External details revisited – A new taxonomy for coding ‘non‐episodic’ content during autobiographical memory retrieval

Integrity of autobiographical memory and episodic future thinking in older adults varies with cognitive functioning

Research has documented changes in autobiographical memory and episodic future thinking in mild cognitive impairment (MCI) and Alzheimer's disease (AD). However, cognitive decline occurs gradually and recent findings suggest that subtle alterations in autobiographical cognition may be evident earlier in the trajectory towards dementia, before AD-related symptoms emerge or a clinical diagnosis has been given. The current study used the Autobiographical Interview to examine the episodic and semantic content of autobiographical past and future events generated by older adults (N = 38) of varying cognitive functioning who were grouped into High (N = 20) and Low Cognition (N = 18) groups based on their Montreal Cognitive Assessment (MoCA) scores. Participants described 12 past and 12 future autobiographical events, and transcripts were scored to quantify the numbers of internal (episodic) or external (non-episodic, including semantic) details. Although the Low Cognition group exhibited a differential reduction for internal details comprising both past and future events, they did not show the expected overproduction of external details relative to the High Cognition group. Multilevel modelling demonstrated that on trials lower in episodic content, semantic content was significantly increased in both groups. Although suggestive of a compensatory mechanism, the magnitude of this inverse relationship did not differ across groups or interact with MoCA scores. This finding indicates that external detail production may be underpinned by mechanisms not affected by cognitive decline, such as narrative style and the ability to contextualize one's past and future events in relation to broader autobiographical knowledge.

Retrieving autobiographical memories in autobiographical contexts: are age-related differences in narrated episodic specificity present outside of the laboratory?

The Autobiographical Interview, a method for evaluating detailed memory of real-world events, reliably detects differences in episodic specificity at retrieval between young and older adults in the laboratory. Whether this age-associated reduction in episodic specificity for autobiographical event retrieval is present outside of the laboratory remains poorly understood. We used a videoconference format to administer the Autobiographical Interview to cognitively unimpaired older adults (N = 49, M = 69.5, SD = 5.94) and young adults (N = 54, M = 22.5, SD = 4.19) who were in their homes at the time of retrieval. Relative to young adults, older adults showed reduced episodic specificity in their home environment, as reflected by fewer episodic or "internal" details (t (101) = 3.23, p = 0.009) and more "external" details (i.e., semantic, language-based details) (t (101) = 3.60, p = 0.003). These findings, along with detail subtype profiles in the narratives, bolster the ecological validity of the Autobiographical Interview and add promise to the use of virtual cognitive testing to improve the accessibility, participant diversity, scalability, and ecological validity of memory research.

Automated scoring of the autobiographical interview with natural language processing

The autobiographical interview has been used in more than 200 studies to assess the content of autobiographical memories. In a typical experiment, participants recall memories, which are then scored manually for internal details (episodic details from the central event) and external details (largely non-episodic details). Scoring these narratives requires a significant amount of time. As a result, large studies with this procedure are often impractical, and even conducting small studies is time-consuming. To reduce scoring burden and enable larger studies, we developed an approach to automatically score responses with natural language processing. We fine-tuned an existing language model (distilBERT) to identify the amount of internal and external content in each sentence. These predictions were aggregated to obtain internal and external content estimates for each narrative. We evaluated our model by comparing manual scores with automated scores in five datasets. We found that our model performed well across datasets. In four datasets, we found a strong correlation between internal detail counts and the amount of predicted internal content. In these datasets, manual and automated external scores were also strongly correlated, and we found minimal misclassification of content. In a fifth dataset, our model performed well after additional preprocessing. To make automated scoring available to other researchers, we provide a Colab notebook that is intended to be used without additional coding.

Episodic-semantic linkage for $1000: New semantic knowledge is more strongly coupled with episodic memory in trivia experts

Some people exhibit impressive memory for a wide array of semantic knowledge. What makes these trivia experts better able to learn and retain novel facts? We hypothesized that new semantic knowledge may be more strongly linked to its episodic context in trivia experts. We designed a novel online task in which 132 participants varying in trivia expertise encoded "exhibits" of naturalistic facts with related photos in one of two "museums." Afterward, participants were tested on cued recall of facts and recognition of the associated photo and museum. Greater trivia expertise predicted higher cued recall for novel facts. Critically, trivia experts but not non-experts showed superior fact recall when they remembered both features (photo and museum) of the encoding context. These findings illustrate enhanced links between episodic memory and new semantic learning in trivia experts, and show the value of studying trivia experts as a special population that can shed light on the mechanisms of memory.

Taking stock of the past: A psychometric evaluation of the Autobiographical Interview

Autobiographical memory (AM) involves a rich phenomenological re-experiencing of a spatio-temporal event from the past, which is challenging to objectively quantify. The Autobiographical Interview (AI; Levine et al. Psychology and Aging, 17(4), 677-689, 2002) is a manualized performance-based assessment designed to quantify episodic (internal) and semantic (external) features of recalled and verbally conveyed prior experiences. The AI has been widely adopted, yet has not undergone a comprehensive psychometric validation. We investigated the reliability, validity, association to individual differences measures, and factor structure in healthy younger and older adults (N = 352). Evidence for the AI's reliability was strong: the subjective scoring protocol showed high inter-rater reliability and previously identified age effects were replicated. Internal consistency across timepoints was robust, suggesting stability in recollection. Central to our validation, internal AI scores were positively correlated with standard, performance-based measures of episodic memory, demonstrating convergent validity. The two-factor structure for the AI was not well supported by confirmatory factor analysis. Adjusting internal and external detail scores for the number of words spoken (detail density) improved trait estimation of AM performance. Overall, the AI demonstrated sound psychometric properties for inquiry into the qualities of autobiographical remembering.

