AUTHOR=Weiss Shennan A. , Bikson Marom TITLE=Open questions on the mechanisms of neuromodulation with applied and endogenous electric fields JOURNAL=Frontiers in Human Neuroscience VOLUME=8 YEAR=2014 URL=https://www.frontiersin.org/journals/human-neuroscience/articles/10.3389/fnhum.2014.00227 DOI=10.3389/fnhum.2014.00227 ISSN=1662-5161