Fig. 3.

Derivation of the optimal pathway activation profile. A: illustrative example of derivation using two DBS protocols per patient in a 2-D pathway activation space. Note that in our problem the space has 14 dimensions. Values of P_i denote the corresponding UPDRS-III scores for $i$-th patient, “+” and “−” subscripts refer to the more and less effective stimulation protocols, respectively. Divergent datapoints, i.e. those with a large difference in percent activation (a fraction of axons in the pathway that elicited an action potential in response to the DBS pulse) and small difference in motor improvement (P₄ here), were not considered for the derivation of the optimal profile. B: the intrapatient interprotocol UPDRS-III improvement in the training cohort with and without the normalization by the mean of percent activation differences. The normalized metric was used to select datapoints for the derivation of the optimal profile.