Evidence of Impaired Remote Experience-near Semantic Memory in Medial Temporal Lobe Amnesia

Neuropsychological research suggests that "experience-near" semantic memory, meaning knowledge attached to a spatiotemporal or event context, is commonly impaired in individuals who have medial temporal lobe amnesia. It is not known if this impairment extends to remotely acquired experience-near knowledge, which is a question relevant to understanding hippocampal/medial temporal lobe functioning. In the present study, we administered a novel semantic memory task designed to target knowledge associated with remote, "dormant" concepts, in addition to knowledge associated with active concepts, to four individuals with medial temporal lobe amnesia and eight matched controls. We found that the individuals with medial temporal lobe amnesia generated significantly fewer experience-near semantic memories for both remote concepts and active concepts. In comparison, the generation of abstract or "experience-far" knowledge was largely spared in the individuals with medial temporal lobe amnesia, regardless of whether the targets for retrieval were remote or active concepts. We interpret these findings as evidence that the medial temporal lobes may have a sustained role in the retrieval of semantic memories associated with spatiotemporal and event contexts, which are cognitive features often ascribed to episodic memory. These results align with recent theoretical models proposing that the hippocampus/medial temporal lobes support cognitive processes that are involved in, but not exclusive to, episodic memory.

Effects of Healthy and Neuropathological Aging on Autobiographical Memory: A Meta-Analysis of Studies Using the Autobiographical Interview

OBJECTIVES

A meta-analytic review was conducted to assess the effects of healthy aging, amnestic mild cognitive impairment (MCI), and Alzheimer's disease (AD) on naturalistic autobiographical memory using the Autobiographical Interview, a widely used, standardized assessment that derives measures of internal (episodic) and external (nonepisodic) details from freely recalled autobiographical narratives.

METHODS

A comprehensive literature search identified 21 aging, 6 MCI, and 7 AD studies (total N = 1,556 participants). Summary statistics for internal and external details for each comparison (younger vs older or MCI/AD vs age-matched comparison groups) and effect size statistics were extracted and summarized using Hedges' g (random effects model) and adjusted for the presence of publication bias.

RESULTS

The pattern of reduced internal and elevated external details in aging was robust and consistent across nearly all 21 studies. MCI and-to a greater extent-AD were associated with reduced internal details, whereas the external detail elevation faded with MCI and AD. Although there was evidence of publication bias on reporting of internal detail effects, these effects remained robust after correction.

DISCUSSION

The canonical changes to episodic memory observed in aging and neurodegenerative disease are mirrored in the free recall of real-life events. Our findings indicate that the onset of neuropathology overwhelms the capacity of older adults to draw upon distributed neural systems to elaborate on past experiences, including both episodic details specific to identified events and nonepisodic content characteristic of healthy older adults' autobiographical narratives.

Posterior hippocampal CA2/3 volume is associated with autobiographical memory recall ability in lower performing individuals

People vary substantially in their capacity to recall past experiences, known as autobiographical memories. Here we investigated whether the volumes of specific hippocampal subfields were associated with autobiographical memory retrieval ability. We manually segmented the full length of the two hippocampi in 201 healthy young adults into DG/CA4, CA2/3, CA1, subiculum, pre/parasubiculum and uncus, in the largest such manually segmented subfield sample yet reported. Across the group we found no evidence for an association between any subfield volume and autobiographical memory recall ability. However, when participants were assigned to lower and higher performing groups based on their memory recall scores, we found that bilateral CA2/3 volume was significantly and positively associated with autobiographical memory recall performance specifically in the lower performing group. We further observed that this effect was attributable to posterior CA2/3. By contrast, semantic details from autobiographical memories, and performance on a range of laboratory-based memory tests, did not correlate with CA2/3 volume. Overall, our findings highlight that posterior CA2/3 may be particularly pertinent for autobiographical memory recall. They also reveal that there may not be direct one-to-one mapping of posterior CA2/3 volume with autobiographical memory ability, with size mattering perhaps only in those with poorer memory recall.

Autobiographical event memory and aging: older adults get the gist

We propose that older adults' ability to retrieve episodic autobiographical events, although often viewed through a lens of decline, reveals much about what is preserved and prioritized in cognitive aging. Central to our proposal is the idea that the so-called gist of an autobiographical event is not only spared with normal aging but also well adapted to serve memory-guided behavior in older age. To support our proposal, we review cognitive and brain evidence indicating an age-related shift toward gist memory. We then discuss why this shift likely arises from more than age-related decline and instead partly reflects a natural, arguably adaptive, outcome of experience, motivation, and mode-of-thinking factors. Our proposal reveals an upside of age-related memory changes and identifies important research questions.

Hippocampus and temporal pole functional connectivity is associated with age and individual differences in autobiographical memory

Recollection of one's personal past, or autobiographical memory (AM), varies across individuals and across the life span. This manifests in the amount of episodic content recalled during AM, which may reflect differences in associated functional brain networks. We take an individual differences approach to examine resting-state functional connectivity of temporal lobe regions known to coordinate AM content retrieval with the default network (anterior and posterior hippocampus, temporal pole) and test for associations with AM. Multiecho resting-state functional magnetic resonance imaging (fMRI) and autobiographical interviews were collected for 158 younger and 105 older healthy adults. Interviews were scored for internal (episodic) and external (semantic) details. Age group differences in connectivity profiles revealed that older adults had lower connectivity within anterior hippocampus, posterior hippocampus, and temporal pole but greater connectivity with regions across the default network compared with younger adults. This pattern was positively related to posterior hippocampal volumes in older adults, which were smaller than younger adult volumes. Connectivity associations with AM showed two significant patterns. The first dissociated connectivity related to internal vs. external AM across participants. Internal AM was related to anterior hippocampus and temporal pole connectivity with orbitofrontal cortex and connectivity within posterior hippocampus. External AM was related to temporal pole connectivity with regions across the lateral temporal cortex. In the second pattern, younger adults displayed temporal pole connectivity with regions throughout the default network associated with more detailed AMs overall. Our findings provide evidence for discrete ensembles of brain regions that scale with systematic variation in recollective styles across the healthy adult life span.

Jacques PL. The influence of shifting perspective on episodic and semantic details during autobiographical memory recall

Shifting to a novel visual perspective during retrieval influences autobiographical memories (AM) and can lead to persistent changes in memories. Adopting an observer-like compared to an own eyes perspective reduces episodic information during AM recall, but less is known regarding how viewpoint influences semantic information. In the current study, we investigated how shifting from an own eyes to an observer-like perspective during narrative recall of AMs influences episodic and semantic information. Shifting perspective reduced the number of episodic details associated with emotions and thoughts, and also led to similar reductions in personal semantics. We replicated prior research showing that shifting perspective reduces emotional intensity in subsequent memories, but these subjective changes were not coupled with objective changes in a narrative recall. Our findings suggest that shifting perspective influences the interplay between episodic and semantic information during proximate recall and subjective changes when memories are later recalled.

