Increase of Structural Disorder Along Neurites Is Leading Cause for Diffusivity Drop in Acute Ischemia

Dmitry S. Novikov¹, Jens H. Jensen², Joseph A. Helpern²

The types of microstructural architecture in any media (including living tissues) are classified in terms of the long-time tail exponent in the molecular velocity autocorrelation function. The specific value of the power-law exponent obtained from the oscillating gradient spin echo measurement in rat cerebral gray matter characterizes the relevant tissue anatomy that restricts water diffusion. It is argued that short-range disorder, likely due to spines and varicosities, provides the chief hindrance to diffusion along dendrites and axons and that the increase in this structural disorder is a primary cause of the diffusivity drop in ischemic stroke.