FASD: Prenatal alcohol exposure alters development of brain function

fMRI scan of working memory activation in typically-developing children. 

Credit: The Saban Research Institute

In the first study of its kind, Prapti Gautam, PhD, and colleagues from The Saban Research Institute of Children's Hospital Los Angeles found that children with fetal alcohol spectrum disorders (FASD) showed weaker brain activation during specific cognitive tasks than their unaffected counterparts.

These novel findings suggest a possible neural mechanism for the persistent attention problems seen in individuals with FASD.

The results of this study will be published in Cerebral Cortex on August 4.

"Functional magnetic resonance imaging (fMRI) has been used to observe brain activity during mental tasks in children with FASD, but we are the first to utilize these techniques to look at brain activation over time," says Gautam.

"We wanted to see if the differences in brain activation between children with FASD and their healthy peers were static, or if they changed as children got older."

FASD encompasses the broad spectrum of symptoms that are linked to in utero alcohol exposure, including cognitive impairment, deficits in intelligence and attention and central nervous system abnormalities.

These symptoms can lead to attention problems and higher societal and economic burdens common in individuals with FASD.

During the period of childhood and adolescence, brain function, working memory and attention performance all rapidly improve, suggesting that this is a crucial time for developing brain networks.

To study how prenatal alcohol exposure may alter this development, researchers observed a group of unaffected children and a group of children with FASD over two years.

They used fMRI to observe brain activation through mental tasks such as visuo-spatial attention, how we visually perceive the spatial relationships among objects in our environment, and working memory.

"We found that there were significant differences in development brain activation over time between the two groups, even though they did not differ in task performance," notes Elizabeth Sowell, PhD, director of the Developmental Cognitive Neuroimaging Laboratory at The Saban Research Institute and senior author on the manuscript.

"While the healthy control group showed an increase in signal intensity over time, the children with FASD showed a decrease in brain activation during visuo-spatial attention, especially in the frontal, temporal and parietal brain regions."

These results demonstrate that prenatal alcohol exposure can change how brain signaling develops during childhood and adolescence, long after the damaging effects of alcohol exposure in utero.

The atypical development of brain activation observed in children with FASD could explain the persistent problems in cognitive and behavioral function seen in this population as they mature.

Fetal Alcohol Syndrome (FASD): Prenatal exposure to alcohol disrupts brain circuitry

Prenatal exposure to alcohol severely disrupts major features of brain development that potentially lead to increased anxiety and poor motor function, conditions typical in humans with Fetal Alcohol Spectrum Disorders (FASD), according to neuroscientists at the University of California, Riverside.

In a groundbreaking study, the UC Riverside team discovered that prenatal exposure to alcohol significantly altered the expression of genes and the development of a network of connections in the neo-cortex—the part of the brain responsible for high-level thought and cognition, vision, hearing, touch, balance, motor skills, language, and emotion—in a mouse model of FASD.

Prenatal exposure caused wrong areas of the brain to be connected with each other, the researchers found.

These findings contradict the recently popular belief that consuming alcohol during pregnancy does no harm.

"If you consume alcohol when you are pregnant you can disrupt the development of your baby's brain," said Kelly Huffman, assistant professor of psychology at UC Riverside and lead author of the study that appears in the Nov. 27 issue of The Journal of Neuroscience, the official, peer-reviewed publication of the Society of Neuroscience.

Study co-authors are UCR Ph.D. students Hani El Shawa and Charles Abbott.

"This research helps us understand how substances like alcohol impact brain development and change behavior," Huffman explained.

"It also shows how prenatal alcohol exposure generates dramatic change in the brain that leads to changes in behaviour.

Although this study uses a moderate- to high-dose model, others have shown that even small doses alter development of key receptors in the brain."

Researchers have long known that ethanol exposure from a mother's consumption of alcohol impacts brain and cognitive development in the child, but had not previously demonstrated a connection between that exposure and disruption of neural networks that potentially leads to changes in behaviour.

Huffman's team found dramatic changes in intra-neocortical connections between the frontal, somato-sensory and visual cortex in mice born to mothers who consumed ethanol during pregnancy.

The changes were especially severe in the frontal cortex, which regulates motor skill learning, decision-making, planning, judgment, attention, risk-taking, executive function and sociality.

