Microelectrode Recording in Functional Neurosurgery

Microelectrode recording (MER) involves the use of high-impedance electrodes to record neuronal activity during stereotactic targeting before lesion creation or implantation of deep brain stimulator electrodes. Originally developed in the era when only ventriculography was available, MER is used today to confirm location of subcortical structures seen on MRI and correct for stereotactic targeting error and brain shift. Each of the common targets used for neuromodulation for movement disorders has a characteristic signature of activity on MER that can allow for detailed mapping with unparalleled precision. MER also provides information about how cellular activity changes in disease states and with treatment and can be a valuable research tool. However, improvements in imaging technology and stereotactic technique have mitigated some of the benefits, and MER may be associated with increased complexity and risk of complications without necessarily improving postoperative outcome. Although excellent outcomes have been reported with and without MER, a direct comparison has never been performed. With the advent of new technologies for intraoperative targeting, the role of MER in the stereotactic implantation of deep brain stimulation electrodes is likely to continue to evolve.