Aging Memory Research Articles

The self‐memory system: Exploring developmental links between self and memory across early to late childhood

AbstractThis study tests whether developments in self‐knowledge and autobiographical memory across early to late childhood are related. Self‐descriptions and autobiographical memory reports were collected from 379 three‐ to eleven‐year‐old predominantly white Scottish children, Mage = 90.3 months, SD = 31.1, 54% female. Episodic memory was measured in an enactment task involving recall and source monitoring of performed and witnessed actions. The volume and complexity of self‐knowledge and autobiographical memory reports increased with age, as did source monitoring ability and recall bias for own actions. Regression analyses and structural equation modeling confirmed a close association between these developments. These results inform our theoretical understanding of the development of the self‐memory system in childhood, which may contribute to the gradual offset of childhood amnesia.

Immune-activation model mice escape infantile amnesia, retain early memories

Immune-activation model mice escape infantile amnesia, retain early memories

Factors that contribute to an inability to remember an important aspect of a traumatic event

ABSTRACT Dissociative amnesia is controversial. We tested other factors that could contribute to an inability to remember an important aspect of a traumatic event: how traumatic the event was, organic amnesia, dissociative state, childhood amnesia, expression suppression, sleep disturbance, repeated experiences, and ordinary forgetting. Trauma survivors who reported an inability to remember an important aspect of a traumatic event rated the event as traumatic as trauma survivors who reported no such inability to remember. Moreover, all cases of an inability to remember an important aspect of the traumatic event could be explained by at least one factor other than dissociative amnesia. These findings are contrary to dissociative amnesia. Compared to participants who reported no inability to remember an important aspect of the traumatic event, participants who did report an inability to remember were more likely to (1) have felt disconnected from their body during the traumatic event, which may have altered memory encoding, (2) have experienced sleep problems in the year after the traumatic event, which may have reduced memory consolidation, and (3) have experienced the traumatic event repeatedly, which may have led to less detailed memories. These findings have implications for the inclusion of dissociative amnesia in the DSM.

Immune activation state modulates infant engram expression across development.

Infantile amnesia is possibly the most ubiquitous form of memory loss in mammals. We investigated how memories are stored in the brain throughout development by integrating engram labeling technology with mouse models of infantile amnesia. Here, we found a phenomenon in which male offspring in maternal immune activation models of autism spectrum disorder do not experience infantile amnesia. Maternal immune activation altered engram ensemble size and dendritic spine plasticity. We rescued the same apparently forgotten infantile memories in neurotypical mice by optogenetically reactivating dentate gyrus engram cells labeled during complex experiences in infancy. Furthermore, we permanently reinstated lost infantile memories by artificially updating the memory engram, demonstrating that infantile amnesia is a reversible process. Our findings suggest not only that infantile amnesia is due to a reversible retrieval deficit in engram expression but also that immune activation during development modulates innate, and reversible, forgetting switches that determine whether infantile amnesia will occur.

Gremlins in childhood amnesia research.

Gremlins in childhood amnesia research.

The Infantile Amnesia Phenomenon and the Beginning of Autobiographical Memories

The first years of life are characterized by an absence or paucity of memories, a condition known as infantile amnesia (IA). This study examines the distribution of the early memory recall of young adults, considering the distinction between the first (0–3) and the second (4–6) epoch of IA. We used five categories to classify memories: Perceptual-Visual Fragment, General Semantic Memory, Episodic Fragment, Repeated Episode, Single Episode. Fifty-five students (20 males; mean age = 20.85) were asked to remember their earliest events. We were also interested in understanding the presence of content features. Remembering at first epoch were low; in the second epoch, the frequency of memory increased. Results showed as the presence and number of different types of memory decrease the likelihood of memory being structured as episodic. The participants reported more elements of perceptual-visual fragments, episodic fragments, semantic memories, or repeated events when a well-organized episodic memory does not emerge. These results suggest that the episodic system assumes the role of organizer of the experience and becomes the most relevant form of memory with respect a less structured form of partial remembering. Significant differences were observed in the content features of the different memory types. The offset of IA has a complex articulation, and the complete episodic memories are the last step in the different development stages.

