  Deep Brain Stimulation (DBS) is an established and powerful treatment method
in various neurological disorders. It involves chronically delivering
electrical pulses to a certain stimulation target in the brain in order to
alleviate the symptoms of a disease. Traditionally, the effect of DBS on neural
tissue has been modeled based on the geometrical intersection of the static
Volume of Tissue Activated (VTA) and the stimulation target. Recent studies
suggest that the Dentato-Rubro-Thalamic Tract (DRTT) may serve as a potential
common underlying stimulation target for tremor control in Essential Tremor
(ET). However, clinical observations highlight that the therapeutic effect of
DBS, especially in ET, is strongly influenced by the dynamic DBS parameters
such as pulse width and frequency, as well as stimulation polarity. This study
introduces a computational model to elucidate the effect of the stimulation
signal shape on the DRTT under neural input. The simulation results suggest
that achieving a specific pulse amplitude threshold is necessary before
eliciting the therapeutic effect through adjustments in pulse widths and
frequencies becomes feasible. Longer pulse widths proved more likely to induce
firing, thus requiring a lower stimulation amplitude. Additionally, the
modulation effect of bipolar configurations on neural traffic was found to vary
significantly depending on the chosen stimulation polarity and the direction of
neural traffic. Further, bipolar configurations demonstrated the ability to
selectively influence firing patterns in different fiber tracts.
