Abstract
Brain development is a highly regulated process with significant morphological and functional transformations during early embryogenesis. Here, we quantified the optical attenuation coefficient (OAC) during murine embryonic brain development with a focus on crucial areas, including the forebrain, midbrain, and hindbrain from embryonic day (E)9.5 to E13.5. At earlier developmental stages, the estimation of OAC in these regions is comparatively low due to the low cell density and more straightforward pattern of extracellular matrix (ECM) composition, which results in minimal scattering and signal attenuation. However, as the embryo grows (by E13.5), increased ECM density and vascularization, along with the formation of blood vessels, contribute to enhanced signal attenuation, thereby reducing light penetration. As a result of gradual changes in cellular composition, tissue architecture, and extracellular matrix density, the study's findings demonstrate an increasing trend in OAC across the midbrain, hindbrain, and forebrain during embryonic development from E9.5 to E13.5.