Photo age: Temporal preferences for external memory across the lifespan

AbstractAutobiographical memories show a temporal pattern with relatively many events recalled from the recent past (recency) and from adolescence to early adulthood (reminiscence bump), and very few events recalled from the first few years of life (childhood amnesia). The current study examined a temporal pattern for external memory – information stored outside of one's brain. Three survey studies asked participants to choose which age(s) in their life they would most want to keep photos from, supposing they had many photos from every year. Participants chose 1 year of photos in Study 1, which sampled undergraduates (N= 499, median age = 19), and in Study 2, which sampled online participants using stratified age brackets (N= 252, age range 18–82). Participants chose 3 years of photos in Study 3, which sampled online participants over 40 using stratified age brackets (N= 240, age range 40–93). Participants’ choices largely showed preferences for time periods likely to be well remembered (recency and the reminiscence bump). Qualitative coding of participants’ reasons for their choices showed common themes, such as positive emotions, connections to other people and pets, life milestones, personal growth, and school. Results suggest that in the case of photos, external memory served to mostly enhance or enrich internal memory and less often to compensate for internal memory.

Legal aspects of memory: a report issued by the Psychology and Law Sections of the British Academy

We describe the commissioning, publication, and contents of a report on legal aspects of memory. The report was the result of a unique collaboration between the Psychology and Law �Sections� of the British Academy that brought together the contributions of memory and legal experts from both inside and outside the Academy. The report briefly summarises psychological research on memory and is designed to be of practical value to busy legal and criminal justice professionals. Topics covered include memory concepts, memory development including childhood amnesia, interviewing witnesses, the effects of suggestion and misinformation, the effects of trauma on recall, adult memory for childhood events, factors affecting eyewitness identification, conditions such as psychiatric and neurological disorders that may impair memory, issues in the memory of suspects such as deception and reported amnesia, and the role of the expert witness in court.

Learning and memory : neurosciences perspectives

Learning is the process of acquiring new or modifyingexisting knowledge, skills, behaviors or preferences (Schachter et al., 2010)
 
 
 Memory is the faculty of encoding, storing and retreiving information (Squire, 2009)
 
 Basic forms of learning were demonstrated at earlier and earlier stages of development, including in utero (Blumberg et al., 2010, Kail and Spear, 1984)
 
 There are multiple brain learning/memory systems, age-specific ecological adaptions, and acquisition-vs.-expression of learning (Krasnegor et al., 1986, Shair et al., 1991, Spear and Campbell, 1979). 
 
 
 Rats show “infantile amnesia” (Campbell and Campbell, 1962, Campbell and Spear, 1972). The discovery that rodents show poor long-term memory for experiences occurring in infancy suggested that the human phenomenon has a biological basis. 
 
 The neurobiology of learning and memory during adolescence showed specific sex/gender effects (Spear, 2009, Raznahan 2019).
 
 There is a strong relationship between neurobiological and behavioral changes specifically during the adolescent period: alterations in fronto-striatal systems during adolescence impact risky decision making and vulnerability to social pressures, which may ultimately provide a framework for the development of reward-related learning abilities (DePasque & Galvan 2017).
 
 Involvement of NMDA glutamate receptors in impairments in fearextinction during adolescence, and how the role of NMDA receptorsmay differ during this stage of development compared to adults and juveniles (Baker and Richardson 2017). 
 
 The maturation of cortical noradrenergic systems contributes to executive function (Mokler and colleagues 2017). 
 
 

Maternal enrichment increases infantile spatial amnesia mediated by postnatal neurogenesis modulation.

Infantile amnesia, the inability to form long-lasting episodic memories, is a phenomenon extensively known but with no clear understanding of its origins. However, a recent study showed that high rates of hippocampal postnatal neurogenesis degrade episodic-like memories in infants a few days after memory acquisition. Additionally, new studies indicate that exposure to an enriched environment in mice leads to high hippocampal neurogenesis in their offspring. Nevertheless, it is still unclear how this intergenerational trait affects the persistence of hippocampal memories. Therefore, we evaluated spatial memory retention in the offspring of enriched female mice after weaning to address this question. Ten days after spatial learning, we tested memory retention, observing that the offspring of enriched dams increased spatial memory failure; this finding correlates with high proliferation rates in the hippocampus. Furthermore, we evaluated the causal relationship between postnatal hippocampal neurogenesis and memory failure using the antiproliferative drug Temozolomide (TMZ), which rescued spatial memory retrieval. Finally, we evaluated neuronal activity in the hippocampus quantifying the cells expressing the immediate early gene c-Fos. This evaluation showed engram modifications between groups. This neural activity pattern indicates that the high neurogenesis rates can modify memory engrams and cognitive performance. In conclusion, the inherited increase of hippocampal neurogenesis by enriched dams leads to plastic changes that exacerbate infantile amnesia in a spatial task.

