Brain Functional Imaging

utilizing nonlinear endomicroscopy imaging of neurons and glial cells.

Introduction:

The mechanisms of how the brain processes information by neurons and supporting cells remain an active and fascinating research topic in neuroscience. The development of an ultracompact (1-2 mm in diameter) and ultra lightweight (0.5 g) fiber-optic scanning endomicroscope for single and/or two-photon fluorescence (SPF/TPF) imaging offers new opportunities to enable an unprecedented panoramic view of cortical activities (such as Ca+ activity) of many neurons in population. Imaging can be conducted while an animal is awake and/or engages in natural behaviors. The information over a population of neurons afforded by the new technology would not be possible to get with the traditional electrode recording technique or with the animal anesthetized.

TPF microscopy has been widely employed for direct in vivo brain imaging, but only with the animal’s head held still under the microscope objective lens. To enable simultaneous observation of macro-scale animal behavior and the underlying neuronal dynamics on an awake, freely-behaving animal, a flexible miniature microscopy device is indispensable. Our newly-developed ultralight two-photon microscope features high detection sensitivity and high signal-to-noise ratio, and is able to clearly visualize cellular structures of unstained tissues. Initial experiment results on GCaMP3 mouse models have demonstrated its strong potential for freely-walking mouse brain imaging.

Functional Imaging Results:

The figures below highlight the potential of the technology for functional imaging of brain tissues, which can be applied to various applied neuroscience studies.

Figure 1. TPF imaging of an NG2-mEGFP mouse brain under anesthesia. (Click to enlarge and view detailed caption).

Figure 2. In vivo dynamic TPF imaging of astrocytes in a Glast-Cre;R26-lsl-GCaMP3 transgenic mouse model under anesthesia. (Click to enlarge and view detailed caption).



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