Brain stimulus pattern optimization using scalp and cortical electrode arrays

Abstract

Electrical stimulation of human brain to modulate on-going brain activity has become a topic of great interest in both clinical and research communities. The standard approach to deliver electrical currents to the brain uses two electrodes: one stimulation electrode and one return electrode with interchangeable roles over time. In order to more precisely direct the injected current to a particular brain region of interest (ROI), there has been increasing interest in the use of arrays of many small electrodes, known as "dense electrode array". Two brain stimulation modalities that often make use of dense arrays are transcranial direct current stimulation (tDCS) and electrocorticography (ECoG) stimulation. Dense array tDCS makes use of scalp electrode arrays to deliver electical currents noninvasively while ECoG electrode grids are placed directly on the cortical surface for improved spatial specificity. Although the overall clinical objective may differ in dense array tDCS and ECoG stimulation, they both can benefit from systematic optimization methods to determine the optimal electrode stimulus patterns.