Multiple sclerosis: What have we learned?

Abstract

In their article, “Gray matter involvement in multiple sclerosis,” Dr. Istvan Pirko and his coauthors review recent information about multiple sclerosis (MS) ( Neurology 2007;68:634–642). Most research focuses on how MS affects the myelin—a substance that coats the nerves and is mainly made of fat. The authors of this article describe what MS does to the nerve cell bodies (gray matter, see below) of the brain. Although research is always going on in this area, there is more research to show that involvement of the gray matter predicts the injury that can occur in MS. Brain cells are called neurons. Neurons are made up of a cell body. In the brain (and spinal cord), the cell bodies are grouped together in organized ways. When looking at the brain with the naked eye, these groups of cell bodies have a grayish color, and so they are called gray matter. The outer layer of the brain is one area where cell bodies are grouped together; this region of gray matter is called the cerebral cortex. Deeper in the brain are other groups of cell bodies. These are also called gray matter but they are separate from the cerebral cortex and are called nuclei. The two areas of gray matter are connected together in many ways. The connections between these areas allow us to speak and think. Nerve cells talk to each other using electrical and chemical signals. These signals must be sent very fast. In order for this to occur, cells must be connected by “wires.” These wires …