Supracortical Microstimulation: Advances in Microelectrode Design and In Vivo Validation

Electrical stimulation of the brain is being developed as a treatment for an increasing number of neurological disorders. Technologies for delivering electrical stimulation are advancing rapidly and vary in specificity, coverage, and invasiveness. Supracortical microstimulation (SCMS), characterized by microelectrode contacts placed on the epidural or subdural cortical surface, achieves a balance between the advantages and limitations of other electrical stimulation technologies by delivering spatially precise activation without disrupting the integrity of the cortex. However, in vivo experiments involving SCMS have not been comprehensively summarized. Here, we review the field of SCMS, focusing on recent advances, to guide the development of clinically translatable supracortical microelectrodes. We also highlight the gaps in our understanding of the biophysical effects of this technology. Future work investigating the unique electrochemical properties of supracortical microelectrodes and validating SCMS in nonhuman primate preclinical studies can enable rapid clinical translation of innovative treatments for humans with neurological disorders.