Inferring danger with minimal aversive experience

Memory Boost for Recurring Emotional Events Is Driven by Initial Amygdala Response Promoting Stable Neocortical Patterns across Repetitions

Emotionally arousing events are typically vividly remembered, which is generally adaptive but may contribute to mental disorders such as post-traumatic stress disorder. Previous research on emotional memory focused primarily on events that were experienced only once, leaving the memory mechanisms underlying repeatedly encountered emotional events largely unexplored. Here, we aimed to elucidate the brain mechanisms associated with memory for recurring emotional events. Specifically, we sought to determine whether the memory enhancement for recurring emotional events is linked to more variable neural representations, as predicted by the encoding-variability hypothesis, or to more stable representations across repetitions, as suggested by a memory reinstatement account. To investigate this, we repeatedly presented healthy men and women with images of emotionally negative or neutral scenes during three consecutive runs in an MRI scanner. Subsequent free recall was, as expected, enhanced for emotional compared with neutral images. Neural data showed that this emotional enhancement of memory was linked to (1) activation of the amygdala and anterior hippocampus during the initial encounter of the emotional event and (2) increased neural pattern similarity in frontoparietal cortices across event repetitions. Most importantly, a multilevel-moderated mediation analysis revealed that the impact of neocortical pattern stability across repetitions on emotional memory enhancement was moderated by amygdala activity during the initial exposure to the emotional event. Together, our findings show that the amygdala response during the initial encounter of an emotional event boosts subsequent remembering through a more precise reinstatement of the event representation during subsequent encounters of the same event.

Memory Under Stress: From Adaptation to Disorder

Stressful events are ubiquitous in everyday life. Exposure to these stressors initiates the temporally orchestrated release of a multitude of hormones, peptides, and neurotransmitters that target brain areas that have been critically implicated in learning and memory. This review summarizes recent insights on the profound impact of stress on 4 fundamental processes of memory: memory formation, memory contextualization, memory retrieval, and memory flexibility. Stress mediators instigate dynamic alterations in these processes, thereby facilitating efficient responding under stress and the creation of a decontextualized memory representation that can effectively aid coping with novel future threats. While they are generally adaptive, the same stress-related changes may contribute to the rigid behaviors, uncontrollable intrusions, and generalized fear responding seen in anxiety disorders and posttraumatic stress disorder. Drawing on recent discoveries in cognitive neuroscience and psychiatry, this review discusses how stress-induced alterations in memory processes can simultaneously foster adaptation to stressors and fuel psychopathology. The transition from adaptive to maladaptive changes in the impact of stress on memory hinges on the nuanced interplay of stressor characteristics and individual predispositions. Thus, taking individual differences in the cognitive response to stressors into account is essential for any successful treatment of stress-related mental disorders.

Building Resilience: The Stress Response as a Driving Force for Neuroplasticity and Adaptation

People exhibit an extraordinary capacity to adjust to stressful situations. Here, we argue that the acute stress response is a major driving force behind this adaptive process. In addition to immediately freeing energy reserves, facilitating a rapid and robust neurocognitive response, and helping to reinstate homeostasis, the stress response also critically regulates neuroplasticity. Therefore, understanding the healthy acute stress response is crucial for understanding stress resilience-the maintenance or rapid recovery of mental health during and after times of adversity. Contemporary resilience research differentiates between resilience factors and resilience mechanisms. Resilience factors refer to a broad array of social, psychological, or biological variables that are stable but potentially malleable and predict resilient outcomes. In contrast, resilience mechanisms refer to proximate mechanisms activated during acute stress that enable individuals to effectively navigate immediate challenges. In this article, we review literature related to how neurotransmitter and hormonal changes during acute stress regulate the activation of resilience mechanisms. We integrate literature on the timing-dependent and neuromodulator-specific regulation of neurocognition, episodic memory, and behavioral and motivational control, highlighting the distinct and often synergistic roles of catecholamines (dopamine and norepinephrine) and glucocorticoids. We conclude that stress resilience is bolstered by improved future predictions and the success-based reinforcement of effective coping strategies during acute stress. The resulting generalized memories of success, controllability, and safety constitute beneficial plasticity that lastingly improves self-control under stress. Insight into such mechanisms of resilience is critical for the development of novel interventions focused on prevention rather than treatment of stress-related disorders.

Context-dependent modulation of spatial attention: prioritizing behaviourally relevant stimuli

Human attention can be guided by semantic information conveyed by individual objects in the environment. Over time, we learn to allocate attention resources towards stimuli that are behaviourally relevant to ongoing action, leading to attention capture by meaningful peripheral stimuli. A common example includes, while driving, stimuli that imply a possibly hazardous scenario (e.g. a pedestrian about to cross the road) warrant attentional prioritization to ensure safe proceedings. In the current study, we report a novel phenomenon in which the guidance of attention is dependent on the stimuli appearing in a behaviourally relevant context. Using a driving simulator, we simulated a real-world driving task representing an overlearned behaviour for licensed drivers. While driving, participants underwent a peripheral cue-target paradigm where a roadside pedestrian avatar (target) appeared following a cylinder cue. Results revealed that, during simulated driving conditions, participants (all with driver's licenses) showed greater attentional facilitation when pedestrians were oriented towards the road compared to away. This orientation-specific selectivity was not seen if the 3-D context was removed (Experiment 1) or the same visual scene was presented, but participants' viewpoints remained stationary (Experiment 2), or an inanimate object served as a target during simulated driving (Experiment 3). This context-specific attention modulation likely reflects drivers' expertise in automatically attending to behaviourally relevant information in a context-dependent manner.

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.

Dynamic threat-reward neural processing under semi-naturalistic ecologically relevant scenarios

Studies of affective neuroscience have typically employed highly controlled, static experimental paradigms to investigate the neural underpinnings of threat and reward processing in the brain. Yet our knowledge of affective processing in more naturalistic settings remains limited. Specifically, affective studies generally examine threat and reward features separately and under brief time periods, despite the fact that in nature organisms are often exposed to the simultaneous presence of threat and reward features for extended periods. To study the neural mechanisms of threat and reward processing under distinct temporal profiles, we created a modified version of the PACMAN game that included these environmental features. We also conducted two automated meta-analyses to compare the findings from our semi-naturalistic paradigm to those from more constrained experiments. Overall, our results revealed a distributed system of regions sensitive to threat imminence and a less distributed system related to reward imminence, both of which exhibited overlap yet neither of which involved the amygdala. Additionally, these systems broadly overlapped with corresponding meta-analyses, with the notable absence of the amygdala in our findings. Together, these findings suggest a shared system for salience processing that reveals a heightened sensitivity toward environmental threats compared to rewards when both are simultaneously present in an environment. The broad correspondence of our findings to meta-analyses, consisting of more tightly controlled paradigms, illustrates how semi-naturalistic studies can corroborate previous findings in the literature while also potentially uncovering novel mechanisms resulting from the nuances and contexts that manifest in such dynamic environments.