Routes to the past: neural substrates of direct and generative autobiographical memory retrieval

Direct access to specific autobiographical memories is lower in healthy middle-aged to older adult Apolipoprotein E ε4 carriers compared to non-carriers

Recent research suggests that the retrieval of autobiographical memories among cognitively healthy middle-aged and older adults is sensitive to the Apolipoprotein E ε4 (APOE4) allele, a genetic marker that increases the risk of Alzheimer's disease (AD) dementia. However, whether the APOE4-associated alteration in autobiographical memory retrieval encompasses rapid (i.e. direct retrieval) or iterative (i.e. generative retrieval) processes remains unclear. In the present study, 39 APOE4 carriers and 45 non-carriers (ages 60-80) who scored within normal limits on neuropsychological testing were cued to generate specific autobiographical events. We examined group differences in direct and generative retrieval and correlated direct and generative retrieval rates with performance on neuropsychological tests. Direct retrieval rates were lower in the APOE4 carriers compared to non-carriers. Episodic memory positively correlated with direct retrieval rates across the sample, though this relationship became non-significant when factoring in age and sex. There were no significant findings related to successful generative retrieval rates and its efficiency. In summary, compared to non-carriers, cognitively unimpaired middle-aged to older adult APOE4 carriers demonstrated greater difficulty, rapidly reconstructing specific autobiographical events without the support of semantic memory, suggesting that early autobiographical memory retrieval processes demonstrate vulnerability to AD-related risk factors.

Emotional and temporal order effects - a comparison between word-cued and important autobiographical memories recall orders

The retrieval mechanisms associated with the recall of autobiographical memories (AMs) may differ according to the cueing method used to elicit AMs. In the present study, we provide a systematic comparison between word-cued and important AMs in terms of two recall order effects, namely a temporal and an emotional order effect. The sample comprised 104 adults aged between 59 and 90 years. On two measurement occasions, participants recalled up to 20 word-cued and 15 important AMs. For each memory, participants provided their age at the time when the event occurred (age-at-event) and rated its emotionality. Order effects were analysed based on multivariate multilevel model with autoregressive effects for emotionality and age-at-event, respectively. Whereas word-cued AMs showed a stronger emotional order effect, important AMs were recalled temporarily ordered. Individuals differed in the extent to which they ordered AMs along a temporal or emotional dimension. These differences could partly be explained by personality traits. For instance, higher scores on neuroticism were associated with a stronger emotional order effect in both memory types. Findings are discussed in terms of the retrieval mechanisms that are involved in the recall of word-cued and important memory recall and how they may be affected by personality.

On the retrieval of earliest memories

Earliest memories were examined with respect to recollection type (i.e., remember-know), retrieval type (i.e., direct-generative), retrieval speed, and memory fluency (i.e., phonemic, semantic, and autobiographical). A total of 137 young adults (94 females; Mage = 20.47, SDage = 1.57) reported their earliest memories and specified their recollection and retrieval types for reported memories. They further dated their recollections by reporting the age at event, rated event characteristics and completed the phonemic, semantic, and autobiographical memory fluency tasks. Remembered and known earliest memories were similar in retrieval speed, but remembered memories were more prevalent. For retrieval type, direct and generative retrieval were similar in prevalence, but direct retrieval was faster in recalling the earliest memories. Directly retrieved memories were dated earlier than generated ones, but no such pattern in dating was observed for remember-know distinction. In terms of memory fluency, none of the three fluency tasks predicted the retrieval speed, recollection and retrieval type. For event characteristics, significant differences were observed only for vividness and rehearsal for both retrieval and recollection type. The present study is the first to explore recollection and retrieval type, retrieval speed, memory fluency together with dating and event characteristics in the context of earliest memories.

The anterior medial hippocampus contributes to both recall and familiarity-based memory for scenes

The hippocampus is usually associated with recall memory, whereas its contribution to familiarity-based memory is debated. Growing evidence support the idea that this structure participates to any cognitive process performed on scene representations. In parallel, differences in functional specialisation and cortical connectivity were found across the longitudinal and transverse axes of the hippocampus. Here we reanalysed functional MRI data from 51 participants showing stronger engagement of the hippocampus in recall, familiarity-based recognition and rejection, and visual discrimination, of scenes compared to single objects. A conjunction analysis between these four tasks revealed a set of occipital, medial temporal, posterior cingulate, and parietal regions, matching the scene construction network described in the literature. Crucially, we found that the anterior medial part of the hippocampus was consistently involved in all tasks investigated for scene stimuli. These findings support that the hippocampus can contribute to both recall and familiarity-based memory, depending on stimulus type. More generally, this bolsters the recent proposal that circumscribed regions within the hippocampus may underpin specific cognitive mechanisms.

The Role of Autobiographical Resilience Memories in Emotion Regulation: An Account of Age Differences in Mnemonic and Positive Reappraisal

A lifetime of resilience through emotionally challenging experiences may benefit older adults, lending to emotion regulation mastery with time. Yet the influence of autobiographical experiences on momentary reappraisal, the reinterpretation of negative stimuli as more positive, has never been empirically tested. This online study examined the extent to which associating life memories of resilience with novel negative scenarios enhanced reappraisal efficacy and reduced difficulty to reappraise. Younger and older adults reappraised negative images by associating reappraisals to freely selected autobiographical resilience memories, cued autobiographical resilience memories, or by finding situational silver linings without mnemonic association (control). Changes in image emotional intensity ratings revealed no difference across reappraisal conditions for younger adults, while older adults most effectively down-regulated emotional intensity using the control reappraisal strategy. Older adults found autobiographical memories more helpful for mood regulation and less difficult to implement, and identified greater similarities between novel negative scenarios and their memories than younger adults. Surprisingly, greater similarity between resilience memories and negative images was associated with lower reappraisal efficacy for both age groups. Findings demonstrate the age-equivalent benefits of utilizing reappraisals associated with past narratives of resilience and suggest a sacrifice of immediate hedonic benefit for disproportionately greater subjective benefits with age.

