Pre-encoding stress induced changes in perceived stress, blood pressure and cortisol are differentially associated with recollection and familiarity.

Stress before encoding is often linked to impaired memory. Further influences of stress on memory are arousal of the to be learned material and memory retrieval type (free recall vs. recognition). In the current study we tested the influence of stress on memory encoding for neutral and negative arousing pictures in healthy young adults. A total of 80 participants (40 men) were subjected either to the socially evaluated cold pressure test or a control condition before encoding of arousing and neutral pictures. One day later participants underwent a recognition test. Results show different relationships between the obtained stress markers and recognition memory. Higher perceived stress ratings predicted poorer overall accuracy for arousing material. Lower perceived stress ratings and larger blood pressure increase predicted higher recollection values for arousing material. In contrast, a larger cortisol increase predicted lower familiarity values for arousing material. Concluding, activity of the sympathetic nervous system (SNS) and a lower feeling of perceived stress predict better recollection. HPA axis activity predicts lower familiarity. Pre-encoding induced changes in the perceived feeling of stress, activity of the SNS, and activity of the HPA axis show specific and distinct relationships to recognition memory.