Episodic Past, Future, and counterfactual thinking in Relapsing-Remitting Multiple sclerosis

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Performance in episodic past, future or counterfactual thinking in relapsing-remitting MS and controls was explored.

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Behavioral and diffusion weighted imaging were used to evaluate associations between white matter integrity and group differences in performance.

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Relative to controls, MS patients showed reductions in episodic details across all three simulations.

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Reduced white matter integrity in three association tracts predicted this reduction in episodic details during counterfactual simulations.

Multiple sclerosis (MS) is a progressive disease characterized by widespread white matter lesions in the brain and spinal cord. In addition to well-characterized motor deficits, MS results in cognitive impairments in several domains, notably in episodic autobiographical memory. Recent studies have also revealed that patients with MS exhibit deficits in episodic future thinking, i.e., our capacity to imagine possible events that may occur in our personal future. Both episodic memory and episodic future thinking have been shown to share cognitive and neural mechanisms with a related kind of hypothetical simulation known as episodic counterfactual thinking: our capacity to imagine alternative ways in which past personal events could have occurred but did not. However, the extent to which episodic counterfactual thinking is affected in MS is still unknown. The current study sought to explore this issue by comparing performance in mental simulation tasks involving either past, future or counterfactual thoughts in relapsing-remitting MS. Diffusion weighted imaging (DWI) measures were also extracted to determine whether changes in structural pathways connecting the brain’s default mode network (DMN) would be associated with group differences in task performance. Relative to controls, patients showed marked reductions in the number of internal details across all mental simulations, but no differences in the number of external and semantic-based details. It was also found that, relative to controls, patients with relapsing-remitting MS reported reduced composition ratings for episodic simulations depicting counterfactual events, but not so for actual past or possible future episodes. Additionally, three DWI measures of white matter integrity—fractional anisotropy, radial diffusivity and streamline counts—showed reliable differences between patients with relapsing-remitting MS and matched healthy controls. Importantly, DWI measures associated with reduced white matter integrity in three association tracts on the DMN—the right superior longitudinal fasciculus, the left hippocampal portion of the cingulum and the left inferior longitudinal fasciculus—predicted reductions in the number of internal details during episodic counterfactual simulations. Taken together, these results help to illuminate impairments in episodic simulation in relapsing-remitting MS and show, for the first time, a differential association between white matter integrity and deficits in episodic counterfactual thinking in individuals with relapsing-remitting MS.

Rethinking the distinction between episodic and semantic memory: Insights from the past, present, and future

On the 50th anniversary of Tulving's introduction of the celebrated distinction between episodic and semantic memory, it seems more than fitting to revisit his proposal in light of recent conceptual and methodological advances in the field. This Special Issue of Memory & Cognition brings together researchers doing cutting-edge work at the intersection between episodic and semantic memory to showcase studies directly probing this psychological distinction, as well as articles that seek to provide conceptual and theoretical accounts to understand their interaction. The 14 articles presented here highlight the need to critically examine the way in which we conceptualize not only the relationship between episodic and semantic memory, but also the interplay between declarative and non-declarative memory, and the myriad implications of such conceptual changes. In many ways, we suggest this Special Issue might serve as a call to action for our field, inspiring future work to challenge pre-existing conceptions and stimulate new directions in this fast-moving field.

Temporal pole volume is associated with episodic autobiographical memory in healthy older adults

Recollection of personal past events differs across the lifespan. Older individuals recall fewer episodic details and convey more semantic information than young. Here we examine how gray matter volumes in temporal lobe regions integral to episodic and semantic memory (hippocampus and temporal poles, respectively) are related to age differences in autobiographical recollection. Gray matter volumes were obtained in healthy young (n = 158) and old (n = 105) adults. The temporal pole was demarcated and hippocampus segmented into anterior and posterior regions to test for volume differences between age groups. The Autobiographical Interview was administered to measure episodic and semantic autobiographical memory. Volume associations with episodic and semantic autobiographical memory were then assessed. Brain volumes were smaller for older adults in the posterior hippocampus. Autobiographical memory was less episodic and more semanticized for older versus younger adults. Older adults also showed positive associations between temporal pole volumes and episodic autobiographical recall; in the young, temporal pole volume was positively associated with performance on standard laboratory measures of semantic memory. Exploratory analyses revealed that age-related episodic autobiographical memory associations with anterior hippocampal volumes depended on sex. These findings suggest that age differences in brain structures implicated in episodic and semantic memory may portend reorganization of neural circuits to support autobiographical memory in later life.

Troubled past: A critical psychometric assessment of the self-report Survey of Autobiographical Memory (SAM)

The Survey of Autobiographical Memory (SAM) was designed as an easy-to-administer measure of self-perceived autobiographical memory (AM) recollection capacity. We provide a comprehensive psychometric evaluation of the SAM in younger and older adults. First, we evaluated the reliability of the SAM as a measure of self-perceived recollective capacity. Next, we tested whether the SAM was a valid measure of episodic and autobiographical memory performance, as assessed with widely used performance-based measures. Finally, we investigated associations between the SAM, cognitive measures and self-reported assessments of psychological functioning. The SAM demonstrated reliability as a self-report measure of perceived recollective capacity. High internal consistency was observed across subscales, with the exception of SAM-semantic. Evidence for independence among the subscales was mixed: SAM-episodic and SAM-semantic items showed poor correspondence with respective subscales. Good correspondence was observed between the future and spatial items and their SAM subscales. The SAM showed limited associations with AM performance as measured by the Autobiographical Interview (AI), yet was broadly associated with self-reported AI event vividness. SAM scores were weakly associated with performance-based memory measures and were age-invariant, inconsistent with known age effects on declarative memory. Converging evidence indicated that SAM-episodic and SAM-semantic subscales are not independent and should not be interpreted as specific measures of episodic or semantic memory. The SAM was robustly associated with self-efficacy, suggesting an association with confidence in domain general self-report abilities. We urge caution in the use and interpretation of the SAM as a measure of AM, pending revision and further psychometric validation.

