Comparison of tissue clearing achieved with six hydrophilic tissue clearing methods. Comparison of clearing efficacies of SeeDB (A), SeeDBp (B), SeeDB2 (C), 80% TDE (D), LUCID (E), and OPTIClear (F) on rat brain samples (3 mm thickness) with both PACA-Light and PACA-Glow. All tissue clearing time course are shown in Supplementary Figures S6, S7. Optical images showing samples after clearing (red dotted line), along with any changes in sample size upon tissue processing, are included (see also Supplementary Figure S12). (G) Comparison of clearing efficacies of sixteen hydrophilic tissue clearing. Three discs from three distinct brain regions (B1: prefrontal cortex and basal ganglia, B2: cerebral cortex and midbrain/diencephalon, B3: cerebellum) were generated and analyzed for each sample. Each color line and bar point to assessment values of empty (black) and refractive index matching solution (blue) of each protocol, and three distinct regions of the brain the B1 (square, red), B2 (diamond, violet), and B3 (triangle, sky blue). Green bars point to assessment values of the glow light (unit) in the dark. Results represent three replicates of each experiment, and data are presented as the mean ± SD (standard deviation). The transparency of the cleared brain was evident against a patterned background (length:width = 5 mm:5 mm).