The Fear Gene; The Caring Hormone

Fear gene discovered:

The researchers identified a gene in mice that controls reactions to impending danger by firing certain neurons in the brain. Mice that don't have the gene, called stathmin, simply don't react to situations that should scare the rodent pants off them.

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"For those who experience fear too much, stathmin-based drugs may provide an important relief," Rutgers University scientist Gleb Shumyatsky told LiveScience. "Also, after trauma these drugs may help to forget bad experiences."

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Fear plays a key role in survival, so all mammals have an efficient memory system to deal with it. While you can't recall the name of someone you just met, a memory of fright can last a lifetime.

The stathmin gene is normally prevalent in the brain's amygdala. It controls fear of predators, heights and others that are considered instinctive, as well as fears that are learned through specific events.

In the study, mice heard a tone and were given an electric shock. The mice without the stathmin gene reacted less strongly. In a second test, the stathmin-free mice were more likely to venture into open spaces that the others naturally avoided.

Meanwhile, researchers are probing a hormone that causes caring and empathy:

The lack of emotional care given to infants in some Romanian and Russian orphanages has provided researchers an opportunity to study the hormonal basis of the mother-child bond.

Researchers led by Seth D. Pollak of the University of Wisconsin have found that these children, even three and a half years after adoption into Wisconsin families, produce two critical hormones in a different pattern from children with traditional upbringings.

The hormones, oxytocin and vasopressin, are small proteins produced by the pituitary gland in the center of the brain. Although they influence bodily functions like giving milk and the water balance, they also have a range of effects on social behavior, at least in laboratory rodents and monkeys.

These include fostering positive interactions with other individuals, notably the social bonds between mother and child and the sexual bonds between male and female.

In June this year, oxytocin was reported to elevate the level of trust among people who received a nasal spray of it before playing a game created to test their tolerance for being betrayed by other players. The game was created by an economist, Ernst Fehr of the University of Zurich.

Dr. Pollak and his colleagues have looked at how the two hormones are involved in shaping the bonds between mother and child. In normally raised children aged about 4½ years, they found, oxytocin levels rise after half an hour of physical interaction with their mothers.

But the previously neglected children in their study did not show this oxytocin jump, Dr. Pollak and his colleagues write in today's Proceedings of the National Academy of Sciences. The hormone levels were measured from samples of the children's urine.

Dr. Pollak believes that oxytocin acts through the brain's reward system and gives infants a positive feeling about social interactions. The finding that the adopted children in the study apparently get less of an oxytocin reward could explain why some children from Eastern Europe, as they grow older, have difficulty forming social relationships.

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The new finding can be interpreted in several ways. One possibility, Dr. Nelson said, is that there is a sensitive period in the first two years of life for developing a strong relationship, and that later relationships depend on the biological mechanism having been set correctly, as judged by the oxytocin response.

It could be that the previously neglected children have missed this critical window of development, Dr. Nelson said. Or, the biological system may be flexible and it will just take longer for the children to develop a normal oxytocin response. .

The best possible intervention for neglected orphan children would seem to be adoption into loving families. But maybe this is not enough and if so, the oxytocin measurements may point to the need to do something else, Dr. Nelson said.

Sociopaths and psychopaths could be cured by oxytocin therapy?

Maybe there's something to that "bad upbringing" business after all. Missing the developmental stage where human beings learn the capacity for caring and empathy, some go on to be adults capable of cruelty without the twinge of conscience.

Oxytocin, alsocalled "the trust hormone," was discussed before here.

All of this provokes an interesting discussion on the nature of evil, and whether the somewhat common description of evil or cruel individuals -- "He just has a head full of bad wiring and bad chemicals" -- is more true than we knew.

Which isn't to say anything about not jailing people who do terrible things. Even if there's a chemical basis for their cruelty, you lock them up for practical reasons, like just not wanting them to kill anymore.

But what if a genuinely evil psychopath, a butcher, undergoes oxytocin therapy and suddenly becomes a normal human being with empathy for his fellow humans and an aversion to harming them? Does that guy get paroled?

Also: Is there any sort of therapy to cure women of their need for "snuggling"? And also: "talking"?

posted by Ace at 09:55 AM

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