Adult-child conversations have a more significant impact on language development than exposing children to language through one-on-one reading alone, according to a new study in the July issue of Pediatrics, the journal of the American Academy of Pediatrics.

"Pediatricians and others have encouraged parents to provide language input through reading, storytelling and simple narration of daily events," explains study's lead author, Dr. Frederick J. Zimmerman, associate professor in the Department of Health Services in the UCLA School of Public Health. "Although sound advice, this form of input may not place enough emphasis on children's role in language-based exchanges and the importance of getting children to speak as much as possible."

The study of 275 families of children ages 0-4 was designed to test factors that contribute to language development of infants and toddlers. Participants' exposure to adult speech, child speech and television was measured using a small digital language recorder or processor known as the LENA System. This innovative technology allowed researchers to hear what was truly going on in a child's language environment, facilitating access to valuable new insights.

The study found that back-and-forth conversation was strongly associated with future improvements in the child's language score. Conversely, adult monologueing, such as monologic reading, was more weakly associated with language development. TV viewing had no effect on language development, positive or negative.

Zimmerman adds, "What's new here is the finding that the effect of adult-child conversations was roughly six times as potent at fostering good language development as adult speech input alone."

Each day, children hear an average of some 13,000 words spoken to them by adults and participate in about 400 conversational turns with adults. More conversations mean more opportunities for mistakes and therefore more opportunities for valuable corrections. Furthermore, they also provide an opportunity for children to practice new vocabulary.

Parents should be encouraged not only to provide language input to their children through reading or storytelling but also to engage their children in two-sided conversations, the study concludes.

"Talk is powerful, but what's even more powerful is engaging a child in meaningful interactions — the 'give and take' that is so important to the social, emotional and cognitive development of infants and toddlers," says Dr. Jill Gilkerson, language research director at LENA Foundation and a study co-author.

"It is not enough to speak to children," Zimmerman adds. "Parents should also engage them in conversation. Kids love to hear you speak, but they thrive on trying speech out for themselves. Give them a chance to say what's on their minds, even if it's 'goo goo gah.'"

Impulsive boys with inadequate supervision, poor families and deviant friends are more likely to commit criminal acts that land them in juvenile court, according to a new study published in the Journal of Child Psychology and Psychiatry. The most surprising finding from the 20-year study, conducted by researchers from the Université de Montréal and University of Genoa, was how help provided by the juvenile justice system substantially increased the risk of the boys engaging in criminal activities during early adulthood.

"For boys who had been through the juvenile justice system, compared to boys with similar histories without judicial involvement, the odds of adult judicial interventions increased almost seven-fold," says study co-author Richard E. Tremblay, a professor of psychology, pediatrics and psychiatry at the Université de Montréal and a researcher at the Sainte-Justine University Hospital Research Center.

The research team sought out boys from kindergarten who were at risk for delinquent behavior and who were enrolled at 53 schools from the poorest neighbourhoods in Montreal. Some 779 participants were interviewed annually from the age of 10 until 17 years. By their mid-20s, some 17.6 percent of participants ended up with adult criminal records for infractions that included homicide (17.9 percent); arson (31.2 percent); prostitution (25.5 percent); drug possession (16.4 percent) and impaired driving (8.8 percent).

"The more intense the help given by the juvenile justice system, the greater was its negative impact," Dr. Tremblay stresses. "Our findings take on even greater importance given that the juvenile justice system in the province of Quebec has the reputation of being among the best. Most countries spend considerable financial resources to fund programs and institutions that group deviant youths together in order to help them. The problem is that delinquent behavior is contagious, especially among adolescents. Putting deviant adolescents together creates a culture of deviance, which increases the likelihood of continued criminal behavior."

"Two solutions exist for this problem," adds Dr Tremblay. "The first is to implement prevention programs before adolescence when problem children are more responsive. The second is to minimize the concentration of problem youths in juvenile justice programs, thereby reducing the risk of peer contagion."

