Martínez-Marcos A, Lanuza E, Halpern M
Department of Anatomy and Cell Biology, Health Science Center at Brooklyn, State University of New York, Brooklyn, New York 11203, USA.
J Comp Neurol. 1999 Sep 13;412(1):51-68. doi: 10.1002/(sici)1096-9861(19990913)412:1<51::aid-cne4>3.0.co;2-m.
Although recent studies in squamate reptiles have importantly clarified how chemical information is processed in the reptilian brain, how the amygdala relays chemosensory inputs to the hypothalamus to influence chemically guided behaviors is still poorly documented. To identify these chemosensory pathways, the amygdalo-hypothalamic projections, intra-amygdaloid circuitry and afferents from the lateral cortex (LC) to the amygdala were investigated by injecting conjugated dextran-amines into the hypothalamus, amygdala, and LC of garter snakes. The amygdala was divided into olfactory recipient (ventral anterior and external amygdalae), vomeronasal recipient (nucleus sphericus, NS, and medial amygdala, MA), and nonchemosensory (e.g., posterior dorsal ventricular ridge, PDVR, and dorsolateral amygdaloid nucleus, DLA) subdivisions. Rostroventral (LCrv) and dorsocaudal subdivisions of the LC were distinguished. In addition to receiving afferents from the main olfactory bulb, the olfactory amygdala receives afferents from NS and projects to the NS, PDVR, and dorsal hypothalamus. The NS has only a minor projection to the lateral hypothalamus, whereas the MA, which receives afferents from the LCrv and NS, has projections to the ventromedial hypothalamic (VMH) and lateral posterior hypothalamic nuclei. Among the nonchemosensory amygdaloid structures, the PDVR receives afferents from the LCrv and the olfactory amygdala and projects to the VMH, whereas DLA receives afferents from the LCrv and NS, and projects to the periventricular hypothalamus. These results substantially clarify the olfactory and vomeronasal tertiary connections and demonstrate that parts of the nonchemosensory amygdala play a major role in relaying chemosensory information to the hypothalamus.
尽管近期关于有鳞目爬行动物的研究已重要地阐明了化学信息在爬行动物大脑中是如何被处理的，但杏仁核如何将化学感觉输入传递至下丘脑以影响化学引导行为的过程仍鲜有记载。为了确定这些化学感觉通路，通过将共轭葡聚糖胺注射到束带蛇的下丘脑、杏仁核和外侧皮质（LC）中，研究了杏仁核 - 下丘脑投射、杏仁核内神经回路以及从LC到杏仁核的传入神经。杏仁核被分为嗅觉接受区（腹侧前杏仁核和外侧杏仁核）、犁鼻器接受区（球状核，NS，和内侧杏仁核，MA）以及非化学感觉区（例如，后背侧室嵴，PDVR，和背外侧杏仁核，DLA）。区分了LC的吻腹侧（LCrv）和背尾侧亚区。除了接受来自主嗅球的传入神经外，嗅觉杏仁核还接受来自NS的传入神经，并投射至NS、PDVR和背侧下丘脑。NS仅向外侧下丘脑有少量投射，而接受来自LCrv和NS传入神经的MA则投射至腹内侧下丘脑（VMH）和下丘脑外侧后核。在非化学感觉性杏仁核结构中，PDVR接受来自LCrv和嗅觉杏仁核的传入神经，并投射至VMH，而DLA接受来自LCrv和NS的传入神经，并投射至室周下丘脑。这些结果极大地阐明了嗅觉和犁鼻器的三级连接，并表明非化学感觉性杏仁核的部分区域在将化学感觉信息传递至下丘脑方面发挥着主要作用。
