Collective events and individual affect shape autobiographical memory.

How do collective events shape how we remember our lives? We leveraged advances in natural language processing as well as a rich, longitudinal assessment of 1,000 Americans throughout 2020 to examine how memory is influenced by two prominent factors: surprise and emotion. Autobiographical memory for 2020 displayed a unique signature: There was a substantial bump in March, aligning with pandemic onset and lockdowns, consistent across three memory collections 1 y apart. We further investigated how emotion, using both immediate and retrieved measures, predicted the amount and content of autobiographical memory: Negative affect increased recall across all measures, whereas its more clinical indices, depression and posttraumatic stress disorder, selectively increased nonepisodic recall. Finally, in a separate cohort, we found pandemic news to be better remembered, surprising, and negative, while lockdowns compressed remembered time. Our work connects laboratory findings to the real world and delineates the effects of acute versus clinical signatures of negative emotion on memory.

Intracranial Recordings of the Human Orbitofrontal Cortical Activity during Self-Referential Episodic and Valenced Self-Judgments.

We recorded directly from the orbital (oPFC) and ventromedial (vmPFC) subregions of the orbitofrontal cortex (OFC) in 22 (9 female, 13 male) epilepsy patients undergoing intracranial electroencephalography (iEEG) monitoring during an experimental task in which the participants judged the accuracy of self-referential autobiographical statements as well as valenced self-judgments (SJs). We found significantly increased high-frequency activity (HFA) in ∼13% of oPFC sites (10/18 subjects) and 16% of vmPFC sites (4/12 subjects) during both of these self-referential thought processes, with the HFA power being modulated by the content of self-referential stimuli. The location of these activated sites corresponded with the location of fMRI-identified limbic network. Furthermore, the onset of HFA in the vmPFC was significantly earlier than that in the oPFC in all patients with simultaneous recordings in both regions. In 11 patients with available depression scores from comprehensive neuropsychological assessments, we documented diminished HFA in the OFC during positive SJ trials among individuals with higher depression scores; responses during negative SJ trials were not related to the patients' depression scores. Our findings provide new temporal and anatomical information about the mode of engagement in two important subregions of the OFC during autobiographical memory and SJ conditions. Our findings from the OFC support the hypothesis that diminished brain activity during positive self-evaluations, rather than heightened activity during negative self-evaluations, plays a key role in the pathophysiology of depression.

A smartphone intervention that enhances real-world memory and promotes differentiation of hippocampal activity in older adults.

The act of remembering an everyday experience influences how we interpret the world, how we think about the future, and how we perceive ourselves. It also enhances long-term retention of the recalled content, increasing the likelihood that it will be recalled again. Unfortunately, the ability to recollect event-specific details and reexperience the past tends to decline with age. This decline in recollection may reflect a corresponding decrease in the distinctiveness of hippocampal memory representations. Despite these well-established changes, there are few effective cognitive behavioral interventions that target real-world episodic memory. We addressed this gap by developing a smartphone-based application called HippoCamera that allows participants to record labeled videos of everyday events and subsequently replay, high-fidelity autobiographical memory cues. In two experiments, we found that older adults were able to easily integrate this noninvasive intervention into their daily lives. Using HippoCamera to repeatedly reactivate memories for real-world events improved episodic recollection and it evoked more positive autobiographical sentiment at the time of retrieval. In both experiments, these benefits were observed shortly after the intervention and again after a 3-mo delay. Moreover, more detailed recollection was associated with more differentiated memory signals in the hippocampus. Thus, using this smartphone application to systematically reactivate memories for recent real-world experiences can help to maintain a bridge between the present and past in older adults.

Precision mapping of the default network reveals common and distinct (inter) activity for autobiographical memory and theory of mind.