Radicalizing simulationism: Remembering as imagining the (nonpersonal) past

ABSTRACT On the simulation theory of memory, to remember is to imagine an event from the personal past. McCarroll has recently argued that, because it implies not only that a genuine memory need not be caused by the rememberer’s experience of the remembered event but also that the rememberer need not even have experienced that event, simulationism is unable, first, to explain infantile amnesia (the inability to remember events that occurred in one’s early childhood) and, second, to rule out certain “impossible” memories (namely, memories of events that occurred before one was born). Responding to McCarroll, this paper argues that simulationism is in fact able to explain infantile amnesia but concedes that it is unable to rule out pre-birth memories. It goes on to argue, however, that, rather than leading us to reject the theory, this should lead us to endorse a radicalized simulationism on which to remember is simply to imagine an event from the past, regardless of whether that event belongs to the personal past.

Çocukluk Çağı Amnezisi: Hatırlanan İlk Çocukluk Anısı Yaşı İle İlişkili Faktörlerin İncelenmesi

Childhood amnesia is a condition defined as the inability to fully recall autobiographical memories produced in the early stages of development during adulthood. Although it is generally accepted that the first memories remembered belong to the average age of 3-4 years, the age to which the first childhood memory belongs is controversial. In this study, it was aimed to determine the age of the first childhood memory remembered in young adults and to examine the effect of gender, memory-related factors, attachment styles and childhood traumatic events on the age of memory. 137 university students participated in the study. The participants were asked to write down the first memory they remembered and fill out a questionnaire evaluating the characteristics of the memory such as the age of the memory and the level of mediocrity, clarity, emotional intensity, integrity. In addition, the participants' october traumatic experiences and attachment styles were also evaluated. Keywords: Memory, childhood, amnesia

The effects of early weaning on Pavlovian fear conditioning in young rats.

Early life stress enhances memory for Pavlovian fear conditioning. Stress enhancements on fear conditioning following early weaning, however, have yet to be studied in periweaning rats. Early weaning is a relevant animal model for human early life trauma, and Pavlovian fear conditioning is useful for identifying links between stress-induced developmental changes and behavior. We hypothesized that early weaning-on postnatal day (P)15-would lead to higher levels of conditional freezing relative to rats weaned later in life. Periweaning rats were trained with a discrete conditional stimulus (CS) and a shock unconditional stimulus (US), and tested 1 or 15 days later. Enhanced retention was observed in early weaned rats receiving forward paired CS-US training in Experiment 1, though this did not replicate in the second experiment. Despite overall enhancements in early weaned rats in Experiment 1, infantile amnesia effects were not overcome in young rats tested 15 days after training. Enhanced freezing levels in early weaned rats were not observed in subjects receiving unpaired CS, US training, and sensitivity to the US was not different due to age at weaning. Potential mechanisms underlying weaning-related enhancements and considerations for future studies including the role of social transmission of fear information are discussed.

Recovery of memory from infantile amnesia is developmentally constrained.

Episodic memories formed during infancy are rapidly forgotten, a phenomenon associated with infantile amnesia, the inability of adults to recall early-life memories. In both rats and mice, infantile memories, although not expressed, are actually stored long term in a latent form. These latent memories can be reinstated later in life by certain behavioral reminders or by artificial reactivations of neuronal ensembles activated at training. Whether the recovery of infantile memories is limited by developmental age, maternal presence, or contingency of stimuli presentation remains to be determined. Here, we show that the return of inhibitory avoidance memory in rats following a behavioral reactivation consisting of an exposure to the context (conditioned stimuli [CS]) and footshock (unconditioned stimuli [US]) given in a temporally unpaired fashion, is evident immediately after US and is limited by the developmental age at which the reactivations are presented; however, it is not influenced by maternal presence or the time interval between training and reactivation. We conclude that one limiting factor for infantile memory reinstatement is developmental age, suggesting that a brain maturation process is necessary to allow the recovery of a “lost” infantile memory.

