A comparative study of the 3D precentral gyrus model for unipolar and bipolar current stimulations.

Cortical stimulation (CS) is an appealing method for treating stroke and other disorders by promoting functional recovery. It is necessary to study the effect of different cortical stimulation types through numerical simulations in order to understand the underlying mechanism. In this paper, we simulated four types of invasive CS - unipolar ECS (epidural CS), bipolar ECS, unipolar SCS (subdural CS), and bipolar SCS - to investigate and compare the effects of stimulation types. Current stimulation was considered to increase the observability of the comparison between ECS and SCS. The simulation results obtained from the 3D precentral gyrus model showed ECS and SCS had similar current density distributions with higher stimulated current. However, the differences between bipolar and unipolar stimulation are significant with higher stimulated current. As stimulated current increased, unipolar CS penetrated deeper and wider regions than bipolar CS, so it can be more effective for functional recovery.