Diurnal emotional reactivity: Ultradian changes at neural and behavioral levels in men

Event-related potentials were recorded while participants watched different sets of unpleasant and neutral pictures every 15 min for 3 h. Emotional feelings induced by unpleasant pictures were also assessed with self-rating scales at the end of each picture set.

Whereas brain processing of neutral pictures remained stable over time, a late positive component elicited by unpleasant pictures presented ultradian oscillations varying between 65 and 110 min in 77% of the participants, mainly in the right centro-posterior area. Ultradian rhythms were also observed for values self-rating the intensity of unpleasant feelings. Correlative analyses performed between brain and behavioral ultradian oscillations indicated that these rhythms follow a temporal opposite pattern.