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Random Walks in Model Brain Tissue

Conventional methods are based on a simplified picture of Gaussian diffusion characteristic of non-confined liquids. However, more detailed experiments show that water in brain tissue tends to exhibit essential deviations from patterns of Gaussian diffusion.

The propagation of water molecules in the brain is affected by multiple factors such as compartmentalization, restrictions and anisotropy imposed by the cellular microstructure. Interfacial interactions with the cell membranes (“bound water”) and exchange may further complicate the measured response. Due to the heterogeneity and complexity of tissue microstructure, a differentiation between the various contributions to the average NMR signal in in vivo studies represents a difficult task.

The aim of this work is to conduct random-walk Monte Carlo simulations in well-defined model systems and to establish the relations between dynamic properties and structure in a quantitative manner. A detailed analysis of the average diffusion propagator and the corresponding signal attenuation is performed. The results are compared with the in vivo data and the implications for the experimental studies are discussed.

Random Walks in Model Brain Tissue

In this project we aim to study how the average diffusion propagator and corresponding signal attenuations depend on the effects of:

1. axon radii and their distribution
2. permeability of cell membranes
3. axon packing density
4. time of observation

Additional Information

Contact Person

Prof. N. J. Shah, PhD

PD Farida Grinberg, PhD