Photonic Probing of Structural Deformation of Brain Tissues due to Stress and Alcohol

Mesoscopic optical physics based Partial Wave Spectroscopy (PWS) and Inverse Participation Ratio (IPR) techniques are sensitive to nanoscale and submicron-scale changes respectively occurring in biological cells. These changes occur due to several factors; stress and fetal alcoholism are deemed to be the major ones. The effects of chronic stress in the adult brain cells and fetal alcoholism on the brain cells of fetus are studied using the respective animal models. PWS studies the effect of stress in the brain tissues by measuring the optical backscattering spectra and quantifying the statistical properties of the nano-architecture of the tissues by the analysis of the fluctuating part of the reflected intensity. Spatially localized optical eigenfunctions of the optical lattices constructed from confocal images of in-utero ethanol-fed pups' brain cells are analyzed to predict nanoto sub-micron level mass density (i.e. refractive index) fluctuations using IPR technique. The results interpreted in terms of physical parameter called disorder strength, Ld given by Ld= <Δn> × lc, Δn being the fluctuation in refractive index and lc being correlation length of the fluctuations, showed quantitative changes in the structural disorder in stress-induced adult mice brain cells and fetal alcoholism-induced pups’ brain cells, bringing visible abnormalities in the brain cells. The potential applications of these techniques