November 25, 2005
Insufficent Myelination Seen As Cause Of Mental Disorders

While decay of myelin due to auto-immune damage is suspected as a cause of multiple sclerosis some UCLA researchers see a much wider role for insufficient myelination as a cause of a large assortment of mental and behavioral disorders.

New evidence points to production of myelin, a fatty insulation coating the brain's internal wiring, as a neural Achilles' heel early in life.

An upcoming application of a novel model of human brain development and degeneration pioneered by a UCLA neuroscientist identifies disruption of myelination as a key neurobiological component behind childhood developmental disorders and addictive behaviors.

Detailed in an article in press with the upcoming annual peer-reviewed publication Adolescent Psychiatry (Hillsdale, N.J.; The Analytic Press Inc.; 2005) the analysis suggests that many factors can disrupt myelination and contribute to or worsen disorders such as autism, attention deficit/hyperactivity disorder and schizophrenia.

Note above that problems with myelination may contribute to addictive behaviors and ADHD.

There's a vicious cycle aspect to this report. Due to insufficient myelination a kid could be more prone to use of addictive drugs. But then the use of the drugs could prevent the myelination process from proceeding. This reminds me of people I know who used a lot of drugs while teenagers who never seem to have grown up since then. Did their drug and alcohol use block their own brain's maturation?

In addition, the analysis suggests that alcohol and other drugs of abuse have toxic effects on the myelination process in some adolescents, contributing to poor treatment outcomes and exacerbating co-existing psychiatric disorders.

Author Dr. George Bartzokis, a professor of neurology at UCLA's David Geffen School of Medicine, concludes that the high incidence of impulsive behaviors that characterize the teen years as well as many psychiatric disorders that occur in the teens and 20s are related to incomplete myelination of inhibitory "stop" brain circuits, while the "go" circuits become fully functional earlier in development. These inhibitory circuits are not on line to quickly interrupt high-risk behaviors that are so prevalent in teens and young adults.

If memory serves the development of the inhibitory circuits does not complete until about age 25. As a consequence of blocked myelin formation are heavy adolescent drug users more prone to impulsive, self-destructive, and violent behaviors even as adults?

There's an aging angle to myelination and demyelination.

"Myelination, a process uniquely elaborated in humans, arguably is the most important and most vulnerable process of brain development as we mature and age," said Bartzokis, who directs the UCLA Memory Disorders and Alzheimer's Disease Clinic and the Clinical Core of the UCLA Alzheimer's Disease Research Center.

"Environmental toxins, genetic predispositions and even diet appear to influence and sometimes disrupt this process," he added. "By shifting our research focus to medications that act on brain metabolism and development, as opposed to brain neurotransmitter chemistry, neuroscientists will likely find a wealth of novel opportunities for addressing the cause of brain disease rather than simply the symptoms."

Myelin is a sheet of lipid, or fat, with very high cholesterol content — the highest of any brain tissue. The high cholesterol content allows myelin to wrap tightly around axons, speeding messages through the brain by insulating these neural "wire" connections.

Bartzokis' analysis of magnetic resonance images and post-mortem tissue data suggests that the production of myelin is a key component of brain development through childhood and well into middle age, when development peaks and deterioration begins (Neurobiology of Aging, January 2004). He also identifies the midlife breakdown of myelin as a key to onset of Alzheimer's disease later in life (Archives of Neurology, March 2003; Neurobiology of Aging, August 2004).

We need rejuvenation therapies that will repair and replace aging myelin sheaths in the brain. Sign me up. I want rejuvenated myelin. Myelin rejuvenation no doubt will be part of the Strategies for Engineered Negligible Senescence (SENS) treatments.

Imagine a future two or three decades hence where parents take their kids in for cell therapies and gene therapies to make their myelin sheaths grow over their inhibitory circuitry more rapidly. Such therapies would reduce adolescent deaths from car accidents and from murder. Plus, the therapies would also reduce adolescent use of destructive drugs.

Adolescent rashness might have been selected for so that males in particular would compete more aggressively for mates. The slow myelination of inhibitory brain circuits might be an obsolete and maladaptive left-over consequence of evolution by natural selection.

