 |
One of the most eye-catching items in Rebecca Compton’s office—aside from her various Van Goghs—is the head. Hairless and disturbingly cherubic, its pupil-less, milky gaze is both unnerving and intriguing.
Assistant Professor of Psychology Compton explains that it’s a phrenology head, which her husband, Jeremy Meyer, found for her a few years ago. “In the late 19th century,” she says, “this was the first real attempt to localize different functions of the brain.” She runs her hands over the smooth porcelain pate, pointing out sizable areas marked “Religious Convictions” and “Conscientiousness.” Apparently, scientists in the 19th century believed that if you were especially conscientious, this area of the brain would feel larger and lumpier. “They really had no methods for looking inside the brain, so feeling the skull was all they had to go on.”
Compton’s own research is evidence of how far we’ve come in deciphering the mysteries of the brain and its functions. A specialist in biopsychology, Compton, who came to Haverford in 1999, focuses on the left and right hemispheres of the brain—how they perceive information, how they communicate with each other, and how they might further understanding of anxiety and depression.
The central Pennsylvania native has been drawn to the field of psychology since high school: “I remember a paper I did for chemistry class on the effects of certain drugs to treat behavioral disorders like depression.” At the time, she saw a future in clinical psychology; then she arrived at Vassar College as an undergraduate and took a course in sensation and perception with an influential professor, Carol Christensen. Here, she received her first exposure to the mechanisms of the brain that allow us to perceive our surroundings. She assisted the professor in her research activities: “That experience helped give me a good sense of what research is about and why it’s exciting.”
She also discovered the benefits of studying psychology from a biological perspective, and how psychology functions as both a social and a natural science. “In terms of our position in the social sciences, we’re interested in people and human behavior as it takes place in a social context and as it is influenced by culture,” she says. “And yet people are also biological organisms, part of the natural world, and the brain is the organ that governs our behavior. It makes sense to try to understand the brain, to allow us to understand what controls our behavior and how our thought processes take place in this physiological organ.” In college she took classes emphasizing the neuroscience approach and was fascinated by syndromes that occurred in people with certain types of brain damage. “This helped me realize how important the brain is, this idea that when the brain is damaged it has a major impact on the ability to perform routine activities.”
At the University of Chicago, Compton’s master’s thesis brought biology and psychology together in an exploration of how women’s hormone levels during the menstrual cycle affected the cognitive processing of the brain’s hemispheres. “Some had argued that when levels of the hormones estrogen and progesterone are relatively high, that facilitated the processes of the left hemisphere, which controls verbal articulation and aspects of language,” she says. “Whereas lower levels facilitated performance by the right hemisphere, which governs functions like spatial processes.” In trying to replicate some of these findings, Compton also looked at the influence of mood, which many earlier studies had not considered. She found that performance by the hemispheres was not associated with changes in hormone levels throughout the menstrual cycle, but rather that cognitive performance by the hemispheres was influenced by mood state rather than cycle phases. “This led me away from looking at hormonal issues and more toward looking at how mood influences performance of the hemispheres.” This has been the thrust of her research ever since.
(Incidentally, two of Compton’s recent students, Caitlin Costello ’02 and Julia Diepold ’02, continued this line of research last year in a senior thesis project investigating possible associations between hormone levels during the menstrual cycle and communication between the hemispheres. They found that as progesterone levels increased, the participants in the study tended to display better interhemispheric communication.)
For her dissertation at the University of Chicago, Compton expanded her study of mood’s effect on the hemispheres. “I was interested in whether mood influenced the ability to attend to information on either the left or right side of space and to shift attention between different locations in space.” For this study, Compton began employing her current methodology: flashing items on either side of a computer screen and asking participants to respond to them. She found that people in sad moods were slower to respond to information on the left side of the screen and slower to shift their attention toward objects on this side of space. Because the right hemisphere controls responses to stimuli on the left side (and vice versa), these results fit with other researchers’ suggestions that sad mood states might diminish the performance of the right hemisphere.
Compton also looked at individual differences in a study where participants viewed a sad film and then completed the computer-based attention-shifting task. When some people showed a stronger mood reaction to the film than others, Compton found a correlation between their reaction and their ability to shift attention from one side of the screen to the other. “One of the reasons I’d like to pursue this is because there’s a new interest in mood regulation, how it is that some people are able to get themselves out of sad mood states while others have difficulty,” she says. “I’m interested in the idea that the ability to shift your attentional focus could be a part of mood regulation.”
From 1997-1999, she was a postdoctoral fellow at the University of Illinois at Urbana-Champaign, assisted by a National Institutes of Mental Health (NIMH) training grant in cognitive psychophysiology. It was here that, while continuing her exploration of the hemispheres’ involvement in emotion, she became more interested in communication between the hemispheres. She was also introduced to brain imaging technology such as EEG and fMRI, functional magnetic resonance imaging. MRI involves getting a structural picture of the brain, analogous to an X-ray, and functional MRI, or fMRI, reveals how activity in the brain, particularly blood flow, changes over time as a person performs certain cognitive tasks.
 |
Activity increased in these
brain regions when people tried to ignore distracting words whose
meaning either conflicted with the ink color of the word (left panel)
or conveyed threatening emotional information (right panel). |
“One of the things it can do is provide more anatomical precision about where in the brain these different processes are taking place,” says Compton, who also extols the benefits of getting a glimpse inside neurologically intact brains. “For a long time, one of the major methods of studying the neural basis of higher level cognition was studying people with brain damage. Functional imaging lets you look at a normal brain.”
