What, exactly, is an alcohol blackout?
The chemical effects that alcohol has on the brain are quite complex. When alcohol reaches the brain through the bloodstream, it affects a part of the brain called the hippocampus-a brain structure tightly involved in the formation and retrieval of memories. The way that information is communicated throughout the brain is from one neuron to the next (see diagram below). Think of a lock-and-key system: The sending neuron releases keys (called neurotransmitters) across what is called the “synapse,” and the receiving neuron contains locks (called receptors). If the key opens the lock-that is, if the neurotransmitter and the receptor match-then the message is passed on from the first neurotransmitter to the second. This continues from the second neurotransmitter to the third, the third to the fourth, and so on. If sufficient quantities of alcohol reach the brain, and thus the hippocampus, the alcohol prevents a receptor (the lock part), called NMDA, from recognizing a neurotransmitter (the
