Lévesque M, Gagnon S, Parent A
Centre de Recherche en Neurobiologie, Hôpital de l'Enfant-Jésus, Québec City, Canada.
Cereb Cortex. 1996 Nov-Dec;6(6):759-70. doi: 10.1093/cercor/6.6.759.
Corticostriatal and corticothalamic projections arising from the second somatosensory area in the rat were studied after labeling small pools of neurons in laminae V and VI with biocytin. Tracing the axon of single neurons revealed the following principles of organization: (i) all corticostriatal and corticothalamic projections arising from layer V cells are collaterals of long-range corticofugal axons that also project below the thalamic level; (ii) all layer V cells that project to the thalamus also project to the striatum; (iii) all layer VI corticothalamic cells project exclusively to the thalamus; (iv) cells of the upper part of lamina VI send collaterals to the thalamic reticular nucleus and arborize in the ventrobasal complex forming rod-like terminal fields; and (v) cells of the lower part of lamina VI also send collaterals to the thalamic reticular nucleus, give off few branches in the ventrobasal complex and terminate principally in the caudal part of the posterior thalamic group. On the basis of these findings, and in the light of previous anatomical studies, it is proposed that the above mentioned organizing principles represent general rules that also apply to corticostriatal and corticothalamic pathways arising from other areas of the neocortex.
在用生物胞素标记大鼠第二体感区第V层和第VI层中的小群神经元后，对源自该区的皮质纹状体和皮质丘脑投射进行了研究。追踪单个神经元的轴突揭示了以下组织原则：(i) 源自第V层细胞的所有皮质纹状体和皮质丘脑投射都是长距离皮质传出轴突的侧支，这些轴突也投射到丘脑水平以下；(ii) 所有投射到丘脑的第V层细胞也投射到纹状体；(iii) 所有第VI层皮质丘脑细胞仅投射到丘脑；(iv) 第VI层上部的细胞向丘脑网状核发出侧支，并在腹侧基底复合体中形成树突，形成杆状终末场；(v) 第VI层下部的细胞也向丘脑网状核发出侧支，在腹侧基底复合体中发出很少分支，并主要终止于丘脑后群的尾部。基于这些发现，并根据先前的解剖学研究，有人提出上述组织原则代表了一般规则，也适用于源自新皮质其他区域的皮质纹状体和皮质丘脑通路。
