Emotion strengthens high-priority memory traces but weakens low-priority memory traces

Elements of episodic memory: insights from artificial agents

Many recent artificial intelligence (AI) systems take inspiration from biological episodic memory. Here, we ask how these 'episodic-inspired' AI systems might inform our understanding of biological episodic memory. We discuss work showing that these systems implement some key features of episodic memory while differing in important respects and appear to enjoy behavioural advantages in the domains of strategic decision-making, fast learning, navigation, exploration and acting over temporal distance. We propose that these systems could be used to evaluate competing theories of episodic memory's operations and function. However, further work is needed to validate them as models of episodic memory and isolate the contributions of their memory systems to their behaviour. More immediately, we propose that these systems have a role to play in directing episodic memory research by highlighting novel or neglected hypotheses as pursuit-worthy. In this vein, we propose that the evidence reviewed here highlights two pursuit-worthy hypotheses about episodic memory's function: that it plays a role in planning that is independent of future-oriented simulation, and that it is adaptive in virtue of its contributions to fast learning in novel, sparse-reward environments. This article is part of the theme issue 'Elements of episodic memory: lessons from 40 years of research'.

Temporal recall in the shadow of emotion: separate emotional contexts during encoding enhance the temporal source memory retrieval

Episodic memory, with its emphasis on temporal-spatial contexts, has been a longstanding focus in memory research. While previous studies have investigated the role of emotion in temporal source memory using emotionally charged stimuli, such as emotional words or images, the influence of a separated emotional context remains less explored. This study sought to understand the impact of separate emotional contexts on temporal source memory. Participants were shown Chinese characters alongside separate emotional contexts (i.e. a neutral or negative picture) and then engaged in either a retrieval practice or a control condition. Finally, they were tested for recognition, temporal source memory, and emotional source memory for all the learned characters. Results revealed that a negative emotional context, unlike a neutral setting, enhanced the accuracy of temporal memory for adjacent neutral characters. However, this negative context reduced the accuracy of recalling the associated emotion. Importantly, the boost in temporal memory due to the emotional context remained even when participants were unsure or mistaken about the associated emotion. This study demonstrates the complex interplay between emotion and temporal memory, underscoring the enhancement effect of separated emotional contexts on temporal recall, irrespective of explicit emotional memory retrieval.

The retrograde effects of negative emotion on memory for conceptually related events: a registered report

Emotional events are often remembered better than neutral ones; however, emotion can also spill over and affect our memory for neutral experiences that precede an emotional event. Theories suggest that emotion can retroactively enhance memory for preceding neutral events that are considered high-priority while impairing memory for events deemed low-priority. However, the impact of conceptual relationships (i.e., semantic connections) between preceding neutral information and emotional events on memory for the preceding information has received little attention. This study investigated the influence of conceptual relatedness on the retroactive effects of emotion on memory. Participants sequentially encoded pairs of images that were high or low in conceptual relatedness, each comprising a neutral object followed by either a negative or neutral image. Participants returned the next day for a recognition memory assessment. The results indicated an interactive effect of emotion and conceptual relatedness on memory: In a "discovery" sample, memory was poorer for images preceding conceptually unrelated negative (vs. neutral) images, while the opposite pattern was seen for conceptually related images. In a "replication" sample, these effects were partially replicated, with the former impairment effect statistically observed but not the latter augmentation effect. Hence, conceptual relatedness affects how negative emotion influences memory.

Memory enhancement for emotional words is attributed to both valence and arousal

We do not memorize items in our surroundings with equal priority. Previous literature has widely shown that emotional stimuli are better remembered than neutral stimuli. However, given emotional stimuli and neutral stimuli often differ in both valence and arousal dimensions, it remains unclear whether the enhancement effects can be attributed to valence, or just to arousal. Importantly, most prior studies relied on a relatively small number of stimuli and non-emotional factors such as word length, imageability and other confounds were hard to control. To address these challenges, we analyzed multiple large databases of recognition memory and free recall tasks from previous research by items with many lexical and semantic covariates included, examining the effects of valence or arousal when controlling for each other. Our results showed a U-shaped relationship between valence and memory performance for both recognition and free recall, and a linear relationship between arousal and memory performance for both tasks. These findings showed that the memory enhancement effects can be attributed to both valence and arousal. We demonstrated these effects with generalizability across many stimuli and controlled for non-emotional factors. Together, these findings disentangle the contribution of valence and arousal in emotional memory enhancement effects and provide insights for current major theories of emotional memory.

Emotional salience modulates the forward-flow of memory

As we navigate our day-to-day lives, we regularly adapt our behaviour according to what we predict may happen next in a given context. When an unexpected event occurs, our predictions about the world are disrupted and must be updated. Unexpected, isolated events, particularly with high emotionality, are also better recalled. In the present work, we investigated how oddballs affect recall dynamics. Seventy young, healthy participants encoded word lists containing either emotional or perceptual oddballs at varying stimulus onset asynchronies followed by free recall. It is well established that after recalling an item, we have a higher probability of recalling items encoded nearby, particularly those that were encoded after the item was recalled, a phenomenon known as forward contiguity of recall. We tested how novelty (oddballs versus control words) modulated forward contiguity as a function of salience type (emotional versus perceptual). The present results provide empirical evidence of forward contiguity modulation selectively by emotional salience and suggest that recall patterns after presenting emotional and perceptual oddballs are mediated by different mechanisms.