Exploring episodic and semantic contributions to past and future thinking performance in Korsakoff's syndrome

Korsakoff's syndrome (KS) is a neuropsychiatric disorder characterized by severe declarative memory disruption. While episodic memory deficits and confabulation are well documented, it remains unclear to what extent semantic memory is compromised in this syndrome. Moreover, how such impairments relate to the capacity for future-oriented thinking remains unknown. Here, we sought to determine the extent to which episodic and semantic forms of past and future thinking are impacted in KS and the interrelationship between different classes of memory in this syndrome. Twenty patients with KS and 17 matched healthy controls took part in this study. We included well-established indices of past and future thinking capacity, enabling us to compare episodic (event-based) versus semantic (nonpersonal knowledge) across past and future conditions. We also included a novel event generation task to probe implausible event simulation (i.e., spending a day on the moon). Our findings revealed marked impairments in KS across all forms of past and future thinking, as well as the generation of episodic details on the implausible event simulation task. Correlation analyses revealed significant associations between implausible event construction and episodic and semantic future thinking in KS; however, no significant associations were found between future thinking performance and confabulation. This study is the first, to our knowledge, to reveal striking impairments in the capacity for past and future thinking across episodic and semantic domains in KS. Our findings resonate with current theoretical perspectives in which the lines between episodic and semantic memory systems are viewed as increasingly blurred.

Subjective Time in Dementia: A Critical Review

The capacity for subjective time in humans encompasses the perception of time's unfolding from moment to moment, as well as the ability to traverse larger temporal expanses of past- and future-oriented thought via mental time travel. Disruption in time perception can result in maladaptive outcomes-from the innocuous lapse in timing that leads to a burnt piece of toast, to the grievous miscalculation that produces a traffic accident-while disruption to mental time travel can impact core functions from planning appointments to making long-term decisions. Mounting evidence suggests that disturbances to both time perception and mental time travel are prominent in dementia syndromes. Given that such disruptions can have severe consequences for independent functioning in everyday life, here we aim to provide a comprehensive exposition of subjective timing dysfunction in dementia, with a view to informing the management of such disturbances. We consider the neurocognitive mechanisms underpinning changes to both time perception and mental time travel across different dementia disorders. Moreover, we explicate the functional implications of altered subjective timing by reference to two key and representative adaptive capacities: prospective memory and intertemporal decision-making. Overall, our review sheds light on the transdiagnostic implications of subjective timing disturbances in dementia and highlights the high variability in performance across clinical syndromes and functional domains.

Age-related changes in ongoing thought relate to external context and individual cognition

Understanding how age-related changes in cognition manifest in the real world is an important goal. One means of capturing these changes involves "experience sampling" participant's self-reported thoughts. Research has shown age-related changes in ongoing thought: e.g., older adults have fewer thoughts unrelated to the here-and-now. However, it is currently unclear how these changes reflect cognitive aging or lifestyle changes. 78 younger adults and 35 older adults rated their thought contents along 20 dimensions and the difficulty of their current activity in their daily lives. They also performed cognitive tasks in the laboratory. In a set of exploratory analyses, we found that older adults spent more time thinking positive, wanted thoughts, particularly in demanding contexts, and less time mind wandering about their future selves. Past-related thought related to episodic memory differently in older and younger adults. These findings inform the use of experience sampling to understand cognitive aging.

Evidence for a pervasive autobiographical memory impairment in Logopenic Progressive Aphasia

Although characterized primarily as a language disorder, mounting evidence indicates episodic amnesia in Logopenic Progressive Aphasia (LPA). Whether such memory disturbances extend to information encoded pre-disease onset remains unclear. To address this question, we examined autobiographical memory in 10 LPA patients, contrasted with 18 typical amnestic Alzheimer's disease and 16 healthy Control participants. A validated assessment, the Autobiographical Interview, was employed to explore autobiographical memory performance across the lifespan under free and probed recall conditions. Relative to Controls, LPA patients showed global impairments across all time periods for free recall, scoring at the same level as disease-matched cases of Alzheimer's disease. Importantly, these retrieval deficits persisted in LPA, even when structured probing was provided, and could not be explained by overall level of language disruption or amount of information generated during autobiographical narration. Autobiographical memory impairments in LPA related to gray matter intensity decrease in predominantly posterior parietal brain regions implicated in memory retrieval. Together, our results suggest that episodic memory disturbances may be an under-appreciated clinical feature of LPA.

What are your thoughts? Exploring age-related changes in episodic and semantic autobiographical content on an open-ended retrieval task

Older adults display impairments in accessing episodic, but not semantic details, when specifically requested to construct autobiographical events. How aging affects access to autobiographical information under conditions of low retrieval constraint remains unclear. We examined the production of episodic and "non-episodic" details in young (n = 25) and older (n = 24) adults on a novel autobiographical narrative task free from constraints on the type of information to be retrieved (Thoughts task), compared with the standard autobiographical memory and picture description tasks. Older adults generated fewer episodic and more non-episodic details on the memory task than young adults, however there was no age difference in detail profiles on the Thoughts task. Under these conditions of low retrieval constraint, narratives of young and older adults consisted of mostly personal and general semantic content. Young adults also provided less episodic and more semantic details on the Thoughts than the memory task, while older adults provided similar amounts of details across tasks. These results reveal that both young and older adults retrieve semantic autobiographical content under minimally constrained retrieval conditions. Moreover, aging may impact upon the ability to shift the detail types (episodic, semantic) provided in response to changing demands of different autobiographical narrative tasks.