This study was funded by the Canadian Institutes of Health Research, the Fonds de la recherche en santé du Québec, the Fonds de recherche sur la société et la culture, the Social Sciences and Humanities Research Council.

Of all the qualities that distinguish humans from other species, how we learn is one of the most significant. In the July 17, 2009 issue of the journal Science, researchers who are at the forefront of neuroscience, psychology, education, and machine learning have synthesized a new science of learning that is already reshaping how we think about learning and creating opportunities to re-imagine the classroom for the 21st century.

“To understand how children learn and improve our educational system, we need to understand what all of these fields can contribute,” explains Howard Hughes Medical Institute investigator Terrence J. Sejnowski, Ph.D., professor and head of the Computational Neurobiology Laboratory at the Salk Institute for Biological Studies and co-director of the Temporal Dynamics of Learning Center (TDLC) at the University of California, San Diego, which is sponsored by the National Science Foundation. “Our brains have evolved to learn and adapt to new environments; if we can create the right environment for a child, magic happens.”

The paper is the first major publication to emerge from a unique collaboration between the TDLC and the University of Washington’s Learning in Informal and Formal Environments (LIFE) Center. The TDLC focuses on the study of learning—from neurons to humans and robots—treating the element of time as a crucial component of the learning process. This work complements the psychological research on child development that is the principal focus of the LIFE Center. Both have been funded as part of the NSF’s Science of Learning initiative.

Among the key insights that the authors highlight are three principles to guide the study of human learning across a range of areas and ages: learning is computational— machine learning provides a unique framework to understand the computational skills that infants and young children possess that allow them to infer structured models of their environment; learning is social—a finding that is supported by studies showing that the extent to which children interact with and learn from a robot depends on how social and responsive its behavior is; and learning is supported by brain circuits linking perception and action— human learning is grounded in the incredibly complex brain machinery that supports perception and action and that requires continuous adaptation and plasticity.

As the only species to engage in organized learning such as schools and tutoring, homo sapiens also draw on three uniquely human social skills that are fundamental to how we learn and develop: imitation, which accelerates learning and multiplies learning opportunities; shared attention, which facilitates social learning; and empathy and social emotions, which are critical to understanding human intelligence and appear to be present even in prelinguistic children.

These and other advances in our understanding of learning are now contributing to the development of machines that are themselves capable of learning and, more significantly, of teaching. Already these “social robots,” which interface with humans through dialogue or other forms of communication and behave in ways that humans are comfortable with, are being used on an experimental basis as surrogate teachers, helping preschool-age children master basic skills such as the names of the colors, new vocabulary, and singing simple songs (see image).

“Social interaction is key to everything,” Sejnowski says. “The technology to merge the social with the instructional is out there, but it hasn’t been brought to bear on the classroom to create a personalized, individualized environment for each student.” He foresees a time when these social robots may offer personalized pedagogy tailored to the needs of each child and help track the student’s mastery of curriculum. “By developing a very sophisticated computational model of a child’s mind we can help improve that child’s performance.”

“For this new science to have an impact it is critical that researchers and engineers embed themselves in educational environments for sustained periods of time,” says coauthor Javier Movellan, Ph.D., co-PI of TDLC’s Social Interaction Network and director of the Machine Perception Laboratory at UC San Diego. “The old approach of scientists doing laboratory experiments and telling teachers what to do will simply not work. Scientists and engineers have a great deal to learn from educators and from daily life in the classroom.” Movellan is collaborating with teachers at the UC San Diego Early Childhood Education Center to develop social robots that assist teachers and create new learning opportunities for children.

What makes social interaction such a powerful catalyst for learning, how to embody key elements in technology to improve learning, and how to capitalize on social factors to teach children better and foster their innate curiosity remain central questions in the new science of learning.

“Our hope is that applying this new knowledge to learning will enhance educators’ ability to provide a much richer and more interesting intellectual and cultural life for everyone,” Sejnowski says.