Dissociations between directly and generatively retrieved autobiographical memories: evidence from ageing

Autobiographical memory research has largely focused on effortful, generative retrieval processes, particularly in cognitive ageing literature. However, recent evidence has shown that autobiographical memories are often retrieved directly, without effortful retrieval processes. In the present study, we examined the retrieval characteristics and the phenomenological qualities of directly and generatively retrieved memories in younger and older adults. Participants recalled autobiographical memories in response to word-cues and reported whether each of their memories was retrieved directly (i.e., memory popped into mind) or generatively (i.e., they actively searched for it), and provided ratings for several retrieval and phenomenological characteristics. Overall, directly retrieved autobiographical memories were recalled faster and with less effort, were more recent, more frequently rehearsed, more vivid, and more positive in valence than generatively retrieved memories. Importantly, while younger adults recalled a higher number of generatively retrieved autobiographical memories than older adults, there were no age effects on the number of directly retrieved memories. We also established the parallel-form reliability of the word-cue method in eliciting autobiographical memories by comparing two sets of word-cues. The results provide novel insights on the dissociable effects of retrieval type and ageing on autobiographical memories. Theoretical and practical implications of these findings are discussed.

Common and distinct correlates of construction and elaboration of episodic-autobiographical memory: An ALE meta-analysis

The recollection of episodic-autobiographical memories (EAMs) entails a complex temporal dynamic, from initial "construction" to subsequent "elaboration" of memories. While there is consensus that EAM retrieval involves a distributed network of brain regions, it is still largely debated which regions specifically contribute to EAM construction and/or elaboration. To clarify this issue, we conducted an Activation Likelihood Estimation (ALE) meta-analysis based on the Preferred Reporting Items for Systematic-Reviews and Meta-Analyses (PRISMA) method. We found common recruitment of the left hippocampus and posterior cingulate cortex (PCC) during both phases. Additionally, EAM construction led to activations in the ventromedial prefrontal cortex, left angular gyrus (AG), right hippocampus, and precuneus, while the right inferior frontal gyrus was activated by EAM elaboration. Although most of these regions are distributed over the default mode network, the current findings highlight a differential contribution according to early (midline regions, left/right hippocampus, and left AG) versus later (left hippocampus, and PCC) recollection. Overall, these findings contribute to clarify the neural correlates that support the temporal dynamics of EAM recollection.

Autobiographical memory and psychopathology: Is memory specificity as important as we make it seem?

Several decades of research have established reduced autobiographical memory specificity, or overgeneral memory, as an important cognitive factor associated with the risk for and maintenance of a range of psychiatric diagnoses. In measuring this construct, experimenters code autobiographical memories for the presence or absence of a single temporal detail that indicates that the remembered event took place on a single, specific, day (Last Thursday when I rode bikes with my son), or multiple days (When I rode bikes with my son). Studies indicate that the specificity of memories and the amount of other episodic detail that they include (e.g., who, what, and where) are related and may rely on the same neural processes to elicit their retrieval. However, specificity and detailedness are nonetheless separable constructs: imperfectly correlated and differentially associated with current and future depressive symptoms and other associated intrapersonal (e.g., rumination) and interpersonal (e.g., social support) outcomes. The ways in which the details of our memories align with narrative themes (i.e., agency, communion, identity) and the coherence with which these details are presented, are also emerging as important factors associated with psychopathology. The temporal specificity of autobiographical memories may be important, but other memory constructs warrant further attention in research and theory, especially given the associations, and dependencies, between each of these constructs. Researchers in this area must consider carefully whether their research questions necessitate a focus on autobiographical memory specificity or whether a more inclusive analysis of other autobiographical memory features is necessary and more fruitful. This article is categorized under: Psychology > Memory.

Single voxel autocorrelation uncovers gradients of temporal dynamics in the hippocampus and entorhinal cortex during rest and navigation

During navigation, information at multiple scales needs to be integrated. Single-unit recordings in rodents suggest that gradients of temporal dynamics in the hippocampus and entorhinal cortex support this integration. In humans, gradients of representation are observed, such that granularity of information represented increases along the long axis of the hippocampus. The neural underpinnings of this gradient in humans, however, are still unknown. Current research is limited by coarse fMRI analysis techniques that obscure the activity of individual voxels, preventing investigation of how moment-to-moment changes in brain signal are organized and how they are related to behavior. Here, we measured the signal stability of single voxels over time to uncover previously unappreciated gradients of temporal dynamics in the hippocampus and entorhinal cortex. Using our novel, single voxel autocorrelation technique, we show a medial-lateral hippocampal gradient, as well as a continuous autocorrelation gradient along the anterolateral-posteromedial entorhinal extent. Importantly, we show that autocorrelation in the anterior-medial hippocampus was modulated by navigational difficulty, providing the first evidence that changes in signal stability in single voxels are relevant for behavior. This work opens the door for future research on how temporal gradients within these structures support the integration of information for goal-directed behavior.

New insights into anatomical connectivity along the anterior–posterior axis of the human hippocampus using in vivo quantitative fibre tracking

The hippocampus supports multiple cognitive functions including episodic memory. Recent work has highlighted functional differences along the anterior–posterior axis of the human hippocampus, but the neuroanatomical underpinnings of these differences remain unclear. We leveraged track-density imaging to systematically examine anatomical connectivity between the cortical mantle and the anterior–posterior axis of the in vivo human hippocampus. We first identified the most highly connected cortical areas and detailed the degree to which they preferentially connect along the anterior–posterior axis of the hippocampus. Then, using a tractography pipeline specifically tailored to measure the location and density of streamline endpoints within the hippocampus, we characterised where these cortical areas preferentially connect within the hippocampus. Our results provide new and detailed insights into how specific regions along the anterior–posterior axis of the hippocampus are associated with different cortical inputs/outputs and provide evidence that both gradients and circumscribed areas of dense extrinsic anatomical connectivity exist within the human hippocampus. These findings inform conceptual debates in the field and emphasise the importance of considering the hippocampus as a heterogeneous structure. Overall, our results represent a major advance in our ability to map the anatomical connectivity of the human hippocampus in vivo and inform our understanding of the neural architecture of hippocampal-dependent memory systems in the human brain.

The brain allows us to perceive and interact with our environment and to create and recall memories about our day-to-day lives. A sea-horse shaped structure in the brain, called the hippocampus, is critical for translating our perceptions into memories, and it does so in coordination with other brain regions. For example, different regions of the cerebral cortex (the outer layer of the brain) support different aspects of cognition, and pathways of information flow between the cerebral cortex and hippocampus underpin the healthy functioning of memory.

