Figure 2
SEEG recordings of Patient 2. (A) Three-dimensional MRI reconstruction of the depth electrodes. The electrodes explored the medial and lateral part of the bilateral frontal lobe, mainly on the right. Electrodes G (from MFG to LatOrG) and H (from MFG to LatOrG, almost parallel to G and more inside) captured the seizure onset. (B) The actual placement of electrodes G and H shown on the 3D MRI image. (C) Seizures started with low-voltage fast activities in the latOrG, then propagated to the MFG and trIFG. SEEG power in the time-frequency plane: SOZ with early rapid discharges and high-frequency energy in latOrG, followed by opIFG, MFG, and trIFG. There was no high-frequency response in the temporal lobe. (D) The high-frequency signal on the 3D reconstruction image showing early involvement of the latOrG (0 s), followed by the activation of the lateral part of the frontal lobe (12 s). (E) The patient had no symptoms at the beginning of the seizure; when propagating to the lateral part of the frontal lobe, he presented with the same symptoms as Patient 1. (F) Based on epileptogenicity index analysis, the seizure onset of the patient was confined to latOrG. (G) Illustration showing sites of thermocoagulation in the latOrG. The patient was seizure-free for 12 months, then seizures recurred; he had right orbitofrontal lobe resection after which no seizures occurred.
opIFG: pars opercularis; MFG: middle frontal gyrus; trIFG: pars triangularis.