title: Extendable, miniaturized multi-modal optical imaging system: cortical hemodynamic observation in freely moving animals.
abstract: Observation of brain activities in freely moving animals has become an important approach for neuroscientists to understand the correlation between brain function and behavior. We describe an extendable fiber-optic-based multi-modal imaging system that can concurrently carry out laser speckle contrast imaging (LSCI) of blood flow and optical intrinsic signal (OIS) imaging in freely moving animals, and it could be extended to fluorescence imaging. Our imaging system consists of 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 multi-mode 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, giving the animal maximum movement capability. The internal optical components are adjustable, allowing for a change in magnification and field of view. We test the system by observing hemodynamic changes during cortical spreading depression (CSD) in freely moving and anesthetized animals by simultaneous LSCI and dual-wavelength OIS imaging. Hemodynamic parameters were calculated. Significant differences in CSD propagation durations between the two states were observed. Furthermore, it is capable of performing fluorescence imaging to explore animal behavior and the underlying brain functional activity further.
authors: Britton Chance Center of Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan 430074, China.
authors: Rui
authors: R
authors: Liu
authors: Qin
authors: Q
authors: Huang
authors: Bing
authors: B
authors: Li
authors: Cui
authors: C
authors: Yin
authors: Chao
authors: C
authors: Jiang
authors: Jia
authors: J
authors: Wang
authors: Jinling
authors: J
authors: Lu
authors: Qingmin
authors: Q
authors: Luo
authors: Pengcheng
authors: P
authors: Li
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology; D001921:Brain / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D059907:Functional Neuroimaging / Q000295:instrumentation*; D017078:Laser-Doppler Flowmetry / Q000295:instrumentation*; D008297:Male; D008853:Microscopy / Q000295:instrumentation*; D008904:Miniaturization; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D051381:Rats; D017208:Rats, Wistar