Researchers who also contributed to this work include Andrew N. Meltzoff, D.Phil., and Patricia K. Kuhl, Ph.D., co-PI and PI, respectively, of the Learning in Informal and Formal Environments (LIFE) Center at the University of Washington

About the Temporal Dynamics of Learning Center

The Temporal Dynamics of Learning Center, in operation since 2006 as one of six Science of Learning centers across the country, is funded by the National Science Foundation.

The TDLC mission is to develop a new science of learning that treats time as a crucial component in the learning process, on time scales that range from milliseconds to years. There is also a particular focus on inreach from the classroom into the labs and translation of the science back into the classroom.

Education is on the cusp of a transformation because of recent scientific findings in neuroscience, psychology, and machine learning that are converging to create foundations for a new science of learning.

Writing in the July 17 edition of the journal Science, researchers report that this shift is being driven by three principles that are emerging from cross-disciplinary work: learning is computational, learning is social, and learning is supported by brain circuits linking perception and action that connect people to one another. This new science of learning, the researchers believe, may shed light into the origins of human intelligence.

"We are not left alone to understand the world like Robinson Crusoe was on his island," said Andrew Meltzoff, lead author of the paper and co-director of the University of Washington's Institute for Learning and Brain Sciences. "These principles support learning across the life span and are particularly important in explaining children's rapid learning in two unique domains of human intelligence, language and social understanding.

"Social interaction is more important than we previously thought and underpins early learning. Research has shown that humans learn best from other humans, and a large part of this is timing, sensitive timing between a parent or a tutor and the child," said Meltzoff, who is a developmental psychologist.

"We are trying to understand how the child's brain works – how computational abilities are changed in the presence of another person, and trying to use these three principles as leverage for learning and improving education," added co-author Patricia Kuhl, a neuroscientist and co-director of the UW's Institute for Learning and Brain Sciences.

University of California, San Diego robotics engineer Javier Movellan and neuroscientist-biologist Terrence Sejnowski are co-authors. The research was funded by the National Science Foundation and the National Institute of Child Health and Human Development. The National Science Foundation has funded large-scale science of learning centers at both universities.

The Science paper cites numerous recent advances in neuroscience, psychology, machine learning and education. For example, Kuhl said people don't realize how computational and social factors interact during learning.

"We have a computer between our shoulders and our brains are taking in statistics all the time without our knowing it. Babies learn simply by listening, for example. They learn the sounds and words of their language by picking up probabilistic information as they listen to us talk to them. Babies at 8 months are calculating statistically and learning," Kuhl said.

But there are limits. Kuhl's work has shown that babies gather statistics and learn when exposed to a second language face to face from a real person, but not when they view that person on television.

"A person can get more information by looking at another person face to face," she said. "We are digging to understand the social element and what does it mean about us and our evolution."

Apparently babies need other people to learn. They take in more information by looking at another person face to face than by looking at that person on a big plasma TV screen," she said. "We are now trying to understand why the brain works this way, and what it means about us and our evolution."

Meltzoff said an important component of human intelligence is that humans are built so they don't have to figure out everything by themselves.

"A major role we play as parents is teaching children where the important things are for them to learn," he said. "One way we do this is through joint visual attention or eye-gaze. This is a social mechanism and children can find what's important – we call them informational 'hot spots' – by following the gaze of another person. By being connected to others we also learn by example and imitation."

Infants, he said, learn by mixing self-discovery with observations of other people for problem-solving.

"We can learn what to do by watching others, and we also can come to understand other people through our own actions," Meltzoff said. "Learning is bi-directional."

The researchers believe that aspects of informal learning, the ways people, particularly children, learn outside school, need to be brought into the classroom.

