Homogeneous processing in the striatal direct and indirect pathways: single body part sensitive type IIb neurons may express either dopamine receptor D1 or D2
Homogeneous processing in the striatal direct and indirect pathways: single body part sensitive type IIb neurons may express either dopamine receptor D1 or D2
复制标题
DOI：
10.1111/ejn.13690
复制
发表时间：
2017-10-01
影响因子：
3.4
通讯作者：
West, Mark O.
中科院分区：
文献类型：
--
作者：
Coffey, Kevin R.;Nader, Miles;West, Mark O.
纹状体中型多棘投射神经元 (MSN) 通过两个分叉回路（直接和间接通路）输出，这两个回路源自表达多巴胺受体 D1 或多巴胺受体 D2 的 MSN 的最小重叠群。直接和间接通路功能的一种现代理论提出，直接通路 MSN 的激活促进所需运动程序的输出，而间接通路 MSN 的激活则抑制竞争性运动程序。另一个理论表明，直接和间接路径的协调时间或同步对于执行精细动作至关重要。这些假设可以通过一种常见类型的纹状体神经元（称为 IIb 型 MSN）进行检验。这些 MSN 簇表现出与单个身体部位的感觉运动活动相关的放电频率的阶段性增加。如果这些 MSN 仅存在于直接通路中，则将提供 D1 MSN 是运动程序特异性的证据，这将为竞争性运动程序的假设提供可信度。然而，如果 IIb 型 MSN 存在于两条途径中，则将为协调时间或同步假设提供证据。我们的结果表明 IIb 型神经元可能表达 D1 或 D2。这一证据支持这样的理论：直接和间接路径的协调时间或同步对于精细运动至关重要。我们还提出了一种模型，其中直接和间接通路充当微分电路，提供了一种可能的机制，通过该机制，D1 和 D2 神经元的协调活动可以向下游结构输出有意义的体感运动信息。
Striatal medium spiny projection neurons (MSNs) output through two diverging circuits, the direct and indirect pathways' which originate from minimally overlapping populations of MSNs expressing either the dopamine receptor D1 or the dopamine receptor D2. One modern theory of direct and indirect pathway function proposes that activation of direct pathway MSNs facilitates output of desired motor programs, while activation of indirect pathway MSNs inhibits competing motor programs. A separate theory suggests that coordinated timing or synchrony of the direct and indirect pathways is critical for the execution of refined movements. These hypotheses are made testable by a common type of striatal neuron known as type IIb MSNs. Clusters of these MSNs exhibit phasic increases in firing rate related to sensorimotor activity of single body parts. If these MSNs were to reside in only the direct pathway, evidence would be provided that D1 MSNs are motor program' specific, which would lend credence to the competing motor programs' hypothesis. However, if type IIb MSNs reside in both pathways, evidence would be provided for the coordinated timing or synchrony' hypothesis. Our results show that type IIb neurons may express either D1 or D2. This evidence supports the theory that the coordinated timing or synchrony of the direct and indirect pathways is critical for refined movements. We also propose a model in which the direct and indirect pathways act as a differentiator circuit, providing a possible mechanism by which coordinated activity of D1 and D2 neurons may output meaningful somatosensorimotor information to downstream structures.