The default network is widely implicated as a common neural substrate for self-generated thought, such as remembering one's past (autobiographical memory) and imagining the thoughts and feelings of others (theory of mind). Findings that the default network comprises subnetworks of regions, some commonly and some distinctly involved across processes, suggest that one's own experiences inform their understanding of others. With the advent of precision functional MRI (fMRI) methods, however, it is unclear if this shared substrate is observed instead due to traditional group analysis methods. We investigated this possibility using a novel combination of methodological strategies. Twenty-three participants underwent multi-echo resting-state and task fMRI. We used their resting-state scans to conduct cortical parcellation sensitive to individual variation while preserving our ability to conduct group analysis. Using multivariate analyses, we assessed the functional activation and connectivity profiles of default network regions while participants engaged in autobiographical memory, theory of mind, or a sensorimotor control condition. Across the default network, we observed stronger activity associated with both autobiographical memory and theory of mind compared to the control condition. Nonetheless, we also observed that some regions showed preferential activity to either experimental condition, in line with past work. The connectivity results similarly indicated shared and distinct functional profiles. Our results support that autobiographical memory and theory of mind, two theoretically important and widely studied domains of social cognition, evoke common and distinct aspects of the default network even when ensuring high fidelity to individual-specific characteristics.NEW & NOTEWORTHY We used cutting-edge precision functional MRI (fMRI) methods such as multi-echo fMRI acquisition and denoising, a robust experimental paradigm, and individualized cortical parcellation across 23 participants to provide evidence that remembering one's past experiences and imagining the thoughts and feelings of others share a common neural substrate. Evidence from activation and connectivity analyses indicate overlapping and distinct functional profiles of these widely studied episodic and social processes.

Brain connectivity patterns associated with individual differences in the access to experience-near personal semantics: a resting-state fMRI study.

It has been proposed that a continuum of specificity exists between episodic and semantic autobiographical memory. Personal semantics have been theorized to situate intermediately on this continuum, with more "experience-near" personal semantics (enPS) closer to the episodic end. We used individual differences in behavior as a model to investigate brain networks associated with the access to episodic autobiographical (EAM) and enPS information, assessing the relation between performance in the EAM and enPS conditions of the Autobiographical Fluency Task (AFT) and intrinsic brain connectivity. Results of an intrinsic connectivity contrast analysis showed that the global connectivity of two clusters in the left and right posterior cingulate cortex (PCC) was predicted by performance in the enPS conditions. Moreover, enPS scores predicted the connectivity strength of the right PCC with the bilateral anterior hippocampus (aHC), anterior middle temporal gyrus (aMTG) and medial orbitofrontal cortex, and the left aMTG and PCC. enPS scores also predicted the connectivity strength of the left PCC with the bilateral HC and MTG. The network highlighted involves parts of the core and of the dorsal medial subsystems of the Default Mode Network, in line with the proposal that enPS represents an intermediate entity between episodic and semantic memory.

Highly Superior Autobiographical Memory (HSAM): A Systematic Review.

Individuals possessing a Highly Superior Autobiographical Memory (HSAM) demonstrate an exceptional ability to recall their own past, excelling most when dates from their lifetime are used as retrieval cues. Fully understanding how neurocognitive mechanisms support exceptional memory could lead to benefits in areas of healthcare in which memory plays a central role and in legal fields reliant on witnesses' memories. Predominantly due to the rareness of the phenomenon, existing HSAM literature is highly heterogenous in its methodologies used. Therefore, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we performed the first systematic review on this topic, to collate the existing behavioural, neuroanatomical, and functional HSAM data. Results from the 20 experimental selected studies revealed that HSAM is categorised by rapidly retrieved, detailed and accurate autobiographical memories, and appears to avoid the normal aging process. Functional neuroimaging studies showed HSAM retrieval seems characterised by an intense overactivation of the usual autobiographical memory network, including posterior visual areas (e.g., the precuneus). Structural neuroanatomical differences do not appear to characterise HSAM, but altered hippocampal resting-state connectivity was commonly observed. We discuss theories of HSAM in relation to autobiographical encoding, consolidation, and retrieval, and suggest future directions for this research.

Cerebellar Contributions to Traumatic Autobiographical Memory in People with Post-Traumatic Stress Disorder.

