O'Hearn E, Molliver M E
Brain Res Bull. 1984 Dec;13(6):709-26. doi: 10.1016/0361-9230(84)90232-6.
Retrograde transport of a fluorescent dye was employed to study the projections from raphe nuclei to neocortex in the rat. The spatial distributions of labeled raphe cells were analyzed quantitatively to determine whether the nuclei are topographically organized with respect to different cortical targets. The dorsal raphe nucleus (DRN), exclusive of the lateral wing regions, has a predominantly (3:1) ipsilateral projection with decreasing numbers of cells projecting to frontal, parietal, and occipital cortex. Overlapping cell groups within the DRN project differentially to these three cortical areas: DRN cells innervating frontal cortex extend more rostrally and laterally than those to either parietal or occipital cortex. The medium raphe and B9 projections are bilaterally symmetric, with equal cell numbers projecting to frontal, parietal, and occipital cortex. The rostro-caudal distributions of cells that project to disparate cortical areas differ in B9 but not in MR. The percentage of cortically projecting cells that are serotonergic is 80% for the DRN, 60% in the MR and 33% in the B9 cell group. The dorsal raphe nucleus and the B9 cell group are organized heterogeneously, and overlapping sets of neurons project differentially upon particular areas of neocortex. In contrast, the median raphe nucleus projects uniformly upon the neocortex and does not exhibit topographic organization. The three rostral raphe nuclei (DR, MR and B9) are each organized according to different rules with regard to their efferent projections to cortex. The differential organization of the raphe nuclei suggests that groups of cells within these three raphe nuclei are likely to innervate different combinations of cortical targets and thus to have different functional effects.
采用荧光染料逆行运输法研究大鼠中缝核向新皮层的投射。对标记的中缝细胞的空间分布进行定量分析，以确定这些核相对于不同皮层靶点是否存在拓扑组织。除侧翼区域外，背侧中缝核（DRN）主要有同侧投射（比例为3:1），投射到额叶、顶叶和枕叶皮层的细胞数量逐渐减少。DRN内重叠的细胞群向这三个皮层区域的投射存在差异：支配额叶皮层的DRN细胞比支配顶叶或枕叶皮层的细胞向更靠前和更外侧延伸。中缝核和B9的投射是双侧对称的，投射到额叶、顶叶和枕叶皮层的细胞数量相等。投射到不同皮层区域的细胞在B9中的头尾分布不同，但在中缝核（MR）中无差异。DRN中投射到皮层的细胞中血清素能细胞的比例为80%，MR中为60%，B9细胞群中为33%。背侧中缝核和B9细胞群组织不均匀，重叠的神经元组对新皮层的特定区域投射不同。相比之下，中缝核向新皮层的投射是均匀的，不表现出拓扑组织。三个吻侧中缝核（DR、MR和B9）在向皮层的传出投射方面各自遵循不同的规则。中缝核的差异组织表明，这三个中缝核内的细胞群可能支配不同组合的皮层靶点，从而具有不同的功能效应。
