SAN FRANCISCO, Nov. 21 (UPI) -- Family ties can pull the cognitive and creative strings of a child's brain, the latest research shows.
Twins have significantly lower IQ in childhood than youngsters making a solo entrance into the world, a difference that cannot be explained by social or economic factors, scientists report in the British Medical Journal.
In a study of 9,832 children born alone and 236 coming as a pair, the investigators found at age 7 the average IQ score for twins was 5.3 points lower than that for their single siblings, a gap that widened to 6 points by age 9.
The father's occupation, social class, mother's age, child's sex and number of older siblings all were discounted as playing a role in the difference. Rather, the twins may be paying a cognitive cost for their typically shorter stay in the womb and a proclivity of some toward impaired fetal growth, David Leon, professor of epidemiology at the London School of Hygiene and Tropical Medicine, and colleagues speculate.
Researchers at Stanford University School of Medicine, on the other hand, found having bipolar parents can pay dividends in creativity. The small study, published in the Journal of Psychiatric Research, showed the offspring of parents with the mood disorder -- even those who did not suffer the condition themselves -- scored higher on creativity tests than those with mentally sound parents.
"I think it's fascinating," says study coauthor Dr. Kiki Chang, assistant professor of psychiatry and behavioral sciences. "There is a reason that many people who have bipolar disorder become very successful, and these findings address the positive aspects of having this illness."
Many scientists see a link between creativity and the mental illness marked by dramatic swings in mood, energy and ability to function, noting a two-to-three-times higher risk of psychosis, mood disorders or suicide among artists and writers than among their more mundane counterparts.
Study coauthor Dr. Terence Ketter, professor of psychiatry and behavioral sciences, says creativity and bipolar disorder may have genetic elements that are passed on through the generations.
The team says more research is needed to determine what role genetics and environment play in creativity and bipolar disorder. As a start, the scientists plan to see how the parents' creativity compares to that of their offspring.
The effect of environment on the brain was brought home in another study reported in the Proceedings of the National Academy of Sciences that found altered social-bonding hormones in orphans adopted from abroad by American families and children living with their biological parents.
The aim of the study was to look into how infants' social experiences affect brain organization, said study author Seth Pollak, a psychologist at the University of Wisconsin in Madison.
The children sent at birth to orphanages, where they experienced little emotional and physical closeness to caregivers, differed from the children who had a more loving start in two hormones: oxytocin and arginine vasopressin, both of them linked to stress regulation and social bonding. A comforting touch or other sign of caring normally elevates the hormone levels.
In the study, the researchers found the orphans had lower startup levels of vasopressin, and their oxytocin levels failed to rise after playing with their adopted mothers.
An early start devoid of warmth and caring can disrupt normal development of these hormonal systems, making it more difficult later on for the child to be calmed or comforted, even by a loving caregiver, Pollak said.
Early experience also may help shape a child's sensory perception, another study shows.
The brain's ability to combine sensory information from a single event -- such as seeing an ambulance and hearing its siren -- speeds reactions, help us identify objects and heightens our awareness, the scientists explain. Their animal research suggests this ability appears to be acquired rather than inherited. And its development may depend on the sensory experiences in the early months of life.
"The way in which this ability develops has profound implications for those who are born blind or deaf, or who suffer from disorders such as autism and dyslexia in which early sensory processes are altered," said Mark Wallace, a neuroscientist at Wake Forest University School of Medicine. "Knowing how these brain circuits mature may one day be used to tailor treatment strategies for those who have problems in basic sensory processes."
Wallace told a meeting of the Society for Neuroscience in Washington he and his team set out to gain further insight into multisensory integration, the brain's ability to combine information from different senses, especially in the higher brain regions such as the neocortex, which is responsible for perceptions.
The cat study supports previous findings that indicate the malleable multisensory brain circuits mature slowly, taking in all the stimuli from the sensory world surrounding the newborn.
"This implies that changes in our early sensory experiences resulting from disease or environmental factors will likely have a substantial impact on brain development," Wallace says.
The proper brain food can be found in taste and touch and sight and sound.
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