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Spotlight on Research
Prenatal Drug Exposure and Brain Development
Does prenatal exposure to addictive drugs affect the development of the brain in ways that make people more likely to engage in risky behavior such as experimenting with addictive, recreational drugs? Prenatal drug exposure is often associated with environments that provide increased opportunities to engage in risky behaviors such as drug use or unprotected sexual intercourse as the child gets older. The increased opportunity for engaging in risky behavior in these environments may dovetail with an increased propensity for engaging in risky behavior caused by the effects of prenatal drug exposure on brain development.
Dr. Tracy Riggins has received a grant to study the effects prenatal drug exposure on risk-taking behavior among teenagers. The research funded by the grant will make use of fMRI (functional magnetic resonance imaging) to determine how prenatal drug exposure affects the neural pathways in the brain that are involved in the assessment of risk. Using fMRI, Dr. Riggins will be able to directly measure neural activation in the brain while teenagers both evaluate a risky choice, reach a decision, and then execute their decision to either carry out the risky action or not.
The participants in the study include a group of teenagers who were exposed to addictive drugs (cocaine or heroin) in the womb along with teenagers from the same community who were not subjected to prenatal drug exposure. The participants in each group are matched on factors such as age, ethnicity and age of first pregnancy. The risk-taking task that will be used in the research has been adapted for use with fMRI from a computer-based risky decision scenario developed by Dr. Carl Lejuez who is also a faculty member at the University of Maryland.
The focus on teenagers in this study is of particular importance for several reasons. First, very little is currently known about how prenatal drug exposure affects teenage behavior. Second, the human brain continues to develop throughout the teenage years. Moreover, the course of this brain development makes teenagers especially susceptible to engaging in risky behavior. The neural pathways in the brain that are involved with experiencing the emotional and physical benefits of reward develop faster than the pathways that are involved with envisioning and evaluating the possible future consequences of current actions. This developmental timeline produces a phase that commonly occurs during the teenage years when the immediate rewards associated with an activity are more salient and meaningful to a person than the possible negative consequences of carrying out the activity. This difference in the time course of brain development renders teenagers more prone to taking risks than adults whose brains are fully developed.
Comparison of fMRI results from the two groups of teenagers will provide insight on whether prenatal drug exposure is associated with differences in brain development. In addition, the fMRI data will indicate if any differences which are observed affect the neural pathways that are involved with both reward and the evaluation of consequences.
The comparison of teenagers who were subjected to prenatal drug exposure with teenagers from the same community who were not is also an important feature of the funded research. Both groups of teenagers live in an environment that provides increased opportunities for engaging in risky behavior. If the teens that experienced prenatal drug exposure are more likely to make risky choices than those that were not, and this difference in engaging in risky behavior is accompanied by differences in brain activity in the regions associated with experiencing rewards and evaluating consequences, then there will be evidence that environmental factors and brain development interact with each other. An environment that tends to be associated with higher than normal rates of prenatal drug exposure may contribute to the birth of children whose brains develop in a manner that contributes to creating an environment that is conducive to prenatal drug exposure.
Risky Behavior and HIV
HIV infection in teenagers is a complex and growing problem. Part of solving the problem involves identifying the personality characteristics that lead young people to engage in risky behaviors that are associated with HIV infection such as drug and alcohol use and unprotected sexual intercourse. Dr Carl Lejuez has received a grant from the National Institutes of Health to carry out a five year study that is designed to determine the extent to which identification of patterns of risk taking behavior in younger adolescents can be used to predict future activity that has an increased chance of exposing the person to HIV infection. If younger people who are more at risk of future HIV infection can be identified, steps can be taken early that may prevent infection later.
How Mirror Neurons Adapt
Mirror neurons in the brain fire when a person performs an action or observes another performing the same action, The mirror neurson system is thought to play a central role in people’s ability to imitate what they see other people do and learn by observing others. Drs. Amanda Woodward and Jose Contreras-Vidal have received a grant from the Office of Naval Research to study the flexibility of the mirror system to adapt to changing circumstances in both children and adults. This project requires simultaneously measuring participants' own actions, their perception of others' actions, and patterns in their brain activity that have been associated with the mirror neuron system. By investigating these processes as they change during infant devleopment and adult skill acquisition, the project will provide a first view of the ways in which the mirror neuron system is changed by experience. The data from these experiments will also be used to develop a neural net model of the areas of the brain that are involved in action and imitation.
Spatial Memory in Bats
Spatial memory is fundamental to everyone's daily life as it enables us to represent our Environment and to orient ourselves with respect to other people and places. Spatial memory
operates on a broad range of time scales to serve a variety of important functions. On short time scales, working spatial memory plays an important role in representing the location of objects in a scene, and over longer time scales, spatial memory is essential for rooting oneself with respect to the environment and finding places. As we sit, stand, walk and reach, spatial working memory plays a fundamental role in guiding behaviors. Spatial memory deficits have been reported in individuals with a variety of clinical conditions, including developmental disorders, depression, schizophrenia, Alzheimer’s disease, temporal lobe epilepsy and victims of stroke. Loss of spatial memory, through injury or disease, is devastating to mental health, but successful new therapeutic interventions can grow out of a deeper understanding of the basic mechanisms that support spatial memory that operate over different scales of time and space. With a continuing grant from the NIMH, Dr. Cynthia Moss explores these mechanisms in the echolocating bat which is an excellent model system to study spatial memory.