"Educators know children spend 80 percent of their waking time away from school and children are learning deeply and enthusiastically in museums, in community centers, from online games and in all sorts of venues. A lot of this learning is highly social and clues from informal learning may be applied to school to enhance learning. Why is it that a kid who is so good at figuring out baseball batting averages is failing math in school?" said Meltzoff.

Even though it appears that babies do not learn from television, technology can play a big role in the science of learning. Research is showing that children are more receptive to learning from social robots, robots that are more human in appearance and more interactive.

"The more that interacting with a machine feels like interacting with a human, the more children – and maybe adults – learn," said Kuhl. "Someday we may understand how technology can help us learn a new language at any age, and, if we could, there are countless schools around the world in which that would be helpful."

"Science is trying to understand the magic of social interaction in human learning," said Meltzoff. "But when it does we hope to embody some of what we learn into technology. Kids today are using high-powered technology – Facebook, Twitter and text messaging – to enhance social interaction. Using technology, children are learning to solve problems collaboratively. Technology also allows us to have a distributed network from which to draw information, a world of knowledge."

A new way to classify sounds in some human languages may solve a problem that has plagued linguists for nearly 100 years--how to accurately describe click sounds distinct to certain African languages.

Cornell University professor Amanda Miller and her colleagues recently used new high-speed, ultrasound imaging of the human tongue to precisely categorize sounds produced by the N|uu language speakers of southern Africa's Kalahari Desert. The research potentially could change how linguists describe "click languages" and help speech scientists understand the physics of speech production.

The African languages studied by Miller use a series of consonants called "clicks" which are unlike most consonants in that they are produced with air going into the mouth rather than out. The N|uu clicks, produced using both the front and back of the tongue, are difficult to characterize.

"When we say 'k' or 't,' the sound is produced by air breathing out of our lungs," said Miller. "But click sounds are produced by breathing in and creating suction within a cavity formed between the front and back parts of the tongue. While linguists knew this, most didn't want to accept it was something people controlled." So they loosely classified these click consonants using imprecise groupings.

"For nearly a century, some of these sounds fell into an imprecise catch-all category that included every type of modification ever reported in a click language," said Miller. "The movements of the tongue at the front of the mouth were quite accurately classified. But tongue movements at the back part of the mouth were not classified properly."

The reason was that prior tools were either too large to carry to fieldwork situations in Southern Africa, or too unsafe. Ultrasound imaging changed that by allowing Miller's research team to use safer, faster, non-invasive technology in the field to view the back part of the tongue.

Early ultrasound tools captured images only at about 30 frames per second, and thus are not able to keep up with the tongue's speed in fast sounds like clicks. The new ultrasound imaging tool is capable of capturing more than 125 frames per second, producing clearer images.

Miller and her colleagues used the high-speed ultrasound imaging to group the clicks more accurately. Her colleagues included Johanna Brugman, Cornell University; Bonny Sands, Northern Arizona University; Levi Namaseb, The University of Namibia; Mats Exter, University of Cologne; and Chris Collins, New York University.

"We wanted to classify clicks in the same way we classify other consonants," said Miller, who was a visiting faculty member at the University of British Columbia during the 2008-2009 academic year. "We think we've been pretty successful in doing that."

N|uu is severely endangered with fewer than 10 remaining speakers, all of whom are more than 60 years of age. Linguists are working diligently to document the unique aspects of this language before it disappears.

She explains her findings in the online version of the Journal of the International Phonetic Association posted on July 10. The National Science Foundation supports the research.

A large study of patients with mild cognitive impairment revealed that results from cognitive tests and brain scans can work as an early warning system for the subsequent development of Alzheimer's disease.

The research found that among 85 participants in the study with mild cognitive impairment, those with low scores on a memory recall test and low glucose metabolism in particular brain regions, as detected through positron emission tomography (PET), had a 15-fold greater risk of developing Alzheimer's disease within two years, compared with the others in the study.

The results, reported by researchers at the University of California, Berkeley, on July 14, at the Alzheimer's Association 2009 International Conference on Alzheimer's Disease in Vienna, Austria, are a major step forward in the march toward earlier diagnoses of the debilitating disease.

