Summary Reminders of happy memories can bring back pleasant feelings tied to the original experience, suggesting an intrinsic value in reminiscing about the positive past. However, the neural circuitry underlying the rewarding aspects of autobiographical memory is poorly understood. Using fMRI, we observed enhanced activity during the recall of positive relative to neutral autobiographical memories in corticostriatal circuits that also responded to monetary rewards. Enhanced activity in the striatum and medial prefrontal cortex was associated with increases in positive emotion during recall and striatal engagement further correlated with individual measures of resiliency. Striatal response to the recall of positive memories was greater in individuals whose mood improved after the task. Notably, participants were willing to sacrifice more tangible monetary rewards in order to reminisce about positive past experiences. Our findings suggest that recalling positive autobiographical memories is intrinsically valuable, which may be adaptive for regulating positive emotion and promoting better well-being.

Much of the work in cognitive neuroscience is shifting from a focus on single brain regions to a focus on the connectivity between multiple brain regions. These inter-regional connectivity patterns contribute to a wide range of behaviors and are studied with models of functional integration. The rapid expansion of the literature on functional integration offers an opportunity to scrutinize the consistency and specificity of one of the most popular approaches for quantifying connectivity: psychophysiological interaction (PPI) analysis. We performed coordinate-based meta-analyses on 284 PPI studies, which allowed us to test a) whether those studies consistently converge on similar target regions and b) whether the identified target regions are specific to the chosen seed region and psychological context. Our analyses revealed two key results. First, we found that different types of PPI studies—e.g., those using seeds such as amygdala and dorsolateral prefrontal cortex (DLPFC) and contexts such as emotion and cognitive control, respectively—each consistently converge on similar target regions, thus supporting the reliability of PPI as a tool for studying functional integration. Second, we also found target regions that were specific to the chosen seed region and psychological context, indicating distinct patterns of brain connectivity. For example, the DLPFC seed reliably contributed to a posterior cingulate cortex target during cognitive control but contributed to an amygdala target in other contexts. Our results point to the robustness of PPI while highlighting common and distinct patterns of functional integration, potentially advancing models of brain connectivity.

Recalling happy memories elicits positive feelings and enhances one's wellbeing, suggesting a potential adaptive function in using this strategy for coping with stress. In two studies, we explored whether recalling autobiographical memories that have a positive content-that is, remembering the good times-can dampen the hypothalamic-pituitary-adrenal axis stress response. Participants underwent an acute stressor or control task followed by autobiographical memory recollection (of only positive or neutral valence). Across both studies, recalling positive, but not neutral, memories resulted in a dampened cortisol rise and reduced negative affect. Further, individuals with greater self-reported resiliency showed enhanced mood, despite stress exposure. During positive reminiscence, we observed engagement of corticostriatal circuits previously implicated in reward processing and emotion regulation, and stronger connectivity between ventrolateral and dorsolateral prefrontal cortices as a function of positivity. These findings highlight the restorative and protective function of self-generated positive emotions via memory recall in the face of stress.A cute stress can leave us feeling anxious and distressed, with detrimental consequences for our physical and mental health 1 . We often use cognitive regulation strategies to suppress these unpleasant feelings altogether (for example, suppression) or to reinterpret the negative situation as something less negative or neutral (for example, cognitive reappraisal) 2 . Despite our best efforts, however, we are not always successful in diminishing unpleasant feelings when using cognitive strategies under stress 3 . This may not be surprising considering that stress is thought to compromise the exact neural circuitry that emotion regulation relies on 4 . Thus, a promising alternative may be to focus on increasing or sustaining positive feelings-a strategy that broadens one's cognitive perspective 5 , and which may foster improved ability to cope with a stressor.One way of bolstering positive emotions is to reminisce about past positive events. Autobiographical memories can bring back emotions tied to the original experience 6 . Retrieving positive memories in particular may be intrinsically valuable, as they rekindle pleasant feelings and engage neural circuitry involved in reward processing, such as the striatum 7 . Such striatal activity correlates with selfreported adaptation to stress (for instance, resiliency) and enhanced mood for some individuals, which is consistent with a role for corticostriatal circuits in sustaining positive mood 8,9 . Thus, savouring happy memories might be significant for one's ability to cope with stress, potentially promoting better decision-making and wellbeing.A critical question remains whether recalling the positive past can facilitate successful resiliency. Experiencing stress activates the hypothalamic-pituitary-adrenal (HPA) axis, which releases a cascade of hormones, including the primary stress hormone cortisol 10 . A heightened cortisol ...

People generally prefer rewards sooner rather than later. This phenomenon, temporal discounting, underlies many societal problems, including addiction and obesity. One way to reduce temporal discounting is to imagine positive future experiences. Since there is overlap in the neural circuitry associated with imagining future experiences and remembering past events, here we investigate whether recalling positive memories can also promote more patient choice. We found that participants were more patient after retrieving positive autobiographical memories, but not when they recalled negative memories. Moreover, individuals were more impulsive after imagining novel positive scenes that were not related to their memories, showing that positive imagery alone does not drive this effect. Activity in the striatum and temporo parietal junction during memory retrieval predicted more patient choice, suggesting that to the extent that memory recall is rewarding and involves perspective-taking, it influences decision-making. Furthermore, representational similarity in the ventromedial prefrontal cortex between memory recall and decision phases correlated with the behavioral effect across participants. Thus, we have identified a novel manipulation for reducing temporal discounting—remembering the positive past—and have begun to characterize the psychological and neural mechanisms behind it.

Although many epidemiological studies suggest the beneficial effects of higher cognitive reserve (CR) in reducing age-related cognitive decline and dementia risk, the neural basis of CR is poorly understood. To our knowledge, the current study represents the first electrophysiological investigation of the relationship between CR and neural reserve (i.e., neural efficiency and capacity). Specifically, we examined whether CR modulates event-related potentials (ERPs) associated with performance on a verbal recognition memory task with three set sizes (1, 4, or 7 letters) in healthy younger and older adults. Neural data showed that as task difficulty increased, the amplitude of the parietal P3b component during the probe phase decreased and its latency increased. Notably, the degree of these neural changes was negatively correlated with CR in both age groups, such that individuals with higher CR showed smaller changes in P3b amplitude and less slowing in P3b latency (i.e., smaller changes in the speed of neural processing) with increasing task difficulty, suggesting greater neural efficiency. These CR-related differences in neural efficiency may underlie reserve against neuropathology and age-related burden.