Decades of research conducted into the brains of non-human primates show that specific regions of the cerebral cortex anatomically connect with different parts of the hippocampus to support this information flow. These insights form the foundation for existing theoretical models of how networks of neurons in the hippocampus and the cerebral cortex are connected. However, the human cerebral cortex has greatly expanded during our evolution, meaning that patterns of connectivity in the human brain may diverge from those in the brains of non-human primates.

Deciphering human brain circuits in greater detail is crucial if we are to gain a better understanding of the structure and operation of the healthy human brain. However, obtaining comprehensive maps of anatomical connections between the hippocampus and cerebral cortex has been hampered by technical limitations. For example, magnetic resonance imaging (MRI), an approach that can be used to study the living human brain, suffers from insufficient image resolution.

To overcome these issues, Dalton et al. used an imaging technique called diffusion weighted imaging which is used to study white matter pathways in the brain. They developed a tailored approach to create high-resolution maps showing how the hippocampus anatomically connects with the cerebral cortex in the healthy human brain. Dalton et al. produced detailed maps illustrating which areas of the cerebral cortex have high anatomical connectivity with the hippocampus and how different parts of the hippocampus preferentially connect to different neural circuits in the cortex. For example, the experiments demonstrate that highly connected areas in a cortical region called the temporal cortex connect to very specific, circumscribed regions within the hippocampus.

These findings suggest that the hippocampus may consist of different neural circuits, each preferentially linked to defined areas of the cortex which are, in turn, associated with specific aspects of cognition. These observations further our knowledge of hippocampal-dependant memory circuits in the human brain and provide a foundation for the study of memory decline in aging and neurodegenerative diseases.

Effects of the use of autobiographical photographs on emotional induction in older adults: a systematic review

There is evidence to support the positive contribution of autobiographical recall based techniques on individuals' quality of life, mood and cognitive functioning. In this review, we analyzed the effects of the use of personal photographs in interventions based on autobiographical memory in older people with and without cognitive impairment. The PRISMA guidelines for systematic reviews were followed. The search was carried out in the electronic databases Web of Sciences (WOS), Medline (PubMed), SCIELO and PsycInfo (American Psychological Association). The articles based on clinical trials selected were evaluated using the PEDRo scale, which is specific to this type of article. Of the 1098 articles initially found, 6 met the inclusion criteria. The final articles focused their intervention on the use of autobiographical photographs as a means of stimulation. The results show that the use of photographs in different autobiographical recall stimulation techniques is associated with higher scores on well-being and quality of life, as well as with improvements in personal identity and cognitive functioning. This suggests that using personal photographs shows promise in enhancing the effect of these types of interventions in healthy or cognitively impaired older adults.

Use of autobiographical stimuli as a mood manipulation procedure: Systematic mapping review

Background

In recent years, mood induction procedures have been developed in experimental settings that are designed to facilitate studying the impact of mood states on biological and psychological processes. The aim of the present study was to conduct a systematic mapping review with the intention of describing the state of the art in the use of different types of autobiographical stimuli for mood induction procedures.

Methods

Based on a search for publications from the period 2000–2021, conducted in four recognised databases (Scopus, Medline (PubMed), PsycINFO and Web of Science), we analysed a total of 126 published articles. Text mining techniques were used to extract the main themes related.

Results

The induction of emotions through autobiographical memories is an area under construction and of growing interest. The data mining approach yielded information about the main types of stimuli used in these procedures, highlighting those that only employ a single type of cue, as well as the preference for verbal cues over others such as musical, olfactory and visual cues. This type of procedure has been used to induce both positive and negative emotions through tasks that require access to personal memories of specific events from a cue, requiring the person to set in motion different cognitive processes. The use of the latest technologies (fMRI, EEG, etc.) is also shown, demonstrating that this is a cutting-edge field of study.

Conclusions

Despite the study of mood induction procedures still being a growing field, the present review provides a novel overview of the current state of the art in the field, which may serve as a framework for future studies on the topic.

Could direct and generative retrieval be two flips of the same coin? A dual-task paradigm study

Autobiographical memories are thought to be retrieved using two possible ways: a generative one, which is effortful and follows a general-to-specific pathway, and a direct one, which is automatic and relatively effortless. These two retrieve processes are known to differ on the quantitative side (especially considering retrieval times), from a qualitative point of view; however, evidence is missing. Here, we aimed to disentangle this question by taking advantage of a dual-task paradigm in which the different tasks tax different executive functions. Participants were asked to perform an autobiographical memory task under three different conditions: no cognitive load, non-visual cognitive load and visual cognitive load. On the quantitative side, results replicated previous findings with generative processes being slower compared with direct ones. Conversely, on the qualitative side, results indicated that the retrieval times of both direct and generative retrieval processes varied similarly according to the dual-task condition, thus supporting the idea that the same memory process could underlie both retrievals.

The forgotten role of absorption in music reward

Interindividual differences in music-related reward have been characterized as involving five main facets: musical seeking, emotion evocation, mood regulation, social reward, and sensory-motor. An interesting concept related to how humans decode music as a rewarding experience is music transcendence or absorption (i.e., music-driven states of complete immersion, including momentary loss of self-consciousness or even time-space disorientation). Here, we investigated the relation between previously characterized facets of music reward and individual differences in music absorption. A first sample of participants (N = 370) completed both the Barcelona Music Reward Questionnaire (BMRQ) and the Absorption in Music Scale (AIMS). Results showed that both constructs were highly interrelated (r = 0.78, p < 0.001), indicating that higher music reward sensitivity is associated with a greater tendency to music-related absorption states. In addition, four items from the AIMS were identified as suitable to be added to an extended version of the BMRQ (eBMRQ). A second sample (N = 550) completed the eBMRQ for a validation study. Exploratory and confirmatory factor analyses on the whole sample (N = 920) showed the reliable psychometric properties of the eBMRQ and suggested that taking into account an absorption facet could contribute to a better characterization of individual differences in the sensitivity to experience music-related reward and pleasure.

