ABSTRACT The optical Kerr effect (OKE) spectroscopy is a powerful technique to study ultrafast dynamics of a material's response to an optical field. In this study, we investigated OKE in Alzheimer's disease (AD) and normal human brain tissues from the hippocampus and Brodmann areas 9 and 17. The Kerr signals from both AD and normal samples exhibited a distinct double‐peak profile, corresponding to the electronic and plasma mechanisms. Analysis of plasma relaxation and dielectric response times revealed that conductivity in the AD hippocampus was approximately 46%–61% higher than in normal tissue, due to an increase in structural inhomogeneity, which may arise from tau and amyloid‐beta (Aβ) protein accumulation and elevated water content. Overall, the mean conductivity across the three regions was 38% higher in AD compared to normal tissue. These findings demonstrate that OKE can provide valuable information on underlying molecular mechanisms of the brain that occur on ultrafast timescale.
Mamani et al. (Sun,) studied this question.