ObjectiveThe time relationship between seizure semiology and epileptic discharges during focal epileptic seizures is a crucial predictor for the localization of epileptogenic zone. Low voltage fast activities (LVFA), especially gamma band oscillations, are confirmed to play a central role in ictogenesis and semiology production. In the present study, we focus on the “electro-clinical correlation” between LVFA in agranulo-dysgranular insulo-cingulate cortices and the sign of “Chapeau de gendarme (CDG)” via detailed analysis of ictal video-stereoencephalography (video-SEEG) of focal epileptic seizures. MethodsWe retrospectively analyzed the ictal video-SEEG of the 7 cases in which CDG signs were presented in habitual seizures and intracerebral electrodes were co-implanted in agranulo-dysgranular insular and cingulate cortices. We calculate the latency of LVFA in each of cortical regions of interest, agranulo-dygranular insular cortex, agranulo-dysgranular cingulate cortex, and the latency of CDG signs via visual and spectral analysis of the ictal SEEG. Moreover, Pearson correlation analysis and linear regression were used to test the time relationship between gamma band oscillations in agranulo-dysgranular insulo-cingulate cortices and generation of CDG signs. ResultsThe co-activation of LVFA occurred in agranulo-dysgranular insulo-cingulate cortices always preceded the appearance of CDG sign in all of the 69 seizures. The LVFA were confirmed as gamma band oscillations via spectral analysis of SEEG. A linear relationship between the latencies of CDG signs and the latencies of co-activation of agranulo-dysgranular insulo-cingulate cortices in gamma band was furth confirmed by Pearson correlation analysis and linear regression. ConclusionsThere is a causal relationship between the involvement of agranulo-dysgranular insulo-cingulate cortices and the generation of CDG sign, and thus the CDG sign could be view as semiological marker of activation of emotional insulo-cingulate cortex in focal epilepsy.