Autobiographical Memory Fluency Reductions in Cognitively Unimpaired Middle-Aged and Older Adults at Increased Risk for Alzheimer's Disease Dementia

OBJECTIVE

Recent research has revealed that cognitively unimpaired older adults who are at higher risk for developing Alzheimer's disease (AD) dementia often exhibit subtle cognitive alterations in their neuropsychological profiles. Emerging evidence suggests that autobiographical memory, which is memory for personal events and knowledge, may be sensitive to early AD-related cognitive alterations. In the present study, we investigated whether the rapid generation of autobiographical memory category exemplars, a retrieval process that taxes the neural network that is vulnerable to early AD, is compromised in cognitively unimpaired middle-aged and older carriers of the e4 allele of the apolipoprotein E gene (APOE4), which increases risk for AD dementia.

METHODS

In addition to standard neuropsychological tests, we administered a fluency task that requires generating exemplars for two types of autobiographical memory, namely episodic memories and personal semantics, to a group of cognitively unimpaired middle-aged and older adults (n = 45) enriched with APOE4 carriers (n = 20).

RESULTS

While no APOE4 deficits were found on standard neuropsychological tests, episodic and personal semantic exemplar generation was reduced in the APOE4 group.

DISCUSSION

Autobiographical memory aberrations associated with a higher risk for AD are evident in fluency and affect both episodic memory and personal semantics.

The Seven Selves of Dementia

The self is a complex and multifaceted phenomenon, encompassing a variety of cognitive processes and psychosocial influences. Considering this, there is a multiplicity of "selves," the current review suggesting that seven fundamental self-processes can be identified that further our understanding of the experience of dementia. These include (1) an embodied self, manifest as corporeal awareness; (2) an agentic self, related to being an agent and influencing life circumstances; (3) an implicit self, linked to non-conscious self-processing; (4) a critical self, which defines the core of self-identity; (5) a surrogate self, based on third-person perspective information; (6) an extended self, including external objects or existences that are incorporated into the self; and, finally, (7) an emergent self, a property of the self-processes that give rise to the sense of a unified self. These are discussed in relation to self-awareness and their use in making sense of the experience of dementia.

The relationship between hippocampal subfield volumes and autobiographical memory persistence

Structural integrity of the human hippocampus is widely acknowledged to be necessary for the successful encoding and retrieval of autobiographical memories. However, evidence for an association between hippocampal volume and the ability to recall such memories in healthy individuals is mixed. Here we examined this issue further by combining two approaches. First, we focused on the anatomically distinct subregions of the hippocampus where more nuanced associations may be expressed compared to considering the whole hippocampal volume. A manual segmentation protocol of hippocampal subregions allowed us to separately calculate the volumes of the dentate gyrus/CA4, CA3/2, CA1, subiculum, pre/parasubiculum and uncus. Second, a critical feature of autobiographical memories is that they can span long time periods, and so we sought to consider how memory details persist over time by conducting a longitudinal study whereby participants had to recall the same autobiographical memories on two visits spaced 8 months apart. Overall, we found that there was no difference in the total number of internal (episodic) details produced at Visits 1 and 2. However, further probing of detail subcategories revealed that specifically the amount of subjective thoughts and emotions included during recall had declined significantly by the second visit. We also observed a strong correlation between left pre/parasubiculum volume and the amount of autobiographical memory internal details produced over time. This positive relationship was evident for particular facets of the memories, with remembered events, perceptual observations and thoughts and emotions benefitting from greater volume of the left pre/parasubiculum. These preliminary findings expand upon existing functional neuroimaging evidence by highlighting a potential link between left pre/parasubiculum volume and autobiographical memory. A larger pre/parasubiculum appears not only to protect against memory decay, but may possibly enhance memory persistence, inviting further scrutiny of the role of this brain region in remote autobiographical memory retrieval.

Searching for the past: Exploring the dynamics of direct and generative autobiographical memory reconstruction among young and cognitively normal older adults

Episodic autobiographical memories (EAMs) can come to mind through two retrieval routes, one direct (i.e., an EAM is retrieved almost instantaneously) and the other generative (i.e., by using autobiographical/general knowledge to cue an EAM). It is well established that normal cognitive aging is associated with a reduction in the retrieval of EAMs, but the contributions of direct or generative reconstruction to the age-related shift toward general memories remain unknown. Prior studies also have not clarified whether similar cognitive mechanisms facilitate the ability to successfully reconstruct EAMs and elaborate them in event-specific detail. To address these gaps in knowledge, young and older participants were asked to reconstruct EAMs using a "think-aloud" paradigm and then describe in detail a subset of retrieved memories. An adapted scoring procedure was implemented to categorize memories accessed during reconstruction, and the Autobiographical Interview (AI) scoring procedure was utilized for elaboration scoring. Results indicated that in comparison with young adults, older adults not only engaged in direct retrieval less often than young adults but they also more often ended generative retrieval at general events instead of EAMs. The ability to elaborate EAMs with internal details was positively associated with the ability to use generative retrieval to reconstruct EAMs in both young and older adults, but there was no relationship between internal detail elaboration and direct retrieval in either age group. Taken together, these results indicate age-related differences in direct and generative retrieval contribute to overgeneral autobiographical memory and they support a connection between generative retrieval and elaboration.

Reminders activate the prefrontal-medial temporal cortex and attenuate forgetting of event memory

Replicas of an aspect of an experienced event can serve as effective reminders, yet little is known about the neural basis of such reminding effects. Here we examined the neural activity underlying the memory-enhancing effect of reminders 1 week after encoding of naturalistic film clip events. We used fMRI to determine differences in network activity associated with recently reactivated memories relative to comparably aged, non-reactivated memories. Reminders were effective in facilitating overall retrieval of memory for film clips, in an all-or-none fashion. Prefrontal cortex and hippocampus were activated during both reminders and retrieval. Peak activation in ventro-lateral prefrontal cortex (vPFC) preceded peak activation in the right hippocampus during the reminders. For film clips that were successfully retrieved after 7 days, pre-retrieval reminders did not enhance the quality of the retrieved memory or the number of details retrieved, nor did they more strongly engage regions of the recollection network than did successful retrieval of a non-reminded film clip. These results suggest that reminders prior to retrieval are an effective means of boosting retrieval of otherwise inaccessible episodic events, and that the inability to recall certain events after a delay of a week largely reflects a retrieval deficit, rather than a storage deficit for this information. The results extend other evidence that vPFC drives activation of the hippocampus to facilitate memory retrieval and scene construction, and show that this facilitation also occurs when reminder cues precede successful retrieval attempts. The time course of vPFC-hippocampal activity during the reminder suggests that reminders may first engage schematic information meditated by vPFC followed by a recollection process mediated by the hippocampus.

