Fiber multi-modal optical imaging of brain activity

Investigating brain activity during behavior has become one of the most attractive approaches for neuroscience researches. We developed a fiber-optic-based multi-modal optical imaging system that can detect optical fluorescent signal and hemodynamic changes simultaneously in awake animal. The imaging system integrates laser speckle contrast imaging (LSCI), spectral imaging of optical intrinsic signal (OIS), and wide-field fluorescent imaging together to provide the capability of recording the changes in calcium, blood flow, blood volume and blood oxygenation simultaneously. The imaging system consists of three parts: a multi-source illuminator, a fiber multi-channel optical imaging unit, and a head-mounted microscope. The imaging fiber bundle delivers optical images from the head-mounted microscope to the multi-channel optical imaging unit. Illuminating fiber bundles transmit light to the head-mounted microscope, which has a mass of less than 1.5 g and includes a gradient index lens. The internal optical components are adjustable, allowing for a change in the magnification and field of view. Using this system, hemodynamic and fluorescent changes during cortical spreading depression (CSD) in freely moving and anesthetized animals were investigated.