The first part of her postdoctoral study dealt with past research findings indicating that when people are anxious, they selectively pay attention to threatening information in the environment. Compton and her fellow researchers wanted to relate this study to the two sides of the brain. They found that the right hemisphere was more involved in this attentional bias: “We know from lots of other studies that the right hemisphere is better at distinguishing between different types of emotional content, any stimuli that carry emotional meaning.”
The second part of her study involved the Stroop task, in which participants are asked to name the color of a set of words flashed on a computer screen, ignoring the meaning of the word and focusing only on its hue. “A lot of research has shown that if the word meaning and the color conflict, it screws you up,” says Compton. “For example, if the word is ‘red’ but its color is blue, you have trouble ignoring the meaning of the word and reporting the color correctly.” A number of brain imaging studies had explored how certain regions of the brain were especially active in the difficult conditions of the Stroop task. Compton’s team asked the question: are the same brain systems at work when one is trying to ignore emotional information? “Behavioral studies of people with anxiety disorders had shown that these people had trouble ignoring the meaning of threatening emotional words, like ‘danger,’ so they were slower to name the word’s color,” says Compton. In her study, she discovered that the answer to her question was partly “yes,” partly “no.” “Some of the same frontal lobe regions that are involved in selecting one aspect to pay attention to, while filtering out another aspect of the information, were involved whether or not that information was emotional,” she says. “But we also found that some right hemisphere regions were especially activated by these threatening words, more so than with words that were not emotional.”
Most recently, Compton has completed a study funded by a grant from NIMH on the emotional factors tied to communication between the hemispheres, using faces as part of her research. “There had been studies showing that, in many situations when you’re trying to complete a cognitive task, it helps to have both hemispheres working on the problem,” she says. “But in the past, the tasks used to study this communication were emotionally boring, such as viewing two letters flashed on the screen; it’s hard to inject any emotional meaning into that situation.” In developing a more emotionally resonant task, Compton turned to faces, asking participants to decide whether or not the two faces on the screen before them had matching expressions. Sometimes the faces were projected on opposite sides of the screen, and sometimes on the same side, sending information to the same hemisphere. The study indicated that subjects were faster to make the correct judgments when the faces were presented on opposite sides, thus requiring both hemispheres to send information between them.
To follow up, Compton has been considering the influence of anxiety on this interhemispheric communication of information about facial expressions. “A couple of my studies found that people who tend to worry a lot were not as good at communicating information between the hemispheres,” she says. “This suggests a way in which worry may interfere with thought processes.” She has also explored the possibility that anxious people may show better interhemispheric communication if the faces presented to them were both angry, harkening back to the theory that anxiety heightens one’s awareness of threatening stimuli. To examine this further, Compton arranged face-matching tasks and included a bit of manipulation: she led some participants to believe that they were being watched and evaluated through a one-way mirror as they performed the task. She later found that the hemispheres better communicated information about happy faces rather than angry—except in the condition where anxiety-prone participants thought they were being watched. There, they scored equally on matching both happy and angry faces. “This shows that the emotional relevance of what you’re viewing affects how quickly that information is sent around to different regions of the brain,” says Compton. Her article detailing some of these results appears in the November issue of the journal Neuropsychologia.
When discussing her research, Compton bubbles with a student’s sort of enthusiasm. It’s clear there’s nothing in the world she’d rather be doing. She loves the systematic approach of developing a controlled experiment to answer a question; she loves testing the theory; she even loves data analysis. “I guess I’m kind of a geek,” she jokes. “It’s really exciting to see what the patterns in the data look like; it gives you a sense of discovery.” She has also been pleasantly surprised by the creativity involved in research: “It’s the sense of trying to solve a problem or address a new problem that other people haven’t already tackled. There’s also creativity in terms of interpreting the results of your experiment; they might not match your preconception, forcing you to completely rethink things.”
While she’s on leave during the 2002-2003 academic year, Compton will continue to study the influence of anxiety on interhemispheric communication. She would like to start a new project exploring individual disparities in coping styles. “We all experience sad events in life,” she says, “but people differ dramatically in how they respond to those mood states.” Researchers have described two main patterns: rumination, a repetitive dwelling on sad feelings, and distraction, shifting attention to something else. “I’m really interested in how these two different patterns of coping relate to right and left hemisphere functions,” she says.
And as always, her phrenology head will be on display in her office, bald and vacant as ever, reminding both visitors and Compton herself of a less fortunate time when the only way to study the brain’s hemispheres was with one’s bare hands.