Cell radius and membrane permeability in the developing brain

Motivation: Axon and soma radii and membrane permeability are important features of brain structure and pathology but in-vivo noninvasive measurement of these biomarkers is challenging due to complex tissue architectures and inherent simplifying assumptions in MR biophysical models. Goal(s): We study membrane permeability and axon and soma radii of the developing brain during the first 5 years of life, the most dynamic and complex postnatal neurodevelopment. Approach: Different microstructure models were fitted to 389 diffusion MRI scans of 217 subjects. Measurements and developmental trends were compared with histological evidence. Results: MF-SMSI yields results that are closest to histological expectations with biologically plausible developmental trends. Impact: Noninvasive measurements of cell physical properties in the developing brain were compared with histological evidence. We present a method that yields results that are closest to histological expectations with biologically plausible developmental trends. The method can potentially facilitate neurodevelopmental studies.