Neural correlates of autobiographical memory retrieval in children and adults

Autobiographical memory (AM) is a critically important form of memory for life events that undergoes substantial developmental changes from childhood to adulthood. Relatively little is known regarding the functional neural correlates of AM retrieval in children as assessed with fMRI, and how they may differ from adults. We investigated this question with 14 children ages 8–11 years and 14 adults ages 19–30 years, contrasting AM retrieval with semantic memory (SM) retrieval. During scanning, participants were cued by verbal prompts to retrieve previously selected recent AMs or to verify semantic properties of words. As predicted, both groups showed AM retrieval-related increased activation in regions implicated in prior studies, including bilateral hippocampus, and prefrontal, posterior cingulate, and parietal cortices. Adults showed greater activation in the hippocampal/parahippocampal region as well as prefrontal and parietal cortex, relative to children; age-related differences were most prominent in the first 8?sec versus the second 8?sec of AM retrieval and when AM retrieval was contrasted with semantic retrieval. This study is the first to characterise similarities and differences during AM retrieval in children and adults using fMRI.     

A role for affect in the link between episodic simulation and prosociality

Prospection and prosociality are hallmarks of our species. Little is known, however, about how our ability to imagine or simulate specific future events contributes to our capacity for prosociality. Here, we investigated this relationship, revealing how the affective response that arises from a simulated prosocial event motivates a willingness to help a person in need. Across two experiments, people reported being more willing to help in specific situations after simulating future helping events that elicited positive (versus negative or neutral) affect. Positive affect increased engagement of theory of mind for the person in need, which in turn informed prosocial responses. Moreover, the subjective experience of scene imagery and theory of mind systematically couple together depending on the affective valence of future simulations, providing new insight into how affective valence guides a prosocial function of episodic simulation.     

Superior episodic memory in inconsistent-handers: a replication and extension using fNIRS

A large body of evidence supports the existence of a robust handedness difference in episodic memory retrieval, with inconsistent-handedness being associated with superior memory across a wide variety of paradigms, including superior retrieval of lab-based and real world memories. Despite superior episidoc memory in inconsistent-handers, and despite neuroanatomical and neurophysiological differences in cortical regions between inconsistent- and consistent-handers, we are aware of no studies to date that have examined physiological activity in the brains of inconsistent- versus consistent-handers while engaged in memory tasks. The purpose of this paper, therefore, is to present a first look at this issue, using functional near-infrared spectroscopy (fNIRS) as a simple, non-invasive measure of frontal lobe activity during encoding and recall of list words in inconsistent- and consistent-handers. Behaviourally, we replicated prior studies, finding a significant inconsistent-handed advantage in free recall. Using fNIRS-derived oxygenated haemoglobin (O₂Hb) as a measure of frontal lobe activity, we found the first evidence for handedness differences in brain activity that are associated with the handedness differences in episodic retrieval. Specifically, the primary finding was that increased O₂Hb in the right hemisphere during recall was associated with better retrieval, but for consistent-handers only.     

Reconstructing the times of past and future personal events

Humans have the remarkable ability to mentally travel through past and future times. However, while memory for the times of past events has been much investigated, little is known about how imagined future events are temporally located. Using a think-aloud protocol, we found that the temporal location of past and future events is rarely directly accessed, but instead mostly relies on reconstructive and inferential strategies. References to lifetime periods and factual knowledge (about the self, others, and the world) were most frequently used to determine the temporal location of both past and future events. Event details (e.g., places, persons, or weather conditions) were also used, but mainly for past events. Finally, the results showed that events whose temporal location was directly accessed were judged more important for personal goals. Together, these findings shed new light on the mechanisms involved in locating personal events in past and future times.     