Negative emotions enhance memory-guided attention in a visual search task by increasing frontoparietal, insular, and parahippocampal cortical activity

Previous literature demonstrated that long-term memory representations guide spatial attention during visual search in real-world pictures. However, it is currently unknown whether memory-guided visual search is affected by the emotional content of the picture. During functional magnetic resonance imaging (fMRI), participants were asked to encode the position of high-contrast targets embedded in emotional (negative or positive) or neutral pictures. At retrieval, they performed a visual search for targets presented at the same location as during encoding, but at a much lower contrast. Behaviorally, participants detected more accurately targets presented in negative pictures compared to those in positive or neutral pictures. They were also faster in detecting targets presented at encoding in emotional (negative or positive) pictures than in neutral pictures, or targets not presented during encoding (i.e., memory-guided attention effect). At the neural level, we found increased activation in a large circuit of regions involving the dorsal and ventral frontoparietal cortex, insular and parahippocampal cortex, selectively during the detection of targets presented in negative pictures during encoding. We propose that these regions might form an integrated neural circuit recruited to select and process previously encoded target locations (i.e., memory-guided attention sustained by the frontoparietal cortex) embedded in emotional contexts (i.e., emotional contexts recollection supported by the parahippocampal cortex and emotional monitoring supported by the insular cortex). Ultimately, these findings reveal that negative emotions can enhance memory-guided visual search performance by increasing neural activity in a large-scale brain circuit, contributing to disentangle the complex relationship between emotion, attention, and memory.

How emotional contexts modulate item memory in individuals with high and low negative affect and worry

Emotional stimuli are usually remembered with high confidence. Yet, it remains unknown whether-in addition to memory for the emotional stimulus itself-memory for a neutral stimulus encountered just after an emotional one can be enhanced. Further, little is known about the interplay between emotion elicited by a stimulus and emotion relating to affective dispositions. To address these questions, we examined (1) how emotional valence and arousal of a context image preceding a neutral item image affect memory of the item, and (2) how such memory modulation is affected by two hallmark features of emotional disorders: trait negative affect and tendency to worry. In two experiments, participants encoded a series of trials in which an emotional (negative, neutral, or positive) context image was followed by a neutral item image. In experiment 1 (n = 42), items presented seconds after negative context images were remembered better and with greater confidence compared to those presented after neutral and positive ones. Arousal ratings of negative context images were higher compared to neutral and positive ones and the likelihood of correctly recognizing an item image was related to higher arousal of the context image. In experiment 2 (n = 59), better item memory was related to lower trait negative affect. Participants with lower trait negative affect or tendency to worry displayed higher confidence compared to those with high negative affect or tendency to worry. Our findings describe an emotional "carry-over" effect elicited by a context image that enhances subsequent item memory on a trial-by-trial basis, however, not in individuals with high trait negative affect who seem to have a general memory disadvantage.

Emotion and prospective memory: effects of emotional targets and contexts

Event-based prospective memory (PM) refers to the ability to remember to perform a delayed and intended action when an event is encountered in the future. Whether emotional targets promote PM performance is still controversial. The reason for these inconsistent findings may be related to the degree of target arousal and context valence (the valence of ongoing task trials) in the previous studies. This study aimed to investigate the separate and combined effects of target valence, arousal, and context valence on event-based PM through two experiments. The results showed that the participants were faster and more accurate in responding to positive, negative, and high-arousal PM targets. Interestingly, an interaction effect of target valence, arousal, and context valence was observed, implying that their individual effects on PM performance cannot be understood in isolation. These findings demonstrate that positive, negative, and high-arousal PM targets can enhance PM performance. In addition, the results provided support for both the emotion enhancement account and the emotion-saliency account, depending upon whether the valence of the PM target matched or did not match the valence of the context. Moreover, context valence can modulate the effect of arousal on PM across different target valences.

Pupil size tracks cue-trace interactions during episodic memory retrieval

Our ability to remember past events requires not only storing enduring engrams or memory traces of these events, but also successfully reactivating these latent traces in response to appropriate cues at the time of retrieval-a process that has been termed ecphory. However, relatively little is known about the processes that facilitate the dynamic interactions between retrieval cues and stored memory traces that are critical for successful recognition and recollection. Recently, an intriguing link between pupil dilation and recognition memory has been identified, with studied items eliciting greater pupil dilation than unstudied items during retrieval. However, the processes contributing to this "pupillary old/new effect" remain unresolved, with current explanations suggesting that it reflects the strength of the underlying memory trace. Here, we explore the novel hypothesis that the pupillary old/new effect does not index memory strength alone, but rather reflects the facilitation of cue-trace interactions during episodic memory retrieval that may be supported by activity within the pupil-linked locus coeruleus-noradrenergic (LC-NA) arousal system. First, we show that the magnitude of pupil dilation is influenced by the degree of overlap between cue and trace information. Second, we find that the magnitude of pupil dilation reflects the amount of study contextual information reinstated during retrieval. These findings provide a novel framework for understanding the pupillary old/new effect, and identify a potential role for the LC-NA system in recognition memory retrieval.

Negative emotion amplifies retrieval practice effect for both task-relevant and task-irrelevant information

Selective retrieval of task-relevant information often facilitates memory retention of that information. However, it is still unclear if selective retrieval of task-relevant information can alter memory for task-irrelevant information, and the role of emotional arousal in it. In two experiments, we used emotional and neutral faces as stimuli, and participants were asked to memorise the name (who is this person?) and location (where does he/she come from?) associated with each face in initial study. Then, half of the studied faces were presented as cues, and participants were asked to retrieve the corresponding names (Experiment 1) or locations (Experiment 2). Finally, all the faces were presented and participants were asked to retrieve both the corresponding names and locations. The results of the final test showed that retrieval practice not only enhanced memory of task-relevant information but also enhanced memory of task-irrelevant information. More importantly, negative emotion amplified the retrieval practice effect overall, with a larger retrieval-induced benefit for the negative than neutral condition. These findings demonstrated an emotional arousal amplification effect on retrieval-induced enhancement effects, suggesting that the advantage of the retrieved memory representations can be amplified by emotional arousal even without explicit goals in a task setting.

