Embodiments provide an apparatus and method for detection of aberrant neural-electric activity (ANEA) in the brain causing an epileptic seizure or other neurologic condition. One embodiment provides an apparatus for detection of ANEA comprising an introducer having at least one lumen. The introducer is introduced into brain tissue through an opening in the skull. A reference electrode is positioned at an introducer distal portion. A plurality of electrode members are advanceable within the at least one lumen with each member having an insulated portion and an exposed distal portion. The members have a non-deployed state in the introducer and a deployed state when outwardly advanced out of the introducer. In the deployed state, the members are substantially orthogonal to each other with the exposed distal portions defining a detection volume capable of determining an electric field vector produced by the ANEA and the direction of a foci of the ANEA.