An information flow technique for category related evoked potentials

A general mathematical technique is developed for information flow among various subsystems of a system when two or more classes of stimuli are presented to the system. The technique is validated by various simulation studies and then applied to a brain system. The usefulness of the technique is demonstrated for visual event related potentials (ERPs) obtained from human subjects suffering from phobias. The stimuli are briefly flashed words and phrases. The world classes are pleasant, unpleasant, conscious, and unconscious. It demonstrated that the information flow is suppressed under supraliminal presentation of the unconscious class, but is strong under subliminal presentation. The technique has the potential of being an objective indicator of conflictual relationships in these patients. The principle of the technique can be applied to any system in which interactions among subsystems are to be analyzed.