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Bringing the Power of Science to Bear on Drug Abuse and Addiction

3: How a neuron works

How a neuron works Illustration used with permission, courtesy of Lydia V. Kibiuk and the Society for Neuroscience

Neurons are unique because they can send information from the brain to the rest of the body. Your brain communicates with the rest of your body by sending messages from one neuron to the next and ultimately to the muscles and organs of the body. Neurons can also store information as memories.

Typically, a neuron contains three important parts: a cell body that directs all activities of the neuron; dendrites (the part that looks like tree branches), which are short fibers that receive messages from other neurons and relay those messages to the cell body; and the axon, a long single fiber that transmits messages from the cell body to dendrites of other neurons. Every moment, messages are moving with amazing speed back and forth from neuron to neuron. As a matter of fact, scientists often compare the activity of neurons to the way electricity works.

A neuron communicates with other neurons at special places called synapses or synaptic clefts. To send a message, a neuron releases a chemical messenger, or neurotransmitter, into the synaptic cleft. From there, the neurotransmitter crosses the synapse and attaches to key sites called receptors on the next neuron in line. When neurotransmitters attach to these receptors, they cause changes inside the receiving neuron and the message is delivered.

Neurons communicate with each other through a network of interconnected cells that scientists are still trying to fully understand. Scientists do know that this complex communication system within the brain can be disrupted by the chemicals in drugs. Did you know that more than 400 chemicals are in a marijuana leaf? And over 4,000 chemicals besides nicotine are in tobacco!

This page was last updated January 2007

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