Progress in the Field of Micro-Electrocorticography

Abstract

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.

Decoding Movement From Electrocorticographic Activity: A Review

“…Previous studies have reported a range of promising results regarding the possibility of building BCIs that employ ECoG recordings to enable motor functions. With the rapid developments in ECoG technologies (Shokoueinejad et al, 2019), surgical implantation procedures and mathematical algorithms for neural decoding, it is reasonable to expect that a variety of practical, fully-implantable (Vansteensel et al, 2016) ECoG-based neural prostheses will emerge for enabling motor and sensory functions to neurologically impaired patients.…”

Electrochemical Evaluation of a Multi-Site Clinical Depth Recording Electrode for Monitoring Cerebral Tissue Oxygen

“…As impedance is inversely proportional to recording site size but should be low as to decrease noise in recording [25,38]. In microelectrodes, where high impedance due to size can become a limiting factor, surface area is typically increased through roughening or functionalization [39,40].…”

Flexible Electrocorticography Electrode Array for Epileptiform Electrical Activity Recording under Glutamate and GABA Modulation on the Primary Somatosensory Cortex of Rats

“…Commercial ECoG electrodes (Ad-Tech Medical Instrument Corporation, USA), with millimeter electrode diameters (typically 2–3 mm) and pitches, are available to monitor cortical activity and locate the seizure focus during surgical diagnosis [ 13 , 14 ]. In the last decade, in order to obtain higher spatial resolution of cortical signals, there has been an evolution of ECoG into micro-electrocorticography (µECoG) by scaling down the dimensions of ECoG electrodes to micron size [ 15 ].…”