REVERSE BRAIN ATROPHY WITH EXERCISE?

Science told us in the past that we’re born with all the brain cells we will ever have (the moral of the story being “take care of what you’ve got, because you ain’t gonna get no more”). Well, surprise, surprise! New research shows that the old tale is not true.

In the late 1990s, several lines of research began turning investigators’ concepts of mood disorders upside down.

BRAIN CELL REGENERATION
Research showing that neurogenesis—the birth of new brain cells—can continue throughout life. They have found that the process of neurogenesis is an ongoing one, with new brain cells being born even as old brain cells die off. Researchers have also found that depression appears to inhibit this birth of new brain cells. In animal studies, stress puts a halt to the process of neurogenesis. Under stress, existing cells shrink and the total number of cells decreases. Exercise and “environmental enrichment,” on the other hand, have a beneficial effect. In humans, there are hints that exercise may help reverse brain atrophy.

THE ROLE OF DEPRESSION
People who’ve had depression are likelier to have a smaller hippocampus (a part of the brain that plays a role in emotion and is associated with memory and learning). The more severe and long-lasting the depression, the greater the loss of brain volume. This process of brain atrophy also affects the frontal lobes, which are involved in managing emotional reactions. The good news is that most of the change seems to be related to cell shrinkage, rather than outright cell death, and thus can potentially be reversed.

HOW DO ANTIDEPRESSANTS HELP?
What about the familiar neurotransmitters such as serotonin and norepinephrine? They are still understood to play a significant role in mood disorders—but with a new twist. Most people are familiar with the research that underlies the use of fluoxetine (Prozac) and similar antidepressants. These drugs block the reuptake of certain neurotransmitters at receptor sites in the brain, thus increasing the concentrations of serotonin and other neurotransmitters in the synapses (gaps) between cells in the brain. This increase is believed to be responsible for the elevation of mood.

PROMISING DISCOVERIES
The twist? More recently, instead of focusing on tinkering with the level of neurotransmitters between cells, researchers have looked at what happens when the neurotransmitter binds to the cell membrane. The reactions that then go on inside the cell are now thought to be more important to the cell’s functioning than the binding of the neurotransmitter to the outside. For instance, researchers have found that antidepressants increase levels of brain derived neurotrophic factor (BDNF), which helps nourish neurons, helping them become more active and make more connections to other cells. Researchers also have found that antidepressants are involved in neurogenesis—at least in rats, increasing the production of new neurons in the rat hippocampus.

THE CAVEAT
The extent of the response varies among individuals and may be moderated by how severe a person’s depression has been, and how often it has recurred. And psychotherapy still has a role to play because how we interpret a stressful event can have a significant impact on our emotional response and ability to recover.

The above was excerpted from The Anatomy of Mood -- Biology and the Brain, published by Johns Hopkins Medical Research Hospital. For more information, go to www.johnshopkinshealthalerts.com.

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In a recent comment, Tim Wang asked about whether I plan to publish a collection of the posts I have authored in the past and the answer is yes! Watch for the first volume of Vonnies Health Spot to appear by the end of January 2008! Soon there will also be CDs available and in the future we hope to produce DVDs of health lectures and exercises.

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Disclaimer: The purpose of this weblog is not to dispense medical advice nor in any way is meant to be construed as diagnostic or prescriptive. Always check with your physician before beginning any new program or trying any of the items discussed in the posts that appear on this site.

Comments

[psychiatry emr]

Physical activity has a bounty of benefits.Studies have also shown a link between exercise and a reduced risk of certain
cancers and other health disease.Thanks for this post!

neurology emr | internal medicine emr

[Timothy W.]

I was amazed by the fact that we can actually "replenish" the brain cells and even reverse the "degenerated" ones ... truly amazing!!!

I am so glad my voice has been heard. Thank you Vonnie! I truly look forward to having a bound hardcopy of your collection in this blog. My best wishes to you and yours!

Best Regards,
Timothy W.