The Neuro-Protective Lifestyle

Your Astrocytes To The Rescue!

Posted on 08. Nov, 2008 by Kerry Friesen, M.D..

ASTROCYTES: NOT JUST FILLER ANYMORE

For decades, neurons have gotten all the glory. They’re smart, sexy, sleek, sophisticated, lightning fast and extremely elitist since they make up only 10% of the brain.

Sandwiched between 100 billion neurons—more or less—you’ll find 10 times as many “glial” cells, (from the latin for glue). Astrocytes are the most abundant type of glial cell and for decades were thought to do little more than provide structural support for our massive neural network and clean-up cellular debris when necessary.

ASTROCYTES, NEUROGENESIS AND SYNAPTIC PLASTICITY

Astrocytes may in fact hold the neurochemical key to two fundamental areas of continued brain growth—neurogenesis (the creation of a new neuron) and synaptic plasticity (the strengthening of neuron to neuron connectivity).

Here’s how it works.

Neurons manufacture two different forms of the same growth factor known as BDNF (brain-derived neurotrophic factor). Synaptic transmission and connectivity (read learning and memory) are influenced by the type of BDNF present. Previously it was thought that neurons were responsible for the entire process. It appears now that astrocytes are capable of fine-tuning synaptic plasticity and thus enhance learning and memory by regulating the amount of BDNF present in neuronal synapses.

REGENERATION AND REPAIR

In keeping with the sub-merged super-hero metaphor (hint: it’s the title of the post), astrocytes apparently possess free-radical scavenging and metal ion chelating properties.

When astrocytes detect neuronal injury, they respond by overproducing metallothionein (MT). MT as it turns out is a powerful neuroprotective agent that is capable of preventing the oxidative stress and subsequent neuroinflammation caused by free radicals and thought to be the causative factor for most neurodegenerative disorders.

ASTROCYTES HAVE AN EVIL SIDE

For all the good they do, astrocytes still can go bad. David Welch was diagnosed with a low-grade astrocytoma in December 2004. While low-grade astrocytomas represent only 6% of all brain tumor and ordinarily have an expected 90% 5 year survival—David’s medical course has taken a different turn.

Check out 38 LEMON, for an emotionally stirring and poignant look inside David’s mind as he chronicles* his experience with the evil side of an astrocyte that just won’t go away….

*WARNING: David’s brain surgery video is not for the squeamish.
Link to the National Cancer Institute: Brain Tumor Database

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Five Brain Myths Busted

Posted on 25. Apr, 2008 by Kerry Friesen, M.D..

Myth #1

Alcohol kills brain cells.

It does a number on your limbic system and disrupts communication between message-carrying dendrites in your cerebellum – but it doesn’t kill them. The greater the alcohol intake obviously, the greater the amount of disruption. Over time, chronic alcohol ingestion (it takes a lot of alcohol – Zane Lamprey and Steve McKenna-style lots) depletes thiamine levels in the body and brain causing Wernicke-Korsakoff disease. W-K patients develop a profound amnesia, a characteristic eye-movement disorder and persistent confusion – that’s when you know (or don’t) you’ve gone too far!

Myth #2

Brain cells (neurons) are fixed from birth and never regenerate.

This is a hang-over (pun intended) from the 19th century when Spanish histologist (Nobel Prize winning histologist), Santiago Ramon y Cajal, pontificated freely on the structure of the brain. We now know however, that neurons in vital areas of the brain – the hippocampus for one – are constantly regenerating. Survival of brand-new baby neurons is tenuous, so caution is warranted. Loss of sleep and excess stress all serve to decrease survivability. Blueberries on the other hand – give neurogenesis a boost!

Myth #2

Our brains are just massive super-computers.

Nope. Complex neural-networks we are not. Believe it not, what separates the human brain from super-computers is not the ability to learn – but the capacity to forget. Once a neural-network “learns” something, it is hard-wired into the system forever. No going back. You may now start singing the virtues of a volatile memory. No, wait, forget that!

Myth #3

The brain does not change.

On the contrary, this IS the dawning of the age of “plasticity” neuroplasticity that is. Neuroplasticity happens when all of your brain cells (neurons, glia), join forces with your circulatory system to increase your capacity for learning and memory. As a result, the absolute number of synaptic transmissions increases as does the nature of the synapse itself. Remember, synaptic transmission is the “business-end” of the neuron and is critical to enhancing brain function. But get this, overtime more neuronal refinement occurs through “synaptic pruning”. Synaptic pruning eliminates weak synaptic connections thus reinforcing the stronger ones. If that’s not brain changing, then I don’t know what is!

Myth #4

Memory loss is a “normal” part of aging.

Difficulty learning new material and a slightly longer recall time, can be seen as part of the normal aging process. Dramatic memory loss, difficulty following directions, repeating phrases or stories in the same conversation however, should not be considered normal. A simple two-minute screening test can help distinguish between the two.

Myth #5

We only use 10 percent of our brains.

Ok it’s time for this one to go. This fallacy continues to survive despite an abundance of evidence to the contrary. Everyone from Sigmund Freud to Albert Einstein is invoked to lend credibility to this myth. More recently a UK documentary by Professor John Lorber of Sheffield University featured a handful of pediatric patients with remarkably little brain tissue and yet average or even above-average intelligence. CT scanning confirmed it. This may seem convincing at first blush, but CT scanning is now ancient technology. Functional MRI images consistently show that we use all of our brains – all of the time. And with that, it’s time for the ten-percent myth to go!

Look for more brain myths to be busted. Paradigm shifts are an essential part of the scientific process – just ask Thomas Kuhn.

Strange is the new normal.

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