Feasibility of simultaneous fMRI and optical imaging for head-fixed freely-behaving mice

For simultaneous optical imaging and fMRI with freely-behaving mice, head-fixed without body restriction in minimal stress awake state, optimizations were conducted on multiple aspects, including multi-wavelength optical imaging system for both optical intrinsic signals and extrinsic fluorescence studies of genetically encoded calcium indicators (GECI) and voltage indicators (GEVI) mice with tube lens design instead of imaging fiber bundle, transparent cranial window development, integrated quadrature coil in head holder, and the designed belt treadmill/ virtual reality (VR) system to fit a customized rodent cradle in the commonly used 12cm ID gradient for the small animal MRI system.