Drinking affects the brain by working on the cerebellum, cerebrum, limbic system, and frontal lobe.
Alcohol interacts with many neurotransmitters in the brain that are believed to be important for mood regulation. For instance, alcohol can decrease levels of serotonin while increasing norepinephrine. Alcohol also impacts specific sets of receptors on cells in these regions (GABA receptors) which may affect their activity depending on which type of receptor is located at any given spot (positive effects if they are excitatory; negative effects if they are inhibitory). These changes account for most short-term behavioral effects of alcohol including sleepiness or sedation or impaired motor functioning like slower reaction time and impaired balance.