Post-traumatic stress disorder (PTSD) is a debilitating mental health condition characterized by recurrent re-experiencing of traumatic events. Despite increasing evidence suggesting that the cerebellum is involved in PTSD pathophysiology, it remains unclear whether this involvement is related to symptoms directly resulting from previous trauma exposure, such as involuntary re-experiencing of the traumatic events, or reflects a broader cerebellar engagement in negative affective states. In this study, we investigated the specific role of the cerebellum in PTSD by employing a script reactivation paradigm with personalized traumatic and sad autobiographical memories in 28 individuals diagnosed with chronic PTSD. Functional magnetic resonance imaging (fMRI) data were collected while participants listened to their own autobiographical narratives recounted by a third person. Activation in the right cerebellar lobule VI was uniquely associated with traumatic autobiographical recall and was parametrically modulated by the severity of re-experiencing symptoms. In contrast, cerebellar Crus II showed increased activation during both traumatic and sad autobiographical recall, suggesting a broader involvement in processing negative emotions. Our findings highlight the unique contribution of the right cerebellar lobule VI in the processing of traumatic autobiographical memories, potentially through its engagement in low-level representation of sensory and emotional aspects of traumatic events.

Brain Functional Correlates of Recall of Life Events in Medication-Naïve Adolescents with Borderline Personality Disorder.

INTRODUCTION: Recall of autobiographical events has been found to be impaired in borderline personality disorder (BPD), but few studies have examined if this impairment has brain functional correlates. This study evaluated brain functional alterations during autobiographical recall using medication-naive adolescent patients to avoid potential confounding effects of treatment. METHODS: Thirty-two adolescent female patients with BPD who were never-medicated and without psychiatric comorbidity and 33 matched healthy females underwent fMRI while they viewed individualized cue words that evoked autobiographical memories. Control conditions included viewing non-memory-evoking cues and a low-level baseline (cross-fixation). RESULTS: During autobiographical recall, in comparison to the low-level baseline, the BPD patients showed increased brain activity in regions including the posterior hippocampus, the lingual and calcarine cortex, and the precuneus compared to the healthy controls. The BPD patients also showed a failure to deactivate the right dorsolateral prefrontal cortex during autobiographical recall. No patient-control differences were found when memory-evoking words were compared to non-memory-evoking words. DISCUSSION/CONCLUSIONS: This study finds evidence of hippocampal/lingual/calcarine/precuneus hyperactivation to stimuli that evoke autobiographical memories in patients with BPD. As the changes were seen in never-treated patients without other comorbidities, they could be considered intrinsic to the disorder. Our study also adds to existing evidence for failure of deactivation in BPD, this time outside the default mode network.

Semantic-to-autobiographical memory priming occurs when stimuli are presented below the threshold of awareness.

A number of studies have now shown that general information processing causes the activation of memories in the autobiographical memory system. These studies have shown that general processing of words, sounds, objects, or pictures primes autobiographical memories on voluntary and involuntary autobiographical memory tasks (the Crovitz cue-word task and the vigilance task). Deemed semantic-to-autobiographical memory priming, our goal in the current study was to demonstrate that this form of priming causes the unconscious activation of autobiographical memories (autobiographical automaticity) at the point of priming. Participants named words under subliminal and supraliminal conditions and then received a test of priming (the vigilance task). The results showed that words that were processed below the threshold of awareness were equally likely as words processed above the threshold of awareness to prime the production of involuntary autobiographical memories on the vigilance task. The results support the idea that autobiographical memory activations in semantic-to-autobiographical priming is both unintentional and unconscious.

When you look at your past: Eye movement during autobiographical retrieval.

Until recently, little was known about whether or how autobiographical memory (i.e., memory of personal information) activates eye movement. This issue is now being addressed by several studies demonstrating not only how autobiographical memory activates eye movement, but also how eye movement influences the characteristics of autobiographical retrieval. This paper summarizes this research and presents a hypothesis according to which fixations and saccades during autobiographical retrieval mirror the construction of the visual image of the retrieved event. This hypothesis suggests that eye movements during autobiographical retrieval mirror the attempts of the visual system to generate and manipulate mental representations of autobiographical retrieval. It offers a theoretical framework for a burgeoning area of research that provides a rigorous behavioral evaluation of the phenomenological experience of memory.

