Your brain develops over your lifetime in response to your experiences. Most of the changes are due to the formation of new connections called synapses between brain cells called neurons. When we learn new skills, new connections are made. Over time, these skills might become "hard-wired" into the architecture of the brain cells and no longer require conscious effort.
The ability of the brain to create new connections between neurons is called plasticity.
While the brain once was thought incapable of change into adulthood, increasingly, research is demonstrating our potential for brain plasticity throughout our lives. The brain's ability to remodel itself based on learning and new experiences is vital for long-term memory. Plasticity is also the basis for patients experiencing brain injury or stroke to be able to relearn tasks such as talking or writing. Through therapy and practice, the brain can recruit new areas and new pathways to help restore function. Age-related cognitive decline might be delayed or prevented by increased mental activity, such as learning and problem-solving, thereby increasing the number and strength of connections in the brain, called brain reserve.
Brain plasticity can contribute to disease as well. Evidence indicates that changes in plasticity might be involved in chronic pain syndromes; neurodegenerative diseases such as Alzheimer's disease and Huntington's disease; and in some psychiatric disorders such as depression, anxiety disorder, anorexia nervosa, bulimia and obsessive-compulsive disorder. Scientific evidence strongly suggests that frequent experience with addictive substances, including alcohol, narcotics, cocaine, sugar and fat, causes lasting changes in brain circuitry, which might explain why these addictions are so difficult to conquer.
Similar studies also indicate these brain changes in compulsive gamblers.
Brain function is dictated in part by genetic influences. This might explain why some diseases and behaviors, including addiction and obesity, run in families. However, the genetic instructions encoded in our genes also may be "changed" by certain molecules that attach to the DNA. This DNA modification also might be hereditary but also can be triggered by environmental factors such as smoking, drinking and diet.
These DNA changes were first found by cancer researchers. Now, findings suggest similar mechanisms might be at work in causing neurological and behavioral disorders. As we learn more about these environmental forces, we might be better able to treat or even prevent neurological illnesses.