"Not all people with mild cognitive impairment go on to develop Alzheimer's, so it would be extremely useful to be able to identify those who are at greater risk of converting using a clinical test or biological measurement," said the study's lead author, Susan Landau, a post-doctoral fellow at UC Berkeley's Helen Wills Neuroscience Institute and the Lawrence Berkeley National Laboratory.

"The field, in general, is moving toward ways to select people during earlier stages of Alzheimer's disease, including those who show no outward signs of cognitive impairment," said Dr. William Jagust, a faculty member of UC Berkeley's Helen Wills Neuroscience Institute and principal investigator of the study. "By the time a patient is diagnosed with Alzheimer's disease, there is usually little one can do to stop or reverse the decline. Researchers are trying to determine whether treating patients before severe symptoms appear will be more effective, and that requires better diagnostic tools than what is currently available."

In the latest study, researchers compared a variety of measurements that had previously shown promise as early detectors of Alzheimer's. The measurements included scores on the Auditory Verbal Learning Test; the volume of the hippocampus, the part of the brain associated with the formation of new memory; the presence of the apolipoprotein E4 gene, which has been linked to increased risk of Alzheimer's; certain proteins found in the cerebrospinal fluid; and glucose metabolism detected in PET brain scans. A low rate of glucose metabolism in a particular brain region is considered a sign of poor neural function, most likely due to the loss of synapses in that area.

"What's really novel about our study is that we evaluated all of these biomarkers in the same subjects, so we could more easily compare the predictive value of any one measure over the others," said Landau. "The Auditory-Verbal Learning Test, which measures memory recall ability, and the PET scans measuring glucose metabolism were the two markers that clearly stood out over the others."

The researchers pointed out that other measurements - in particular, hippocampus volume and the cerebrospinal fluid markers - also showed promise in predicting disease progression. However, when considering all the measurements together, PET scans and memory recall ability were the most consistent predictors. The researchers expect to have more complete information about which measures serve as the best predictors in a year as they continue to gather data for this ongoing study.

An earlier study led by Jagust, a professor with joint appointments at UC Berkeley's School of Public Health and the Lawrence Berkeley National Laboratory, found that PET scans and magnetic resonance imaging (MRI) could detect neurological changes in asymptomatic people who subsequently developed dementia or mental impairment, although it was too soon to say if those people would go on to develop Alzheimer's.

The research is part of the nationwide Alzheimer's Disease Neuroimaging Initiative, a 60-center study funded by the National Institute on Aging. The ultimate goal of the initiative is to find a biomarker for Alzheimer's that would predict individuals who will later develop Alzheimer's disease. Ideally, this marker would be identifiable very early, even in individuals who do not yet show signs of mental impairment.

Jagust heads the initiative's research on PET imaging. The UC Berkeley study includes those patients who had measures for all biomarkers.

What is going on in teenagers' brains as their drive for peer approval begins to eclipse their family affiliations? Brain scans of teens sizing each other up reveal an emotion circuit activating more in girls as they grow older, but not in boys. The study by Daniel Pine, M.D., of the National Institute of Mental Health (NIMH), part of National Institutes of Health, and colleagues, shows how emotion circuitry diverges in the male and female brain during a developmental stage in which girls are at increased risk for developing mood and anxiety disorders.

"During this time of heightened sensitivity to interpersonal stress and peers' perceptions, girls are becoming increasingly preoccupied with how individual peers view them, while boys tend to become more focused on their status within group pecking orders," explained Pine. "However, in the study, the prospect of interacting with peers activated brain circuitry involved in approaching others, rather than circuitry responsible for withdrawal and fear, which is associated with anxiety and depression."

Pine, Amanda Guyer, Ph.D., Eric Nelson, Ph.D., and colleagues at NIMH and Georgia State University, report on one of the first studies to reveal the workings of the teen brain in a simulated real-world social interaction, in the July, 2009 issue of the Journal Child Development.