Continuously changing memories: a framework for proactive and non-linear consolidation

The traditional view of long-term memory is that memory traces mature in a predetermined 'linear' process: their neural substrate shifts from rapidly plastic medial temporal regions towards stable neocortical networks. We propose that memories remain malleable, not by repeated reinstantiations of this linear process but instead via dynamic routes of proactive and non-linear consolidation: memories change, their trajectory is flexible and reversible, and their physical basis develops continuously according to anticipated demands. Studies demonstrating memory updating, increasing hippocampal dependence to support adaptive use, and rapid neocortical plasticity provide evidence for continued non-linear consolidation. Although anticipated demand can affect all stages of memory formation, the extent to which it shapes the physical memory trace repeatedly and proactively will require further dedicated research.

The power of negative and positive episodic memories

The power of episodic memories is that they bring a past moment into the present, providing opportunities for us to recall details of the experiences, reframe or update the memory, and use the retrieved information to guide our decisions. In these regards, negative and positive memories can be especially powerful: Life’s highs and lows are disproportionately represented in memory, and when they are retrieved, they often impact our current mood and thoughts and influence various forms of behavior. Research rooted in neuroscience and cognitive psychology has historically focused on memory for negative emotional content. Yet the study of autobiographical memories has highlighted the importance of positive emotional memories, and more recently, cognitive neuroscience methods have begun to clarify why positive memories may show powerful relations to mental wellbeing. Here, we review the models that have been proposed to explain why emotional memories are long-lasting (durable) and likely to be retrieved (accessible), describing how in overlapping—but distinctly separable—ways, positive and negative memories can be easier to retrieve, and more likely to influence behavior. We end by identifying potential implications of this literature for broader topics related to mental wellbeing, education, and workplace environments.

Resting-state functional connectivity does not predict individual differences in the effects of emotion on memory

Emotion-laden events and objects are typically better remembered than neutral ones. This is usually explained by stronger functional coupling in the brain evoked by emotional content. However, most research on this issue has focused on functional connectivity evoked during or after learning. The effect of an individual’s functional connectivity at rest is unknown. Our pre-registered study addresses this issue by analysing a large database, the Cambridge Centre for Ageing and Neuroscience, which includes resting-state data and emotional memory scores from 303 participants aged 18–87 years. We applied regularised regression to select the relevant connections and replicated previous findings that whole-brain resting-state functional connectivity can predict age and intelligence in younger adults. However, whole-brain functional connectivity predicted neither an emotional enhancement effect (i.e., the degree to which emotionally positive or negative events are remembered better than neutral events) nor a positivity bias effect (i.e., the degree to which emotionally positive events are remembered better than negative events), failing to support our pre-registered hypotheses. These results imply a small or no association between individual differences in functional connectivity at rest and emotional memory, and support recent notions that resting-state functional connectivity is not always useful in predicting individual differences in behavioural measures.

Grounding the Attentional Boost Effect in Events and the Efficient Brain

Attention and memory for everyday experiences vary over time, wherein some moments are better attended and subsequently better remembered than others. These effects have been demonstrated in naturalistic viewing tasks with complex and relatively uncontrolled stimuli, as well as in more controlled laboratory tasks with simpler stimuli. For example, in the attentional boost effect (ABE), participants perform two tasks at once: memorizing a series of briefly presented stimuli (e.g., pictures of outdoor scenes) for a later memory test, and responding to other concurrently presented cues that meet pre-defined criteria (e.g., participants press a button for a blue target square and do nothing for a red distractor square). However, rather than increasing dual-task interference, attending to a target cue boosts, rather than impairs, subsequent memory for concurrently presented information. In this review we describe current data on the extent and limitations of the attentional boost effect and whether it may be related to activity in the locus coeruleus neuromodulatory system. We suggest that insight into the mechanisms that produce the attentional boost effect may be found in recent advances in the locus coeruleus literature and from understanding of how the neurocognitive system handles stability and change in everyday events. We consequently propose updates to an early account of the attentional boost effect, the dual-task interaction model, to better ground it in what is currently known about event cognition and the role that the LC plays in regulating brain states.

Emotional Context Shapes the Serial Position Curve

Emotional contexts affect memory processes. However, the impact of contextual priming as a function of the emotional valence on the recall of neutral information is not fully understood. The aim of the present study was to evaluate how a conditioning of emotional context during encoding may influence the subsequent memory of otherwise neutral materials in a well-established phenomenon as the serial position effect. Participants performed a free recall task for neutral words in three conditions: (i) word list alone; (ii) word list coupled with positive or neutral images; and (iii) word list coupled with negative or neutral images. Images were presented before each word stimulus. In three different experiments, the emotional context during the word list presentation was manipulated separately for primacy and recency clusters, and for the middle words ('middlecy'). Emotional context affects free recall of neutral stimuli, changing the serial position curve effect across conditions. Namely, emotional images presented in the primacy and recency clusters worsen accuracy, whereas their occurrence in the 'middlecy' cluster reduces the oblivion. The present findings show that the typical pattern related to the serial position curve for neutral information can be shaped by the conditioning of emotional context. Findings have implications in medical-legal contexts in the case of the recollection of events with high emotional content.

Asymmetrical cross-modal influence on neural encoding of auditory and visual features in natural scenes

Natural scenes contain multi-modal information, which is integrated to form a coherent perception. Previous studies have demonstrated that cross-modal information can modulate neural encoding of low-level sensory features. These studies, however, mostly focus on the processing of single sensory events or rhythmic sensory sequences. Here, we investigate how the neural encoding of basic auditory and visual features is modulated by cross-modal information when the participants watch movie clips primarily composed of non-rhythmic events. We presented audiovisual congruent and audiovisual incongruent movie clips, and since attention can modulate cross-modal interactions, we separately analyzed high- and low-arousal movie clips. We recorded neural responses using electroencephalography (EEG), and employed the temporal response function (TRF) to quantify the neural encoding of auditory and visual features. The neural encoding of sound envelope is enhanced in the audiovisual congruent condition than the incongruent condition, but this effect is only significant for high-arousal movie clips. In contrast, audiovisual congruency does not significantly modulate the neural encoding of visual features, e.g., luminance or visual motion. In summary, our findings demonstrate asymmetrical cross-modal interactions during the processing of natural scenes that lack rhythmicity: Congruent visual information enhances low-level auditory processing, while congruent auditory information does not significantly modulate low-level visual processing.