Factors influencing developmental differences in retention of Pavlovian fear conditioning.

Modern nonhuman animal research on the rapid forgetting of memories formed early in life-often termed "infantile amnesia"-has focused on neurobiological changes occurring between learning and retention testing to explain age differences in memory. Developmental differences in initial learning have received less attention as a contributing factor to infantile amnesia effects. The present study identifies conditions under which associative learning and memory are comparable between pre and postweaning rats across multiple training-testing intervals. Postnatal day (P) 17-18 or P24-25 littermates were trained with white noise conditional stimuli (CSs) alone, forward-paired, or explicitly unpaired with floor shock unconditional stimuli (USs), and tested for retention at intervals ranging between 5 min and 15 days later. Findings from within- and across-institution replications revealed that age differences in CS freezing were influenced by (a) the associative nature of the CS and US at training, (b) the number of CS, US presentations at training, and (c) the interval between training and testing. Rats trained on P17 or 18 displayed robust retention comparable to rats trained on P24 or 25 only when training in younger rats involved additional forward-paired CS-US presentations. Poor long-term retention observed at multiple training-testing intervals in rats trained on P17 or 18 was overcome with many additional forward-paired CS-US presentations at training. Conditions necessary for appropriate developmental comparisons of learning and memory relevant to the future neurobiological studies are discussed. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

“I Remember Having Chicken Pox at Age 3”: How Can Age Manipulations Affect One’s Earliest Childhood Memories?

Adults’ reports of earliest autobiographical memories from before the age of 3 are typically scarce. However, recent research suggests that the age range of this childhood amnesia is flexible when participant instructions provide a context in which earlier or later ages of childhood events are plausible (Kingo et al., 2013). This age manipulation may be more or less effective depending on the type of memories, i.e., event memories that describe a specific event, or fragments / snapshots that describe elements of a past event. One earlier study showed that after reading an early age example, the age in event memories was younger than after a late age example, whereas this difference was less pronounced in snapshot memories (Wessel et al., 2019). The present aim was to examine the malleability of the age in earliest childhood memories and replicate this age manipulation by memory type interaction as well as the overall effects of the age manipulation demonstrated earlier (Wessel et al., 2019). Three studies varied the age in example event memories and fragments (early, late, or no age). Overall, the results suggested that age information affects the reported age, but not necessarily more for event memories than for fragments. That is, all present studies failed to replicate the age manipulation by memory type interaction reflecting that relative to the early condition, event memories in the late condition were older than snapshot memories (Wessel et al., 2019). Even though we cannot conclude that a true effect does not exist, the original finding may be taken as reflecting a false positive.

Associative memory persistence in 3- to 5-year-olds.

Adults struggle to recollect episodic memories from early life. This phenomenon-referred to as "infantile" and "childhood amnesia"-has been widely observed across species and is characterized by rapid forgetting from birth until early childhood. While a number of studies have focused on infancy, few studies have examined the persistence of memory for newly learned associations during the putative period of childhood amnesia. In this study, we investigated forgetting in 137 children ages 3-5years old by using an interactive storybook task. We assessed associative memory between subjects after 5-min, 24-h, and 1-week delay periods. Across all delays, we observed a significant increase in memory performance with age. While all ages demonstrated above-chance memory performance after 5-min and 24-h delays, we observed chance-level memory accuracy in 3-year-olds following a 1-week delay. The observed age differences in associative memory support the proposal that hippocampal-dependent memory systems undergo rapid development during the preschool years. These data have the potential to inform future work translating memory persistence and malleability research from rodent models to humans by establishing timescales at which we expect young children to forget newly learned associations.

