Your [--1--] is home to about a trillion bacteria. And they pay rent. They protect you from infection, they [--2--] energy for you from what you eat and, if researchers are right, they affect your mental health as well. Because a new study shows that the bacteria that live in your intestines can influence your emotions and behavior. The work appears in the journal Gastroenterology. [Premysl Bercik et al, The Intestinal Microbiota Affect Central Levels of Brain-Derived Neurotropic Factor and Behavior in Mice]

Scientists found that treating adult mice with oral antibiotics not only messed with the balance of bugs in their bellies, but it changed their brain chemistry and behavior. The normally [--3--] became less cautious and less anxious, perhaps because the gut bacteria influenced a boost in a protein that promotes neural growth. And taking the mice off the drug restored their original [--4--] balance and behavior.

To confirm that the bacteria themselves were responsible, the scientists took mice that were raised in germ-free cages, animals that also happened to be naturally passive, and fed them bacteria from mice that were more active and daring. Sure enough, the newly infected mice grew more energetic and bold. So if you react to someone in a hostile way, you might [--5--] be giving them a bellyful.
【视听版科学小组荣誉出品】
digestive tract harvest timid creatures intestinal literally
肚子里的“情绪” 我们的消化肠道中居住着无数细菌。当然,它们不是无偿居住,它们从我们吃的食物中获取能量,保护我们不受感染。如果研究人员猜测正确,它们同时还影响着我们的心理健康。一项新的研究显示,住在我们肠道中的细菌可以影响到我们的情绪和行为。此研究结果发布在《肠胃病学》期刊上。[Premysl Bercik 等,肠道微生物影响小鼠脑源性神经中枢因素与行为] 科学家发现,用口服抗生素治疗成年老鼠不仅打乱了小鼠腹内微生物平衡,还改变了它们的大脑化学物质和行为。可能因为肠道细菌极大的影响了促进神经系统生长的蛋白质,原本胆小的小老鼠变得大大咧咧,也没那么躁动不安了。停用药物后,小鼠就恢复了它们原本的肠道平衡和行为表现。 为确认是细菌本身产生的作用,科学家将一些天性消极的小鼠放到无菌笼中饲养,并喂养它们活跃大胆的小鼠身上的细菌。于是,这些新近被感染的小鼠变得更加活跃和强壮。所以,如果你讨厌某人,你可能就真的应验了那句“一肚子的意见”。