When norm violations are spontaneously detected: an electrocortical investigation

One fundamental function of social norms is to promote social coordination. Moreover, greater social coordination may be called for when tight norms govern social relations with others. Hence, the sensitivity to social norm violations may be jointly modulated by relational goals and a belief that the social context is tight (vs loose). We tested this analysis using an electrocortical marker of norm-violation detection (N400). Ninety-one young American adults were subliminally primed with either relational or neutral goals. Then they saw behaviors that were either norm-violating or normal. In the relational priming condition, the norm-violation N400 increased as a function of the perceived tightness of societal norms. In the control priming condition, however, the norm-violation N400 was weak regardless of perceived tightness. Thus, normative tightness was associated with increased neural processing of norm violations only when relational goals were activated. Implications for norm psychology are discussed.

Associations between phasic arousal and decisions under risk in younger and older adults

Higher arousal is linked to simple decision strategies and an increased preference for immediate rewards in younger adults, but little is known about the influence of arousal on decision making in older adults. In light of age-related locus coeruleus-norepinephrine system declines, we predicted a reduced association between arousal and decision behavior in older adults. Younger and older participants made a series of choices between smaller, higher-probability and larger, lower-probability financial gains. Each choice was preceded by the presentation of a high-arousal or low-arousal sound. Pupil dilation was continuously recorded as an index of task-evoked arousal. Both age groups showed significant modulation of pupil dilation as a function of arousal condition. Higher-arousal sounds were associated with shorter response times, particularly in younger adults. Furthermore, higher-arousal sounds were associated with greater risk aversion in younger adults and greater risk seeking in older adults, in line with an arousal-related amplification of baseline preferences in both age groups. Jointly, these findings help inform current theories of the effects of arousal on information processing in younger and older adults.

The interaction between reward and the task-irrelevant emotional context in memory

Reward improves task performance while the emotional contexts irrelevant to the task impair task performance. An interaction between reward and the task-irrelevant emotional context has been discovered by some studies using perceptual tasks. However, it is unclear that how memory performance would be affected by both variables. This study aimed to answer this question and explore the role of arousal induced by emotional stimuli, to which was seldomly paid attention by previous studies. We conducted two experiments with the study-test paradigm. The first difference between the experiments was the way that the emotional stimuli were presented. They were presented with the words (Experiment 1) or separately (Experiment 2). The second difference was that the manipulation of the emotional arousal was phasic (Experiment 1) or tonic (Experiment 2). Both experiments showed that the reward effect was greater in emotional context compared to the neutral context, which is not only due to the poorer memory of no reward-associated words but also the better memory of reward-associated words in emotional contexts especially in negative one. These results supported the view that emotional arousal enhanced the memory of high priority stimuli (reward-associated words) and impaired the memory of low priority stimuli (no reward-associated words).

Reward anticipation selectively boosts encoding of gist for visual objects

Reward anticipation at encoding enhances later recognition, but it is unknown to what extent different levels of processing at encoding (gist vs. detail) can benefit from reward-related memory enhancement. In the current study, participants (N = 50) performed an incidental encoding task in which they made gist-related or detail-related judgments about pairs of visual objects while in anticipation of high or low reward. Results of a subsequent old/new recognition test revealed a reward-related memory benefit that was specific to objects from pairs encoded in the attention-to-gist condition. These findings are consistent with the theory of long-axis specialization along the human hippocampus, which localizes gist-based memory processes to the anterior hippocampus, a region highly interconnected with the dopaminergic reward network.

Age differences in vulnerability to distraction under arousal

Aging affects brain circuitry involved in both inhibition and arousal. In this study, we tested whether older adults are more or less prone to distraction from emotionally arousing events than young adults. To do so, we examined how arousing taboo distractor words affected concurrent 1-back task performance and subsequent memory for distractors. Our second goal was to examine how the arousal level of 1 item can modulate processing of preceding neutral distractors (taboo-minus-1 distractors). During the task, participants first made 1-back judgments about target pictures that were superimposed with to-be-ignored neutral or taboo distractors. Relative to young adults, older adults were more distracted by taboo than neutral words on the 1-back task and remembered more of the taboo distractors on a later incidental recognition task. Furthermore, young adults showed better suppression of taboo-minus-1 distractors than neutral distractors, whereas in older adults, arousal did not facilitate suppression of taboo-minus-1 distractors. This effect appeared to require attentional control as adding an unrelated attentional load during the 1-back task eliminated the beneficial effect of arousal for young adults' suppression of taboo-minus-1 distractors. Finally, when top-down attentional guidance was provided by increasing the goal relevance of target pictures, both groups showed enhanced suppression of taboo-minus-1 distractors versus other neutral distractors. Together, these findings imply that the effect of arousal on distractibility in aging may arise from an interaction between top-down and bottom-up processes. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Emotional oddball: A review on memory effects

How do emotional stimuli influence perception, attention, and ultimately memory? This debate at the cross-section of emotion and cognition research has a long tradition. The emotional oddball paradigm (EOP) has frequently been applied to investigate the detection and processing of (emotional) change detection (Schlüter & Bermeitinger, 2017). However, the EOP has also been used to reveal the effects of emotional deviants on memory for serially presented stimuli. In this integrative article, we review the results of 29 experiments published between the years 2000 and 2017. Based on these data, we provide an overview of how the EOP is applied in the context of memory research. We also review and integrate the empirical evidence for memory effects in the EOP (with a special focus on retrograde and anterograde emotion-induced effects) and present theories of emotional memory as well as their fit with the results obtained by the EOP. Directions for future research are presented that would help to address important issues of the current debate around emotion-induced memory effects.