Uncertainty salience reduces the accessibility of episodic future thoughts.

We live in uncertain times and how this pervasive sense of uncertainty affects our ability to think about the future remains largely unexplored. This study aims to investigate the effects of uncertainty salience on episodic future thinking-the ability to mentally represent specific future events. Experiment 1 assessed the impact of uncertainty on the accessibility of episodic future thoughts using an event fluency task. Participants were randomly assigned to either an uncertainty induction or control condition, and then were asked to imagine as many future events as possible that could happen in different time periods. The results showed that participants in the uncertainty condition produced fewer events, suggesting that uncertainty salience reduced the accessibility of episodic future thoughts. Experiment 2 investigated in further detail the mechanisms of production of episodic future thoughts that are affected by uncertainty. The results showed that uncertainty primarily reduced the accessibility of previously formed future thoughts (i.e., memories of the future) rather than affecting the ability to generatively think about the future and construct events. These findings shed new light on the impact of uncertainty on episodic future thinking, paving the way to further investigation into its implications for decision-making and future-oriented behavior.

Exploring the metamnemonic and phenomenal differences between transitional and mundane events.

In two experiments, we systematically investigated the reasons why people retained certain autobiographical events in their memory, as well as the properties of those events and their predicted memorability. The first experiment used three methods (word-cued, free-recalled, and "memorable, interesting, and/or important") to retrieve event memories, and examined memories from three different time-frames: very recent (within past 7 days), recent (past 2 weeks and 6 months), and older events (at least one year). In addition, data were also collected for an important transitional event recently experienced by all participants ("starting university"). The results revealed that people had access to three types of event memories: memories for life transitions, memories for older distinctive events, and memories for recent mundane events. Participants reported remembering events that were distinctive, first-time experiences, emotionally impactful, or simply because they were recent. They also predicted that older events would be more resistant to forgetting than very recent and recent events. The second experiment examined participants' memorable and forgettable events, and found that memorable events tended to be older, while forgettable events were more likely to be recent. These findings suggested that many retrievable memorable autobiographical memories were neither important nor transitional in nature. The studies contribute to our understanding of people's metamnemonic knowledge about their autobiographical memories.

Language and autobiographical memory development from 5 to 12 years: A longitudinal perspective.

The main aim of this study, with two repeated measurements, was to analyze the development of autobiographical memory in a sample of 78 Spanish participants at ages 5 (Time 1; M = 62.43 months, range: 50-74 months) and 12 (Time 2; M = 142.71 months, range: 132-155 months). Data were collected on autobiographical memory and verbal functions. We analyzed the relation between language and autobiographical memory specificity from a longitudinal perspective and assessed the indirect effect of vocabulary in the relationship between age and specific memory at both temporal moments. The results showed that language skills were positively related with autobiographical memory specificity at preschool age, but not at the second measurement. Furthermore, vocabulary scores appear to mediate the relationship between age and autobiographical specificity when children are in the preschool years, but not later. These findings agree with previous research that consider preschool age to be a crucial period for the development of autobiographical memory and its relations with language, but once basic command of language is acquired, linguistic differences impact much less on individual differences in autobiographical specificity.

Understanding the structure of autobiographical memories: A study of trauma memories from the 1994 Rwandan genocide.

How do we remember traumatic events, and are these memories different in individuals who experience post-traumatic stress? Some evidence suggests that traumatic events are mnemonically enhanced, or include more episodic detail, relative to other types of memories. Simultaneously, individuals with post-traumatic stress disorder (PTSD) have more non-episodic details in all of their memories, a pattern hypothesized to result from impairment in executive function. Here, we explore these questions in a unique population that experienced severely traumatic events more than 20 years ago - individuals who lived through the 1994 genocide in Rwanda. Participants recalled events from the genocide, negative events unrelated to the genocide, neutral events, and positive events. We used the Autobiographical Interview method to label memory details as episodic or non-episodic. We found that memories from the genocide showed robust mnemonic enhancement, with more episodic than non-episodic details, and contained more details overall than any other memory type. This pattern was not impacted by post-traumatic stress. Overall, this study provides evidence that traumatic events create vivid long-lasting episodic memories, in this case even more than 20 years later.

