How rich are false memories in a naturalistic context in healthy aging?

The recall of factual and contextual information is a core characteristic of episodic memory sensitive to aging effects. The innovative aim of the present study was to assess in a naturalistic context the quantity and quality of correct and false free recalls among younger and older adults considering feature binding (What-Where-When-Details) and recollection (Remembering vs. Knowing). Thanks to virtual reality, we designed a multimodal environment simulating a lively town in which we implemented a variant of a DRM task rich in sets of semantically related items (e.g., fruits on a market stall). We asked 30 young and 30 older participants to navigate in the virtual environment, paying attention to the items, and then recall as many items and as much contextual information as possible and indicate the presence of recollection. As expected, older adults produced fewer correct recall but more intrusions than younger adults, and their correct recall was more deficient in binding and recollection. In both age groups, false recall was associated with the correct context inferred from a related set of items. However, the intrusions produced by older adults were highly recollected compared to those of the younger adults, and they were associated with false item-related contextual information.

Mindfulness and false memories: state and dispositional mindfulness does not increase false memories for naturalistic scenes presented in a virtual environment.

Mindfulness attracted increased research interests in the last decade, reporting an overall beneficial effect of this practice on cognitive performances. Nevertheless, recently a possible detrimental impact of mindfulness has been underlined. While the effect of mindfulness on memory remains under-explored, recent studies have observed an increased false-memory susceptibility after mindfulness practice. A possible explanatory mechanism has been suggested, related to the nature of the studied material. For semantically related information, mindfulness would increase false memories; however, the addition of rich perceptual information could prevent this detrimental effect. The present study aimed to verify this hypothesis by testing the impact of state mindfulness induced by a short meditation session, and dispositional mindfulness on the production of false memory for pictorial material presented in a complex virtual environment. We employed a virtual reality version of the Deese-Roediger-McDermott paradigm (DRM), a classical protocol to induce false memories. Contrary to previous studies, we did not observe any effect of mindfulness on false or correct memories (free recall and recognition) after a short mindfulness practice session compared to a control condition. Nonetheless, we found a beneficial effect of mindfulness practice on memory sensitivity. Additionally, we reported a positive and negative effect of dispositional mindfulness on memory outcomes. While the Non-Reactivity facet was associated with overall better memory performances, we observed an association between the Acting with Awareness facet and an increased recollection of lures. We discuss these findings in line with a recent proposal on the link between mindfulness and episodic memory.

The production of false recognition and the associated state of consciousness following encoding in a naturalistic context in aging.

Using virtual reality, we implemented a naturalistic variant of the DRM paradigm in young and older adults to evaluate false recall and false recognition. We distinguished false recognition related to the highest semantic association (the critical lures), semantic similarity (i.e. items that belong to the same semantic category), and perceptual similarity (i.e. items that are similar, but not identical in terms of shape or color). The data revealed that younger adults recalled and recognized more correct elements than older adults did while the older adults intruded more critical items than younger adults. Both age groups produced false recognition related to the critical items, followed by perceptually and then semantically related items. False recognitions were highly recollective as they were mainly associated with a sense of remembering, even more so in older adults than in young adults. The decline of executive functions and working memory predicted age-related increases in false memories.

False memory in normal ageing: empirical data from the DRM paradigm and theoretical perspectives.

False memories refer to falsely remembering something that did not happen or that happened differently. The effects of age on episodic memory underlie both the decline in real memories and the increase in false memories. But, what is the richness and what is the feeling of reality of false memories in the elderly? This mini-review on false memory in young and older adults presents the results from the literature using one of the most used paradigms in the laboratory to study false memories - the Deese-Roediger-McDermott paradigm. This paradigm generally consists in the presentation of semantically associated items-lists (words or images) related to a non-presented critical lure (e.g., bed, rest, awake …, the critical lure is sleep). During free recall or recognition tests, the participants regularly produce false memories (intrusions or false recognitions of the critical lures), increasingly with aging. We specifically ask the question of the richness of the false memory trace in young and older adults in terms of contextual associations (What-Where-When-Details binding) and phenomenological characteristics (remembering, knowing, guessing). We propose to examine this issue using a naturalistic episodic memory task via navigation in a virtual environment enriched with series of associated elements (e.g., vegetables stand) linked to non-presented critical lures (e.g., carrots). Based on preliminary results, we propose an integrative model of memory trace which can explain the differences observed between young and old people on the richness of their false memories.

[False memory in normal aging: empirical data from the DRM paradigm and theoretical perspectives]. / Les faux souvenirs dans le vieillissement normal : données empiriques du paradigme DRM et perspectives théoriques.