Thirty-five-month-old children have spontaneous memories despite change of context for retrieval

ABSTRACT

Many parents have experienced incidents in which their preschool child spontaneously (i.e., without prompting of any kind) recall a previously experienced event. Until recently, such spontaneous memories had only been examined in non-controlled settings (e.g., diary studies). Using a novel experimental paradigm, a previous study has shown that when young children are brought back to a highly distinct setting (same room, same experimenter, same furnishing), in which they previously experienced an interesting event (a Teddy or a Game event), spontaneous memories can be triggered. However, exactly which cues (or combination of cues) are effective for the children’s memory, remains unknown. Here, we used this novel paradigm to examine the possible impact of contextual cues at the time of retrieval. We manipulated whether the 35-month-old children returned to the same room (n?=?40) or to a different, but similarly furnished, room (n?=?40) after one week. The results revealed that although the children returning to a new room produced fewer spontaneous memories than the children returning to the same room, the difference was not significant. Interestingly, despite changing rooms, the children still produced spontaneous memories. Taken together the results may shed new light on the mechanisms underlying childhood amnesia.     

Do process simulations during episodic future thinking enhance the reduction of delay discounting for middle income participants and those living in poverty?

Two studies examined whether episodic future thinking (EFT; pre‐experiencing future events) reduces discounting of future rewards (DD). No studies have investigated whether process simulations (i.e., simulating the process of executing a future event) amplify EFT's reduction of DD. Study 1 examined the effect of incorporating process simulations into EFT (N = 42, M_age = 43.27; 91% female, family income = $75,976) using a 2 × 2 factorial design with type of episodic thinking (process, nonprocess/general) and temporal perspective (EFT, episodic recent thinking) as between‐subjects factors. Study 2 replicated Study 1 in a sample of adults living in poverty (N = 36; M_age = 38.44, 88% female; family income = $25,625). The results of both studies showed EFT reduced DD, but process‐oriented EFT did not amplify the effect of EFT. Our findings suggest the key ingredient in EFT's effect on DD is self‐projection into the future. This was also the first study to show EFT improves DD in a sample living in poverty.     

Self-initiated object-location memory in young and older adults

The present study explored self-initiated object-location memory in ecological contexts, as aspect of memory that is largely absent from the research literature. Young and older adults memorized objects-location associations they selected themselves or object-location associations provided to them, and elaborated on the strategy they used when selecting the locations themselves. Retrieval took place 30 min and 1 month after encoding. The results showed an age-related decline in self-initiated and provided object-location memory. Older adults benefited from self-initiation more than young adults when tested after 30 min, while the benefit was equal when tested after 1 month. Furthermore, elaboration enhanced memory only in older adults, and only after 30 min. Both age groups used deep encoding strategies on the majority of the trials, but their percentage was lower in older adults. Overall, the study demonstrated the processes involved in self-initiated object-location memory, which is an essential part of everyday functioning.     

Is episodic memory performance more vulnerable to depressive affect in older adulthood?

This study examined how age, depressive symptoms, demographic variables, frailty, and health factors jointly influence episodic memory across the lifespan in two large, diverse samples. Hierarchical regression analyses from both samples showed that depressive symptoms negatively impacted episodic memory performance with the effect being more pronounced for older adults. Health and frailty tended not to be associated with episodic memory. However, the main effect of depressive symptoms tended to remain significant over and above other predictors, while the interaction with age was weakened with the addition of demographic variables. The unique contribution of this study is demonstrating that the relationship between depressive symptoms and episodic memory is moderated by age across relatively large non-clinical lifespan samples of adults. The findings indicate the importance of measuring and studying depressive symptoms during the course of aging in order to better understand the complex relationship between age, affect, physical functioning, and memory.     

主观记忆减退老年人情节记忆的行为表现及其脑机制

情节记忆是个体对特定时间,特定地点所经历的特定事件的记忆.主观报告情节记忆下降是主观记忆减退老年人最典型的表现.与健康对照组老年人相比, 主观记忆减退老年人情节记忆下降的速率更快, 罹患老年性痴呆的风险更高, 但其情节记忆加工的脑机制尚不明确.前人研究提示, 主观记忆减退老年人在外在记忆行为尚未出现损伤的情况下, 其大脑情节记忆相关脑区的神经活动已经出现异常.探究主观记忆减退的记忆神经环路关键节点和路径的异常, 揭示神经环路在老年痴呆发生发展中的变化规律, 对深入理解老年痴呆的发病机制有重要的科学意义.同时, 主观记忆减退老年人作为特殊的记忆损伤群体, 对其神经环路的深入探究, 也必将为揭示人类记忆的神经机制做出独特的贡献.