Thirty-four psychiatrically healthy males and females, aged 9 to 17, were ostensibly participating in a study of teenagers' communications via Internet chat rooms. They were told that after an fMRI (functional magnetic resonance imaging) scan, which visualizes brain activity, they would chat online with another teen from a collaborating study site. Each participant was asked to rate his or her interest in communicating with each of 40 teens presented on a computer screen, so they could be matched with a high interest participant (see picture below).

Two weeks later, the teens viewed the same faces while in an fMRI scanner. But this time they were asked to instead rate how interested they surmised each of the other prospective chatters would be in interacting with them.

Only after they exited the scanner did they learn that, in fact, the faces were of actors, not study participants, and that there would be no Internet chat. The scenario was intended to keep the teens engaged –– maintain a high level of anticipation/motivation –– during the tasks. This helped to ensure that the scanner would detect contrasts in brain circuit responses to high interest versus low interest peers.

Although the faces were selected by the researchers for their happy expressions, their attractiveness was random, so that they appeared to be a mix of typical peers encountered by teens.

As expected, the teen participants deemed the same faces they initially chose as high interest to be the peers most interested in interacting with them. Older participants tended to choose more faces of the opposite sex than younger ones. When they appraised anticipated interest from peers of high interest compared with low interest, older females showed more brain activity than younger females in circuitry that processes social emotion.

"This developmental shift suggested a change in socio-emotional calculus from avoidance to approach," noted Pine. The circuit is made up of the nucleus accumbens (reward and motivation), hypothalamus (hormonal activation), hippocampus (social memory) and insula (visceral/subjective feelings).

By contrast, males showed little change in the activity of most of these circuit areas with age, except for a decrease in activation of the insula. This may reflect a waning of interpersonal emotional ties over time in teenage males, as they shift their interest to groups, suggest Pine and colleagues.

"In females, absence of activation in areas associated with mood and anxiety disorders, such as the amygdala, suggests that emotional responses to peers may be driven more by a brain network related to approach than to one related to fear and withdrawal," said Pine. "This reflects resilience to psychosocial stress among healthy female adolescents during this vulnerable period."

Injections of THC, the active principle of cannabis, eliminate dependence on opiates (morphine, heroin) in rats deprived of their mothers at birth. The findings could lead to therapeutic alternatives to existing substitution treatments.

In order to study psychiatric disorders, neurobiologists use animal models, especially maternal deprivation models. Depriving rats of their mothers for several hours a day after their birth leads to a lack of care and to early stress. The lack of care, which takes place during a period of intense neuronal development, is liable to cause lasting brain dysfunction.

The study was carried out by Valérie Daugé and her team at the Laboratory for Physiopathology of Diseases of the Central Nervous System (UPMC / CNRS / INSERM).

Valérie Daugé's team at the Laboratory for Physiopathology of Diseases of the Central Nervous System (UPMC / CNRS / Inserm) analyzed the effects of maternal deprivation combined with injections of tetrahydrocannabinol, or THC, the main active principle in cannabis, on behavior with regard to opiates.

Previously, Daugé and her colleagues had shown that rats deprived of their mothers at birth become hypersensitive to the rewarding effect of morphine and heroin (substances belonging to the opiate family), and rapidly become dependent. In addition, there is a correlation between such behavioral disturbances linked to dependence, and hypoactivity of the enkephalinergic system, the endogenous opioid system.

To these rats, placed under stress from birth, the researchers intermittently administered increasingly high doses of THC (5 or 10 mg/kg) during the period corresponding to their adolescence (between 35 and 48 days after birth). By measuring their consumption of morphine in adulthood, they observed that, unlike results previously obtained, the rats no longer developed typical morphine-dependent behavior. Moreover, biochemical and molecular biological data corroborate these findings. In the striatum, a region of the brain involved in drug dependence, the production of endogenous enkephalins was restored under THC, whereas it diminished in rats stressed from birth which had not received THC.

