Neuron with its component parts and a neutrophil Click for a larger view

The central nervous system consists of the brain and spinal cord, and for the most part it is protected by a blockade of cells and other components called the blood-brain barrier. This blockade keeps circulating white blood cells and their powerful chemical arsenal (and other potentially dangerous substances roaming in blood) away from the body's central command center. Upon infection or injury to the brain, however, inflammatory responses can and do happen. More than anywhere else in the body, the brain very carefully controls the extent of an inflammatory reaction. The release of too many cytokines or other inflammatory molecules can lead to permanent damage to brain cells (neurons).

Neurons resemble other cells in the body in many ways, but they are different due to the presence of long, tendril-like structures called axons and dendrites. These thin extensions are the most vulnerable to damage from inflammatory chemicals. Because axons are like the telephone wires of the body, when they become severed or damaged a communications breakdown can be the result. Examples of neurological conditions in which excessive inflammation destroys axons include multiple sclerosis, a viral or bacterial infection, Lou Gehrig's disease (amyotrophic lateral sclerosis, or ALS), encephalitis, head trauma, and epilepsy. In many cases, the severity of these diseases can be linked to the extent of axon damage.

Researchers have also linked inflammation to Alzheimer's disease. Scientists think that dampening inflammation with medicines may be an effective way to treat some of these debilitating nerve disorders. Anti-inflammatory drugs have been proven to be effective in stalling early-stage multiple sclerosis, and a recent study pointed to a benefit of inflammation-blocking drugs in delaying the onset of Alzheimer's disease.