FIP Virtual Postdoc Seminar "High- and super-resolution light-field imaging"

Light-field fluorescence microscopy can simultaneously record population scale activity of many individual neurons expressing genetically-encoded indicators within volumes of tissue. Conventional light-field microscopy (LFM) suffers from poor lateral resolution when using widefield illumination. Here, we report two types of LFM - light-sheet LFM (LS-LFM) and structured illumination LFM (SI-LFM) - that pattern the illumination to achieve higher spatial resolution than the resolution of conventional LFM. LS-LFM limited background contributions from sources far out of plane by exciting only a small axial range of the sample with a scanned light-sheet. Compared with conventional LFM, LS-LFM produced moderate improvements in spatial resolution, 10 times improvement in the contrast when imaging fluorescent beads, and 3.2× the signal-to-noise ratio in the detection of neural activity when imaging live zebrafish expressing a genetically encoded calcium sensor. SI-LFM obtained high resolution beyond the spatial frequency cutoffs of the light-field design by using patterned grating illumination. Such illumination excited the sample volume with grating patterns that are invariant over the axial direction. SI-LFM obtained a point-spread-function (PSF) that was approximately half the size of the conventional LFM PSF when imaging fluorescent beads. SI-LFM also resolved fine spatial features in lens tissue samples and fixed mouse retina samples.