State of belief, subjective certainty and bliss as a product of cortical dysfunction.

Introduction: Ecstatic seizures are focal epileptic seizures which are fascinating from a phenotypical point of view as they include intense positive affect, feelings of heightened self-awareness and enhanced well-being. They have been previously suggested to arise in the anterior insular cortex, although strong arguments are still lacking.

Methods: We describe the cases of two new patients with ecstatic seizures. Their evaluation included a careful history, encouraging the patient to provide significant details about their ictal symptoms in order to better understand the origin of the sense of bliss and support the hypothesis of an insular involvement according to the current stage of knowledge. Ictal electroencephalographic and blood flow studies complemented these data in one patient.

Results: The comprehensive description of the ictal ecstatic symptoms by the two patients has brought out an unfamiliar sense of absence of doubt which was at the basis of a feeling of meaningfulness and certainty. The ictal single-photon emission computed tomography (SPECT) showed an increased blood flow maximal at the junction of the right dorsal mid-insula and the central operculum.

Conclusions: The unveiling of an ictal sense of certainty during ecstatic seizures might imply, in the light of current knowledge, a defect in the system processing prediction errors within the framework of generalized predictive coding mechanisms of the brain. Accumulative evidence has recently highlighted a crucial role of the anterior insular cortex in this system, particularly in the detection of mismatch/conflict between prediction state and outcome. Abnormal activity related to epileptic seizure in a structure prevents its normal activity: in the anterior insula, it could prevent the detection of prediction errors, and thereby prevent the feeling of ambiguity (and the associated negative emotional component), leading to a blissful state which could be close to the deeper states of meditation.