Such animal models are validated for understanding the neurobiological and behavioral effects of postnatal conditions in humans. In this context, the findings point to the development of new treatments that could relieve withdrawal effects and suppress drug dependence.

The enkephalinergic system produces endogenous enkephalins, which are neurotransmitters that bind to the same receptors as opiates and inhibit pain messages to the brain.

People with Parkinson’s disease have significantly higher blood levels of a particular pesticide than healthy people or those with Alzheimer’s disease, researchers at UT Southwestern Medical Center have found.

In a study appearing in the July issue of Archives of Neurology, researchers found the pesticide beta-HCH (hexachlorocyclohexane) in 76 percent of people with Parkinson’s, compared with 40 percent of healthy controls and 30 percent of those with Alzheimer’s.

The finding might provide the basis for a beta-HCH blood test to identify individuals at risk for developing Parkinson’s disease. The results also point the way to more research on environmental causes of Parkinson’s.

“There’s been a link between pesticide use and Parkinson’s disease for a long time, but never a specific pesticide,” said Dr. Dwight German, professor of psychiatry at UT Southwestern and a senior author of the paper. “This is particularly important because the disease is not diagnosed until after significant nerve damage has occurred. A test for this risk factor might allow for early detection and protective treatment.”

About 1 million people in the U.S. have Parkinson’s, a number expected to rise as the population ages. The disease occurs when brain cells in particular regions die, causing tremors, cognitive problems and a host of other symptoms.

The study involved 113 participants, ages 50 to 89. Fifty had Parkinson’s, 43 were healthy and 20 had Alzheimer’s. The researchers tested the subjects’ blood for 15 pesticides known as organochlorines.

These pesticides, which include the well-known DDT (dichlorodiphenyltrichloroethane), were widely used in the U.S. from the 1950s to the 1970s but are more tightly regulated now. They persist in the environment for years without breaking down. In the body, they dissolve in fats and are known to attack the type of brain nerves that die in Parkinson’s disease, the researchers said.

“Much higher levels of the beta-HCH were in the air, water and food chain when the Parkinson’s patients were in their 20s and 30s,” Dr. German said. “Also, the half-life of the pesticide is seven to eight years, so it stays in the body for a long time.”

Parkinson’s disease is more common among rural men than other demographic groups, but it is not a matter of a single factor causing the devastating disease, Dr. German said.

“Some people with Parkinson’s might have the disease because of exposure to environmental pesticides, but there are also genes known to play a role in the condition,” Dr. German said.

Although the current study points to an interesting link between the pesticide beta-HCH and Parkinson’s, there could be other pesticides involved with the disease, he said.

For example, the pesticide lindane often contains beta-HCH, but lindane breaks down faster. Beta-HCH might simply be a sign that someone was exposed to lindane, with lindane actually causing the damage to the brain, the researchers said.

In future research, Dr. German hopes to test patients from a wider geographical area and to measure pesticide levels in post-mortem brains. He and his team also are collecting blood samples from both patients with Parkinson’s and their spouses to see if a genetic difference might be making the one with Parkinson’s more susceptible to pesticides than the other.

Other UT Southwestern researchers involved in the study were Dr. Padraig O’Suilleabhain, associate professor of neurology; Dr. Ramón Diaz-Arrastía, professor of neurology; and Dr. Joan Reisch, professor of clinical sciences. Researchers from the Robert Wood Johnson Medical School, including lead author Dr. Jason Richardson, and the Environmental and Occupational Health Sciences Institute in New Jersey also participated in the study.

The study was funded by the National Institute of Environmental Health Sciences, the National Institute on Aging, the Dallas Area Parkinsonism Society, Rowe & Co. Inc., the Dallas Foundation and the Michael J. Fox Foundation for Parkinson’s Research.