Common and distinct neural systems support the generation retrieval phase of autobiographical memory and personal problem solving

Prior research has documented engagement of a common 'core' retrieval network during autobiographical memory retrieval and higher-order prospective tasks, such as personal problem solving. This neural overlap has overwhelmingly been documented in the context of the 'elaboration phase' of retrieval, when a single mental event is simulated in detail . However, recollective and prospective tasks are often associated with generic cues, which require the retrieval and consideration of multiple conceptually-related events. This initial 'generation phase' of retrieval has received comparably little attention in the literature, leaving open questions as to how and when autobiographical memory and prospective tasks overlap within the brain. Here, we compare and contrast neural activity between autobiographical memory retrieval and personal problem solving with a focus on the initial generation phase of retrieval. In the MRI scanner, young adults completed both an autobiographical memory and a personal problem solving task. Each task consisted of a generation phase, which required participants to generate multiple past personal events or problem solutions to a given cue and a subsequent elaboration phase, where a single memory or solution was simulated in detail. A multivariate Partial Least Squares analysis revealed patterns of neural overlap between memory and problem solving during the generation phase that were distinct from the elaboration phase. Among regions commonly recruited during the generation phase was the anterior hippocampus, a structure involved in initiating mental construction and integrating concepts. Subsequent analyses demonstrated that the anterior hippocampus interacted with distinct cortical regions as a function of task, in particular the ventromedial prefrontal cortex. Together, these data provide novel evidence that neural overlap between autobiographical memory and personal problem solving does not occur solely in the context of detailed simulation but, instead, is driven by common retrieval demands.

Effective connectivity during autobiographical memory search

INTRODUCTION

We used dynamic causal modeling (DCM) to examine effective connectivity during cued autobiographical memory (AM) search in a left-hemispheric network consisting of six major regions within the large network of brain regions recruited during memory retrieval processes.

METHODS

Functional MRI data were acquired while participants were shown verbal cues describing common life events and requested to search for a personal memory associated with the cue. We examined directed couplings between the ventromedial (vmPFC), dorsomedial (dmPFC), and dorsolateral prefrontal cortices (dlPFC), hippocampus, angular gyrus, and the posterior midline cortex (RSC/PCC/Prec).

RESULTS

During AM search, the vmPFC, dlPFC, and RSC/PCC/Prec acted as primary drivers of activity in the rest of the network. Moreover, when AM search completed successfully (Hits), the effective connectivity of the hippocampus on the vmPFC and angular gyrus was up-modulated. Likewise, there was an increase in the influence of the RSC/PCC/Prec in the activity of the dlPFC and dmPFC. Further analysis indicated that the modulation observed during Hits is primarily a distributed phenomenon that relies on the interplay between different brain regions.

CONCLUSION

These results suggest that prefrontal and posterior midline cortical regions together with the dlPFC largely coordinate the processes underlying AM search, setting up the conditions on which the angular gyrus and the hippocampus may act upon when the outcome of the search is successful.

Meditation and the Wandering Mind: A Theoretical Framework of Underlying Neurocognitive Mechanisms

During the practice of meditation, the tendency of the mind to wander away from the object of focus is ubiquitous. The occurrence of mind wandering in the context of meditation provides individuals a unique and intimate opportunity to closely examine the nature of the wandering mind by cultivating an awareness of ongoing thought patterns, while simultaneously aiming to cultivate equanimity (evenness of temper or disposition) and compassion toward the content of thoughts, interpretations, and bodily sensations. In this article we provide a theoretical framework that highlights the neurocognitive mechanisms by which contemplative practices influence the neural and phenomenological processes underlying spontaneous thought. Our theoretical model focuses on several converging mechanisms: the role of meta-awareness in facilitating an increased moment-to-moment awareness of spontaneous thought processes, the effects of meditation practice on key structures underlying both the top-down cognitive processes and bottom-up sensory processes implicated in attention and emotion regulation, and the influence of contemplative practice on the neural substrates underlying perception and perceptual decoupling.

Flashbulb memory recall in healthy adults - a functional magnetic resonance imaging study

The present study investigated neural activations related to flashbulb memory (FM) recall and examined whether the amygdala and hippocampus are involved in FM recall. 20 healthy adults completed a block design with an FM-condition, where the reception events for a number of potential FM events had to be recalled, and a control condition (FMC) comprising reception events lacking FM characteristics. A definition naming task was used as an implicit baseline. The individual emotional reaction to the FM events (EMO) and self-rated retrieval success were included in the SPM model as modulating parameters. The main contrast of interest were FM > FMC and activations associated with EMO. ROI-analyses on mesiotemporal regions were performed. FM > FMC yielded activations in line with the autobiographical memory network, with mostly left sided-activations. EMO was associated with a more bilateral activation pattern. ROI-analysis revealed activations for EMO in the right amygdala and HATA. FM > FMC was associated with right hippocampal activations. The present findings are compatible with previous research into autobiographical memory, but also show activations for FM recall different from ordinary, not highly emotional autobiographical memories, as EMO is associated with a more bilateral network. Moreover, the amygdala seems to be involved in FM recall.

Context-Dependent Coding of Temporal Distance Between Cinematic Events in the Human Precuneus

How temporal and contextual information interactively impact on behavior and brain activity during the retrieval of temporal order about naturalistic episodes remains incompletely understood. Here, we used fMRI to examine the effects of contextual signals derived from the content of the movie on the neural correlates underlying memory retrieval of temporal-order in human subjects of both sexes. By contrasting SAME versus DIFF storyline conditions during the retrieval of the temporal order of cinematic events, we found that the activation in the precuneus, as well as behavior, are significantly modulated according to storyline condition, supporting our prediction of contextual information contributing to temporal retrieval. We suggest that the precuneus engages in memory retrieval via reconstructive mechanisms, entailing search within a movie-specific, situational knowledge-structure. Furthermore, information-based analyses of multivoxel activity revealed that the precuneus also contains a context-independent linear representation of temporal distances, consistent with a chronological organization of memory traces. We thus put forward that the retrieval of the temporal-order of naturalistic events encoded in rich and dynamic contexts relies on the joint contribution of chronological and reconstructive mechanisms, both of which rely on the medioposterior parietal cortex in humans.SIGNIFICANCE STATEMENT Successful retrieval of episodic memory is dependent on both temporal and contextual signals. However, when contextual signals derived from multiple storylines or narratives are complex and intertwined, the behavioral and neural correlates underpinning the interplay between time and context is not completely understood. Here we characterized the activation level and multivoxel pattern of BOLD signals underlying the modulation of such contextual information during temporal order judgment in the precuneus. Our findings provide us with an elucidation of subprocesses implicating the medial parietal cortex in realizing temporal organization of episodic details.