Neurophysiological evidence for the retrieval practice effect under emotional context

Testing has been demonstrated to enhance memory retention compared to restudy, which is known as the retrieval practice effect. Although much evidence has shown that emotional arousal has an impact on memory retention, little is known about how emotional arousal would influence the retrieval practice effect. To answer this question, the current study used emotional pictures as a context to induce the emotional arousal for restudy or retrieval practice. A Remember/Know paradigm was used in the final test with EEG recordings to examine how the impact of emotional arousal on retrieval practice effect would be reflected in familiarity or recollection. Behavioral results showed that the remembrance was enhanced by the retrieval practice compared to the restudy under both neutral and emotional contexts. Consistently, a parietal old/new effect from 500 to 800 ms was only found for the retrieval practice but not for the restudy condition under both neutral and emotional contexts. These findings indicated that retrieval practice could enhance later recollection when compared to restudy irrespective of emotional or neutral contexts.

Effects of hunger on emotional arousal responses and attention/memory biases

In this study, we examined how emotional arousal interacts with hunger states and the processing of food stimuli. In general, arousal enhances the processing of high-priority information at the expense of lower priority information (Mather & Sutherland, 2011). Because food has been a biologically relevant stimulus in primates throughout evolution, detecting it in the environment and remembering its location has high priority. In our study, inducing arousal enhanced attention to subsequent food stimuli. In addition, we manipulated whether participants were hungry or sated to examine how hunger states would influence emotional processing. Previous research reveals that being hungry is associated with increases in norepinephrine, a key neurotransmitter involved in the arousal response. We found that, when sated, participants showed greater pupil dilation to emotional than neutral stimuli. In contrast, when hungry, pupil dilation responses were as strong to neutral as to emotional stimuli. Thus, when hungry, participants were less effective at differentiating the intensity of arousal responses to emotional versus neutral stimuli because of high arousal responses to neutral stimuli. Memory for food stimuli was enhanced compared with memory for nonfood stimuli for all participants but especially for hungry participants. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Positive emotion enhances association-memory

The influence of emotion on association-memory is often attributed to arousal, but negative stimuli are typically used to test for these effects. While prior studies of negative emotion on association-memory have found impairments, theories suggest that positive emotion may have a distinct effect on memory, and may lead to enhanced association-memory. Here we tested participants' memory for pairs of positive and neutral words using cued recall, supplemented with a mathematical modeling approach designed to disentangle item- versus association-memory effects that may otherwise confound cued-recall performance. In our main experiment, as well as in additional supplemental experiments, we consistently found enhanced association-memory due to positive emotion. Interestingly, we observed enhanced association-memory in pairs composed of two positive words, but not in pairings of one positive and one neutral word, indicating that this enhancement may only when a sufficient amount of positive emotion is present. These results provide further evidence that positive information is processed differently than negative and that, when examining association formation, valence as well as arousal must be considered. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Effects of arousal on biased competition in attention and short-term memory

A recent theory proposes that arousal amplifies the competition between stimulus representations, strengthening already strong representations and weakening already weak representations in perception and memory. Here, we report a stringent test of this arousal-biased competition theory in the context of visual attention and short-term memory. We examined whether pre-trial arousal enhances the bottom-up attentional bias toward physically salient versus less salient stimuli in a multi-letter identification task. Arousal was manipulated by presenting an arousing versus a neutral picture (Experiment 1) or sound (Experiment 2) at the start of each trial. Bayesian statistics revealed strong evidence for the null hypothesis in both experiments: Arousal did not modulate the effects of physical salience on letter identification. The experiments were repeated with EEG measurements and subjective stimulus ratings, which confirmed that the stimuli successfully manipulated physiological and subjective arousal. These results pose a challenge for the arousal-biased competition theory.

Emotional enhancement of memory for neutral information: The complex interplay between arousal, attention, and anticipation

It can be challenging to explain why certain mundane details circumstantial to an emotional event are nonetheless remembered long after the experience. Here, we examined how attention selectively shapes memory for neutral objects that happen to coincide with either an unexpected or anticipated emotional event. Pictures of neutral objects were presented for 2 s and terminated with either a high-intensity shock, a low-intensity shock, or no shock. Recognition memory was tested 24 -hs later in a surprise test. Results showed no effect of shock intensity on memory for attended objects when shocks were unpredictable (Experiment 1). Similarly, there was no effect of shock intensity for attended objects when shock delivery was signaled before the object appeared (Experiment 2). There was a reduction in memory for unattended objects paired with an anticipated high-intensity shock (Experiment 3). Finally, subjects recognized slightly more attended objects paired with a high-intensity shock if shock intensity was signaled one second after the object was encoded (Experiment 4). We conclude that simply pairing objects with high-intensity shocks is insufficient to drive episodic memory enhancements for neutral information. But anticipation of an impending source of arousal can induce bidirectional effects: attending to an impending emotional event interferes with encoding of neutral information, but encoding an object just prior to anticipation of an emotional event can sometimes benefit memory. Overall, these results highlight a complex interplay between arousal, attention, and anticipation on emotion-induced memory for neutral information.

Echoes of Emotions Past: How Neuromodulators Determine What We Recollect

We tend to re-live emotional experiences more richly in memory than more mundane experiences. According to one recent neurocognitive model of emotional memory, negative events may be encoded with a larger amount of sensory information than neutral and positive events. As a result, there may be more perceptual information available to reconstruct these events at retrieval, leading to memory reinstatement patterns that correspond with greater memory vividness and sense of recollection for negative events. In this commentary, we offer an alternative perspective on how emotion may influence such sensory cortex reinstatement that focuses on engagement of the noradrenergic (NE) and dopaminergic (DA) systems rather than valence. Specifically, we propose that arousal-related locus coeruleus-norepinephrine (LC-NE) system activation promotes the prioritization of the most salient features of an emotional experience in memory. Thus, a select few details may drive lower-level sensory cortical activity and a stronger sense of recollection for arousing events. By contrast, states of high behavioral activation, including novelty-seeking and exploration, may recruit the DA system to broaden the scope of cognitive processing and integrate multiple event aspects in memory. These more integrated memory representations may be reflected in higher-order cortical reinstatement at retrieval. Thus, the balance between activation in these neuromodulatory systems at encoding, rather than the valence of the event, may ultimately determine the quality of emotional memory recollection and neural reinstatement.