Examining the episodic-semantic interaction during future thinking - A reanalysis of external details

While traditional analyses of autobiographical construction tend to focus on the 'internal' or episodic details of the narrative, contemporary studies employing fine-grained scoring measures reveal the 'external' component to contain important information relevant to the individual's life story. Here, we used the recently developed NExt scoring protocol to explore profiles of external details generated by patients with Alzheimer's disease (AD) (n = 11) and semantic dementia (SD) (n = 13) on a future thinking task. Overall, distinct NExt profiles were observed for future events in AD and SD. Specifically, AD patients provided significantly more Specific Episode external details compared with Controls. Using voxel-based morphometry, these increased external details within future narratives related to grey matter intensity in medial and lateral frontal regions in AD. By contrast, SD patients displayed an elevation of Specific Episode, Extended Episode, and General Semantic details during future simulation relative to Controls, which related to grey matter intensity of medial and lateral parietal regions. Our findings suggest that the compensatory external details generated during future simulation comprise an array of episodic and semantic details that vary in terms of specificity and self-relevance, which may be differentially affected depending on the locus of underlying neuropathology in dementia. Adopting a fine-grained approach to external details helps to characterise the interplay between episodic and semantic content during future stimulation and suggests potentially differential vulnerability and preservation of distinct components of the constructed narrative in clinical disorders.

Autobiographical recall of a stressful negative event in veterans with PTSD

Posttraumatic stress disorder (PTSD) is characterised by alterations in autobiographical memory for traumatic and non-traumatic events. Studies that focus on event construction - the ability to search for and identify a specific event - have documented overgeneral memory in PTSD. However, the quality of autobiographical memory also depends on the ability to elaborate on an event once constructed by providing additional details. In a prior study, individuals with PTSD generated as many episodic (event-specific) details as trauma-exposed controls when demands on event construction were minimized, albeit the PTSD group generated more non-episodic details. The current study sought to further characterize PTSD-related alterations in event elaboration by asking participants to describe a stressful negative event specified by the experimenter, thus minimizing event construction demands. Narratives were scored for episodic and non-episodic details and relations with measures of executive function and self-reported avoidance were examined. Compared to controls, the PTSD group generated narratives with equivalent episodic detail but greater non-episodic detail, including semantic information and repeated or extended events. Non-episodic detail generation was associated with greater avoidance but not executive functions. Elaborated non-trauma memories may be perceived as overgeneral in PTSD due to greater generation of non-episodic details, rather than diminished episodic detail.

Harnessing Visual Imagery and Oculomotor Behaviour to Understand Prospection

Much of the rich internal world constructed by humans is derived from, and experienced through, visual mental imagery. Despite growing appreciation of visual exploration in guiding episodic memory processes, extant theories of prospection have yet to accommodate the precise role of visual mental imagery in the service of future-oriented thinking. We propose that the construction of future events relies on the assimilation of perceptual details originally experienced, and subsequently reinstantiated, predominantly in the visual domain. Individual differences in the capacity to summon discrete aspects of visual imagery can therefore account for the diversity of content generated by humans during future simulation. Our integrative framework provides a novel testbed to query alterations in future thinking in health and disease.

Dynamic Content Reactivation Supports Naturalistic Autobiographical Recall in Humans

Humans can vividly recall and re-experience events from their past, and these are commonly referred to as episodic or autobiographical memories. fMRI experiments reliably associate autobiographical event recall with activity in a network of "default" or "core" brain regions. However, as prior studies have relied on covert (silent) recall procedures, current understanding may be hampered by methodological limitations that obscure dynamic effects supporting moment-to-moment content retrieval. Here, fMRI participants (N = 40) overtly (verbally) recalled memories for ∼2 min periods. The content of spoken descriptions was categorized using a variant of the Autobiographical Interview (AI) procedure (Levine et al., 2002) and temporally re-aligned with BOLD data so activity accompanying the recall of different details could be measured. Replicating prior work, sustained effects associated with autobiographical recall periods (which are insensitive to the moment-to-moment content of retrieval) fell primarily within canonical default network regions. Spoken descriptions were rich in episodic details, frequently focusing on physical entities, their ongoing activities, and their appearances. Critically, neural activity associated with recalling specific details (e.g., those related to people or places) was transient, broadly distributed, and grounded in category-selective cortex (e.g., regions related to social cognition or scene processing). Thus, although a single network may generally support the process of vivid event reconstruction, the structures required to provide detail-related information shift in a predictable manner that respects domain-level representations across the cortex.SIGNIFICANCE STATEMENT Humans can vividly recall memories of autobiographical episodes, a process thought to involve the reconstruction of numerous distinct event details. Yet how the brain represents a complex episode as it unfolds over time remains unclear and appears inconsistent across experimental traditions. One hurdle is the use of covert (silent) in-scanner recall to study autobiographical memory, which prevents experimenter knowledge of what information is being retrieved, and when, throughout the remembering process. In this experiment, participants overtly described autobiographical memories while undergoing fMRI. Activity associated with the recall and description of specific details was transient, broadly distributed, and grounded in category-selective cortex. Thus, it appears that as events unfold mentally, structures are dynamically reactivated to support vivid recollection.

Semi-automated transcription and scoring of autobiographical memory narratives

Autobiographical memory studies conducted with narrative methods are onerous, requiring significant resources in time and labor. We have created a semi-automated process that allows autobiographical transcribing and scoring methods to be streamlined. Our paper focuses on the Autobiographical Interview (AI; Levine, Svoboda, Hay, Winocur, & Moscovitch, Psychology and Aging, 17, 677-89, 2002), but this method can be adapted for other narrative protocols. Specifically, here we lay out a procedure that guides researchers through the four main phases of the autobiographical narrative pipeline: (1) data collection, (2) transcribing, (3) scoring, and (4) analysis. First, we provide recommendations for incorporating transcription software to augment human transcribing. We then introduce an electronic scoring procedure for tagging narratives for scoring that incorporates the traditional AI scoring method with basic keyboard shortcuts in Microsoft Word. Finally, we provide a Python script that can be used to automate counting of scored transcripts. This method accelerates the time it takes to conduct a narrative study and reduces the opportunity for error in narrative quantification. Available open access on GitHub ( https://github.com/cMadan/scoreAI ), our pipeline makes narrative methods more accessible for future research.

