Low self esteem and the brain
The brain consists of 100 billion neurons. The neuron is like a computer which receives nerve impulses from other grey cells. The contact betwwen two neurons is called a synapse. When a nerve impulse arrives, the synapse releases neurotransmitters like dopamin and serotonin (very important in order to feel more pleasure, it fights anxiety and negative feelings about yourself). The neuron receives nerve impulses from other gray cells through a net of outgrowths called the dendrites.
When we learn something the neurons change, they even get a different shape. Some dendrites disappear and others grow, and there can also grow new dendrites. This is important to remember when you work on your self esteem. It is possible for you to get a better a better self esteem but you need to find out what new thoughts and behaviors you want to acquire and after that you need to repeat them often and during a long time. When you go to a gym you can´t build a strong body by going there five times during one week and then quit. In the same way you can´t build your self esteem by training on your new thoughts and behaviors for one week. In order for the brain to think is worth the effort to change the neurons and let new dendrites grow it has to get many signals, otherwise it thinks that the new learning is too unimportant to make a whole new change because of it.