The Feminine and the Pubertarian: The Pubertarian Novelty According to Freud and Lacan

Countless authors have attempted to theorize the passage from the infantile to the juvenile. This passage is not without consequence, as shown by the changes in the semiological and nosological fields, corroborated by the infantile amnesia subsequent to this phase. We propose to approach this question through a re-reading of Freud’s texts. We shall highlight how Freud’s attempt at qualifying infantile sexuality led him to define more and more clearly what distinguishes it from juvenile sexuality; nevertheless he failed to define the threshold that separates them. Thus, on the one hand he reached the threshold of the impossible whilst on the other, and despite himself, he indicated viable clues to its potential theorization. To Freud, this impossibility constituted an impasse at the time. Contributions from linguistics and structuralism allowed for a theoretical opening towards it. To Lacan, it characterizes the Real, the Other jouissance (specific to woman) and the Other’s lack signifier S (Ⱥ). We shall conclude that the pubertarian novelty is the effect - brought by the Real - of the body’s physiological change when it becomes pubertarian. Our hypothesis is in accordance with what Freud had identified as proper to puberty, namely “the displacement of erogenous zones from the clitoris to the vagina”. We may call this effect the advent of the Feminine, vector of the Other sex, which cannot be inscribed in the infantile, phallocentric world. In other words, it is a bodily experience that has no equivalent in the Symbolic realm. Lacan translated this experience into “there is no signifier to woman’s sex”. This Feminine (the capital F indicates its non-inscription in the Symbolic realm) will, during the time of adolescence, find a formalization - not via a signifier which is defaulted but via an object present in reality (which can be the Other sex’s other as much as any addictive, source of jouissance object).

Is good memory always a good thing? An early offset of infantile amnesia predicts anxiety-like behavior throughout development in rats

Infants tend to forget experiences much more rapidly than older individuals, a phenomenon referred to as infantile amnesia. This robust, cross-species phenomenon is commonly used to examine memory development. However, in this set of experiments, we examined the novel hypothesis that the expression of infantile amnesia is related to resilience/vulnerability. We conditioned infant rats to associate a white noise with shock. Animals were tested for memory of the association ~1 week later. We found that infants that expressed better memory of the aversive association emitted more vocalizations (indicative of higher levels of distress) when separated from their mother earlier in infancy (Experiment 1). Better expression of memory in infancy also predicted higher levels of conditioned fear (Experiment 2) and anxiety-like behavior (in a light-dark box; Experiment 3) in adulthood. Furthermore, probiotic-treatment administered early in development reduced anxiety-like behavior in animals that exhibited good expression of memory for an aversive association learnt in infancy (Experiment 4). However, the same treatment was ineffective if administered in adulthood. Taken together, these results suggest that individual differences in infants’ memory for an aversive association predict anxiety-like behavior throughout development, and that early administration of probiotics can reduce anxiety-like behavior in “at-risk” animals.

The intrinsic neonatal hippocampal network: rsfMRI findings.

Many adults cannot voluntarily recall memories before the ages of 3-5, a phenomenon referred to as "infantile amnesia." The development of the hippocampal network likely plays a significant part in the emergence of the ability to form long-lasting memories. In adults, the hippocampus has specialized and privileged connections with certain cortical networks, which presumably facilitate its involvement in memory encoding, consolidation, and retrieval. Is the hippocampus already specialized in these cortical connections at birth? And are the topographical principles of connectivity (e.g., long-axis specialization) present at birth? We analyzed resting-state hippocampal connectivity in neonates scanned within 1 wk of birth (Developmental Human Connectome Project) and compared it with that of adults (Human Connectome Project). We explored the connections of the whole hippocampus and its long-axis specialization to seven canonical cortical networks. We found that the neonatal hippocampal networks show clear immaturity at birth: adults showed hippocampal connectivity that was unique for each cortical network, whereas neonates showed no differentiation in hippocampal connectivity across these networks. Furthermore, neonates lacked long-axis specialization (i.e., along the anterior-posterior axis) of the hippocampus in its differential connectivity patterns to the cortical networks. This immaturity in connectivity may contribute to immaturity in memory formation in the first years of life.NEW & NOTEWORTHY Although both animal data and human data suggest that the hippocampus is immature at birth, to date, there are no direct assessments of human hippocampal functional connectivity (FC) very early in life. Our study explores the FC of the hippocampus to the cortex at birth, allowing insight into the development of human memory systems. In particular, we find that adults and neonates exhibit vastly different hippocampal connectivity profiles-a finding that likely has large developmental implications.