Classification of general and personal semantic details in the Autobiographical Interview

The Autobiographical Interview (AI) separates internal (episodic) and external (non-episodic) details from transcribed protocols using an exhaustive and reliable scoring system. While the details comprising the internal composite are centered on elements of episodic memory, external details are more heterogeneous as they are meant to capture a variety of non-episodic utterances: general semantics, different types of personal semantics details, metacognitive statements, repetitions, and details about off topic events. Elevated external details are consistently observed in aging and in neurodegenerative diseases. In the present study, we augmented the AI scoring system to differentiate subtypes of external details to test whether the elevation of these details in aging and in frontotemporal lobar degeneration (including mixed frontotemporal/semantic dementia [FTD/SD] and progressive non-fluent aphasia [PNFA]) would be specific to general and personal semantics or would concern all subtypes. Specifically, we separated general semantic details from personal semantic details (including autobiographical facts, self-knowledge, and repeated events). With aging, external detail elevation was observed for general and personal semantic details but not for other types of external details. In frontotemporal lobar degeneration, patients with FTD/SD (but not PNFA) generated an excess of personal semantic details but not general semantic details. The increase in personal but not general semantic details in FTD/SD is consistent with prevalent impairment of general semantic memory in SD, and with the personalization of concepts in this condition. Under standard AI instructions, external details were intended to capture off-topic utterances and were not intended as a direct measure of semantic abilities. Future investigations concerned with semantic processing in aging and in dementia could modify standard instructions of the AI to directly probe semantic content.

The role of the pre-commissural fornix in episodic autobiographical memory and simulation

Neuropsychological and functional magnetic resonance imaging evidence suggests that the ability to vividly remember our personal past, and imagine future scenarios, involves two closely connected regions: the hippocampus and ventromedial prefrontal cortex (vmPFC). Despite evidence of a direct anatomical connection from hippocampus to vmPFC, it is unknown whether hippocampal-vmPFC structural connectivity supports both past- and future-oriented episodic thinking. To address this, we applied a novel deterministic tractography protocol to diffusion-weighted magnetic resonance imaging (dMRI) data from a group of healthy young adult humans who undertook an adapted past-future autobiographical interview (portions of this data were published in Hodgetts et al., 2017a). This tractography protocol enabled distinct subdivisions of the fornix, detected previously in axonal tracer studies, to be reconstructed in vivo, namely the pre-commissural (connecting the hippocampus to vmPFC) and post-commissural (linking the hippocampus and medial diencephalon) fornix. As predicted, we found that inter-individual differences in pre-commissural - but not post-commissural - fornix microstructure (fractional anisotropy) were significantly correlated with the episodic richness of both past and future autobiographical narratives. Notably, these results held when controlling for non-episodic narrative content, verbal fluency, and grey matter volumes of the hippocampus and vmPFC. This study provides novel evidence that reconstructing events from one's personal past, and constructing possible future events, involves a distinct, structurally-instantiated hippocampal-vmPFC pathway.

Zooming In and Out on One's Life: Autobiographical Representations at Multiple Time Scales

The ability to decouple from the present environment and explore other times is a central feature of the human mind. Research in cognitive psychology and neuroscience has shown that the personal past and future is represented at multiple timescales and levels of resolution, from broad lifetime periods that span years to short-time slices of experience that span seconds. Here, I review this evidence and propose a theoretical framework for understanding mental time travel as the capacity to flexibly navigate hierarchical layers of autobiographical representations. On this view, past and future thoughts rely on two main systems-event simulation and autobiographical knowledge-that allow us to represent experiential contents that are decoupled from sensory input and to place these on a personal timeline scaffolded from conceptual knowledge of the content and structure of our life. The neural basis of this cognitive architecture is discussed, emphasizing the possible role of the medial pFC in integrating layers of autobiographical representations in the service of mental time travel.

Music evoked autobiographical memories in people with behavioural variant frontotemporal dementia

Music is highly efficient at evoking autobiographical memories in both healthy and neurological populations. Music evoked autobiographical memories (MEAMs) are preserved in people with Alzheimer's Dementia (AD), and occur at the same frequency as in healthy people. To date there has been no investigation of the integrity of MEAMs in people with non-AD dementia. This study provides the first characterisation of the frequency and specificity of MEAMs and photo evoked autobiographical memories (PEAMs) in 6 people with Behavioural variant frontotemporal dementia (Bv-FTD). We found significantly reduced frequency and specificity of MEAMs and PEAMs in people with Bv-FTD compared with healthy elderly. This supports the known decline in autobiographical memory function in this population, and the integral role of medial frontal regions in the retrieval of MEAMs. Our findings highlight that the mnemonic effects of music vary between people with different types of dementia, which has implications for dementia care.

Do questionnaires reflect their purported cognitive functions?

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Imagery and navigation questionnaires reflect their purported cognitive functions.

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Memory questionnaires reflect autobiographical memory vividness.

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Episodic details and memory questionnaires measure different aspects of memory.

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Imagery questionnaires also correlated with memory vividness and future thinking.

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Single questions modelled performance comparably to established questionnaires.

Questionnaires are used widely across psychology and permit valuable insights into a person’s thoughts and beliefs, which are difficult to derive from task performance measures alone. Given their importance and widespread use, it is vital that questionnaires map onto the cognitive functions they purport to reflect. However, where performance on naturalistic tasks such as imagination, autobiographical memory, future thinking and navigation is concerned, there is a dearth of knowledge about the relationships between task performance and questionnaire measures. Questionnaires are also typically designed to probe a specific aspect of cognition, when instead researchers sometimes want to obtain a broad profile of a participant. To the best of our knowledge, no questionnaire exists that asks simple single questions about a wide range of cognitive functions. To address these gaps in the literature, we recruited a large sample of participants (n = 217), all of whom completed a battery of widely used questionnaires and performed naturalistic tasks involving imagination, autobiographical memory, future thinking and navigation. We also devised a questionnaire that comprised simple single questions about the cognitive functions of interest. There were four main findings. First, imagination and navigation questionnaires reflected performance on their related tasks. Second, memory questionnaires were associated with autobiographical memory vividness and not internal (episodic) details. Third, imagery questionnaires were more associated with autobiographical memory vividness and future thinking than the questionnaires purporting to reflect these functions. Finally, initial exploratory analyses suggested that a broad profile of information can be obtained efficiently using a small number of simple single questions, and these modelled task performance comparably to established questionnaires in young, healthy adults. Overall, while some questionnaires can act as proxies for behaviour, the relationships between memory and future thinking tasks and questionnaires are more complex and require further elucidation.

