Micromechanical Characterization of Brain White Matter with Bi-Directional Orientation of Axonal Fibers

Axonal injury within the white matter of human brain and spinal cord has led to several diseases in the Central Nervous System (Karami and Shankar, [1]). Diffuse axonal injury, one of the forms of Traumatic Brain Injury is caused due to swelling and elongation of axons in case of explosions, small and severe accidents, falling from heights where the brain gets an impact due to sudden movement of skull or hit by an object. A brain tissue model with bidirectional orientation of axonal fibers within the white matter of human brain has been developed. This brain tissue represents a repeating unit cell (RUC) modeled in ABAQUS (finite element software) [2] which comprises of axons and extracellular matrix (Karami and Shankar, [1]). Hyperelastic material properties of white matter sheet corona radiata of a porcine brain with bidirectional orientation of axonal fibers within the extracellular matrix is considered (Karami and Shankar, [1])