In this study we included seven individuals with epilepsy (mean age 28; Table 1). The participants were implanted with subdural ECoG grids and strips (inter-electrode distance 1 cm center-to-center and 2.3 mm exposed surface; Ad-Tech, Racine, USA) to localize the origin epilepsy. They agreed to participate in this study and signed informed consent according to the Declaration of Helsinki (2013). The study was approved by the Medical Ethical Committee of the University Medical Center Utrecht.
The ECoG grids and strips fully or partially covered the hand region of the sensorimotor cortex. The exact location and number of electrodes differed per participant (Figure 1) and depended on the clinical plan to determine the epileptic seizure onset location. Electrodes were localized with a procedure described in Hermes et al. (2010) (link) and Branco et al. (2018) (link), where a post-implantation Computerized Tomography (CT) scan (Philips Tomoscan SR7000, Best, the Netherlands) is co-registered with a pre-implantation T1-weighted anatomical magnetic resonance imaging (MRI) scan (Philips 3T Ingenia or 7T Achieva, Best, the Netherlands; 1 mm isotropic), and displayed on a Freesurfer pial surface (recon-all, http://surfer.nmr.mgh.harvard.edu/).