This award supports development of a fiber-optic multiphoton endoscope (FOME) capable of visualizing cellular details at the micron-scale within the tissues of freely moving animals. The instrument will exploit recent advances in telecom fiber- and micro-optics to allow the user to mount or implant a micro-optical probe on an animal as small as a mouse. The probe will enable visualization of cellular properties and dynamics in animals that are free to move within a behavioral testing chamber. The instrument will use multiphoton fluorescence excitation to provide true three-dimensional imaging with thin optical sectioning possible over distances of several hundred microns within the position of the probe tip. By enabling studies in which macroscopic observations of live animal behavior and physiology are concurrent with microscopic observations of underlying cellular dynamics, the FOME will help uncover new relationships between the organism and the cells within it. The excitation and emission light will be routed to and from the animal using state-of-the-art optical fibers. Fluorescent markers that are either injected or genetically engineered into the animal's cells will selectively tag particular molecular species within specific classes of cells. The user will control imaging sessions remotely from a computer interface, without having to interrupt animal behavior. By combining cellular- and organismic-level analysis, the instrument will facilitate collaborative studies by cellular biologists, physiologists and behavioral scientists. As part of the project, two auxiliary instrument will be constructed for use by trainees and other researchers to pilot new experiments destined for the central FOME imaging station. These auxiliary stations will provide core infrastructure for new undergraduate and graduate curricula on modern optical imaging techniques in the biological sciences and on biophysical aspects of neurons and neural circuits.
