The advantages of mapping slow brain potentials using DC‐coupled graphene micro‐transistors: Clinical and translational applications

• Published in: Clinical and translational medicine 2022-07, Vol.12 (7), p.e968-n/a
• Main Authors: Wykes, Rob. C, Masvidal‐Codina, Eduard, Guimerà‐Brunet, Anton, Garrido, Jose. A
• Format: Article
• Language: English
• Subjects: Arrays; Bandwidths; Biomarkers; Brain research; Clinical medicine; Convulsions & seizures; Electric fields; Epilepsy; Graphene; Localization; Migraine; Neurological disorders; Neurosciences; Scholarships & fellowships; Signal transduction; Stroke; Transistors; Traumatic brain injury
• ISSN: 2001-1326; 2001-1326
• DOI: 10.1002/ctm2.968

[...]UPS include clinically relevant events including preseizure DC shifts (1–3 mV), and large (tens of millivolt) spreading depolarisations (SD) which are thought to play an important role in brain injury and contribute to the pathophysiology associated with migraine with aura, stroke and epilepsy.4 Therefore, the ability to record and map a wide range of brain signals, from UPS to single units, using the same electrophysiological array will greatly advance our understanding of brain diseases and aid the clinical management of patients with diverse neurological disorders and injuries. [...]development of improved electrophysiological devices capable of detecting and mapping wide bandwidth signals with high-fidelity and spatial resolution is warranted.5,6 WHAT ARE GRAPHENE MICRO-TRANSISTORS – HOW DO THEY WORK? A similar layer-specific localisation of ‘active’ DC shifts preceding seizures could be identified.11 Ictal DC shifts can be differentiated into active shifts that precede the seizure and passive shifts that follow the intense neuronal firing at seizure onset.12 Active DC shifts are of particular interest for both clinical and basic research, as they provide an electrophysiological biomarker for seizure onset zone localisation,13 and they can further provide a quantifiable parameter to investigate the mechanisms underlying seizure initiation.14 Chronic implantation of gSGFET probes into the somatosensory cortex of a rat model of absence epilepsy revealed that spontaneous spike-and-wave discharges (5–9 Hz) were phase-coupled to an infraslow oscillation (ISO < 0.1 Hz) most prominent in the superficial layers, suggesting that these ISOs open susceptibility windows for seizure initiation.11 SDs can be associated with seizures and vice versa. Of note, the few studies that have investigated ictal DC shifts report that these signals co-localise with seizure onset zones and are more spatially restricted than conventional EEG recordings.3 Therefore, routine inclusion of accurate DC-coupled recordings to surgical monitoring could result in less extensive, yet more effective surgical resections.16 Additionally, due to the ability to fabricate high channel density probes with small recording sites, the increased spatial resolution and coverage should allow detection of micro-seizures, which may be missed using large interspaced electrodes. Beyond presurgical clinical applications, this technology also offers to provide valuable insight into the involvement of UP