Salazar I, Brennan P A
Sub-Department of Animal Behaviour, University of Cambridge, High Street, Madingley, CB3 8AA, Cambridge, UK.
Brain Res. 2001 Mar 30;896(1-2):198-203. doi: 10.1016/s0006-8993(01)02225-9.
It has recently become apparent that there are two classes of vomeronasal receptor neurons that project to functionally separate anterior and posterior sub-regions of the mammalian accessory olfactory bulb. However, anterograde tracing of the projections from these sub-regions, in the mouse, has revealed that the processing pathways are not segregated at the level of the vomeronasal amygdala. Both sub-regions have overlapping projections to the superficial lamina of the medial and posterior medial cortical nuclei of the amygdala. However, differential projections have been found in the opossum, in which only the posterior sub-region projects to the deeper laminae of the medial amygdala. Therefore, there may be species differences in these projections that are important for the control of reproductive behaviour. This study used an alternative approach of retrogradely tracing mitral/tufted cell projections from different nuclei of the vomeronasal amygdala back to the accessory olfactory bulb of mice. Local injections of the lipophilic tracer DiI were made into the antero-dorsal and postero-ventral divisions of the medial amygdala, and into the postero-medial cortical amygdala. In each case, provided the DiI affected the superficial lamina Ia, labelled mitral/tufted cells were found distributed throughout the anterior-posterior extent of the accessory olfactory bulb. These results confirm that mitral/tufted cells of the anterior and posterior sub-regions of the accessory olfactory bulb project to both the medial and postero-medial cortical nuclei of the amygdala. There was no evidence for differential projections from the anterior and posterior sub-regions accessory olfactory bulb in mice, as has been reported to occur in other species.
最近已经很明显，有两类犁鼻器受体神经元投射到哺乳动物副嗅球功能上分离的前侧和后侧亚区域。然而，在小鼠中对这些亚区域投射的顺行追踪显示，处理通路在犁鼻杏仁核水平并未分离。两个亚区域都有重叠的投射到杏仁核内侧和后内侧皮质核的浅层。然而，在负鼠中发现了不同的投射，其中只有后侧亚区域投射到内侧杏仁核的深层。因此，这些投射可能存在物种差异，这对生殖行为的控制很重要。本研究采用了一种替代方法，即从犁鼻杏仁核的不同核逆向追踪二尖瓣/簇状细胞投射回到小鼠的副嗅球。将亲脂性示踪剂DiI局部注射到内侧杏仁核的前背侧和后腹侧分区，以及后内侧皮质杏仁核。在每种情况下，只要DiI影响浅层Ia，就会发现标记的二尖瓣/簇状细胞分布在副嗅球的前后范围内。这些结果证实，副嗅球前侧和后侧亚区域的二尖瓣/簇状细胞投射到杏仁核的内侧和后内侧皮质核。在小鼠中，没有证据表明副嗅球前侧和后侧亚区域存在不同的投射，而在其他物种中曾有过此类报道。
