Volumetric Refractive Index Measurement and Quantitative Density Analysis of Mouse Brain Tissue with Sub‐Micrometer Spatial Resolution

High‐resolution structural imaging of brain tissue is important for neuroscience research. However, conventional approaches have several limitations, such as the need for exogenous staining, limited accessibility to volumetric information, and qualitative analysis. Herein, high‐resolution label‐free volumetric imaging and analysis of mouse brain tissue are presented using 3D quantitative phase imaging. Measurement of the refractive index distribution of tissue enables direct imaging of the cellular and subcellular structures. Quantification of subcellular organelles is performed in the anatomical regions of the somatosensory cortex, corpus callosum, caudoputamen, and thalamus regions.