Gamma Oscillations and Emotional Memory

Abstract

Increased visual gamma band activity is known to relate to memory and encoding in cognitive tasks and has been shown to be present during arousing compared to neutral stimulus processing. Here, we set out to investigate whether gamma activity is stronger for later remembered compared to later forgotten emotional pictures. Thirty-two healthy participants underwent a passive viewing task in which they viewed 208 (104 arousing (52 pleasant and 52 unpleasant) and 104 neutral) pictures from the International Affective Picture System (IAPS) database while we simultaneously recorded their electroencephalogram (EEG). Immediately after, they performed a recognition task including the 208 target pictures they saw before and 104 new pictures (52 arousing (26 pleasant and 26 unpleasant) and 52 neutral) as lures. We found that arousing pictures (unpleasant ones in particular) were better remembered compared to neutral pictures. Importantly, gamma activity was enhanced for remembered compared to forgotten pictures and this effect was stronger for arousing pictures. We conclude that previous findings regarding enhanced gamma as a signature of subsequent memory generalizes to emotional memory. Our findings therefore shed new light on the role of visual gamma band activity in arousal and memory formation.