REPLY TO LETTER Reply to comment on: Short pulse width widens the therapeutic window of subthalamic neurostimulation

We have read with interest the comment of McDermott et al.1 on our article “Short pulse width widens the therapeutic window of subthalamic neurostimulation”.2 While the authors provide an elegant and sophisticated argument trying to prove our data wrong, they disre-gard a simple rule of experimentation from the view-point of theoretical biophysics: Deep brain stimulation systems do not have a “charge knob ” to control the output of the neurostimulator. As correctly pointed out by McDermott et al., charge is the product of pulse duration and current. Both variables are controlled independently by the programmer and may be used to improve the selectivity of neurostimulation within a mixed nervous tissue containing target elements of deep brain stimulation (DBS) as well as side-effect elements