Washington, Feb 7 : New research on monkeys has found that exposure to moderate levels of prenatal alcohol and stress causes touch sensitivity in offspring.
Researchers from University of Wisconsin-Madison who carried out the study said that it help implications for human children too as sensitivity to touch is one of a number of characteristics which can lead to behavioural or emotional problems in children who over-respond to sensory information.
Researchers led by Mary L Schneider, professor of occupational therapy and psychology at the University of Wisconsin-Madison, studied 38 rhesus monkeys in the age bracket of 5- to 7-years.
These offspring were born to mothers who either drank a moderate dose of alcohol every day during their pregnancies, were exposed to a mild 10-minute stressor during their pregnancies, drank a moderate amount of alcohol and were exposed to the stressor during their pregnancies, or were undisturbed while they were pregnant.
A moderate dose of alcohol for the monkeys was defined as the equivalent of two drinks a day for a human.
The researchers noted that monkey offspring whose mothers had been exposed to alcohol or stress prenatally were disturbed by touch more than those monkey offspring whose mothers were in the control group.
The boffins then used a brain neuro-imaging technique known as positron emission tomography, or PET and found that the monkeys' sensitivities to touch were related to changes in a brain chemical called dopamine in one area of the brain, the striatum.
Regulating dopamine plays a crucial role in mental and physical health. Particularly important for learning, dopamine plays a major role in addictions.
"Our findings with monkeys suggest that when mothers are under stress and/or drink alcohol while pregnant, their offspring are at risk for sensory sensitivities," notes Schneider.
"Our findings also have important implications for women of childbearing age suggesting that sensory sensitivities might be reduced by decreasing stress levels and abstaining from alcohol during pregnancy or if planning pregnancy," she said.
The study appears in the January/February 2008 issue of the journal Child Development.