Three Dimensional Cell Modeling and Micromechanical Homogenization of Heterogeneous Brain Tissue

This study proposes a micromechanical algorithm for analysis and homogenization of heterogeneous brain tissue. The presented method has led to the development of a 3D cell model for homogenization of disordered part of brain matter. The structural complexity of neuron has modeled with low level of simplification in order to achieve more accurate results. In the homogenization process the constituents of brain, neuron and extracellular cell matrix, are assumed to have an elastic behavior. The proposed model is studied in some micromechanical aspects and results indicate the model simulates the tissue behavior reasonably. Results show that because of low length to diameter ratio (aspect ratio) in the cell body, increase in number of neurons in the representative volume element has low effect on improvement of tissue mechanical properties, such as elastic modulus, and the properties are close to the prediction of lower bound or Reuss model. Investigation of stress fields caused by compression load on the representative volume element, as the part of brain tissue, announce that the maximum stress is located in the neuron and specially at the junction of neurites (axon and dendrites) and soma and also along the neurites.