Hoeflinger B F, Bennett-Clarke C A, Chiaia N L, Killackey H P, Rhoades R W
Department of Anatomy, Medical College of Ohio, Toledo 43699-0008, USA.
J Comp Neurol. 1995 Apr 17;354(4):551-63. doi: 10.1002/cne.903540406.
Anterograde and retrograde tracing with biotinylated dextran amine and Phaseolus vulgaris leukoagglutinin was used to assess projection patterns within the vibrissae representation of the rat's primary somatosensory cortex (S-I). Large and small injections of either tracer into the center of the vibrissae representation yielded dense anterograde and retrograde labelling throughout much of the tangential extent of the vibrissae representation within S-I. In all layers, the pattern and extent of retrograde and anterograde label was in rough congruence. The organization of this labelling varied across cortical layers. In layers II and III, labelled fibers extended away from injection sites in all directions and yielded a uniform pattern, which decreased in density with increasing distance from the tracer injection. There was a tendency for labelling to be more extensive along the representation of the row of vibrissae follicles that included the injection site than across rows. There was also a tendency for anterograde labelling to be more extensive in the direction of the representation of follicles more rostral on the face than that injected. In lamina IV, both labelled fibers and cells were restricted for the most part to the septa regions between the barrels. However, a small number of retrogradely labelled neurons were also located in the barrels (approximately one-ninth of the number found in the septa). The pattern observed in laminae II-III was repeated in layers V and VI. In these laminae, there was no evidence of a pattern of intracortical connections related to the vibrissae representation in overlying lamina IV.
使用生物素化葡聚糖胺和菜豆白细胞凝集素进行顺行和逆行示踪，以评估大鼠初级体感皮层（S-I）触须代表区内的投射模式。将两种示踪剂中的任意一种大剂量或小剂量注射到触须代表区的中心，在S-I内触须代表区的大部分切线范围内均产生了密集的顺行和逆行标记。在所有层中，逆行标记和顺行标记的模式和范围大致一致。这种标记的组织在不同皮层层中有所不同。在第II层和第III层，标记纤维从注射部位向各个方向延伸，形成均匀的模式，其密度随着与示踪剂注射距离的增加而降低。沿着包括注射部位的触须毛囊排的代表区，标记往往比跨排更广泛。顺行标记也有沿着面部比注射部位更靠前的毛囊代表区方向更广泛的趋势。在第IV层，标记纤维和细胞大多局限于桶之间的间隔区域。然而，也有少数逆行标记的神经元位于桶内（约为间隔区发现数量的九分之一）。在第V层和第VI层中观察到的模式与第II-III层重复。在这些层中，没有证据表明存在与上层第IV层触须代表区相关的皮质内连接模式。
