  Models of the cortico-basal ganglia network and volume conductor models of
the brain can provide insight into the mechanisms of action of deep brain
stimulation (DBS). In this study, the coupling of a network model, under
parkinsonian conditions, to the extracellular field distribution obtained from
a three dimensional finite element model of a rodent's brain during DBS is
presented. This coupled model is used to investigate the influence of
uncertainty in the electrical properties of brain tissue and encapsulation
tissue, formed around the electrode after implantation, on the suppression of
oscillatory neural activity during DBS. The resulting uncertainty in this
effect of DBS on the network activity is quantified using a computationally
efficient and non-intrusive stochastic approach based on the generalized
Polynomial Chaos. The results suggest that variations in the electrical
properties of brain tissue may have a substantial influence on the level of
suppression of oscillatory activity during DBS. Applying a global sensitivity
analysis on the suppression of the simulated oscillatory activity showed that
the influence of uncertainty in the electrical properties of the encapsulation
tissue had only a minor influence, in agreement with previous experimental and
computational studies investigating the mechanisms of current-controlled DBS in
the literature.