Emotional arousal amplifies competitions across goal-relevant representation: A neurocomputational framework

Emotional arousal often facilitates memory for some aspects of an event while impairing memory for other aspects of the same event. Across three experiments, we found that emotional arousal amplifies competition among goal-relevant representations, such that arousal impairs memory for multiple goal-relevant representations while enhancing memory for solo goal-relevant information. We also present a computational model to explain the mechanisms by which emotional arousal can modulate memory in opposite ways via the local/synaptic-level noradrenergic system. The model is based on neurophysiological observations that norepinephrine (NE) released under emotional arousal is locally controlled by glutamate levels, resulting in different NE effects across regions, gating either long-term potentiation or long-term depression by activating different adrenergic receptors depending on NE concentration levels. This model successfully replicated behavioral findings from the three experiments. These findings suggest that the NE's local effects are key in determining the effects of emotion on memory.

Distraction and facilitation: The impact of emotional sounds in an emoji oddball task

Emotional stimuli are argued to capture attention and consume attentional resources differently depending on their emotional content. The present study investigates the impact of the automatic detection of unexpected and to-be-ignored emotional stimuli on human behavioral responses, and aims to unravel the differences in distraction between two negative emotional stimuli: sadness and anger. Forty participants (M_age = 25.5 years) performed a visual categorization task where angry and sad emoji faces were presented after either a standard neutral tone (in 80% of trials) or a deviant emotional sound (tone changing in pitch; sad or angry sound in 10% of trials each) that was to be ignored. Deviant trials were either congruent (e.g., sad sound-sad face) or incongruent (e.g., angry sound-sad face). Although the stimuli presented to the participants were brief and to-be-ignored, results indicate that participants were significantly more distracted by sad compared to angry stimuli (seen as prolonged response times). Findings are discussed with reference to the nature of the two negative emotions.

Auditory-Induced Negative Emotions Increase Recognition Accuracy for Visual Scenes Under Conditions of High Visual Interference

The effect of emotion on memory is powerful and complex. While there seems to be agreement that emotional arousal generally increases the likelihood that events are remembered, it is somewhat disputed whether also the valence of emotions influences memory. Specifically, several experiments by Kensinger and colleagues have provided evidence for the hypotheses that negative valanced emotions facilitate the encoding of perceptual details. On the other hand, Mather and colleagues have suggested that these results could be explained by confounding relationships of valence and arousal, i.e., that items that generate negative emotions are typically also more arousing. In this study, we provide a conceptual replication of Kensinger’s findings. We employed a novel experimental design, in which the effects of standardized emotional arousing sounds on recognition accuracy for neutral visual scenes was measured. We indirectly manipulated the amount of visual detail that was encoded, by requiring participants to memorize either single exemplars (low interference) or multiple exemplars (high interference) of visual scene categories. With increasing visual overlap in the high interference condition, participants were required to encode a high degree of visual detail to successfully remember the exemplars. The results obtained from 60 healthy human participants confirmed Kensinger’s hypothesis by showing that under conditions of high visual interference, negative valanced emotions led to higher levels of recognition accuracy compared to neutral and positive emotions. Furthermore, based on the normative arousal ratings of the stimulus set, our results suggest that the differential recognition effect cannot be explained by differing levels of arousal.

GANEing traction: The broad applicability of NE hotspots to diverse cognitive and arousal phenomena

The GANE (glutamate amplifies noradrenergic effects) model proposes that local glutamate-norepinephrine interactions enable "winner-take-more" effects in perception and memory under arousal. A diverse range of commentaries addressed both the nature of this "hotspot" feedback mechanism and its implications in a variety of psychological domains, inspiring exciting avenues for future research.

Retrospective Report Revisited: Long-Term Recall in European American Mothers Moderated by Developmental Domain, Child Age, Person, and Metric of Agreement

Retrospective parental reports are common in the developmental science literature, but their validity has been questioned. We investigated the consistency of retrospective maternal recall by comparing original with retrospective maternal reports in three domains (maternal cognitions, mother-reported child and mother behaviors, and observed child and mother behaviors) at three retention intervals (12, 14, and 15 years) in two metrics (individual standing and group level). In a longitudinal study, European American mothers (N=46) provided data when their children were 5, 20, and 48 months of age and retrospective recall data for each age when their children were 16 years. Overall, mothers recalled similar average mean levels (49% of variables explored) or better mean levels (41% of variables) retrospectively; better levels indicating a positive recollection bias. At least moderate consistency in relative standing was evident for 52% of variables. Still, the findings varied somewhat by domain, child age, and person. Retrospective parental reports can provide accurate accounts of the past, but should be used with caution, as their consistency varies and is specific to moderating factors.

Low Arousal Positive Emotional Stimuli Attenuate Aberrant Working Memory Processing in Persons with Mild Cognitive Impairment

Emotional enhancement effects on memory have been reported to mitigate the pathophysiology of Alzheimer's disease (AD). However, relative to their manifestation in persons without pathologic aging, these effects may be reduced in magnitude or even deleterious, especially in tasks that more closely model ecologic memory performance. Based upon a synthesis of such reports, we hypothesized that in persons with AD low arousal positive stimuli would evoke relatively intact emotional enhancement effects, but that high arousal negative stimuli would evoke disordered emotional enhancement effects. To assess this, participants with and without mild cognitive impairment (MCI) presumed to be due to AD performed an emotionally-valenced short-term memory task while encephalography was recorded. Results indicated that for persons with MCI, high arousal negative stimuli led to working memory processing patterns previously associated with MCI presumed due to AD and dementia of the Alzheimer-type. In contrast, low arousal positive stimuli evoked a processing pattern similar to MCI participants' unaffected spouses. Our current findings suggest that low arousal positive stimuli attenuate working memory deficits of MCI due to AD.

