Dopamine

Dopamine is both a neurotransmitter and a neurohormone produced in multiple areas of the brain. As a hormone it is often associated with pleasant experiences. Receiving an unexpected reward may cause your heart to speed up and increase your alertness due to the sudden release of dopamine. As a neurotransmitter it transmits signals associated with concentration and motor skills. Conditions such Parkinson's Disease and schizophrenia are associated with an interruption in the brain's production of dopamine.