The effect of action potential-induced intracellular streaming on neural diffusion weighted imaging: a computational...

Diffusion MRI relies greatly on the apparent diffusion coefficient (ADC) as a key indicator of tissue microstructure, yet the way and the extent to which intracellular dynamics influence it remains elusive. In this work the role of cytoplasmic streaming induced by neuronal activity on ADC in neural cells was investigated. A hippocampal neuron was modeled and the effect of the forces generated by action potential (AP) streaming were numerically simulated. Coupling Navier-Stokes equations with elastic solid equations and AP forces enabled us to obtain the generated intracellular flow which then was used in transport equations to calculate concentration of the diffusion propagator and its variance over the computational domain. A significant increase of 27% in ADC was observed at AP firing frequency of 200 Hertz. Furthermore, this enhancement increases quasi-linearly with frequency. This work demonstrates that the effect of AP-and the subsequent generated intracellular flow-on ADC is non-negligible; therefore, disturbing AP firing can result in a reduction in measured ADC values. These findings could improve the current understanding of ADC reduction under pathological conditions and lay a foundation for future studies on this topic.