Local and Long-Range Circuit Connections to Hilar Mossy Cells in the Dentate Gyrus.
Local and Long-Range Circuit Connections to Hilar Mossy Cells in the Dentate Gyrus.
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DOI：
10.1523/eneuro.0097-17.2017
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发表时间：
2017-03
期刊：
影响因子：
3.4
通讯作者：
Xu X
中科院分区：
文献类型：
--
作者：
Sun Y;Grieco SF;Holmes TC;Xu X
门苔藓细胞是齿状回（DG）的齿状门中突出的神经元能细胞类型，它们已被提出在DG网络中具有关键作用。为了更好地了解苔藓细胞如何促进DG功能，我们应用了新的病毒遗传和功能电路映射方法来定量映射和比较苔藓细胞和齿状颗粒细胞在小鼠中的局部和远程电路连接。苔藓细胞的绝大多数输入包括两个平行的输入从DG内：一个兴奋性输入途径从齿状颗粒细胞和抑制性输入途径从本地DG抑制神经元。苔藓细胞也接受适度的兴奋性和抑制性CA3输入近端CA3子域。苔藓细胞的长距离输入在数量上是稀疏的，并且它们仅容易从内侧隔和隔伞核中识别。相比之下，齿状颗粒细胞从内嗅皮层接收大部分输入。颗粒细胞接受来自门和内侧隔的显著突触输入，并且它们还接受来自远端和近端CA3子场的直接输入，这在现有文献中被低估。我们基于切片的生理映射研究进一步支持了苔藓细胞和颗粒细胞的识别电路连接。总之，我们的数据表明，门苔藓细胞是主要的本地电路集成商，他们发挥调制的活性齿状颗粒细胞以及CA3区通过“背投影”途径。
Hilar mossy cells are the prominent glutamatergic cell type in the dentate hilus of the dentate gyrus (DG); they have been proposed to have critical roles in the DG network. To better understand how mossy cells contribute to DG function, we have applied new viral genetic and functional circuit mapping approaches to quantitatively map and compare local and long-range circuit connections of mossy cells and dentate granule cells in the mouse. The great majority of inputs to mossy cells consist of two parallel inputs from within the DG: an excitatory input pathway from dentate granule cells and an inhibitory input pathway from local DG inhibitory neurons. Mossy cells also receive a moderate degree of excitatory and inhibitory CA3 input from proximal CA3 subfields. Long range inputs to mossy cells are numerically sparse, and they are only identified readily from the medial septum and the septofimbrial nucleus. In comparison, dentate granule cells receive most of their inputs from the entorhinal cortex. The granule cells receive significant synaptic inputs from the hilus and the medial septum, and they also receive direct inputs from both distal and proximal CA3 subfields, which has been underdescribed in the existing literature. Our slice-based physiological mapping studies further supported the identified circuit connections of mossy cells and granule cells. Together, our data suggest that hilar mossy cells are major local circuit integrators and they exert modulation of the activity of dentate granule cells as well as the CA3 region through “back-projection” pathways.