Articles techniques et présentations

In an earlier work we developed a finite element bidomain model of an aplysia abdominal ganglion in order to estimate the sensitivity of this contrast mechanism to changes in cell membrane conductance occurring during a gill-withdrawal reflex. We used our model to determine both current density and magnetic potential distributions within a sample chamber containing an isolated ganglion when it was illuminated with current injected synchronously with the MR imaging sequence, and predicted the resulting changes in MRI phase images. The initial simulation using COMSOL used a passive membrane but we have now introduced a Hodgkin-Huxley membrane model. Results of the improved model demonstrate membrane voltages consistent with those expected and exhibit depolarization behavior when threshold external current densities are exceeded.