Finding Solutions in the Middle East
The relationships and interactions between the Middle East and the West are, in many ways, the center of mass around which the modern world revolves. Terrorism, oil, Iraq, the Israeli-Palestinian conflict, the development of a nuclear weapon capacity in Iran, all of these and more have consumed the world's interest in recent years. Successful resolution of the problems that have arisen between the Middle East and the West depends on negotiation and collaboration between two very different worlds.
With funding from the Army Research Office, Dr. Michele Gelfand heads a team of international scholars that is focused on the problem of how negotiation and collaboration are affected by cultural differences between the Middle East and the West. The endeavor is called Project InterACTION and, in addition to the University of Maryland, it includes researchers from Harvard and Columbia Universities, the University of South Florida and the Naval Postgraduate School. The impact of culture on negotiation and collaboration is a complex and multifaceted problem. The research team reflects this complexity by including investigators from a variety of disciplines including anthropology, behavioral economics, communication, computer science, psychology, and political science. Along with this multidiscplinary approach, the project is bringing to bear a variety of research methods such as laboratory experiments, surveys, interviews, archival analyses, computer simulations, and dynamic and agent-based modeling techniques.
Some of the questions the project seeks to answer include:
- What are the relevant dimensions and cultural constructs in the Middle East that are critical for understanding how culture affects negotiation and collaboration processes across a wide range of situational contexts? For example, how do Middle Eastern ideas about honor (sharaf; irdh), shame (hashham), faith (Imam), connections (wasta), and communication (mubalagha) affect negotiation and collaboration and how do these ideas vary across different areas of the Middle East?
- How does culture affect basic psychological and social processes in negotiations and collaborations? How can two people from markedly different societies and cultures reach a level of understanding and trust necessary to carry out a successful collaboration and how can this trust be restored once it is threatened or broken?
- What are the factors that facilitate cross-cultural negotiation and how can they be enhanced? On the other hand, what are the factors that inhibit collaboration and how can they be avoided?
Project InterACTION maintains its own website which contains more detailed information about the project's goals, methodologies and research questions
Crack, Prostitution and HIV
Crack cocaine is a very powerful and very addictive drug. It also produces a short-lived high, about 5 to 10 minutes on average, with unpleasant aftereffects including depression, irritability and paranoia. This combination produces crack addicts who have strong physiological and psychological drives for a drug that must be replenished frequently to sustain feeling good and avoid feeling bad. In other words, addicts on a high need fast money to buy more crack. A common source for this money, especially for women, is street-level prostitution which typically involves high-risk sexual behavior and an increased risk for HIV. The combination of HIV infection and crack cocaine abuse among women is a serious and growing problem in the United States.
Women who engage in prostitution to make money to buy crack often know that prostitution is dangerous and self-destructive and may express negative attitudes about the sex trade coupled with active attempts to avoid it in the future. And yet they may well return to prostitution to make money for crack. Why do they return to the sex trade when they know it's dangerous and wish to avoid it? The easy answer is that the need for the drug overwhelms their good intentions. The problem lies in understanding how this process works so we can develop the means to help these women break the connection.
Dr. Catalina Kopetz has received a post-doc grant from NIDA to examine the connection between crack addiction and prostitution using the motivation-as-cognition theory of motivation developed by Arie Kruglanski. Motivation as cognition proposes ways in which motivations to achieve goals interact with ideas or beliefs about the world to produce behavior. One facet of the theory draws a distinction between explicit factors (such as the knoweldge that prostitution is dangerous and the intention to avoid engaging in the sex trade) and implicit factors (such as the knowledge based on prior experience that prostitution is an effective means for getting money to buy crack.) By detailing the ways in which these implicit and explicit factors interact, the theory offers both a conceptual background and specific investigation techniques that can be used to asses mental processes that both influence behavior and are difficult to control. Empirical support for this approach could serve as a basis for modifying current approaches and developing new techniques for treating people with substance abuse problems.
The Negative Symptoms of Schizophrenia
Schizophrenia is a disease of the brain that is often persistent, severe, and disabling. Approximately 1.1% of the population age 18 and older in the United States, roughly 2.4 million people, suffer from schizophrenia. The disease is characterized by serious and at times extreme disruptions in perception, thought and emotion. Individuals with schizophrenia often experience hallucinations, delusions, an inability to think clearly or rationally, and a marked lack of emotional response. Some of the more serious symptoms of schizophrenia can be controlled with medication in many patients. However, as is the case with any disease, successful treatment depends on successful diagnosis.
