In this project the PI will develop new techniques to study worm thermotactic behavior in different types of environments with an approach that draws on technological innovation in both physics and biology. At the level of behavior, the PI will develop new assays to track the thermotactic movements of individual animals at high resolution for extended periods of time in two and three dimensions and at the level of neural circuits, the PI will develop an assay for optical recording of the activity of multiple neurons within the intact nervous system. The research program will provide a comprehensive and rigorous understanding of how a worm performs thermotaxis in different environments where it might have to swim, crawl, or burrow towards its preferred temperature. A better understanding of different modes of thermotactic behavior, along with improved methods for manipulating and monitoring neural activity, will provide new insights into how neural circuits give rise to sensory perception, information processing, and motor control during animal navigation. In addition the research program will promote training in the natural sciences through the awarding of undergraduate and graduate research assistantships. It will promote scientific education by integrating aspects of the program into course curricula at Harvard University that is aimed at introducing undergraduate and graduate students to current problems in biophysics and neuroscience. Outreach programs will provide summer internships in neuroscience research to high school students from a small rural community, and to undergraduates at historically black colleges and universities.
Understanding how the brain gives rise to behavior has emerged as a national priority. Only in animal model systems with relatively small numbers of neurons and simple behaviors can we hope to connect brain to behavior with completeness and precision. By understanding such systems, we endeavor towards general principles that apply to larger animals including humans. The overall goal of our project was to understand how sensory patterns are transformed into motor patterns by the 302-neuron nervous system of a freely moving animal, the nematode C. elegans. Our specific goal was to develop a wide range of new behavioral assays to uncover new facets of behavior that had gone unrecognized in traditional behavioral assays. We studied thermotaxis, a particularly important behavior for invertebrates who must rely on the environment to control their own body temperatures. We developed tools to precisely quantify the movements of worms in different thermal conditions, and uncovered a basic set of rules by which the animal organizes its thermotactic behaviors. By developing and applying new methods to use optical microscopy to measure and manipulate brain activity, we were able to show how specific rules of behavior are encoded in the activity patterns of specific sensory neurons and interneurons in the worm nervous system.