Effects of positive personal and non-personal autobiographical stimuli on emotional regulation in older adults

People can regulate negative emotional states using personal episodic information stored in memory. However, amongst older adults, assistance in retrieving personal memories might be needed. As such, positive personal images might better facilitate the retrieval of positive personal memories, relative to generic positive images. The present study induced older adults (N = 40; Mage = 76.28) into a negative mood state using a validated film clip ("Dead Man Walking"; Robbins et al. in Dead Man Walking [Cinta Cinematográfica]. PolyGram Filmed Entertainment, Working Title Films, Estados Unidos, 1995). Participants were then shown positive personal images (album photos) or positive non-personal images from the International Affective Picture System (IAPS) and between-group differences in their mood state and their ability to retrieve positive autobiographical memories were measured. Although participants' moods decreased after the negative mood induction, their mood then recovered after picture cuing regardless of whether images were personal or non-personal. Furthermore, the positive mood evoked by non-personal, but not personal, images was significantly positively associated with self-reported feelings of reliving of the memories evoked by those images. These results suggest that, when pictures from personal life are not available, the selection of images able to generate positive autobiographical memories with a sense of reliving, is a feasible tool for older adult's emotional regulation.

Differential Contributions of Default and Dorsal Attention Networks to Remembering Thoughts and External Stimuli From Real-Life Events

Episodic memories are typically composed of perceptual information derived from the external environment and representations of internal states (e.g., one's thoughts during prior episodes). To date, however, research has mostly focused on the remembrance of external stimuli, such that little is known about how internal mentation is represented within episodic memory. In the present fMRI study, we examined the neural correlates of these 2 components of episodic memories using a novel method of cuing memories from photographs taken during real-life events. We found that, compared with corresponding semantic memory tasks, memories for internal thoughts and external elements were associated with activity in brain areas supporting episodic recollection. Most importantly, however, the 2 kinds of memories also showed differential activation in large-scale brain networks: the remembrance of external elements was associated with greater activity in the dorsal attention network, whereas memories of internal thoughts mainly recruited default network areas. These findings shed new light on the representation of internal and external aspects of prior experience within episodic memory. The default network may contribute to the reinstatement of thoughts experienced during past events, whereas the dorsal attention network may support the allocation of attention to visuospatial features within episodic memory representations.

Mental Control in Musical Imagery: A Dual Component Model

Hearing music in your head is a ubiquitous experience, but the role mental control plays in these experiences has not been deeply addressed. In this conceptual analysis, a dual-component model of mental control in musical imagery experiences is developed and discussed. The first component, initiation, refers to whether the musical imagery experience began voluntarily or involuntarily. The second component, management, refers to instances of control that occur after the experience has begun (e.g., changing the song, stopping the experience). Given the complex nature of this inner experience, we propose a new model combining and integrating four literatures: lab-based auditory imagery research using musical stimuli; involuntary musical imagery; mental rehearsal and composition in musicians; and in vivo studies of musical imagery in everyday environments. These literatures support the contention that mental control of musical imagery is multi-faceted. Future research should investigate these two components of mental control and better integrate the diverse literatures on musical imagery.

Direct and generative autobiographical memory retrieval: How different are they?

Theories of autobiographical memory have emphasised effortful generative retrieval, but recent research indicates that subjectively effortless direct retrieval is common. We compared the processes of direct and generative retrieval. Sixty-five participants retrieved 24 autobiographical memories across three cue types: concrete, emotional, and personal. We recorded retrieval latency, and participants judged direct versus generative retrieval and rated memory specificity, vividness, significance, rehearsal, and emotionality. Overall, direct retrieval was common, especially for personal cues. Directly retrieved memories were recalled faster, were less likely to be specific, and were rated more significant, rehearsed, and emotional than generatively retrieved memories. The speed of both direct and generative retrieval varied similarly according to cue type, suggesting they did not involve fundamentally different cognitive processes. These findings challenge theories that assume direct retrieval bypasses constructive processes. Instead we suggest that both direct and generative retrieval involve construction that is similarly affected by cue concreteness and relevance.

Systema Temporis: A time-based dimensional framework for consciousness and cognition

This study uses a combined categorical-dimensional approach to depict a hierarchical framework for consciousness similar to, and contiguous with, factorial models of cognition (cf., intelligence). On the basis of the longstanding definition of time consciousness, the analysis employs a dimension of temporal extension, in the same manner that psychology has temporally organised memory (i.e., short-term, long-term, and long-lasting memories). By defining temporal extension in terms of the structure of time perception at short timescales (<100 s), memory and time consciousness are proposed to fit along the same logarithmic dimension. This suggests that different forms of time consciousness (e.g., experience, wakefulness, and self-consciousness) are embedded within, or supported by, the ascending timescales of different modes of memory (i.e., short-term, long-term, etc.). A secondary dimension is also proposed to integrate higher-order forms of consciousness/emotion and memory/cognition. The resulting two-dimensional structure accords with existing theories of cognitive and emotional intelligence.

Increased Functional Connectivity of the Angular Gyrus During Imagined Music Performance

The angular gyrus (AG) is a hub of several networks that are involved in various functions, including attention, self-processing, semantic information processing, emotion regulation, and mentalizing. Since these functions are required in music performance, it is likely that the AG plays a role in music performance. Considering that these functions emerge as network properties, this study analyzed the functional connectivity of the AG during the imagined music performance task and the resting condition. Our hypothesis was that the functional connectivity of the AG is modulated by imagined music performance. In the resting condition, the AG had connections with the medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), and precuneus as well as the superior and inferior frontal gyri and with the temporal cortex. Compared with the resting condition, imagined music performance increased the functional connectivity of the AG with the superior frontal gyrus (SFG), mPFC, precuneus, PCC, hippocampal/parahippocampal gyrus (H/PHG), and amygdala. The anterior cingulate cortex (ACC) and superior temporal gyrus (STG) were newly engaged or added to the AG network during the task. In contrast, the supplementary motor area (SMA), sensorimotor areas, and occipital regions, which were anti-correlated with the AG in the resting condition, were disengaged during the task. These results lead to the conclusion that the functional connectivity of the AG is modulated by imagined music performance, which suggests that the AG plays a role in imagined music performance.