Functional interplay of top-down attention with affective codes during visual short-term memory maintenance

Visual short-term memory (VSTM) allows individuals to briefly maintain information over time for guiding behaviours. Because the contents of VSTM can be neutral or emotional, top-down influence in VSTM may vary with the affective codes of maintained representations. Here we investigated the neural mechanisms underlying the functional interplay of top-down attention with affective codes in VSTM using functional magnetic resonance imaging. Participants were instructed to remember both threatening and neutral objects in a cued VSTM task. Retrospective cues (retro-cues) were presented to direct attention to the hemifield of a threatening object (i.e., cue-to-threat) or a neutral object (i.e., cue-to-neutral) during VSTM maintenance. We showed stronger activity in the ventral occipitotemporal cortex and amygdala for attending threatening relative to neutral representations. Using multivoxel pattern analysis, we found better classification performance for cue-to-threat versus cue-to-neutral objects in early visual areas and in the amygdala. Importantly, retro-cues modulated the strength of functional connectivity between the frontoparietal and early visual areas. Activity in the frontoparietal areas became strongly correlated with the activity in V3a-V4 coding the threatening representations instructed to be relevant for the task. Together, these findings provide the first demonstration of top-down modulation of activation patterns in early visual areas and functional connectivity between the frontoparietal network and early visual areas for regulating threatening representations during VSTM maintenance.

Curiosity in old age: A possible key to achieving adaptive aging

Curiosity is a fundamental part of human motivation that supports a variety of human intellectual behaviors ranging from early learning in children to scientific discovery. However, there has been little attention paid to the role of curiosity in aging populations. By bringing together broad but sparse neuroscientific and psychological literature on curiosity and related concepts (e.g., novelty seeking in older adults), we propose that curiosity, although it declines with age, plays an important role in maintaining cognitive function, mental health, and physical health in older adults. We identify the dopaminergic reward system and the noradrenergic system as the key brain systems implicated in curiosity processing and discuss how these brain systems contribute to the relationship between curiosity and adaptive aging.

Locus coeruleus integrity in old age is selectively related to memories linked with salient negative events

The locus coeruleus (LC) is the principal origin of noradrenaline in the brain. LC integrity varies considerably across healthy older individuals, and is suggested to contribute to altered cognitive functions in aging. Here we test this hypothesis using an incidental memory task that is known to be susceptible to noradrenergic modulation. We used MRI neuromelanin (NM) imaging to assess LC structural integrity and pupillometry as a putative index of LC activation in both younger and older adults. We show that older adults with reduced structural LC integrity show poorer subsequent memory. This effect is more pronounced for emotionally negative events, in accord with a greater role for noradrenergic modulation in encoding salient or aversive events. In addition, we found that salient stimuli led to greater pupil diameters, consistent with increased LC activation during the encoding of such events. Our study presents novel evidence that a decrement in noradrenergic modulation impacts on specific components of cognition in healthy older adults. The findings provide a strong motivation for further investigation of the effects of altered LC integrity in pathological aging.

Age differences in selective memory of goal-relevant stimuli under threat

When faced with threat, people often selectively focus on and remember the most pertinent information while simultaneously ignoring any irrelevant information. Filtering distractors under arousal requires inhibitory mechanisms, which take time to recruit and often decline in older age. Despite the adaptive nature of this ability, relatively little research has examined how both threat and time spent preparing these inhibitory mechanisms affect selective memory for goal-relevant information across the life span. In this study, 32 younger and 31 older adults were asked to encode task-relevant scenes, while ignoring transparent task-irrelevant objects superimposed onto them. Threat levels were increased on some trials by threatening participants with monetary deductions if they later forgot scenes that followed threat cues. We also varied the time between threat induction and a to-be-encoded scene (i.e., 2 s, 4 s, 6 s) to determine whether both threat and timing effects on memory selectivity differ by age. We found that age differences in memory selectivity only emerged after participants spent a long time (i.e., 6 s) preparing for selective encoding. Critically, this time-dependent age difference occurred under threatening, but not neutral, conditions. Under threat, longer preparation time led to enhanced memory for task-relevant scenes and greater memory suppression of task-irrelevant objects in younger adults. In contrast, increased preparation time after threat induction had no effect on older adults' scene memory and actually worsened memory suppression of task-irrelevant objects. These findings suggest that increased time to prepare top-down encoding processes benefits younger, but not older, adults' selective memory for goal-relevant information under threat. (PsycINFO Database Record

Locus Coeruleus Activity Strengthens Prioritized Memories Under Arousal

Recent models posit that bursts of locus ceruleus (LC) activity amplify neural gain such that limited attention and encoding resources focus even more on prioritized mental representations under arousal. Here, we tested this hypothesis in human males and females using fMRI, neuromelanin MRI, and pupil dilation, a biomarker of arousal and LC activity. During scanning, participants performed a monetary incentive encoding task in which threat of punishment motivated them to prioritize encoding of scene images over superimposed objects. Threat of punishment elicited arousal and selectively enhanced memory for goal-relevant scenes. Furthermore, trial-level pupil dilations predicted better scene memory under threat, but were not related to object memory outcomes. fMRI analyses revealed that greater threat-evoked pupil dilations were positively associated with greater scene encoding activity in LC and parahippocampal cortex, a region specialized to process scene information. Across participants, this pattern of LC engagement for goal-relevant encoding was correlated with neuromelanin signal intensity, providing the first evidence that LC structure relates to its activation pattern during cognitive processing. Threat also reduced dynamic functional connectivity between high-priority (parahippocampal place area) and lower-priority (lateral occipital cortex) category-selective visual cortex in ways that predicted increased memory selectivity. Together, these findings support the idea that, under arousal, LC activity selectively strengthens prioritized memory representations by modulating local and functional network-level patterns of information processing.SIGNIFICANCE STATEMENT Adaptive behavior relies on the ability to select and store important information amid distraction. Prioritizing encoding of task-relevant inputs is especially critical in threatening or arousing situations, when forming these memories is essential for avoiding danger in the future. However, little is known about the arousal mechanisms that support such memory selectivity. Using fMRI, neuromelanin MRI, and pupil measures, we demonstrate that locus ceruleus (LC) activity amplifies neural gain such that limited encoding resources focus even more on prioritized mental representations under arousal. For the first time, we also show that LC structure relates to its involvement in threat-related encoding processes. These results shed new light on the brain mechanisms by which we process important information when it is most needed.

