Remember the Bugs Bunny cartoons where Yosemite Sam would
get so angry and stressed out that steam would come out of
his ears. In fact, this seemed to happen to a lot of
cartoon characters that lost there cool. Were these guys
actually frying there brains? If so, could they get those
fried brain cells back after they calmed down? It seems
that cartoonists may have correctly predicted some
neurobiology of stress.
Stress biology has been a hot topic in neuroscience for
many years and research emerges all the time to further our
understanding of why stress is so bad for the brain. A new
study reveals an important finding that sheds more light on
maintaining brain fitness during these bouts of stress. But
before getting into the new data, let's back up a little.
Robert Sapolsky, a neuroscientist at Stanford, has been a
prevailing voice in stress biology for some time. He
proposed theories over a decade ago that suggested stress
was actually killing brain cells in a part of the brain
called the hippocampus, a structure crucial for learning
and memory.
In fact, the last ten years or so have revealed some
interesting things about the hippocampus, especially as it
relates to stress. Contrary to years of dogma, we
discovered that the hippocampus is an area of the brain
that is continually giving birth to new neurons. For many
years, we believed that the brain was incapable of making
new neurons after development, but we now know that's not
true. New neurons are being born (and dying) in the
hippocampus all the time.
The trick is to keep the rate of neuron birth in check with
that of neuron death. If you lose more neurons than you
gain, your hippocampus can shrink and whither; and your
ability to learn and remember declines.
Sapolsky's early work showed that stress was a bad thing
for this process. Stress slowed the rate of new neuron
birth, to tip the scales in favor of neuron death. Not only
does this hamper your cognitive abilities, but it may leave
you more susceptible to prolonged stress and create a
viscous cycle.
Later work by a Yale researcher, Ron Duman, showed that
anti-depressants often require new neuron birth in the
hippocampus to have their affect. One a side-note, exercise
is one of the most potent ways to stimulate new neuron
birth in the hippocampus. This is probably why exercise is
such a great anti-depressant.
New research from Duman's group has now pinpointed on of
the big players in how stress works to stop neuron birth in
the hippocampus. They discovered a molecule called IL-1beta
(Interleukin-1 beta) is responsible for putting the breaks
on hippocampal neuron birth. We already knew that IL-1beta
is a hormone involved in inflammation, increased by stress.
We also knew that IL-1beta, itself, could increase some
effects of stress.
What the new finding tells us is that if we focus on
reducing IL-1beta during unhealthily long periods of
stress, we may counter some of the cognitive problems that
too much stress creates. I'm sure this discovery has peaked
the interest of many pharmaceutical companies with
anti-IL-1beta drugs, but there is already a simple way to
reduce this hormone.
Previous studies showed that omega-3s can reduce many
hormones involved in inflammation and that they can
specifically counteract increases in stress, caused by
IL-1beta. Putting this older research in light of the new
study, suggests that omega-3s might actually be able to
protect the hippocampus during stress.
So again, discoveries in molecular biology take us back to
benefits of brain fitness cornerstones that we have been
promoting for some time; in this case, exercise and quality
nutrition. Exercise can increase the birth of new neurons
in your hippocampus and omega-3s may protect them from
stress-induced IL-1beta.
References: PNAS 2008 105(2) 751-756 J. Lipid Res. 2003
44(10):1984-91
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your intelligence with the four cornerstones of Brain
Fitness. Visit http://www.BrainFitForLife.com for FREE
Brain Fitness resources.
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