First-person view of one's body in immersive virtual reality: Influence on episodic memory

Episodic memories (EMs) are recollections of contextually rich and personally relevant past events. EM has been linked to the sense of self, allowing one to mentally travel back in subjective time and re-experience past events. However, the sense of self has recently been linked to online multisensory processing and bodily self-consciousness (BSC). It is currently unknown whether EM depends on BSC mechanisms. Here, we used a new immersive virtual reality (VR) system that maintained the perceptual richness of life episodes and fully controlled the experimental stimuli during encoding and retrieval, including the participant’s body. Our data reveal a classical EM finding, which shows that memory for complex real-life like scenes decays over time. However, here we also report a novel finding that delayed retrieval performance can be enhanced when participants view their body as part of the virtual scene during encoding. This body effect was not observed when no virtual body or a moving control object was shown, thereby linking the sense of self, and BSC in particular, to EMs. The present VR methodology and the present behavioral findings will enable to study key aspects of EM in healthy participants and may be especially beneficial for the restoration of self-relevant memories in future experiments.

Executive Functions, Episodic Autobiographical Memory, Problem-Solving Capacity, and Depression Proposal for a Structural Equations Model

The executive functions play an important role in storing and recovering autobiographical memories, especially episodic memories. These types of memories provide information about solutions and experiences from the past that can be utilized as examples in the present when seeking solutions to any problem. In addition, a close relationship between depression and the executive functions has been widely recognized. This study aims to elaborate a structural equations model that empirically supports the relationships among the executive functions, episodic autobiographical memory, and the adaptive capacity to solve problems, taking into account the depressed mood state. In all, 32 healthy elderly people, 32 patients with Parkinson disease, 32 with amnestic mild cognitive impairment, and 32 with Alzheimer disease were evaluated. Structural equation models were estimated to test the effects among the constructs. The final model shows adequate fit indexes, thus revealing that an individual's problem-solving capacity will depend on the capacity to access the episodic autobiographical memory, which in turn will depend on the maintenance of executive functioning. In a parallel way, the mood state, and specifically depression, will play a modulator role because when there is depressive symptomatology, some capacities that depend on executive control can be diminished.

Remote Memory and the Hippocampus: A Constructive Critique

The hippocampus is known to be recruited during the recall of experiences from our distant past, despite evidence that memory traces in this region vanish over time. Extant theories of systems-level consolidation have yet to accommodate both phenomena. We propose that the hippocampus reconstructs remote memories in the absence of the original trace. It accomplishes this by assembling consolidated neocortical elements into spatially coherent scenes that form the basis of unfolding memory events. This reconstruction is likely facilitated by input from the ventromedial prefrontal cortex. This process-oriented approach to hippocampal recruitment during remote recollection is consistent with its increasingly acknowledged role in constructing mental representations beyond the domain of memory.

Common Recruitment of Angular Gyrus in Episodic Autobiographical Memory and Bodily Self-Consciousness

Parietal cortex and adjacent parts of the temporal cortex have recently been associated with bodily self-consciousness (BSC). Similarly, growing evidence suggests that the lateral parietal cortex is crucial for the subjective aspects of episodic autobiographical memory (EAM), which is based on the conscious experience of reliving past events. However, the neuroanatomical relationship between both fundamental aspects remains currently unexplored. Moreover, despite the wealth of neuroimaging data on EAM, only few neuroimaging studies have examined BSC and even fewer examined those aspects of BSC that are most closely related to EAM. Here, we investigated whether regions in the inferior parietal lobule (IPL) that have been involved in spatial aspects of BSC (self-location and first-person perspective), as described by Ionta et al. (2011) are also active in studies investigating autobiographical memory. To examine this relation, we thus compared the regions indicated in the study by Ionta et al. (2011) based on data in healthy participants and neurological patients, with the results from a meta-analytical study we performed based on functional neuroimaging studies on EAM and semantic autobiographical memory (SAM). We report an anatomical overlap bilaterally in the angular gyrus (AG), but not in other parietal or temporal lobe structures between BSC and EAM. Moreover, there was no overlap between BSC and SAM. These preliminary data suggest that the bilateral AG may be a key structure for the conscious re-experiencing of past life episodes (EAM) and the conscious on-line experience of being located and experiencing the world in first-person (BSC).

Past is prologue: The role of memory retrieval in young children's episodic prospection

Prior research has revealed a strong link between the ability to remember one's past (i.e., episodic memory) and the ability to envision one's future (i.e., episodic prospection). Indeed, the past holds valuable learning experiences that can inform future choices and plans. Although these abilities both emerge during preschool years, there exist few theoretical accounts of how memory processes might support developmental improvements in prospection abilities. We developed a novel paradigm to determine whether young children (3 and 4 years of age) use past knowledge to inform future choices. Experiment 1 revealed that children find it more difficult to retrieve relevant information from their past when they envision the future versus reflect on the past. Experiment 2 facilitated children's access to past event components and, thereby, eased retrieval of relevant components from memory for future event construction. We discuss results in light of recent proposals on the development of episodic prospection.

Neural correlates of free recall of "famous events" in a "hypermnestic" individual as compared to an age- and education-matched reference group

BACKGROUND

Memory performance of an individual (within the age range: 50-55 years old) showing superior memory abilities (protagonist PR) was compared to an age- and education-matched reference group in a historical facts ("famous events") retrieval task.

RESULTS

Contrasting task versus baseline performance both PR and the reference group showed fMRI activation patterns in parietal and occipital brain regions. The reference group additionally demonstrated activation patterns in cingulate gyrus, whereas PR showed additional widespread activation patterns comprising frontal and cerebellar brain regions. The direct comparison between PR and the reference group revealed larger fMRI contrasts for PR in right frontal, superior temporal and cerebellar brain regions.

