Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
Psychoneuroendocrinology. 2010 Jan;35(1):105-13. doi: 10.1016/j.psyneuen.2009.09.007.
Testosterone influences various aspects of affective behavior, which is mediated by different brain regions within the emotion circuitry. Previous neuroimaging studies have demonstrated that testosterone increases neural activity in the amygdala. To investigate whether this could be due to altered regulation of amygdala functioning which is thought to be mediated by the prefrontal cortex, we studied the effects of exogenous testosterone on the interaction between the amygdala and other brain regions. Healthy middle-aged women received a single nasal testosterone dose in a randomized, placebo-controlled, crossover manner, and performed an emotional face matching task while their brain activity was measured with functional MRI. The results show that testosterone rapidly reduced functional coupling of the amygdala with the orbitofrontal cortex, and enhanced amygdala coupling with the thalamus. This suggests that testosterone may reduce the regulatory control over the amygdala, or that testosterone shifts amygdala output away from the orbitofrontal cortex towards the thalamus. Testosterone also reduced functional coupling with the contralateral amygdala. Because interhemispheric amygdala coupling is lower in men than in women, this result suggests that circulating testosterone may contribute to this sexual dimorphism.
睾酮影响情感行为的各个方面，而这些方面是由情感回路中的不同脑区介导的。先前的神经影像学研究表明，睾酮会增加杏仁核的神经活动。为了研究这是否是由于杏仁核功能的调节改变所致，而这种改变被认为是由前额叶皮层介导的，我们研究了外源性睾酮对杏仁核与其他脑区之间相互作用的影响。健康的中年女性以随机、安慰剂对照、交叉的方式接受单次鼻内睾酮剂量，并在进行情绪面孔匹配任务时接受功能磁共振成像测量其大脑活动。结果表明，睾酮可迅速降低杏仁核与眶额皮层的功能耦合，并增强杏仁核与丘脑的耦合。这表明，睾酮可能会降低对杏仁核的调节控制，或者说，睾酮会将杏仁核的输出从眶额皮层转移到丘脑。睾酮还降低了与对侧杏仁核的功能耦合。由于男性的大脑两半球间杏仁核耦合比女性低，因此这一结果表明，循环中的睾酮可能促成了这种性别二态性。