The relationship between episodic detail generation and anterotemporal, posteromedial, and hippocampal white matter tracts

Episodic details populate autobiographical memories with vivid representations of people, objects, and event happenings, and they link events to a specific time and place. Episodic detail generation is believed to be a function of medial temporal lobe (MTL)-cortical interaction, but much remains unclear about how this retrieval process unfolds. In the present study, we combined an autobiographical interview and diffusion magnetic resonance imaging to investigate the relationships of two types of episodic detail, namely details about entities of an event (people and objects) or "event elements" and details about spatiotemporal context, to the integrity of anterotemporal (uncinate fasciculus; UF) and posteromedial (cingulum bundle; CB) cortical pathways. We also measured the relationships of these detail types to the fornix, and the relationship between non-episodic details and these tracts. We found that only episodic detail generation was significantly related to cortical and hippocampal pathways. Notably, the UF was more strongly related to event element details than it was to spatiotemporal context details. In contrast, CB was significantly and similarly related to the generation of event element and spatiotemporal context details (when not controlling for age and global diffusion). The fornix was also significantly related to both types of episodic detail, although the relationship to spatiotemporal context was particularly robust. These findings support the idea that anterotemporal cortical regions are related to the retrieval of episodic details about the entities that are incorporated into autobiographical events. Our findings also align with the notion that posteromedial and hippocampal-cortical involvement support the retrieval of episodic details.

Beyond episodic remembering: elaborative retrieval of lifetime periods in young and older adults

Relative to young adults, cognitively normal older adults commonly generate more semantic details and fewer episodic details in their descriptions of unique life events. It remains unclear whether this reflects a specific change to episodic memory or a broader alteration to autobiographical narration. To explore age differences across different types of autobiographical narration, we created a lifetime period narrative task that involves describing extended events. For comparison, participants also described unique life events. All autobiographical narratives were scored for episodic, semantic, and other detail generation. Relative to young adults, older adults generated more detailed narratives for remote and recent lifetime periods, which was driven by their increased retrieval of personal and general semantic details. Older adults also generated more semantic details for unique life event narratives, along with reduced episodic detail. More broadly, in both groups lifetime period narratives were largely based on semantic details, whereas episodic details were more prominent in the descriptions of unique life events. These findings indicate that the elevated generation of semantic details associated with normal cognitive aging is reflected in multiple types of autobiographical narration. We suggest that lifetime period narration is a spared aspect of autobiographical memory among older adults.

Anomalies of Autobiographical Memory

OBJECTIVES

In this paper, I review three 'anomalies' or disorders in autobiographical memory: neurological retrograde amnesia (RA), spontaneous confabulation, and psychogenic amnesia.

METHODS

Existing theories are reviewed, their limitations considered, some of my own empirical findings briefly described, and possible interpretations proposed and interspersed with illustrative case-reports.

RESULTS

In RA, there may be an important retrieval component to the deficit, and factors at encoding may give rise to the relative preservation of early memories (and the reminiscence bump) which manifests as a temporal gradient. Spontaneous confabulation appears to be associated with a damaged 'filter' in orbitofrontal and ventromedial frontal regions. Consistent with this, an empirical study has shown that both the initial severity of confabulation and its subsequent decline are associated with changes in the executive function (especially in cognitive estimate errors) and inversely with the quantity of accurate autobiographical memories retrieved. Psychogenic amnesia can be 'global' or 'situation-specific'. The former is associated with a precipitating stress, depressed mood, and (often) a past history of a transient neurological amnesia. In these circumstances, frontal control mechanisms can inhibit retrieval of autobiographical memories, and even the sense of 'self' (identity), while compromised medial temporal function prevents subsequent retrieval of what occurred during a 'fugue'. An empirical investigation of psychogenic amnesia and some recent imaging studies have provided findings consistent with this view.

CONCLUSIONS

Taken together, these various observations point to the importance of frontal 'control' systems (in interaction with medial temporal/hippocampal systems) in the retrieval and, more particularly, the disrupted retrieval of 'old' memories.

"All is not lost"-Rethinking the nature of memory and the self in dementia

Memory and the self have long been considered intertwined, leading to the assumption that without memory, there can be no self. This line of reasoning has led to the misconception that a loss of memory in dementia necessarily results in a diminished sense of self. Here, we challenge this assumption by considering discrete facets of self-referential memory, and their relative profiles of loss and sparing, across three neurodegenerative disorders: Alzheimer's disease, semantic dementia, and frontotemporal dementia. By exploring canonical expressions of the self across past, present, and future contexts in dementia, relative to healthy ageing, we reconcile previous accounts of loss of self in dementia, and propose a new framework for understanding and managing everyday functioning and behaviour. Notably, our approach highlights the multifaceted and dynamic nature in which the temporally-extended self is likely to change in healthy and pathological ageing, with important ramifications for development of person-centred care. Collectively, we aim to promote a cohesive sense of self in dementia across past, present, and future contexts, by demonstrating how, ultimately, 'All is not lost'.

On the role of autobiographical knowledge in shaping belief in the future occurrence of imagined events

Recent studies suggest that different forms of episodic simulation—mental representations of past, future, or atemporal events—recruit many of the same underlying cognitive and neural processes. This leads to the question whether there are distinctive hallmark characteristics of episodic future thinking: the subjective sense that imagined events belong to and will occur in the personal future. In this study, we aimed at shedding light on the cognitive ingredients that contribute to this sense of future occurrence by asking participants to imagine personal and experimenter-provided future events associated with high or low degrees of belief in future occurrence and then to reflect on the bases for their beliefs. Results showed that contextualising autobiographical knowledge (i.e., articulating links between items of information associated with imagined future events, goals, and personal characteristics) is a critical aspect of belief in future occurrence, and autobiographical knowledge can be flexibly used to either support or suppress belief in future occurrence. These findings indicate that episodic future thought not only depends on simulation processes (i.e., the construction of detailed mental representations for future events) but also requires that imagined events are meaningfully integrated within an autobiographical context.

