Petrulis Aras
Neuroscience Institute, Georgia State University, Atlanta, GA 30302-5030, USA.
Behav Brain Res. 2009 Jun 25;200(2):260-7. doi: 10.1016/j.bbr.2008.10.027. Epub 2008 Oct 30.
Recognizing the individual and sexual identities of conspecifics is critical for adaptive social behavior and, in most mammals this information is communicated primarily by chemosensory cues. Due to its heavy reliance on odor cues, we have used the Syrian hamster as our model species for investigating the neural regulation of social recognition. Using lesion, electrophysiological and immunocytochemical techniques, separate neural pathways underlying recognition of individual odors and guidance of sex-typical responses to opposite-sex odors have been identified in both male and female hamsters. Specifically, we have found that recognition of individual odor identity requires olfactory bulb connections to entorhinal cortex (ENT) rather than other chemoreceptive brain regions. This kind of social memory does not appear to require the hippocampus and may, instead, depend on ENT connections with piriform cortex. In contrast, sexual recognition, through either differential investigation or scent marking toward opposite-sex odors, depends on both olfactory and vomeronasal system input to the corticomedial amygdala. Preference for investigating opposite-sex odors requires primarily olfactory input to the medial amygdala (ME) whereas appropriately targeted scent marking responses require vomeronasal input to ME as well as to other structures. Within the ME, the anterior section (MEa) appears important for evaluating or classifying social odors whereas the posterodorsal region (MEpd) may be more involved in generating approach to social odors. Evidence is presented that analysis of social odors may initially be done in MEa and then communicated to MEpd, perhaps through micro-circuits that separately process male and female odors.
识别同种个体的身份和性别特征对于适应性社会行为至关重要，在大多数哺乳动物中，这些信息主要通过化学感应线索进行传递。由于对气味线索的高度依赖，我们选用叙利亚仓鼠作为模型物种来研究社会识别的神经调节机制。运用损伤、电生理和免疫细胞化学技术，在雄性和雌性仓鼠中均已确定了识别个体气味以及引导对异性气味产生典型性别反应的不同神经通路。具体而言，我们发现识别个体气味特征需要嗅球与内嗅皮质（ENT）相连，而非其他化学感受脑区。这种社会记忆似乎并不需要海马体，而是可能依赖于ENT与梨状皮质的连接。相比之下，通过对异性气味进行差异化探究或气味标记来进行性别识别，则依赖于嗅觉和犁鼻器系统向皮质内侧杏仁核的输入。对探究异性气味的偏好主要需要嗅觉输入到内侧杏仁核（ME），而适当定向的气味标记反应则需要犁鼻器输入到ME以及其他结构。在ME内部，前部（MEa）对于评估或分类社会气味似乎很重要，而后背侧区域（MEpd）可能更多地参与产生对社会气味的趋近行为。有证据表明，对社会气味的分析可能最初在MEa中进行，然后或许通过分别处理雄性和雌性气味的微电路传递给MEpd。
