Separate lines of research have demonstrated that rises in cortisol can benefit memory consolidation, as can the occurrence of sleep soon after encoding. For the first time, we demonstrate that pre-learning cortisol interacts with sleep to benefit memory consolidation, particularly for negative arousing items. Resting cortisol levels during encoding were positively correlated with subsequent memory, but only following a period of sleep. There was no such relation following a period of wakefulness. Using eye tracking, we further reveal that for negative stimuli, this facilitative effect may arise because cortisol strengthens the relationship between looking time at encoding and subsequent memory. We suggest that elevated cortisol may "tag" attended information as important to remember at the time of encoding, thus enabling sleep-based processes to optimally consolidate salient information in a selective manner. Neuroimaging data suggest that this optimized consolidation leads to a refinement of the neural processes recruited for successful retrieval of negative stimuli, with the retrieval of items attended in the presence of elevated cortisol and consolidated over a night of sleep associated with activity in the amygdala and vmPFC.

Although it has been suggested that many effects of emotion on memory are attributable to attention, in the present study we addressed the hypothesis that such effects may relate to a number of different factors during encoding or postencoding. One way to look at the effects of emotion on memory is by examining the emotion-induced memory trade-off, whereby enhanced memory for emotional items often comes at the cost of memory for surrounding background information. We present evidence that this trade-off cannot be explained solely by overt attention (measured via eyetracking) directed to the emotional items during encoding. Participants did not devote more overt attention to emotional than to neutral items when those items were selectively remembered (at the expense of their backgrounds). Only when participants were asked to answer true/false questions about the items and the backgrounds-a manipulation designed to affect both overt attention and poststimulus elaboration-was there a reduction in selective emotional item memory due to an increase in background memory. These results indicate that the allocation of overt visual attention during encoding is not sufficient to predict the occurrence of selective item memory for emotional items.Keywords Memory . Attention . Emotion . Eye-tracking Emotional information is usually remembered better than neutral information (see Reisberg & Heuer, 2004), but the mechanisms behind this enhancement are still unclear. The increased memory for emotional information may be due to a number of different factors. For example, emotional stimuli may be more likely to attract and sustain attention (Anderson, 2005;Calvo & Lang, 2004), and emotional stimuli may also be more likely to evoke cognitive processing, elaboration, and rehearsal (Hamann, 2001;Libkuman, Stabler, & Otani, 2004).Many studies have provided evidence for the emotional prioritization of attention. People are quicker to notice emotional information within a visual array (Öhman, Flykt, & Esteves, 2001), are more likely to notice emotional words that are presented very quickly (Anderson & Phelps, 2001), and are more susceptible to interference from emotional than from neutral distractors (McKenna & Sharma, 1995;Schimmack & Derryberry, 2005). These behavioral effects of emotion on attention have also been shown in studies that have used eye gaze as a measure of overt visual attention: People tend to fixate first and to look longer at emotional pictures that are presented side by side with neutral pictures (Calvo & Lang, 2004;Nummenmaa, Hyönä, & Calvo, 2006). In addition, people fixate longer on irrelevant emotional distractor pictures than on neutral ones (Bannerman, Milders, & Sahraie, 2009;Calvo & Lang, 2004;Koster, Crombez, Verschuere, & De Houwer, 2004;Nummenmaa et al., 2006;Sarter, Givens, & Bruno, 2001). Thus, it seems that attention is initially focused on emotional information and that it is harder for participants to disengage attention from that information.The attention mediation hypothesis of the emoti...

This study examined how valence and arousal affect the processes linked to subsequent memory for emotional information. While undergoing an fMRI scan, participants viewed neutral pictures and emotional pictures varying by valence and arousal. After the scan, participants performed a recognition test. Subsequent memory for negative or high arousal information was associated with occipital and temporal activity, while memory for positive or low arousal information was associated with frontal activity. Regression analyses confirmed that for negative or high arousal items, temporal lobe activity was the strongest predictor of later memory whereas for positive or low arousal items, frontal activity corresponded most strongly with later memory. These results suggest that the types of encoding processes relating to memory (e.g., sensory vs. elaborative processing) can differ based on the affective qualities of emotional information.Research has consistently shown that emotional information is remembered better than nonemotional information. The enhancement in memory for emotional information exists for positive as well as for negative stimuli, and for nonarousing as well as arousing stimuli. However, the processes supporting the memory enhancement are likely to differ depending on the valence (how positive/pleasant or negative/unpleasant) and arousal (how exciting/ agitating or calming/subduing) of the emotion elicited by the stimuli (see Kensinger, 2004;LaBar, 2007 for discussion).The vast majority of studies that have examined the neural processes that support memory enhancement for emotional information have focused on the influence of the arousal dimension in relation to the "memory modulation hypothesis" of emotional memory (Cahill, 2000;Canli, Zhao, Brewer, Gabrieli, & Cahill, 2000;Canli, Desmond, Zhao, & Gabrieli, 2002;McGaugh, 2004). This hypothesis proposes that interactions between the amygdala and the hippocampus guide successful encoding and consolidation of emotionally arousing information. In support of this hypothesis, a number of studies have revealed that activity in the amygdala and the hippocampus corresponds with the likelihood that emotionally arousing information is later remembered (reviewed by Phelps, 2004;LaBar & Cabeza, 2006). These interactions between the amygdala and the hippocampus appear to modulate memory for both positive and negative information, so long as it is arousing (e.g., Dolcos, LaBar, & Cabeza, 2004a;Kensinger & Schacter, 2006;Sharot, Delgado, & Phelps, 2004). By contrast, interactions between these regions seem not to play a critical role in influencing memory for emotional experiences that are of insufficient arousal to trigger autonomic responses (e.g., Kensinger & Corkin, 2004;Anderson, Yamaguchi, Grabski, & Lacka, 2006). Address correspondence to: Katherine R. Mickley, Boston College, McGuinn Hall, 140 Commonwealth Ave., Chestnut Hill, MA 02467, Phone: 617-552-3108, Fax: 617-552-0523, mickley@bc.edu. NIH Public Access Author ManuscriptPsychophysiology. Author...