Obtaining semantic-to-autobiographical memory priming on the vigilance task with non-verbal cues.

Recent research has shown that the activation of semantic memories leads to the activation of autobiographical memories. Known as semantic-to-autobiographical memory priming, this form of priming has been demonstrated to prime involuntary and voluntary autobiographical memories with a wide variety of different primes (i.e., various verbal and non-verbal stimuli). However, only verbal cues have been used in the memory measures, leaving open the question of how non-verbal cues might function. Our goal in the current study was to show that non-verbal cues are also involved in semantic-to-autobiographical memory priming. Participants were primed with words, and then they were treated to an involuntary autobiographical memory task (the vigilance task) where they received either word cues or pictorial cues. The results showed that both the word cues and the pictorial cues had captured primed involuntary memories on the vigilance task relative to controls. The results support the idea that semantic-to-autobiographical memory primes occur with both verbal and non-verbal cues, potentially indicating substantial cue diversity. The results also further support the idea that semantic-to-autobiographical memory priming may play an important role in the production of involuntary autobiographical memories in everyday life.

An experimental approach: Investigating the directive function of autobiographical memory.

Why do we have autobiographical memory and how is it useful? Researchers have proposed a directive function; our experiences guide our behavior, particularly when faced with an open-ended problem. Two experiments (one between-participant and one mixed design) were therefore conducted to test whether success autobiographical memories - any experience when the participant felt successful and competent - are helpful for generating solutions to problem scenarios. One research aim was to experimentally test the directive function as current experimental evidence is limited and results are mixed. Consequently, it is unclear if and how autobiographical memory is helpful for open-ended problem solving. Another aim was to test whether self-efficacy is an important factor that supports open-ended problem solving and thus the directive function. Although success memories enhanced self-ratings of self-efficacy across both experiments, in samples of undergraduate students there was no experimental effect of success autobiographical memories on problem solving. Instead, some participants across the memory and control conditions in both experiments, even when not instructed, recalled autobiographical memories related to the problem scenarios presented in the problem-solving task, and these participants did better at problem solving than those who did not. This may hint to a directive function and is perhaps one reason why there is no experimental effect. Sample and experimental design differences are discussed as potential factors that may contribute to non-significant effects in this study but significant effects in others. Our results highlight the complexity of the directive function, and the difficulty of experimentally testing how autobiographical memory directs behavior.

Predicting the likelihood and amount of fading, fixed, flourishing, and flexible positive and negative affect of autobiographical memories.

The emotions attributed to an event can change from occurrence to recall. Autobiographical memories (AMs) exhibit fixed affect (i.e., no change in emotionality), fading affect (i.e., a decrease in emotional intensity), flourishing affect (i.e., an increase in emotional intensity), and flexible affect (i.e., change of valence). Mixed-effects multinomial models were used to predict the likelihood of the different affect change categories. Mixed-effects regression models were used to predict the amount of emotional change within each category. Predictors at the event-level were initial intensity, social rehearsal, and recall frequency. Predictors at the participant-level were components of subjective wellbeing. Analyses were based on 1,748 AMs reported by 117 young participants in response to 16 event cues. Frequency biases, and biases in the amount of change across positive and negative emotionality, were found for all types of emotional change. Specifically, there was more fading of negative (29.98%) than positive affect (11.90%), more flourishing of positive (34.27%) than negative affect (9.61%), and more AMs changing from negative to positive valence (13.33%) than vice versa (3.95%). These biases were also evident in the amount of change within the categories. Moreover, slightly more AMs remained fixed in positive (49.89%) than negative affect (47.08%). Both event and participant level predictors were significantly associated with the likelihood of different affect change categories and the amount of emotional change within the categories. The present findings highlight the importance of considering the different ways in which AMs change emotionally from occurrence to later recall.