Psychological and Cognitive Markers of Behavioral Variant Frontotemporal Dementia-A Clinical Neuropsychologist's View on Diagnostic Criteria and Beyond

Behavioral variant frontotemporal dementia (bvFTD) is the second leading cognitive disorder caused by neurodegeneration in patients under 65 years of age. Characterized by frontal, insular, and/or temporal brain atrophy, patients present with heterogeneous constellations of behavioral and psychological symptoms among which progressive changes in social conduct, lack of empathy, apathy, disinhibited behaviors, and cognitive impairments are frequently observed. Since the histopathology of the disease is heterogeneous and identified genetic mutations only account for ~30% of cases, there are no reliable biomarkers for the diagnosis of bvFTD available in clinical routine as yet. Early detection of bvFTD thus relies on correct application of clinical diagnostic criteria. Their evaluation however, requires expertise and in-depth assessments of cognitive functions, history taking, clinical observations as well as caregiver reports on behavioral and psychological symptoms and their respective changes. With this review, we aim for a critical appraisal of common methods to access the behavioral and psychological symptoms as well as the cognitive alterations presented in the diagnostic criteria for bvFTD. We highlight both, practical difficulties as well as current controversies regarding an overlap of symptoms and particularly cognitive impairments with other neurodegenerative and primary psychiatric diseases. We then review more recent developments and evidence on cognitive, behavioral and psychological symptoms of bvFTD beyond the diagnostic criteria which may prospectively enhance the early detection and differential diagnosis in clinical routine. In particular, evidence on specific impairments in social and emotional processing, praxis abilities as well as interoceptive processing in bvFTD is summarized and potential links with behavior and classic cognitive domains are discussed. We finally outline both, future opportunities and major challenges with regard to the role of clinical neuropsychology in detecting bvFTD and related neurocognitive disorders.

Pervasive autobiographical memory impairments in Huntington's disease

Autobiographical memory dysfunction is a pervasive feature of neurodegenerative disorders, but less is known about the integrity of autobiographical memory in Huntington's disease (HD). Deficits in anterograde verbal episodic memory on traditional neuropsychological tests have been detected in HD, however, whether personally-relevant autobiographical retrieval is also affected is unknown. We examined autobiographical memory performance in 26 participants genetically confirmed to have HD who were in the peri-manifest stage of the disease (including 12 in the late premanifest stage and 14 who were early diagnosed), and 24 matched controls using the Autobiographical Interview (AI), a semi-structured interview assessing retrieval of autobiographical details from discrete epochs across the lifetime. Relative to controls, people with HD exhibited global episodic autobiographical memory impairments, regardless of recency or remoteness of the memory being retrieved. While specific cues bolstered the retrieval of episodic (internal) details in HD participants, their performance remained significantly below that of controls. Moreover, following probing, people with HD retrieved more extraneous (external) details not directly related to the autobiographical event they originally retrieved, including semantic details, repetitions, and metacognitive statements. Our results reveal marked autobiographical memory dysfunction in HD, not directly attributable to strategic retrieval deficits, and suggest that autobiographical memory impairment may represent an overlooked feature of the cognitive phenotype of HD.

The Functions of Prospection - Variations in Health and Disease

Much of human life revolves around anticipating and planning for the future. It has become increasingly clear that this capacity for prospective cognition is a core adaptive function of the mind. Here, we review the role of prospection in two key functional domains: goal-directed behavior and flexible decision-making. We then survey and categorize variations in prospection, with a particular focus on functional impact in clinical psychological conditions and neurological disorders. Finally, we suggest avenues for future research into the functions of prospection and the manner in which these functions can shift toward maladaptive outcomes. In doing so, we consider the conceptualization and measurement of prospection, as well as novel approaches to its augmentation in healthy people and managing its alterations in a clinical context.

The role of hippocampus in the retrieval of autobiographical memories in patients with amnestic Mild Cognitive Impairment due to Alzheimer's disease

The role of the hippocampus and neocortical areas in the retrieval of past memories in pre-dementia Alzheimer's disease (AD) patients was investigated. The aim was to assess whether the hippocampus has a temporary role in memory trace formation, according to the Cortical Reallocation Theory (CRT), or whether it continuously updates and enriches memories, according to the Multiple Trace Theory. According to the former theory, hippocampal damage should affect more recent memories, whereas the association cortex is expected to affect memories of the entire lifespan. In the second case, damage to either the hippocampus or the association cortices should affect memories of the entire lifespan. Seventeen patients with amnestic Mild Cognitive Impairment due to AD were submitted to autobiographical (i.e., episodic and semantic personal) memory assessment. Patients underwent MRI for the acquisition of T1-weighted brain volumes. Voxel-based morphometry was used to assess correlations between grey matter (GM) volumes and autobiographical memory. Correlation analyses revealed a strict association between GM volumes in the hippocampus and patients' ability to retrieve the most recent but not the oldest autobiographical memories in both aspects, episodic and semantic. Moreover, patients' GM volumes in the pre-frontal and temporal polar areas were associated with recollection of episodic and semantic events, respectively. Finally, GM volumes in the precuneus and occipital cortex were associated with retrieval of the most recent episodic events. These findings indicate that the hippocampus has a specific time-dependent role; thus, they support the CRT.

Characterization of Music and Photograph Evoked Autobiographical Memories in People with Alzheimer's Disease

BACKGROUND

Music evoked autobiographical memories (MEAMs) have been documented in people with Alzheimer's disease (AD), but it is unclear whether music is more effective than other familiar stimuli at evoking memories.

OBJECTIVE

To explore the frequency and specificity of memories in response to famous songs compared with photographs of famous events (photograph evoked autobiographical memories, PEAMs), and whether stimuli from the period of the reminiscence bump (10-30 years of age) were more likely to elicit memories.

METHODS

10 participants with AD and 10 aged-matched healthy elderly people reported memories following exposure to 2 songs (longest time at number one in Australian music charts) and 2 photographs (of prominent famous events) from each decade from 1930 to 2010.

RESULTS

PEAMs were more frequent than MEAMs in healthy elderly (p < 0.05), but no such differences were observed among people with AD. There was no difference in the frequency of MEAMs between groups, but people with AD showed a significant decline in the frequency of PEAMs. In both groups, MEAMs were typically less specific than PEAMs and comprised semantic knowledge or repeated/extended events. Stimuli from when participants were aged 10-30 years triggered more frequent memories compared with stimuli from later decades, but this was only statistically significant for MEAMs.

CONCLUSION

Our findings indicate a preserved mnemonic effect of music relative to pictures in this patient population, corroborating suggestions that MEAMs represent an island of preservation during the progression of AD.