Advanced Miniature Microscopy for Brain Imaging

To image neuronal activities down to single spines in freely behaving animal has already been the holy grail of neuroscientists. To achieve that goal, two-photon microscope must be miniaturized to be attached to the animal without interfering animal movements. In the past fifteen years, many groups have published different designs, albeit that none of them is not widely used by the neuroscience community. Here, we have summarized the major challenges that prevent prevalent applications of current miniature two-photon microscopy (TPM) for high-resolution imaging in freely behaving mice, and different configurations that may be used to address each challenge. Based on this theoretical analysis, we have provided detailed design of our high-resolution, miniaturized two-photon microscope (FHIRM-TPM) and its latest revisions that enable volumetric imaging capability and larger field of view and deeper penetration depth.