Future Reflections Winter 2012
by Hilary Richardson
From the Editor: The Summer 2010 issue of Future Reflections included a short announcement about a study on brain development in blind and sighted children that was being conducted by the Massachusetts Institute of Technology (MIT). Now, a year and a half later, the study is well underway. In this article Hilary Richardson, a member of the research team, describes the study and discusses some of the preliminary findings.
Right now is an incredibly exciting time to be a developmental neuroscientist. A developmental neuroscientist studies the minds and brains of children in order to understand how we grow and learn and how a baby's mind transforms to that of an adult. By studying young children, scientists can ask questions about how the brain supports learning a language, how and when we learn that other people may hold beliefs that are different from our own, and how we come to understand and make reasonable moral evaluations. Studying how the mind and brain develop will illuminate which mental abilities we are born with and how we are shaped by our experiences.
In the past ten years it has become possible to ask questions such as these by studying children's brain development with magnetic resonance imaging (MRI). MRI is a very safe procedure we can use to take pictures of people's brains. Images that show the brain's anatomy, or shape, appear as still photographs. The brain's function is shown through a functional MRI, or fMRI, as a series of images over time, much like a movie. MRI technology lets us study the brain as it does the things we otherwise take for granted in our everyday lives, such as processing language, perceiving social interactions, and interpreting visual images. We can study how the brain typically processes these stimuli and how this neural response changes with age. We can also study how mind and brain development are different in children who have unique developmental experiences, such as children who are blind.
I am fortunate to be involved in this research through my work with Dr. Marina Bedny and Dr. Rebecca Saxe at the Massachusetts Institute of Technology. These researchers have already studied language and social cognition in blind adults, using behavioral tests (question and answer) and fMRI. Their research shows that the part of the brain that is used for seeing in sighted people gets recycled for many other jobs in blind people, including understanding language. Scientists used to think that only a small number of specially evolved regions, unique to the human brain, could ever be involved in processing language. By contrast, recent studies suggest the brain is extremely adaptable; parts of the brain typically used for vision can switch to understanding the meanings of words and sentences. This remarkable discovery highlights how experience dramatically alters brain development.
To understand better how and when the brain accomplishes this change, we are now working with children who are blind. Does this change happen during childhood, or does it occur as the result of aging or learning to read Braille? Does the visual part of the brain take on a specific part of language processing? What does the development of the typical language brain regions look like in children who are blind?
From a practical perspective, the results of this study may eventually have an impact on educational planning for blind children. In the more distant future, the results may inform decisions about the timing of possible treatments for the restoration of vision. We always caution parents that this study will have no direct benefit for their children. However, we take this research program as an opportunity to communicate with children, their families, and the blind community about our studies and about neuroscience in general, and we learn a great deal from the families that take part in our studies.
So far, twelve congenitally blind children between the ages of four and seventeen have participated in our study. We are actively recruiting more blind children from across the country to come visit us. When a family is interested in the study, we talk with the parents and child about the research and explain what the testing day is like. If the family wishes to participate, we arrange a trip to MIT. Though the testing only takes about half a day, most families stay in Cambridge for one to two nights, and we cover travel expenses.
We try to make the testing day a fun learning experience, and we share with children the excitement of being a part of real science. We help the children become familiar with the scanning environment by practicing in a "mock" scanner. While they are in the practice scanner, children listen to music or hear a story.
Next we head to the real scanner. The children are given an opportunity to learn about the scanner by touch. We explain how it works, how we use it to learn about the brain, and what questions we are hoping to answer. When the child is ready, we start the scan.
During the first part of the scan, the child listens to a story or music of his/her choice while we take anatomical still photographs of the brain. Then the child plays a game that involves listening to stories and music while we measure brain activity related to the various types of stimuli. Using this task we can study the response to language and music in different parts of the brain, including regions typically recruited for vision.
The whole scan takes thirty to forty minutes. After the scan, we take a break and eat lunch. The last part of the testing day is the behavioral testing. A certified teacher of the visually impaired (TVI) administers tasks that assess Braille reading, language, and math ability. Throughout the day the children are encouraged to take breaks and are provided with snacks. Each child receives an Amazon gift card and small brain-related prizes for participating in the testing. We also print pictures of the child's brain for the parents to keep.
The families that have taken part in our studies have enjoyed their experiences at our lab. For Marina, Rebecca, and me, this project is incredibly fun and interesting. We have had the opportunity to meet some fantastic kids, and we have immensely enjoyed getting to know them and their families.
Though we are still collecting data, our preliminary findings suggest that the functional reorganization of the brain that we have observed in blind adults begins in early childhood. We find that some visual areas respond to language and others to music in children as young as four years of age. This project is an important step toward understanding how the mind and brain develop, how abstract knowledge such as language is represented in the brain, and how experience plays a role in each of these processes.
Our findings so far encourage us to continue and expand our work. In future studies we will work with a more varied population of blind children, including those with some residual vision, in order to see how varying levels of visual experience affect brain development. Looking forward, we are eager to expand our relationships with blind individuals, parents of blind children, educators, researchers in related fields, and clinicians. Our work has benefited tremendously from the help of the blind community. We are also incredibly grateful to the families that have made our research possible. We extend a warm thank-you to the National Association of Parents of the Visually Impaired (NAPVI) and to the National Braille Press for their encouragement and support.
We would love to talk to you. If you have questions or would like more information about this research, please contact Hilary Richardson and Marina Bedny by phone at (617) 286-6476 or by email at [email protected]. Also, please check out our website for this study at <http://kidsbrains.mit.edu/bkids.html>.