The symptoms of schizophrenia are divided into two classes, positive and negative. Symptoms such as hallucinations or delusions are classified as positive because they involve a distortion of normal function. Negative symptoms involve a loss of normal function and can include a diminished capacity to experience pleasure (anhedonia), decreased social affiliation (asociality), lack of motivation or drive (avolition or apathy), decreased outward expression of emotion (flat or blunted affect), and diminished speech (alogia).
While drug treatments can be used to control the more overt positive symptoms of schizophrenia, the negative symptoms do not respond well to medication and can often disrupt the schizophrenic’s ability to function within a community. Improved treatment and care for those suffering from schizophrenia involves enhancing our understanding of negative symptoms. The problem is complicated, however, because of challenges in the accurate clinical assessment of these symptoms.
Dr. Jack Blanchard is part of a team of investigators from the University of Maryland, the University of Pennsylvania, UCLA, and the University of California at Berkeley that has received grants from the National Institutes of Mental Health (NIMH) to develop a new assessment instrument that is specifically designed for an accurate and exacting assessment of the negative symptoms of schizophrenia. The need for such an assessment tool was identified by an NIMH-sponsored conference as the most important thing needed to advance our understanding of the negative symptoms of schizophrenia.
The research project will involve several iterations of development, test and refinement of the assessment instrument. The goal is to produce an interview measure that is capable of identifying the negative symptoms of schizophrenia in a reliable and valid manner. By combining the efforts of Dr. Blanchard with his colleagues at the other three universities, the team will be able to develop and test the assessment tool across a clinically and ethnically diverse group of people who suffer from schizophrenia.
Improving Cognitive Abilities
Recent advances in cognitive neuroscience have produced a wealth of new and important results. One of the more interesting is the support for the finding that both the functional capabilities and the neural structures of the brain change in response to experience for both children and adults. This term for this idea is “neural plasticity” and it has profound implications not only for how people learn but for how cognitive abilities can be maintained and improved as people move past childhood.
The idea that intensive practice can produce improvements in cognitive abilities such as thinking, reasoning and language use because of neural plasticity is especially promising. For example, consider a task that is used by cognitive psychologists who study short-term or working memory that is called an n-back task. In an n-back task a person sees a long sequence of items such as words and every so often is asked to remember the word that was shown n words previously in the sequence. For example, if n = 3 we have a 3-back task and the person would be asked to remember the word that was shown 3 words before the current word. To do this task, you always have to keep the most recent three words in the sequence in working memory as the sequence of words progresses.
After extensive, regular practice, a person will get better at an n-back task. Now, what happens if after all of this practice the items in the sequence are changed from words to pictures of simple shapes like circles and triangles? On the one hand, the areas of the brain that are involved in processing words are different from the areas of the brain that process shapes; on the other hand, the areas of the brain that are used when you are keeping the last three things you saw in working or short-term memory are the same whether these things are words or shapes. Will practicing and getting better at the task with words, result in also getting better when doing the task with shapes even though the task was not practiced with shapes? The answer is “yes”.
When a person practices a simple task like the n-back task neural plasticity results in strengthening of the neural pathways that are involved in doing the task so that these pathways work more quickly or reliably than they did before. Practice has produced changes in the brain and these changes result in better performance on the task. Performance of other tasks that share some of the same neural pathways can also be improved. Extensive, controlled practice of one task can result in improvement in a variety of cognitive abilities that make use of the same neural pathways as the task that was practiced.
Dr. Michael Dougherty has received a grant from the Office of Naval Research to carry out a far-reaching investigation of neural plasticity as it relates to the improvement of more advanced cognitive abilities. Much of the research carried out to date has focused on how practice of simple cognitive tasks like the n-back task can improve other simple cognitive tasks. Dr. Dougherty will be examining how practice of simple cognitive tasks can improve more complex cognitive abilities such as verbal and quantitative reasoning, and language learning and comprehension that make use of some of the same neural pathways as the simple tasks.
Dr. Dougherty will also carry out fMRI (functional magnetic imaging) studies to identify precisely which areas of the brain are involved in performing different tasks. Identifying the specific neural pathways that are involved in performing different tasks is an important step in being able to design simple tasks that can be used to improve more complex cognitive abilities.
If changes in both the neural structures and the functional abilities of the brain underlie the fact that practicing one task can improve performance in a task that uses some of the same neural pathways, then we would expect that the improvements we see in task performance would last over time. Dr. Dougherty will examine this issue as well.
We might also expect that improvement in complex cognitive abilities like reasoning and language comprehension would benefit performance in high-stress situations where there are competing demands on attention, the cost of a mistake can be high, and time pressure is a factor. Dr. Dougherty’s research will also examine these questions.
One of the goals of Dr. Dougherty’s research project is to develop a set of cognitive tasks and a training regimen that uses these tasks to improve higher order cognitive abilities. Successful completion of the project has the potential to help people in high-pressure situations such as soldiers in combat, air-traffic controllers, or hospital emergency room personnel do their jobs more efficiently and accurately. It also has the potential to help people engaged in reasoning or language comprehension in normal, everyday activities.
