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  Topic: Genetic control of social behavior, Missing genes cause behavior defect.< Next Oldest | Next Newest >  

Posts: 41
Joined: April 2005

(Permalink) Posted: July 18 2005,10:34   


Williams syndrome, a rare hypersocial disability, is linked to damaged amygdala

July 18, 2005

Twenty-one missing genes on chromosome 7 is what it takes to create a person who is hypersocial - loving and open and trusting of everyone, yet uniquely clueless to the nuances of specific social cues. There is no "stranger danger." Everyone is treated like a favorite long-lost relative.

And while such people have a penchant for all things human, virtually all have heightened fears of nonhumans, such as snakes and elevators.

Now, federal scientists studying 14 adults with this disability, called Williams syndrome, have identified the precise area in the brain that is responsible for the exaggerated fearlessness and fearfulness.

"They are super nice and overly friendly," said Dr. Andreas Meyer-Lindenberg, a scientist at the National Institute of Mental Health who has spent the last six years studying the syndrome.

One in 7,500 will be born missing this complement of genes.

"Understanding what is going on in their brains will tell us a lot about human nature and social cognition," Meyer-Lindenberg said. His latest study appeared July 11 in the journal Nature Neuroscience.

Gifted in adversity

Many with Williams syndrome are shorter than average and share facial features that make them appear elf-like. Many have congenital heart problems. Many have borderline IQ scores, with very high verbal abilities, but low math ability. Their ability to construct things visually is all but absent: They can't find their way around a neighborhood and even an easy puzzle proves too complex.

On the other hand, they are extremely verbal and use language in a colorful and interesting way. Many also possess a great command for music. They don't understand spatial boundaries and can move uncomfortably close to people. While they don't pick up such social cues, they seem far more empathetic than normal, picking up even the slightest sadness in others and reaching out to comfort.

The federal researchers had a hunch that the missing genes somehow led to a damaged amygdala, a region of the brain that governs fear and emotion. Their idea was to put Williams patients into a brain scanner and study brain activity as they looked at pictures.

They found that the amygdala didn't respond to social threats (the pictures with threatening people) while it became overly active when the person was shown threatening pictures that did not involve people.

They traced the connections to an area in the orbital frontal cortex, where they found abnormalities of structure and function. "This region doesn't communicate with the amygdala like it does in normal people when they are experiencing emotions," Meyer-Lindenberg said. Studies on people who have had direct damage to the orbital frontal lobe have altered personalities and become wildly disinhibited.

This region is linked to decision-making, judgment and the processing of social information.

'Difficult to fit in'

As friendly as people with Williams syndrome are, none of the people in the federal study married. They ranged in age from 19 into the late 40s.

"A lot of people don't know how to treat us," said Denise Lanzon of Smithtown, now 25. "It was difficult to fit in with the other kids."

Lanzon has just completed a college music program designed for people with Williams. She has a boyfriend who also has the syndrome. Her anxieties can get the best of her, however. She is terrified of thunderstorms and snakes.

Parents often worry about these children, said Dolores Mavro of Douglas Manor whose daughter, 33-year-old Jessica, has the syndrome. She now works in a family business in Montauk. "She's struck up conversations that she should not have," Mavro said. "But for the most part, she always wins people over."

For more information: The Williams Syndrome Association: www.williams-syndrome.org.; NIMH scientist Meyer-Lindenberg's Web site is http://snp.nimh.nih.gov

These behaviors most likely did not "evolve" as a result of random mutations and natural selection, they've been hard-wired into the brain from the beginning. When you see people with the genes disabled, you can clearly see the important role they play in human behavior.
The logical conclusion that flows from this is that most likely a large amount of what makes us human is similarly hard-wired into our brains, rather than learned.

The aggressiveness that leads to war, crime and violence may be directed by genetic sequences that we did not "evolve", but inherited from our ancestors.

The down side of this is that these behaviors are probably able to be modified to a small extent, but overall, are largely intractable. The notion that poverty, neglect and other social factors cause crime and anti-social behavior must be revisted in light of this new information

(also see Carl Zimmer's article on musical hallucinations at "The Loom")


Posts: 846
Joined: April 2005

(Permalink) Posted: Aug. 16 2005,16:34   

now if you only understood half of what you read charlie, your post would actually make some sense.

extrapolation from a genetic disorder to make broad proclamations about the evolution of behavior and interaction of genes and environment on behavior is simply not warranted.

that evolution did not "produce" the abnormality described is obvious, but not particularly instructive.

You can't assume that there is an "underlying" behavior that is simply masked by the presence or lack thereof of a specific set of genes.  It simply doesn't work that way.

Why do you bother continuing in this vein?  I'm not even a specialist in this field,  but managed to learn enough in graduate school alone to know you are way off base here.

I don't understand why you so adamantly refuse to go and learn anything about the subjects you seem to be so interested in.

nuff said.

  1 replies since July 18 2005,10:34 < Next Oldest | Next Newest >  


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