Sex-specific processing of social cues in the medial amygdala.
Sex-specific processing of social cues in the medial amygdala.
复制标题
DOI：
10.7554/elife.02743
复制
发表时间：
2014-06-03
期刊：
影响因子：
7.7
通讯作者：
Dulac C
中科院分区：
文献类型：
--
作者：
Bergan JF;Ben-Shaul Y;Dulac C
在物种内部和物种之间进行动物-动物识别，对于避免捕食者和社会互动至关重要。尽管它在协调对动物暗示的反应方面发挥了重要作用，但犁鼻系统处理信息的基本原理仍然未知。杏仁内侧核(Mea)在犁鼻通路中占据中心位置，位于下丘脑防御和社会反应中心的上游。我们已经确定了小鼠MEA中感觉反应的特征，并发现了新的特性，这些特性为犁鼻信息转化为性别和物种特异性反应提供了新的线索。特别是，我们发现MEA显示了一定程度的刺激选择性和显著的性别二态感觉表征，这在副嗅球的上游中继器(AOB)中没有观察到。此外，我们的结果表明，中枢性二态回路的发展需要在青春期附近的类固醇信号来组织感觉刺激的功能表征。DOI：http://dx.doi.org/10.7554/eLife.02743.001许多动物为了与自己物种的其他成员交流，会释放和检测被称为信息素的化学物质。动物也依赖来自其他物种的化学信号来警告它们，例如，附近有捕食者。这些化学信号中的许多存在于汗液、泪水、尿液和唾液中，是由位于鼻腔底部的一种名为犁鼻器的结构检测到的。当这个器官检测到特定的化学信号时，它会将信息广播到大脑区域的网络，从而产生适当的行为反应。这个网络中的两个结构，副嗅球和内侧杏仁核，在信号到达最终目的地--大脑的一个称为下丘脑的区域--之前，扮演着重要的角色。该信号激活了下丘脑，触发了动物行为的改变。虽然这条通路的解剖细节已经得到了广泛的研究，但信息实际上是如何沿着它传递的还不清楚。现在，Bergan等人。通过记录暴露在特定刺激下的麻醉小鼠大脑中的信号，为这一过程提供了洞察力。在雄性和雌性小鼠中，副嗅球神经元的反应相似，而杏仁内侧核中的神经元在雄性小鼠中表现出对女性尿液的偏好，在雌性小鼠中表现出对男性尿液的偏好。这是首次直接证明雄性和雌性哺乳动物大脑中感觉处理的差异。这些差异被认为是性激素，特别是雌激素，在发育过程中对大脑回路产生作用的结果。与此一致的是，与对照组相比，雌激素水平降低的雄性小鼠杏仁内侧核中的神经元显示出对雌性尿液的偏好降低。同样，与对照组相比，之前在幼鼠时期暴露于高水平雌激素的雌性小鼠对雄性尿液的偏好有所降低。除了增加对化学信号--包括信息素--如何影响啮齿动物对其他动物的反应的理解外，Bergan等人的工作。为行为性别差异背后的神经机制提供了线索。DOI：http://dx.doi.org/10.7554/eLife.02743.002
Animal–animal recognition within, and across species, is essential for predator avoidance and social interactions. Despite its essential role in orchestrating responses to animal cues, basic principles of information processing by the vomeronasal system are still unknown. The medial amygdala (MeA) occupies a central position in the vomeronasal pathway, upstream of hypothalamic centers dedicated to defensive and social responses. We have characterized sensory responses in the mouse MeA and uncovered emergent properties that shed new light onto the transformation of vomeronasal information into sex- and species-specific responses. In particular, we show that the MeA displays a degree of stimulus selectivity and a striking sexually dimorphic sensory representation that are not observed in the upstream relay of the accessory olfactory bulb (AOB). Furthermore, our results demonstrate that the development of sexually dimorphic circuits in the MeA requires steroid signaling near the time of puberty to organize the functional representation of sensory stimuli. DOI: http://dx.doi.org/10.7554/eLife.02743.001 Many animals emit and detect chemicals known as pheromones to communicate with other members of their own species. Animals also rely on chemical signals from other species to warn them, for example, that a predator is nearby. Many of these chemical signals—which are present in sweat, tears, urine, and saliva—are detected by a structure called the vomeronasal organ, which is located at the base of the nasal cavity. When this organ detects a particular chemical signal, it broadcasts this information to a network of brain regions that generates an appropriate behavioral response. Two structures within this network, the accessory olfactory bulb and the medial amygdala, play an important role in modifying this signal before it reaches its final destination—a region of the brain called the hypothalamus. Activation of the hypothalamus by the signal triggers changes in the animal's behavior. Although the anatomical details of this pathway have been widely studied, it is not clear how information is actually transmitted along it. Now, Bergan et al. have provided insights into this process by recording signals in the brains of anesthetized mice exposed to specific stimuli. Whereas neurons in the accessory olfactory bulb responded similarly in male and female mice, those in the medial amygdala showed a preference for female urine in male mice, and a preference for male urine in the case of females. This is the first direct demonstration of differences in sensory processing in the brains of male and female mammals. These differences are thought to result from the actions of sex hormones, particularly estrogen, on brain circuits during development. Consistent with this, neurons in the medial amygdala of male mice with reduced levels of estrogen showed a reduced preference for female urine compared to control males. Similarly, female mice that had been previously exposed to high levels of estrogen as pups showed a reduced preference for male urine compared to controls. In addition to increasing understanding of how chemical signals—including pheromones—influence the responses of rodents to other animals, the work of Bergan et al. has provided clues to the neural mechanisms that underlie sex-specific differences in behaviors. DOI: http://dx.doi.org/10.7554/eLife.02743.002