acting on multiple targets, 5-HT orchestrates a fundamental shift in representation of convergent auditory and multisensory pathways, enhancing the potency of non-auditory signals in a classical auditory pathway.
许多研究已经探讨了神经调质如何影响突触功能，但对于它们如何在微电路水平上改变计算知之甚少。在背侧耳蜗核（DCN）中，一个整合来自两个不同通路的听觉和多感觉输入的区域，5-羟色胺（5-HT）增强了主要细胞的兴奋性，预测了感觉阈值的普遍降低。令人惊讶的是，我们发现，从电路水平来看，5-HT 仅增强来自多感觉输入的信号，而降低来自听觉纤维的信号。这种影响仅部分可以通过对听觉神经末梢的作用来解释。相反，5-HT 通过同时增强主要细胞和特定于通路的前馈抑制性中间神经元的兴奋性，使一个输入通路的处理偏向。因此，5-HT 通过作用于多个靶点，协调了会聚的听觉和多感觉通路的表示的根本转变，增强了经典听觉通路上非听觉信号的效力。
