Broadwell R D
J Comp Neurol. 1975 Oct 1;163(3):329-45. doi: 10.1002/cne.901630306.
The efferent connections of the main and accessory olfactory bulbs in the female albino rabbit have been studied using the autoradiographic method for tracing axonal pathways. Following unilateral injections of 3H-proline or 3H-leucine into the main olfactory bulb, radioactively labeled material transported intraaxonally by axoplasmic flow in an anterograde direction from soma to axon terminal is present ipsilaterally in the superficial half of the plexiform layer (IA) of: the entire circumference of the olfactory peduncle, the tenia tecta, the full mediolateral extent of the olfactory tubercle, the entire length of the prepyriform cortex, a transition area between the prepyriform cortex and the horizontal limb of the nucleus of the diagonal band, the nucleus of the lateral olfactory tract, the anterior cortical and posterolateral cortical amygdaloid nuclei (periamygdaloid areas 1, rostral half of 2, 5 of Rose, '31), and the ventrolateral entorhinal cortex (entorhinal areas 1, 2, 4, 5, 7 of Rose, '31). No subcortical or contralateral projection of main bulb efferents was found. After a unilateral injection of 3H-leucine into the accessory olfactory bulb, transported material could be followed caudally along the dorsal surface of the ipsilateral lateral olfactory tract. This heavily labeled projection is distinct from the unlabeled lateral olfactory tract and has been termed the accessory olfactory tract. Beginning at the level of the caudal third of the olfactory tubercle and extending caudally to the nucleus of the lateral olfactory tract is a group of small neurons intimately associated with the accessory olfactory tract. This cell group is referred to as the bed nucleus of the accessory olfactory tract. Projection sites of the accessory bulb include the bed nucleus of the accessory olfactory tract and layer IA of the medial nucleus and the posteromedial cortical nucleus of the amygdala (periamygdaloid areas 3, 4, PAM, caudal half of 2, 6 of Rose, '31). An additional accessory bulb efferent projection was found to enter the stria terminalis at the level of the medial amygdaloid nucleus and could be traced to a posterior segment of the bed nucleus of the stria terminalis. The autoradiographic findings indicate that the accessory olfactory bulb connects with portions of the amygdala that do not receive afferent input from the main olfactory bulb and provide evidence for the existence of two distinct and separate olfactory systems.
利用放射自显影法追踪轴突通路，对雌性白化兔主嗅球和副嗅球的传出连接进行了研究。在单侧将³H-脯氨酸或³H-亮氨酸注入主嗅球后，通过轴浆流从胞体向轴突终末顺行运输的放射性标记物质，同侧存在于以下部位的丛状层（IA）浅层：嗅柄的整个圆周、带状层、嗅结节的整个内外侧范围、梨状前皮质的全长、梨状前皮质与斜角带核水平支之间的过渡区域、外侧嗅束核、杏仁前皮质核和杏仁后外侧皮质核（罗斯，1931年，杏仁周区1、2的前半部分、5），以及腹侧内嗅皮质（罗斯，1931年，内嗅区1、2、4、5、7）。未发现主嗅球传出纤维的皮质下或对侧投射。在单侧将³H-亮氨酸注入副嗅球后，可沿同侧外侧嗅束背面向尾侧追踪运输物质。这条标记密集的投射与未标记的外侧嗅束不同，并被称为副嗅束。从嗅结节尾侧三分之一水平开始并向尾侧延伸至外侧嗅束核的是一组与副嗅束密切相关的小神经元。这个细胞群被称为副嗅束床核。副嗅球的投射部位包括副嗅束床核以及杏仁内侧核和杏仁后内侧皮质核的IA层（罗斯，1931年，杏仁周区3、4、PAM、2的后半部分、6）。还发现副嗅球的另一传出投射在杏仁内侧核水平进入终纹，并可追踪至终纹床核的后段。放射自显影结果表明，副嗅球与杏仁核中未接受主嗅球传入输入的部分相连，并为存在两个不同且独立的嗅觉系统提供了证据。
