Through using a high resolution MRI to study myelin sheaths, an insulator around the brain's wiring, researchers found that the brain connections developed later in life were the first to deteriorate. Researchers are hoping to use these results to further examine how lifestyle plays a part in brain aging and then come up with a medication that would delay the aging process or work as a preventative to Alzheimer's.

This study sheds some light on the role of myelin in brain development and degeneration. The study also stresses the importance of using this type of MRI to study the relationship between aging and Alzheimer's disease.

Myelin is defined as a layer of fat that contains a substantial amount of cholesterol, which enables it to wrap tightly around axons rapidly sending messages through the brain by insulating the brain connections. Production of myelin is churned out in greater amounts as the brain ages and continues to grow into adulthood. This process results in increased cholesterol levels, which eventually lead to production of a toxic protein that works with other toxins in attacking the brain.

The production of all these toxins soon begin to alter the brain connections and at a certain point results in the creation of destructive plaques. The formation of plaque then start to disrupt the brain connections developed in the later years in the cortex of people with Alzheimer's disease.

Researchers compared the functioning of the brain to the Internet and explained that the brain's processing speed and quality is dependant on how well it is able to process information. The performances of these functions, for the most part, are dependent on the insulation of the brain's wiring. Similar to the Internet, as we grow older, the myelin insulation becomes weaker and leads to a gradual slowing down of the speed and quality of our internal Internet.

Researchers claimed that this MRI could be used to identify specific deteriorating areas of the myelin sheath surrounding the brain.

As part of the study, researchers studied how the deterioration of myelin affected two areas of the brain, the splenium and genu regions. The splenium region is responsible for early brain development essential to vision. The genu on the other hand, centered on more complex brain connections that developed later in life such as decision making, memory and impulse control.

Conclusions From the Study

• The brain connections in the genu region degenerated three times as fast as the spenium region
• Deterioration of myelin is much more prevalent in Alzheimer's patients than in healthy elderly adults
• The breakdown of myelin is a strong contributor to the development of Alzheimer's

EurekAlert July 12, 2004