Meredith Grey (narration): Adrenaline is the body's response to stressful situations. It's one of many vital chemical compounds our bodies produce that alter our state of consciousness. Oxytocin makes us feel bonded with others. Dopamine makes us more alert and motivates us to seek reward. A lack of serotonin has been linked to depression. GABA, an amino acid neurotransmitter, helps reduce anxiety. And endorphins create a heightened state of happiness. Like the kind we feel when we win. Surgeons can benefit from altered states of consciousness, but only when they're achieved naturally. The lows drive us to do better. The highs of saving a life are the rewards of a job well done. And then there are times when our state of mind is altered and it has nothing to do with brain chemistry. New opportunities open us up to greater possibilities. New information and a new perspective can permanently shift our consciousness and the way we see the world will never be the same.