The author of this theory is thought to be the Spanish doctor and founder of neurobiology, Santiago Ramon y Cajal. He argued that all neural pathways are immutable and fixed. The experience process is associated with the respiratory rhythm. If a person is worried, breathing becomes frequent and shallow, which causes the brain and other organs to stop receiving sufficient oxygen. As a result, the process of neuron atrophy begins. This is irreversible. This theory resonated widely, and many people (including doctors) took it on faith ===without even thinking that a person loses tens of thousands of neurons per day. If they weren't recovering, then most of us would be mentally retarded by the age of 30. So they are certainly recovering! We can hinder or help this process through our actions. ## What influences the life of nerve cells? __Intellectual load.__ No need to do quantum physics or learn three foreign languages at the same time. It is about the regular cognitive activity. Watching educational programs, reading books, studying history, or learning new culinary recipes—any activity related to the development of a new one is preventing neuronal degradation. __Overeating.__ According to one theory, there is a direct link between being overweight and a reduced rate of neuronal regeneration. Eating an excess of 20 % or more calories a day almost halves the rate of synthesis. It is not yet clear whether this applies in 100 % of cases. __Chronic stress.__ Long-term psycho-emotional stress makes the adrenal glands produce the hormones cortisol and adrenaline, which inhibit the synthesis of neurons. __Alcohol.__ Ethanol and its breakdown products accumulate in the brain tissues. Previously, it was believed that this directly destroys the neural fibers. In fact, the processes of neurons are destroyed, which means that the signal no longer passes through them. Because of this, the mechanism does not work and atrophies. The recovery rate drops by 50-70 %. However, the good news is that if you cut out alcohol, things will bounce back pretty quickly. __The use of certain drugs.__ The use of psychotropic drugs has an especially negative effect on the state of nerve cells. The mechanism is similar to the one that alcohol has on the body: drugs block the transmission of nerve impulses. __Lack of sleep.__ The body's biological clock is designed in such a way that the synthesis of cortisol weakens closer to nighttime, and melatonin is more actively produced. If this fails, the production of cortisol increases and the metabolism in the cerebral structures slows down. While the amount of sleep is important, getting quality overnight sleep is equally important.