Wednesday, June 20, 2007

The Brain, Part 1: Drugs, Alcohol & The Adolescent Brain

Discover magazine is one of my favorite magazines ever. Their recent special publication, The Brain: An Owner's Manual is absolutely riveting to me because it reiterates a lot of information that I knew for a fact, but had a hard time backing up with any credible sources because it was information that I just knew and I couldn't remember where I read it years ago. I implore every single one of my readers to seek out and purchase a copy of this magazine, if you can still find it, because it will tell you things about the way your brains work that you might never have suspected, and it's all backed up by expert research from prestegious institutions.

For the interest of the lazy or those who may find it hard to locate since it actually came out several months ago, I'm going to be reprinting several choice selections from the first few articles that I feel are highly important for everyone to read. I've taken the liberty of boldfacing the areas of keenest interest. I didn't find these articles online. I actually took the time to type out the selections verbatim. This took me a significant amount of effort to type, so please at least take the time to read and consider the information, despite the fact that it isn't actually going to be in any way funny.

I'm starting out with selections from the article on the teen-aged brain, focusing on how it responds to drug and alcohol abuse. This is a topic I feel strongly about. We should not permit children or teenagers to abuse drugs, smoke, or consume alcohol at least until the legally permitted ages, and very highly likely even several years after that because it. damages. their. brains. Period. The end. The evidence is presented below.
Few who have weathered the tumultuous teen years could deny suffering major lapses of judgment during this rite of passage. And while adolescents may look like adults, and occasionally behave like adults, a glimpse inside their brains tells a radically different story. "Not long ago, it was assumed that the brain was grown-up — 'fully cooked' — by the end of childhood," says Jay N. Giedd, chief of brain imaging at the child psychiatry branch of the National Institutes of Health in Bethesda, Maryland. "Now we know better."

A flurry of research over the last decade has revealed that the cerebral cortex is undergoing riotous changes at this time of life. Neurotransmitters radically transform in number and type, fomenting a lust for experimentation and risk taking. New connections are being forged between centers of higher conceptual thinking. Myelination — the insulation of circuits to speed signal transmission — jumps precipitously. "In a second flowering, akin to early childhood, the wiring scheme of the cerebral cortex is becoming richer, more complex, and efficient," Giedd says.

Nowhere is this change more profound than in the frontal cortex — especially the so-called prefrontal cortex, the portion just behind the forehead that is widely credited for being the seat of higher judgment, wisdom, and forethought. The very last part of the brain to develop, the prefrontal cortex is what allows adults to weigh actions — like drinking before driving — against their consequences. It is the part of the brain that helps us resist peer pressure and stops us from doing stupid things we may later regret. Functioning as the brain's CEO, it also enables adults to prioritize their actions and gives them a leg up at multitasking — for example, yakking on a cell phone while driving. "The very late blossoming of the prefrontal cortex," says Giedd, "goes a long way toward explaining why teens and cars are such a deadly combination."
[The missing segment from this article appears here.]
A sudden abundance of dopamine in the prefrontal cortex at puberty triggers further upheavals. A significant function of dopamine is to focus the adolescent's attention on reward-associated cues in the environment, explains Susan Andersen, an expert on the teen brain at Harvard Medical School. By evolution's design, it seems, teenagers are suddenly scanning the horizon for sexual partners and the skills, tools, and provisions needed to strike out on their own. "That's a good thing," says Andersen, "but with that shift in focus also comes a heightened sensitivity to stress and a new passion to seek out novel or thrilling sensations." Worse, it makes drug experimentation more exciting — and at least in the case of stimulants — more addictive.

Andersen studies addiction to cocaine in rats by training them to associate different environments with either a placebo or the drug — a procedure called place conditioning. When juvenile rats are given the option of entering the habitat where a moderate dose of cocaine is readily available, they shun that space. "They don't like how cocaine makes them feel," says Andersen, " and children are the same. They don't like stimulants." Similarly, older rats and people aren't attracted to cocaine. But adolescents are a different story. At the outset of puberty, animals suddenly find the cocaine environment immensely attractive. And they will seek out the drug more even as they mature into adulthood. Research on human teens exactly parallels this finding. "If you look at stimulant abuse according to age, there's very little risk until you hit puberty," says Andersen. "But between 11 and 14, the risk jumps four times."

This may also be true of nicotine, the stimulant in tobacco. At the University of California at Irvine, researchers are now reporting very similar results in place-conditioning studies of rats addicted to nicotine. And paralleling this finding, humans who make it to their late teens without succumbing to its seductive clutches are much less likely to take up smoking later.

Alcohol similarly appeals to teens eager to experiment, but unlike stimulants it possesses a significant risk of addiction beyond a narrow sensitive period — possibly because alcohol's action on the brain is more diffuse. Among other things, its depressant properties dampen feelings of social awkwardness — a powerful lure to teens and young adults. ... While it may take years of heavy boozing before they fall prey to cirrhosis of the liver, it's a myth that teens are more resilient to alcohol's toxic effects than adults, warns Scott Swartzwelder, a neuropsychologist at Duke University and at the U.S. Department of Veterans Affairs. "The developing brain is more vulnerable to chemical insults," he says.

A decade ago, Swartzwelder surprised the scientific community by showing that alcohol disrupts the hippocampus, the brain's memory center, more severely in adolescent rats than in older rats. More recently, he and others have extended that finding to humans. Alcohol also damages the prefrontal cortex, regardless of age. Since this part of the brain is changing rapidly in adolescence, teens who regularly abuse alcohol are particularly susceptible to its harmful action. Alcohol's one-two punch to the hippocampus and the prefrontal cortex can translate into long-lasting, and possibly even permanent, cognitive defects. Even three weeks after abstaining from alcohol, teens who were former binge drinkers scored more poorly on tests of verbal and nonverbal recall than their non-drinking peers.

Adolescents who only occasionally drink still face unique hazards. Research shows that the same amount of alcohol impairs memory and learning performance more in both younger animals and humans relative to their older counterparts. Yet, paradoxically, teens are actually less sedated by alcohol than adults. That spells big trouble, says Swartzwelder. "While an adult who drinks heavily might literally conk out, a teen who consumes the same amount is still alert," he says. "So the teenager may pick a fight in a bar or get behind the wheel of a car or engage in any number of perilous activities."
(Apologies to original writer Kathleen McAuliffe and Discover magazine.)

1 Comments:

Anonymous Anonymous said...

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6:32 PM  

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