Share |      Randall Parker, 2005 November 25 11:58 AM  Brain Development


Comments
Patrick said at November 26, 2005 2:26 AM:

Wouldn't it be annoying if those males who didn't get the treatment, got all the girls.

michael vassar said at November 26, 2005 4:29 PM:

I'm pretty sure that, robotic cars, surveillence, biomonitoring, and rapid emergency response are much more practical ways to reduce murder and car accidents then neural engineering. Also, in thirty drugs we could easily have safe drugs with more appeal than today's addictive ones if the government permitted such research.

Randall Parker said at November 26, 2005 4:57 PM:

Michael,

What will come first? Robotic cars or methods to accelerate brain development? The answer is not obvious to me.

I can see robotic cars on specially instrumented interstate highways easily 10 or 20 years before robotic cars get good enough for surface streets in cities or rural roads. The surface street problem is much harder to solve. Well, where do most auto deaths happen? I do not know.

Murder is a lot harder to reduce by the methods you list. A bullet in the head will wreck the mind even if the body can be kept alive. I do not know what surveillance can do about lethal fights between people who know each other.

As for drugs that are fun but not addictive: Will we get such drugs before or after we get biotechnology for accelerating brain development?

Also, what about people who are hard coded by their genes to never development as much inhibitory circuits as the average person? Once we have the genetic and neural technologies for assigning high probabilities for violent behavior to some small fraction of society do you think the average person will support or oppose shoving the development of such minds in safer directions? My guess is that people will demand the widespread use of brain development altering drugs. After all, millions of prescriptions for Ritalin and similar drugs get written for kids every year

Bob Mottram said at November 27, 2005 1:54 AM:

It's not surprising that factors which effect myelinisation have a significant effect upon mental development and performance. When you look at pictures of dissected brains all that "white matter" is axons. These are the cables which allow neurons to communicate with each other, and the signals which pass down these cables are insulated with myelin, just like copper electrical cables insulated with plastic. If the myelin is degraded then the elctrical signals passing around the brain and body dissipate more rapidly, and most importantly the speed at which one neuron can communicate with each other is reduced (like going from broadband to dialup). Many people don't realise that communication within the brain does not happen instantaneously, and the timings with which one part of the brain communicates with another are critical for setting up synchronous modes of activity at various frequencies. If synchronous states in the thalamo-cortical system cannot be properly established this has a direct effect upon attention, hence more impulsive behavior or attention deficit.

PacRim Jim said at November 27, 2005 3:07 AM:

Re-egineer the human body to use encrypted radio-frequency signals rather than slow neural impulses. Then myelin will be unneeded. (Of course, the whole brain would have to be redesigned to store information holographically and multilocally.)

crush41 said at November 27, 2005 12:07 PM:

"Well, where do most auto deaths happen?"

The interstates are safer:

"But according to a new study, more than half—52 percent—of traffic fatalities in the United States between 1999 and 2003 occurred on neighborhood roads, making those trips more dangerous than you think.

What's especially startling about the statistic is that vehicle travel on these roads accounted for only 28 percent of travel during that period, the report says.

The study, compiled by nonprofit group The Road Information Program (TRIP), found that there has been an average of 22,127 traffic fatalities annually on the nation's rural, non-Interstate roads between 1999 and 2003; during the same
period, there was an average of 42,301 people killed each year in traffic accidents on all roads in the U.S."

It makes sense that neighborhood roads would be three times as dangerous, even at lower speeds. There's more attention required, more potential distractions, a greater chance of head-on collisions due to the proximity of vehicles going the other direction, and the need for more coordination between drivers. I'm assuming robotic cars would be tenable in the nearer future because interstate driving is so much less complicated.

Lou Pagnucco said at November 30, 2005 8:34 PM:

I am not sure it's relevant to other demyelinating conditions, but glucosamine supplements have been
found to slow the development and reduce the symptoms in animal models of multiple sclerosis.

See the reference "Multiple Sclerosis - OTC Glucosamine may provide some relief" at URL:
http://www.medicalnewstoday.com/medicalnews.php?newsid=34218

betty rivera said at November 25, 2008 9:50 PM:

i had chemo as a child and i suffer from all of the symptoms of chemo brain, i would be willing to do a study, they said i have bipolar,anxity n depression, but now that my memory is severly impaired ==i think iit mayb e chemo brain, if any1 has advice on where to go to get tratment for this, pleasde email me @ realmom27@yahoo.com thank u so much

step said at October 31, 2011 7:14 AM:

I am now very confused. I have been reading articles about mental disorder and I have bumped to so many causes. Can it be possible that someone will just summarize the causes of mental illness like ADHD or ADD It that possible?

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