Meta-memory (prediction) of specific autobiographical recall: An experimental approach using a modified autobiographical memory test.

Autobiographical memory specificity is known to contribute to better mental health, social problem-solving, and episodic future thinking. While numerous studies have addressed variables that affect autobiographical memory specificity, little is known regarding the meta-memory processes that underpin memory retrieval. In this study, we introduced two meta-memory constructs, ease of retrieval judgments and anticipation of negative emotion evoked, which potentially affect autobiographical memory specificity. Participants (N = 109) first rated the ease of retrieval and anticipated emotions for positive and negative words used in a subsequent autobiographical memory test. We used the Optional Instructions of the Autobiographical Memory Test, in which participants were instructed that "specific memories are better, but other memories are permissible," allowing them to adjust how much cognitive effort they spent on generative retrieval after a failure of direct retrieval. They also self-judged whether each retrieval was generative (using additional cues with cognitive effort) or direct (immediate recall without much cognitive effort). Results showed that for generative retrieval, ease of retrieval was associated with greater specific and general memories and fewer omissions. A more negative anticipated emotion was associated with fewer specific memories and greater omissions, but was not with general memories. These results suggest that low retrievability and anticipated negative emotion prevent individuals from devoting efforts to generative retrieval. The lack of association between anticipated negative emotion and general memory calls into question the functional avoidance hypothesis regarding autobiographical memory specificity. We discussed how participants judged these meta-memories and directions for future research.

The days we never forget: Flashbulb memories across the life span in Alzheimer's disease.

Alzheimer's disease (AD) is characterized by autobiographical memory deficits, with the ability to retrieve episodic-rich memories being particularly affected. Here, we investigated the influence of AD on a specific subtype of episodic memories known as flashbulb memories (i.e., the ability to remember the personal circumstances for the reception of important news events). We examined the frequency, characteristics, and the temporal distribution of flashbulb memories across the life span. To this aim, 28 older adults diagnosed with AD and a matched sample of 29 healthy older controls were probed for flashbulb memories for two historical events from each decade of their lives. They also estimated the subjective degree of reexperiencing for the memories reported. AD participants showed impaired access to flashbulb memories, the frequency of reported memories being lower than for healthy older adults. However, qualitative aspects of AD participants' flashbulb memories were quite similar to those of the controls, as no group differences were obtained with respect to the canonical categories or degree of reexperience. AD participants' flashbulb memories clustered during the early years of their life, consistent with a reminiscence bump, whereas healthy controls also reported memories dated to later lifetime periods. Our results suggest that probing for personal memories of important public events may serve as a powerful cue for detailed episodic memories in AD.

Effects of social anxiety and self-schemas on the impact and meaningfulness of positive versus negative social autobiographical memories.

OBJECTIVE: Social anxiety is characterized by maladaptive self-schemas about being socially undesirable. Self-schemas are deeply held beliefs which are derived from negative autobiographical memories of painful social experiences. In contrast to the plethora of past research on negative memories in social anxiety, almost no research has investigated objectively positive social autobiographical memories. In this preregistered study, we examined the effects of social anxiety and self-schemas on the appraised impact and meaningfulness of retrieved positive versus negative social autobiographical memories. METHOD: Participants recruited via Prolific (final n = 343) were randomized to one of two conditions in which they were instructed to retrieve, orally narrate, and appraise a positive or negative social autobiographical memory of a specific experience from their personal past where they felt either valued or unvalued, respectively. RESULTS: Results demonstrated that participants rated their positive memories as more impactful and meaningful than negative memories overall, but this effect was reversed for participants who endorsed having either stronger negative self-schemas or greater social anxiety symptoms, for whom negative memories were more impactful. Additionally, participants who endorsed having stronger positive self-schemas rated their negative memories as significantly less impactful and their positive memories as nearly more impactful. CONCLUSION: Together, these results elucidate how self-schemas and social anxiety are related to autobiographical memory appraisals, paving the way for future research on memory-based therapeutic interventions for social anxiety disorder.