The scientific goal of this project is to understand the mechanisms by which the external environment shapes the way the nervous system is wired. The brains of developing organisms face an immense challenge since they must allow the organisms to function within their environment even while the nervous system is not yet fully developed. It is not fully known how the brain achieves the balance between early function and the need to remain flexible. One strategy employed by the brain to achieve this is through a process called neural plasticity, which allows brain circuits to adapt to patterns of sensory input received from the external environment. This project uses the developing visual system of frog tadpoles as a model for early brain development. Experiments will study the correlation between the developmental emergence of visually-guided swimming behavior to the properties of tiny electrical signals generated in the tadpole brain in response to visual stimuli. This will allow investigators to first map neural circuits involved in processing visual stimuli and then to understand the role of the visual environment in building this circuitry through neural plasticity. For example, if visual input is required for proper wiring of visual circuits, then tadpoles raised in a dark environment or under conditions in which communication between the eye and brain is disrupted, are expected to develop abnormally. This study will also focus on mechanisms by which the brain can adapt to deficits in sensory input to achieve normal function. Together, these experiments will provide important insight into the mechanisms by which the brain's complex circuitry emerges during development and which allow it to adapt to a changing environment. A second goal of this project is to develop an educational program which will allow high-school students from underrepresented minority groups to engage first-hand in this research. This program will allow for two students each year to come to Brown and participate in a basic Neuroscience course and work in Dr. Aizenman's laboratory over the summer. The ultimate goal is to encourage these students to pursue a career in the life sciences by providing first-hand laboratory experience and mentoring. In addition, the program will also provide training opportunities to undergraduate and graduate students in the laboratory.
This CAREER proposal had two principal goals. The first scientific goal was to understand how the external world shapes the wiring of the developing brain, using the visual system of African clawed frog (Xenopus) tadpoles as a model. The second educational goal was to develop an educational program which will allow high-school students from underrepresented minority groups to engage first-hand in this research with the ultimate goal of encouraging them to pursue a career in the life sciences. In the first goal, this study found that early visual experience allows the tadpole visual system to become more precise in its function, by altering the pattern of connections between brain cells. This highlights the importance of enriched environments during early development and is a central mechanism for the development of the nervous system. This research resulted in eight publications in scholarly journals. For the second goal, we had nine high school students from underrepresented minority groups and economically disadvantaged backgrounds come to brown form a Summer Neuroscience course and to work in the PIs laboratory. The students were tracked after the program and several enrolled in four-year colleges or are in the process of applying. These colleges included Brown, University of Pennsylvania, Duke, URI and others.The program has now been expanded to include several other faculty at Brown, allowing it to bring in even more students.
