how meth affects the brain.

The brain's reward center is one of its most powerful and primitive structures. Buried deep in the brain, the pathway triggers good feelings to encourage certain behaviors. Activities such as eating a good meal, having sex or making friends feel good partly because our brains are wired to encourage repetition of behaviors critical for survival. normal

normal

The reward pathway causes certain brain cells to release a chemical called dopamine. The molecules bind to receptors on a different cell and trigger good feelings. The feelings only last a few minutes because the first cell quickly sucks the dopamine back inside.

on meth

Amphetamines such as meth put normal dopamine pathways into overdrive. Meth makes brain cells release too much dopamine, which overstimulates the receiving cell.

after meth

The brain responds to prolonged meth use by trying to lessen dopamine stimulation. It pares back nerve endings that release dopamine and removes dopamine receptors from the receiving cell.