Brain science has made huge strides in recent years, but the human mind still holds countless mysteries: How does that white and gray matter, pulsing with electricity, define who we are, what we do, how we feel? For decades, technology brought few answers.
But now a new tool, functional MRI (magnetic resonance imaging) is opening up a whole new realm for researchers, allowing them to look inside the human brain as volunteers complete tasks, experience emotions, and react to drugs.
Tara White, an assistant professor of community health at Brown University’s Warren Alpert Medical School, is using fMRI to explore the neural basis of individual differences in people’s moods, emotions and vulnerability to substance abuse and addiction.
She answered questions about her research.
PBN: Your lab focuses on what you call “affective neuroscience.” How much knowledge is there in this field already?
WHITE: Affective neuroscience is the study of neural mechanisms of emotion, which is a field with roots in neuroscience and psychology. In psychology much effort has been focused on delineating the basic structure of emotion; in neuroscience, much effort has gone into identifying the circuitry involved in specific emotional processes.
What fascinates me is the intersection between emotion and individual differences. People differ in the frequency and intensity with which they experience basic emotional states; their feelings of positive mood, sociability, anxiety, fearfulness, how spontaneous they are.
Differences in these emotional tendencies are, intriguingly, entirely decoupled; what you know about someone’s gregariousness, for instance, does not tell you anything about how anxious they may feel when speaking publicly; how fearful they may be in the face of physical danger; or whether they like to plan or be spontaneous.
Compared to our knowledge about other brain processes like visual function or motor control we know much less about the real neural foundation of these very important differences in the human experience. Finding out these mechanisms drives my work, and the work of others in the field.
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PBN: Does your research support the notion of an addiction-prone personality?
WHITE: So far my data indicate that some of the most interesting and productive traits – gregariousness, goal-directedness, physical fearlessness – appear to co-vary with the sensitivity of the monoamine systems dopamine and norepinephrine in humans.
These personality traits are beneficial and adaptive. Sociability and fearlessness have real impact in our society; think about firefighters, first responders, entrepreneurs, leaders. These traits are thus clearly beneficial and deserve our attention.
What’s interesting is that normal variation in these systems increases, as a side effect, the impact drugs have when they are consumed. For instance, amphetamine (a stimulant) can produce greater subjective positive emotion in people who are trait-wise fearless or sociable, compared to people who are lower on these traits.
Rather than an “addictive personality,” these data are telling us about the absolute respect we should have for our biological systems of emotion, both in ourselves and in the people around us. We need to protect these systems from drug and alcohol misuse, because they are such an essential component of who we are.
PBN: How much is your research geared to informing public health initiatives and community-based prevention and treatment efforts?
WHITE: My work is funded by National Institute on Drug Abuse and by foundations interested in reducing alcohol misuse, such as the Alcohol Research Foundation and the Center for AIDS Research.
The public health impact of drug and alcohol misuse is absolutely staggering. The financial costs alone are estimated at half a trillion dollars annually in the U.S. There is currently no effective treatment for addiction to psychostimulants like cocaine and street methamphetamine, and addiction is a chronically relapsing condition.
Brown has an exceptional dissemination network, the Addiction Technology Transfer Center of New England. This network’s mission is to take research findings and disseminate them directly to medical personnel, patients and clinics. Efforts at prevention, effectively targeted with regard to normal traits that could constitute a vulnerability to drug effects, could be one way to help protect people before they begin to experiment with drugs and alcohol. This is one of the long-term goals of my research program.
PBN: How do you conduct your studies?
WHITE: Like most biomedical studies, my studies involve multiple assessment steps, inclusion and exclusion criteria, and research and human protections to insure integrity. I use protocols that are designed to minimize the impact of potential confounding factors while maximizing our ability to measure the variables of interest.
In science what you are doing is predicting portions of the variance. Because of this, you must not only effectively measure what you are interested in, but you must also reduce the contributions of random noise. In humans particularly, for whom so many factors cannot be controlled, both steps are critically important for your ability to learn about the interplay between emotion, personality and the brain.
PBN: How does this affect the volunteers? I would think that having my brain thoroughly analyzed by fMRI, and learning that, say, alcohol affects me differently than most people, could make a real impact.
WHITE: This is a real hope of this work. What you are talking about is personalized medicine, and we certainly are not there yet.
Learning that one’s brain, because of one’s unique biology and life experience, may be more sensitive to certain substances or situations is a very powerful take-home message. It could significantly reduce the likelihood that people would distance themselves from issues about their drug or alcohol intake, because it is directly relevant to them as individuals.
Ultimately this line of work could produce a better understanding of the factors that make us who we are, and the ways in which we need to protect ourselves, our neural systems, and the neural systems of the people around us from drug and alcohol misuse.
To learn more about White’s research, visit her lab’s website.
