title: Chronic wide-field imaging of brain hemodynamics in behaving animals.
abstract: Chronically monitoring cerebral activities in awake and freely moving status is very important in physiological and pathological studies. We present a novel standalone micro-imager for monitoring the cerebral blood flow (CBF) and total hemoglobin (HbT) activities in freely moving animals using the laser speckle contrast imaging (LSCI) and optical intrinsic signal (OIS) methods. A new cranial window method, using contact lens and wide field optics, is also proposed to achieve the chronic and wide-field imaging of rat's cerebral cortex. The hemodynamic activities of rats' cortex were measured for the first time without restriction of cables or fibers in awake and behaving animals. Chronic imaging showed the increase of CBF and HbT in motor cortex when the rats were climbing on the cage wall. Interestingly, the CBF activation of supplying vessel was smaller than that of parenchyma. Furthermore, after the climbing, CBF demonstrated fully return to the baseline while HbT showed a delayed recovery. The standalone micro-imager technology provides new possibilities of brain imaging in cognitive neuroscience studies.
authors.affiliation: Institute of Biomedical Engineering, School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA; pengmiao@shu.edu.cn.
authors.forename: Peng
authors.initials: P
authors.lastname: Miao
authors.affiliation: Institute of Biomedical Engineering, School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China.
authors.forename: Lingke
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Institute of Biomedical Engineering, School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Li
authors.affiliation: Institute of Biomedical Engineering, School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China.
authors.forename: Yiguang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Biomedical Engineering, School of Communication and Information Engineering, Shanghai University, Shanghai 200444, China.
authors.forename: Shihan
authors.initials: S
authors.lastname: Feng
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA.
authors.forename: Qihong
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA; nitish@jhu.edu.
authors.forename: Nitish V
authors.initials: NV
authors.lastname: Thakor
keywords: (110.6150) Speckle imaging; (170.0110) Imaging systems; (170.2655) Functional monitoring and imaging; (170.3880) Medical and biological imaging; (170.5380) Physiology