Emerging Directions in Emotional Episodic Memory

Building upon the existing literature on emotional memory, the present review examines emerging evidence from brain imaging investigations regarding four research directions: (1) Social Emotional Memory, (2) The Role of Emotion Regulation in the Impact of Emotion on Memory, (3) The Impact of Emotion on Associative or Relational Memory, and (4) The Role of Individual Differences in Emotional Memory. Across these four domains, available evidence demonstrates that emotion- and memory-related medial temporal lobe brain regions (amygdala and hippocampus, respectively), together with prefrontal cortical regions, play a pivotal role during both encoding and retrieval of emotional episodic memories. This evidence sheds light on the neural mechanisms of emotional memories in healthy functioning, and has important implications for understanding clinical conditions that are associated with negative affective biases in encoding and retrieving emotional memories.

Only "efficient" emotional stimuli affect the content of working memory during free-recollection from natural scenes

Emotional events are thought to have privileged access to attention and memory, consuming resources needed to encode competing emotionally neutral stimuli. However, it is not clear whether this detrimental effect is automatic or depends on the successful maintenance of the specific emotional object within working memory. Here, participants viewed everyday scenes including an emotional object among other neutral objects followed by a free-recollection task. Results showed that emotional objects-irrespective of their perceptual saliency-were recollected more often than neutral objects. The probability of being recollected increased as a function of the arousal of the emotional objects, specifically for negative objects. Successful recollection of emotional objects (positive or negative) from a scene reduced the overall number of recollected neutral objects from the same scene. This indicates that only emotional stimuli that are efficient in grabbing (and then consuming) available attentional resources play a crucial role during the encoding of competing information, with a subsequent bias in the recollection of neutral representations.

Lost in Time and Space: States of High Arousal Disrupt Implicit Acquisition of Spatial and Sequential Context Information

Biased cognition during high arousal states is a relevant phenomenon in a variety of topics: from the development of post-traumatic stress disorders or stress-triggered addictive behaviors to forensic considerations regarding crimes of passion. Recent evidence indicates that arousal modulates the engagement of a hippocampus-based "cognitive" system in favor of a striatum-based "habit" system in learning and memory, promoting a switch from flexible, contextualized to more rigid, reflexive responses. Existing findings appear inconsistent, therefore it is unclear whether and which type of context processing is disrupted by enhanced arousal. In this behavioral study, we investigated such arousal-triggered cognitive-state shifts in human subjects. We validated an arousal induction procedure (three experimental conditions: violent scene, erotic scene, neutral control scene) using pupillometry (Preliminary Experiment, n = 13) and randomly administered this method to healthy young adults to examine whether high arousal states affect performance in two core domains of contextual processing, the acquisition of spatial (spatial discrimination paradigm; Experiment 1, n = 66) and sequence information (learned irrelevance paradigm; Experiment 2, n = 84). In both paradigms, spatial location and sequences were encoded incidentally and both displacements when retrieving spatial position as well as the predictability of the target by a cue in sequence learning changed stepwise. Results showed that both implicit spatial and sequence learning were disrupted during high arousal states, regardless of valence. Compared to the control group, participants in the arousal conditions showed impaired discrimination of spatial positions and abolished learning of associative sequences. Furthermore, Bayesian analyses revealed evidence against the null models. In line with recent models of stress effects on cognition, both experiments provide evidence for decreased engagement of flexible, cognitive systems supporting encoding of context information in active cognition during acute arousal, promoting reduced sensitivity for contextual details. We argue that arousal fosters cognitive adaptation towards less demanding, more present-oriented information processing, which prioritizes a current behavioral response set at the cost of contextual cues. This transient state of behavioral perseverance might reduce reliance on context information in unpredictable environments and thus represent an adaptive response in certain situations.

Top-down modulation of alpha power and pattern similarity for threatening representations in visual short-term memory

Recent studies have shown that top-down attention biases task-relevant representations in visual short-term memory (VSTM). Accumulating evidence has also revealed the modulatory effects of emotional arousal on attentional processing. However, it remains unclear how top-down attention interacts with emotional memoranda in VSTM. In this study, we investigated the mechanisms of alpha oscillations and their spatiotemporal characteristics that underlie top-down attention to threatening representations during VSTM maintenance with electroencephalography. Participants were instructed to remember a threatening object and a neutral object in a cued variant delayed response task. Retrospective cues (retro-cues) were presented to direct attention to the hemifield of a threatening object (i.e., cue-to-threat trials) or a neutral object (i.e., cue-to-neutral trials) during a retention interval prior to the probe test. We found a significant retro-cue-related alpha lateralisation over posterior regions during VSTM maintenance. The novel finding was that the magnitude of alpha lateralisation was greater for cue-to-threat objects compared to cue-to-neutral ones. These results indicated that directing attention towards threatening representations compared to neutral representations could result in greater regulation of alpha activity contralateral to the cued hemifield. Importantly, we estimated the spatiotemporal pattern similarity in alpha activity and found significantly higher similarity indexes for the posterior regions relative to the anterior regions and for the cue-to-threat objects relative to cue-to-neutral objects over the posterior regions. Together, our findings provided the oscillatory evidence of greater top-down modulations of alpha lateralisation and spatiotemporal pattern similarity for attending to threatening representations in VSTM.