CONCLUSIONS

It was concluded that PR generally recruits brain regions as normal memory performers do, but in a more elaborate way, and furthermore, that he applied a memory-strategy that potentially includes executively driven multi-modal transcoding of information and recruitment of implicit memory resources.

The neural signature of emotional memories in serial crimes

Neural plasticity is the process whereby semantic information and emotional responses are stored in neural networks. It is hypothesized that the neural networks built over time to encode the sexual fantasies that motivate serial killers to act should display a unique, detectable activation pattern. The pathological neural watermark hypothesis posits that such networks comprise activation of brain sites that reflect four cognitive components: autobiographical memory, sexual arousal, aggression, and control over aggression. The neural sites performing these cognitive functions have been successfully identified by previous research. The key findings are reviewed to hypothesise the typical pattern of activity that serial killers should display. Through the integration of biological findings into one framework, the neural approach proposed in this paper is in stark contrast with the many theories accounting for serial killers that offer non-medical taxonomies. The pathological neural watermark hypothesis offers a new framework to understand and detect deviant individuals. The technical and legal issues are briefly discussed.

What versus Where: Investigating how Autobiographical Memory Retrieval Differs when Accessed with Thematic versus Spatial Information

Autobiographical memory research has investigated how cueing distinct aspects of a past event can trigger different recollective experiences. This research has stimulated theories about how autobiographical knowledge is accessed and organized. Here, we test the idea that thematic information organizes multiple autobiographical events whereas spatial information organizes individual past episodes by investigating how retrieval guided by these two forms of information differs. We used a novel autobiographical fluency task in which participants accessed multiple memory exemplars to event theme and spatial (location) cues followed by a narrative description task in which they described the memories generated to these cues. Participants recalled significantly more memory exemplars to event theme than to spatial cues; however, spatial cues prompted faster access to past memories. Results from the narrative description task revealed that memories retrieved via event theme cues compared to spatial cues had a higher number of overall details, but those recalled to the spatial cues were recollected with a greater concentration on episodic details than those retrieved via event theme cues. These results provide evidence that thematic information organizes and integrates multiple memories whereas spatial information prompts the retrieval of specific episodic content from a past event.

Posterior and prefrontal contributions to the development posttraumatic stress disorder symptom severity: an fMRI study of symptom provocation in acute stress disorder

Acute stress disorder (ASD) is predictive of the development of posttraumatic stress disorder (PTSD). In response to symptom provocation, the exposure to trauma-related pictures, ASD patients showed increased activation of the medial posterior areas of precuneus and posterior cingulate cortex as well as of superior prefrontal cortex in a previous study. The current study aimed at investigating which activated areas are predictive of the development of PTSD. Nineteen ASD patients took part in an fMRI study in which they were shown personalized trauma-related and neutral pictures within 4 weeks of the traumatic event. They were assessed for severity of PTSD 4 weeks later. Activation contrasts between trauma-related and neutral pictures were correlated with subsequent PTSD symptom severity. Greater activation in, among others, right medial precuneus, left retrosplenial cortex, precentral and right superior temporal gyrus as well as less activation in lateral, superior prefrontal and left fusiform gyrus was related to subsequently increased PTSD severity. The results are broadly in line with neural areas related to etiological models of PTSD, namely multisensory associative learning recruiting posterior regions on the one hand and failure to reappraise maladaptive cognitions, thought to involve prefrontal areas, on the other.

A short cut to the past: Cueing via concrete objects improves autobiographical memory retrieval in Alzheimer's disease patients

Older adults diagnosed with Alzheimer's disease (AD) have difficulties accessing autobiographical memories. However, this deficit tends to spare memories dated to earlier parts of their lives, and may partially reflect retrieval deficits rather than complete memory loss. Introducing a novel paradigm, the present study examines whether autobiographical memory recall can be improved in AD by manipulating the sensory richness, concreteness and cultural dating of the memory cues. Specifically, we examine whether concrete everyday objects historically dated to the participants' youth (e.g., a skipping rope), relative to verbal cues (i.e., the verbal signifiers for the objects) facilitate access to autobiographical memories. The study includes 49 AD patients, and 50 healthy, older matched control participants, all tested on word versus object-cued recall. Both groups recalled significantly more memories, when cued by objects relative to words, but the advantage was significantly larger in the AD group. In both groups, memory descriptions were longer and significantly more episodic in nature in response to object-cued recall. Together these findings suggest that the multimodal nature of the object cues (i.e. vision, olfaction, audition, somatic sensation) along with specific cue characteristics, such as time reference, texture, shape, may constrain the retrieval search, potentially minimizing executive function demands, and hence strategic processing requirements, thus easing access to autobiographical memories in AD.

Lost in distractors: Reduced Autobiographical Memory Specificity and dispersed activation spreading over distractors in working memory

Studies on autobiographical memory retrieval highlight the prominence of rapid and direct access to a specific event memory. Because it has been believed that autobiographical memory retrieval mostly relies on an effortful generative process, there is little empirical evidence on the early stage of information processing that contributes to autobiographical memory specificity (AMS). Therefore, we investigated the associations between AMS and automatic activation of information stimulated by rapid presentation of emotional words. Study 1 involved a visual search task to assess activation of various distractors in working memory. Participants with reduced AMS showed a tendency to activate distractors that were not semantically associated with preceding cues. In Study 2, we manipulated the levels of AMS by using a computerized version of Memory Specificity Training (c-MeST) to observe the changes in the activation of distractors. Results showed that increases in AMS were associated with decreases in activation of cue-unassociated distractors. These findings suggest that reduced AMS can be characterized by dispersed activation spreading over semantically unassociated distractors in automatic information selection of working memory. Because we also found an association between depressive symptoms and AMS, the role of automatic information processing in the relation between reduced AMS and depression is discussed.

Neuroscience-Inspired, Behavioral Change Program for University Students

It is clear that environmental influences impact the structure and function of the human brain, and thus, thoughts, actions, and behaviors. These in turn influence whether an individual engages in high-risk (drugs, alcohol, violence) or health-promoting (exercise, meditation, music) activities. The developmental mismatch between cortical and subcortical maturation of the transitional age brain places college students at risk for negative outcomes. This article argues that the prescription of incentive-based behavioral change and brain-building activities simply make good scientific, programmatic, and financial sense for colleges and universities. The authors present University of Vermont Wellness Environment as an example.