Experimental and theoretical characterization of the voltage distribution generated by deep brain stimulation.
Deep brain stimulation (DBS) is an established therapy for the treatment of Parkinson's disease and shows great promise for numerous other disorders. While the fundamental purpose of DBS is to modulate neural activity with electric fields, little is known about the actual voltage distribution generated in the brain by DBS electrodes and as a result it is difficult to accurately predict which brain areas are directly affected by the stimulation. The goal of this study was to characterize the spatial and temporal characteristics of the voltage distribution generated by DBS electrodes. We experimentally recorded voltages around active DBS electrodes in either a saline bath or implanted in the brain of a non-human primate. Recordings were made during voltage-controlled and current-controlled stimulation. The experimental findings were compared to volume conductor electric field models of DBS parameterized to match the different experiments. Three factors directly affected the experimental and theoretical voltage measurements: 1) DBS electrode impedance, primarily dictated by a voltage drop at the electrode-electrolyte interface and the conductivity of the tissue medium, 2) capacitive modulation of the stimulus waveform, and 3) inhomogeneity and anisotropy of the tissue medium. While the voltage distribution does not directly predict the neural response to DBS, the results of this study do provide foundational building blocks for understanding the electrical parameters of DBS and characterizing its effects on the nervous system.
Miocinovic
Svjetlana
S
Department of Biomedical Engineering, Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
Lempka
Scott F
SF
Russo
Gary S
GS
Maks
Christopher B
CB
Butson
Christopher R
CR
Sakaie
Ken E
KE
Vitek
Jerrold L
JL
McIntyre
Cameron C
CC
D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology / Q000528:radiation effects*; D002462:Cell Membrane / Q000502:physiology; D003198:Computer Simulation; D046690:Deep Brain Stimulation / Q000379:methods*; D025802:Electric Capacitance; D017097:Electric Impedance; D004567:Electrodes, Implanted / Q000592:standards; D004574:Electromagnetic Fields; D004582:Electronics, Medical / Q000295:instrumentation / Q000379:methods; D008253:Macaca mulatta; D008564:Membrane Potentials / Q000502:physiology / Q000528:radiation effects*; D008959:Models, Neurological; D012815:Signal Processing, Computer-Assisted; D013238:Stereotaxic Techniques / Q000295:instrumentation; D020531:Subthalamic Nucleus / Q000033:anatomy & histology / Q000502:physiology / Q000528:radiation effects; D013788:Thalamus / Q000033:anatomy & histology / Q000502:physiology / Q000528:radiation effects