Autism Risk: Exposure to high pollution levels during pregnancy

Women in the U.S. exposed to high levels of air pollution while pregnant were up to twice as likely to have a child with autism as women who lived in areas with low pollution, according to a new study from Harvard School of Public Health (HSPH).

It is the first large national study to examine links between autism and air pollution across the U.S.

Andrea Roberts

"Our findings raise concerns since, depending on the pollutant, 20% to 60% of the women in our study lived in areas where risk of autism was elevated," said lead author Andrea Roberts, research associate in the HSPH Department of Social and Behavioral Sciences.

The study appeared online June 18, 2013 in Environmental Health Perspectives.

Exposure to diesel particulates, lead, manganese, mercury, methylene chloride and other pollutants are known to affect brain function and to affect the developing baby.

Two previous studies found associations between exposure to air pollution during pregnancy and autism in children, but those studies looked at data in just three locations in the U.S.

The researchers examined data from Nurses' Health Study II, a long-term study based at Brigham and Women's Hospital involving 116,430 nurses that began in 1989.

Among that group, the authors studied 325 women who had a child with autism and 22,000 women who had a child without the disorder.

They looked at associations between autism and levels of pollutants at the time and place of birth. They used air pollution data from the U.S. Environmental Protection Agency to estimate women's exposure to pollutants while pregnant.

They also adjusted for the influence of factors such as income, education, and smoking during pregnancy.

The results showed that women who lived in the 20% of locations with the highest levels of diesel particulates or mercury in the air were twice as likely to have a child with autism as those who lived in the 20% of areas with the lowest levels.

Other types of air pollution—lead, manganese, methylene chloride, and combined metal exposure—were associated with higher autism risk as well.

Women who lived in the 20% of locations with the highest levels of these pollutants were about 50% more likely to have a child with autism than those who lived in the 20% of areas with the lowest concentrations.

Most pollutants were associated with autism more strongly in boys than girls. However, since there were few girls with autism in the study, the authors said this finding should be examined further.

Marc Weisskopf

Senior author Marc Weisskopf, associate professor of environmental and occupational epidemiology at HSPH, said, "Our results suggest that new studies should begin the process of measuring metals and other pollutants in the blood of pregnant women or newborn children to provide stronger evidence that specific pollutants increase risk of autism. A better understanding of this can help to develop interventions to reduce pregnant women's exposure to these pollutants."

Asthma in Children: Exposure to traffic-related air pollution

New research conducted in 10 European cities has estimated that 14% of chronic childhood asthma is due to exposure to traffic pollution near busy roads.

Chronic burden of near-roadway traffic pollution in 10 European cities

The results are comparable to the burden associated with passive smoking: the World Health Organization (WHO) estimates that between 4% and 18% of asthma cases in children are linked to passive smoking.

The findings, published online today (22 March 2013) ahead of print in the European Respiratory Journal, come as the European Commission has declared 2013 the 'Year of Air', which highlights the importance of clean air for all and focuses on actions to improve air quality across the EU.

Until now, traffic pollution was assumed to only trigger asthma symptoms and burden estimations did not account for chronic asthma caused by the specific range of toxicants that are found near heavily used roads along which many Europeans live.

The researchers used a method known as population-attributable fractions to assess the impact of near-road traffic pollution.

This calculates the proportional reduction in disease or death that would occur if exposure to a risk factor were reduced to a lower level.

The new research used data from existing epidemiological studies which found that children exposed to higher levels of near-road traffic-related pollution also had higher rates of asthma, even when taking into account a range of other relevant factors such as passive smoking or socioeconomic factors.

The researchers aimed to take these findings further and estimate how many asthma cases could be avoided if exposure was removed.

The results found that 14% of asthma cases across the 10 cities could be attributed to near-road traffic pollution. The findings also take into account differences in the health of the overall population in different cities.

Lead author, Dr Laura Perez at the Swiss Tropical and Public Health Institute, said: "Air pollution has previously been seen to trigger symptoms but this is the first time we have estimated the percentage of cases that might not have occurred if Europeans had not been exposed to road traffic pollution. In light of all the existing epidemiological studies showing that road-traffic contributes to the onset of the disease in children, we must consider these results to improve policy making and urban planning."

The above story is reprinted from materials provided by European Lung Foundation