Eight HYPOTHALAMIC HAMARTOMA patients underwent EEG-fMRI. All had gelastic seizures (GS) and seven developed other seizure types. Using a general linear model, spike-related activation/deactivation was analyzed individually by applying a hemodynamic response function before, at, and after spike onset (time-shift model = −8–+4 s). Group analysis was also performed. The sensitivity of EEG-fMRI in identifying the hypothalamic hamartoma interface was compared with SISCOM in HYPOTHALAMIC HAMARTOMA patients having unilateral hypothalamic attachment.