Can you really lose weight without eating carbohydrates? Why does spicy food and running make people feel good? Can dopamine make people happier? Why is it so difficult to quit smoking? These problems may seem different, but they are actually related to the same substance - neurotransmitters in our brains. You may not be familiar with the word, but you must have heard of dopamine and adrenaline. Alzheimer's disease, Parkinson's disease, ADHD and other common diseases in our life are related to various neurotransmitters. Antidepressants, anti anxiety drugs, sleeping pills, as well as cigarettes, wine and coffee, which are often exposed in life, also work by affecting neurotransmitters. "Without neurotransmitters, our memory, happiness, desire, learning ability and so on cannot exist in the present form." In brain correspondent: understanding your neurotransmitters, Zhao Sijia, a postdoctoral fellow in neuroscience at Oxford University, systematically and life-oriented formally introduced neurotransmitters to readers. In short, neurotransmitters are like messengers in the brain - cells in the brain use them to communicate and exchange information with other cells. This book discusses seven common neurotransmitters, including dopamine, serotonin, norepinephrine, acetylcholine and glutamate. The author gives a vivid and interesting introduction to each neurotransmitter, including where it comes from, where it goes, the main brain functions and some interesting knowledge points. In Zhao Sijia's view, each neurotransmitter is full of personality. She designed different "paper man" images: dopamine is a short man with blond hair and blue eyes, serotonin is a gentle and steady bosom sister, norepinephrine is a hot-blooded boy who always wears sportswear, and acetylcholine is a school bully with excellent memory. If love is regarded as a wonderful chemical reaction, the order of neurotransmitters may be as follows: "norepinephrine decides not to do it, dopamine decides forever, and serotonin decides who speaks first." When you meet the person you like, and your face turns red and your heart beats uncontrollably, it is norepinephrine related to impulse and awakening that plays a role; Your brain will not be able to concentrate on the reward, just as your brain will be full of dopamine after you receive the ordinary reward. At the same time, in love, the content of serotonin in the brain is low, and you may become impulsive and irrational - serotonin itself has a calming and relaxing effect. Most of the common antidepressants on the market are also committed to maintaining and increasing the content of serotonin in the brain. Many people regard dopamine as a "pleasure substance" with half understanding, but in fact, dopamine does not directly produce subjective pleasure, but participates in the process of pleasure through "reward prediction error". Dopamine is not the more the better. The higher its level, the more impulsive people will have, and the stronger the desire to "want". Smoking is addictive, which is related to it. After inhaling a cigarette, nicotine will quickly enter the brain through the blood-brain barrier within 10 seconds, indirectly stimulating the nerve cells responsible for managing the reward system to secrete dopamine and produce a sense of pleasure. However, the brain will gradually adapt to such signals. When smoking is stopped, the nerve cells in relevant regions will find it difficult to adapt to this low-level activation state, and people will experience various discomfort caused by withdrawal, which also explains why it is so difficult to quit smoking. Endorphins are closer to real pleasure substances than dopamine. It is a kind of "brain self-produced and self-marketed painkiller", which can inhibit the transmission of pain signals in the brain. Other studies suggest that laughter may stimulate the brain to produce endorphins to increase the pain threshold. Why is it that although you sweat profusely after exercise, you feel great in your heart? Zhao Sijia explained, "When you start exercising, the brain sees it as a little stress. When you face stress, the brain automatically generates endorphins. Exercise can promote the production of endorphins in a short time because high exercise will deplete the glycogen in your muscles, which will make you feel muscle pain. In order for your body to continue to exercise, the brain will release endorphins into the body to relieve pain." In addition, the intake of capsaicin can also stimulate the secretion of endorphins, which is also the reason why eating spicy hot pot makes people feel good. Even if spicy hot pot is tempting, many dieters who are committed to controlling calories avoid it. In recent years, carbohydrates such as rice and noodles have been included in the weight loss forbidden zone. Zhao Sijia believes that low-carbon water or carbon free water diet may indeed help reduce calorie intake, but it is not necessarily a good thing from the perspective of neuroscience. The key to this problem is serotonin, which has the function of relaxation and calmness. The amount of serotonin is related to tryptophan in the brain. Only when the carbohydrate content in the blood is high, the pancreas will produce more insulin to help tryptophan enter the brain as much as possible and increase the production of serotonin. An extreme diet without carbohydrates may lead to anxiety, insomnia and the urge to "especially eat carbohydrates" due to low levels of serotonin. Similar public cognitive misunderstandings are exactly what Zhao Sijia intended to write this book. "Now the information flow is huge and there are many views, but the knowledge reserve is difficult to keep pace with the times, so we are easily led by the information flow." Zhao Sijia said, "someone once asked me a question. Since dopamine brings happiness to people, will I be happy if I eat dopamine directly? Can I supply happiness on demand like insulin? If you understand that dopamine is not equal to happiness, and the imbalance of dopamine will lead to addiction, you will understand that such a problem has problems in direction." There is no "smart medicine" in the world, but many people still hope to improve their learning ability by taking medicine. According to Zhao Sijia, "If you know a little about the brain and how the neurotransmitters in the brain that control our memory and learning ability work, you can understand that even with such drugs, the effect may not be more useful than coffee. Coffee is the most widely used cognitive enhancer in the world. There is a neurotransmitter in the brain called adenosine. The more adenosine, the more people want to sleep. The caffeine in coffee can inhibit adenosine, that is Because of this, drinking coffee has the effect of keeping people awake. " Only when we master enough knowledge and have a basic understanding of a field can we know the "good or bad" and "boundary" of a problem, and then form our own independent point of view. This is also Zhao Sijia's view of the unique charm of popular science works, that is, they do not output views, but only spread knowledge. "My goal is that at least readers have a basic judgment on the rationality of relevant issues. This is probably more practical and valuable for ordinary readers." Zhao Sijia said. (outlook new era)