Gomez D M, Newman S W
Department of Anatomy and Cell Biology, University of Michigan, Ann Arbor 48109-0616.
J Comp Neurol. 1992 Mar 8;317(2):195-218. doi: 10.1002/cne.903170208.
The medial nucleus of the amygdala is important for the neural control of reproductive behavior in the adult male Syrian hamster. Two types of signals are essential for this behavior, chemosensory stimuli and gonadal steroids; these signals appear to be received in different parts of the medial nucleus. The anterior region receives input from olfactory and vomeronasal systems, both of which are required for this behavior, whereas the posterior region receives gonadal hormone inputs. Behavioral studies have also suggested a functional differentiation of these two areas; electrolytic lesions of the anterior, but not the posterior, part eliminates normal sexual behavior. In this study, the efferent projections of the anterior and posterior divisions of the medial nucleus of the amygdala in the Syrian hamster were analyzed throughout the forebrain after injections of the anterograde neuronal tracer, Phaseolus vulgaris-leucoagglutinin. Neurons of the anterior, but not the posterior, medial nucleus, were found to project to numerous olfactory bulb projection areas and to the ventral striatopallidal complex. Within areas of the chemosensory circuitry that control reproductive behavior, the anterior region of the medial nucleus projects to the intermediate part of the posterior bed nucleus of the stria terminalis and the lateral part of the medial preoptic area, whereas the posterior region of the medial nucleus projects to the medial parts of these areas. Differences in targets were also observed in the ventromedial nucleus of the hypothalamus where the anterior region projects to the core while the posterior part projects to the shell of this nucleus. Furthermore, reciprocal projections between the anterior and posterior regions of the medial nucleus were observed. Taken together, these studies support the hypothesis that the anterior and posterior regions of the medial amygdaloid nucleus provide substantially different contributions to the control of reproductive behaviors.
杏仁核内侧核对于成年雄性叙利亚仓鼠生殖行为的神经控制至关重要。对于这种行为，两种类型的信号必不可少，即化学感觉刺激和性腺类固醇；这些信号似乎在内侧核的不同部位被接收。前部区域接收来自嗅觉和犁鼻系统的输入，这两者对于这种行为都是必需的，而后部区域接收性腺激素输入。行为研究也表明这两个区域存在功能分化；前部而非后部的电解损伤会消除正常的性行为。在本研究中，在注射顺行性神经元示踪剂菜豆白细胞凝集素后，分析了叙利亚仓鼠杏仁核内侧核前部和后部在整个前脑的传出投射。发现杏仁核内侧核前部而非后部的神经元投射到许多嗅球投射区域和腹侧纹状体苍白球复合体。在控制生殖行为的化学感觉回路区域内，杏仁核内侧核的前部区域投射到终纹床核后部的中间部分和内侧视前区的外侧部分，而杏仁核内侧核的后部区域投射到这些区域的内侧部分。在下丘脑腹内侧核也观察到了靶标的差异，其中前部区域投射到该核的核心，而后部投射到该核的壳。此外，还观察到杏仁核内侧核前部和后部区域之间的相互投射。综上所述，这些研究支持了这样一种假设，即杏仁核内侧核的前部和后部区域对生殖行为的控制有显著不同的贡献。
