White E L, Keller A
J Comp Neurol. 1987 Aug 1;262(1):13-26. doi: 10.1002/cne.902620103.
The objective of this study was to identify the components involved in a local synaptic circuit in the mouse cerebral cortex. The local axon collaterals of corticothalamic (CT) projection cells in the posteromedial barrel subfield area of primary somatosensory cortex were labeled by the retrograde transport of horseradish peroxidase injected into the ipsilateral thalamus. Thalamocortical (TC) axon terminals in the same region of cortex were labeled by lesion induced degeneration. CT axon terminals synapsed preferentially with dendritic shafts, whereas TC axon terminals synapsed mainly with dendritic spines. Some dendrites received both CT and TC synapses. Dendrites were interpreted to belong to nonspiny multipolar cells. These results indicate that a reciprocal synaptic relationship exists in the cortex between nonspiny multipolar cells and CT projection cells. Both CT projection cells and nonspiny multipolar neurons have been shown previously to receive TC synapses (White and Hersh: J. Neurocytol. 11:137-157, '82; White, Benshalom, and Hersch: J. Comp. Neurol. 229:311-320, '84). These findings imply that a triadic relationship involving afferent input and populations of CT projection and intrinsic neurons is a basic feature of the synaptic organization of the cerebral cortex.
本研究的目的是确定小鼠大脑皮质局部突触回路中涉及的组成部分。将辣根过氧化物酶注入同侧丘脑，通过逆行运输标记初级体感皮层后内侧桶状亚区皮质丘脑（CT）投射细胞的局部轴突侧支。通过损伤诱导变性标记皮质同一区域的丘脑皮质（TC）轴突终末。CT轴突终末优先与树突干形成突触，而TC轴突终末主要与树突棘形成突触。一些树突同时接受CT和TC突触。树突被解释为属于无棘多极细胞。这些结果表明，在皮质中，无棘多极细胞与CT投射细胞之间存在相互的突触关系。先前已表明，CT投射细胞和无棘多极神经元都接受TC突触（怀特和赫什：《神经细胞学杂志》11:137 - 157，1982年；怀特、本沙洛姆和赫什：《比较神经学杂志》229:311 - 320，1984年）。这些发现意味着涉及传入输入以及CT投射和内在神经元群体的三联关系是大脑皮质突触组织的一个基本特征。
