Since the 1940s electrocorticography (ECoG) devices and, more recently, in the last decade, micro-electrocorticography (µECoG) cortical electrode arrays were used for a wide set of experimental and clinical applications, such as epilepsy localization and brain⁻computer interface (BCI) technologies. Miniaturized implantable µECoG devices have the advantage of providing greater-density neural signal acquisition and stimulation capabilities in a minimally invasive fashion. An increased spatial resolution of the µECoG array will be useful for greater specificity diagnosis and treatment of neuronal diseases and the advancement of basic neuroscience and BCI research. In this review, recent achievements of ECoG and µECoG are discussed. The electrode configurations and varying material choices used to design µECoG arrays are discussed, including advantages and disadvantages of µECoG technology compared to electroencephalography (EEG), ECoG, and intracortical electrode arrays. Electrode materials that are the primary focus include platinum, iridium oxide, poly(3,4-ethylenedioxythiophene) (PEDOT), indium tin oxide (ITO), and graphene. We discuss the biological immune response to µECoG devices compared to other electrode array types, the role of µECoG in clinical pathology, and brain⁻computer interface technology. The information presented in this review will be helpful to understand the current status, organize available knowledge, and guide future clinical and research applications of µECoG technologies.
Keywords: ECoG; brain–computer interface; electrocorticography; electrophysiology; graphene; in vivo imaging; micro-electrocorticography; neural electrode array; neural interfaces; tissue response; µECoG.
Conflict of interest statement
Multiple authors have financial or intellectual property interests in technologies that are described in this review or in the more general area of neuroengineering. J.C.W., D.-W.P., M.S., and Z.M. all have patents on technology described in this review. J.C.W. has an equity interest in NeuroOne Medical (Minnetonka, MN) and NeuroNexus (Ann Arbor, MI), companies that manufacture microfabricated electrode arrays for research and clinical applications.
Mapping the Fine Structure of Cortical Activity With Different micro-ECoG Electrode Array GeometriesX Wang et al. J Neural Eng 14 (5), 056004. PMID 28597847.We observed that µECoG recordings reliably revealed multi-focal cortical somatosensory response patterns, in which response peaks were often less than 1 cm apart and woul …
A Novel µECoG Electrode Interface for Comparison of Local and Common Averaged Referenced SignalsAJ Williams et al. Conf Proc IEEE Eng Med Biol Soc 2018, 5057-5060. PMID 30441477.Micro-electrocorticography (µECoG) is a minimally invasive neural interface that allows for recording from the surface of the brain with high spatial and temporal resolut …
Context-dependent Relationship in High-Resolution micro-ECoG Studies During Finger MovementsCH Kuo et al. J Neurosurg 1-9. PMID 31026831.HG-filtered µECoG signals effectively identify dominant regions associated with thumb and index finger movement. For pinch, the µECoG signal comprises a combination of th …
The Potential for a Speech Brain-Computer Interface Using Chronic ElectrocorticographyQ Rabbani et al. Neurotherapeutics 16 (1), 144-165. PMID 30617653. - ReviewA brain-computer interface (BCI) is a technology that uses neural features to restore or augment the capabilities of its user. A BCI for speech would enable communication …
Direct Electrical Stimulation in Electrocorticographic Brain-Computer Interfaces: Enabling Technologies for Input to CortexDJ Caldwell et al. Front Neurosci 13, 804. PMID 31440127. - ReviewElectrocorticographic brain computer interfaces (ECoG-BCIs) offer tremendous opportunities for restoring function in individuals suffering from neurological damage and fo …
Cited by 2 PubMed Central articles
Decoding Movement From Electrocorticographic Activity: A ReviewK Volkova et al. Front Neuroinform 13, 74. PMID 31849632. - ReviewElectrocorticography (ECoG) holds promise to provide efficient neuroprosthetic solutions for people suffering from neurological disabilities. This recording technique com …
Editorial for the Special Issue on Neural Electrodes: Design and ApplicationsJJ Pancrazio et al. Micromachines (Basel) 10 (7). PMID 31336980.Neural electrodes enable the recording and stimulation of bioelectrical activity from the nervous system [...].