False memories refer to falsely remembering something that did not happen or that happened differently. The effects of age on episodic memory underlie both the decline in real memories and the increase in false memories. But, what is the richness and what is the feeling of reality of false memories in the elderly? This mini-review on false memory in young and older adults presents the results from the literature using one of the most used paradigms in the laboratory to study false memories - the Deese-Roediger-McDermott paradigm. This paradigm generally consists in the presentation of semantically associated items-lists (words or images) related to a non-presented critical lure (e.g., bed, rest, awake …, the critical lure is sleep). During free recall or recognition tests, the participants regularly produce false memories (intrusions or false recognitions of the critical lures), increasingly with aging. We specifically ask the question of the richness of the false memory trace in young and older adults in terms of contextual associations (What-Where-When-Details binding) and phenomenological characteristics (remembering, knowing, guessing). We propose to examine this issue using a naturalistic episodic memory task via navigation in a virtual environment enriched with series of associated elements (e.g., vegetables stand) linked to non-presented critical lures (e.g., carrots). Based on preliminary results, we propose an integrative model of memory trace which can explain the differences observed between young and old people on the richness of their false memories.

Young and Older Adults Benefit From Sleep, but Not From Active Wakefulness for Memory Consolidation of What-Where-When Naturalistic Events.

An extensive psychological literature shows that sleep actively promotes human episodic memory (EM) consolidation in younger adults. However, evidence for the benefit of sleep for EM consolidation in aging is still elusive. In addition, most of the previous studies used EM assessments that are very different from everyday life conditions and are far from considering all the hallmarks of this memory system. In this study, the effect of an extended period of sleep was compared to the effect of an extended period of active wakefulness on the EM consolidation of naturalistic events, using a novel (What-Where-When) EM task, rich in perceptual details and spatio-temporal context, presented in a virtual environment. We investigated the long-term What-Where-When and Details binding performances of young and elderly people before and after an interval of sleep or active wakefulness. Although we found a noticeable age-related decline in EM, both age groups benefited from sleep, but not from active wakefulness. In younger adults, only the period of sleep significantly enhanced the capacity to associate different components of EM (binding performance) and more specifically the free recall of what-when information. Interestingly, in the elderly, sleep significantly enhanced not only the recall of factual elements but also associated details and contextual information as well as the amount of high feature binding (i.e., What-Where-When and Details). Thus, this study evidences the benefit of sleep, and the detrimental effect of active wakefulness, on long-term feature binding, which is one of the core characteristics of EM, and its effectiveness in normal aging. However, further research should investigate whether this benefit is specific to sleep or more generally results from the effect of a post-learning period of reduced interference, which could also concern quiet wakefulness.

Episodic Memory Assessment and Remediation in Normal and Pathological Aging Using Virtual Reality: A Mini Review.

Life expectancy is constantly increasing in developed countries. Unfortunately, a longer life does not always correspond to a healthier life, as even normal aging is associated with cognitive decline and increased risk factors for neurodegenerative diseases. Episodic memory (EM) is one of the most vulnerable cognitive functions in aging, and its decline is the hallmark of typical Alzheimer's disease. This memory system is defined as the ability to acquire and recollect personally experienced episodes associated with a specific affective, spatial, and temporal context. However, most of the neuropsychological and experimental tasks currently employed to assess EM consist in learning simple material (e.g., list of words) in highly stereotyped contexts. In the same vein, classical paper-and-pencil or numeric remediation tools have shown their limitations in the transfer of acquired skills to daily life. Virtual reality (VR), thanks to its immersive properties, and the possibility of delivering realistic and complex scenarios, seems a promising tool to address the limitations of the assessment and remediation of EM. Here, we review existing studies employing VR in normal and pathological aging to assess and reeducate EM. Overall, we show that VR has been mainly used via non-immersive systems. Further studies should, therefore, test the impact of different degrees of immersion. Moreover, there is a lack of VR remediation tools specifically targeting EM. We propose that future studies should fill this gap, addressing in particular the adaptivity of VR remediation protocols.

Does virtual reality have a future for the study of episodic memory in aging?

Episodic memory is the memory of personally lived events located in time and space, it shapes our identity and allows us to project ourselves into the past and the future. This form of memory is vulnerable to the effects of age and its alteration, hindering the autonomy of the subjects, can predict the evolution towards neurodegenerative disorders. Hence, a better understanding of this type of memory is a priority in the field of public health. Actually, traditional neuropsychological tools are often decontextualized, using simplistic situations that did not require the mobilization of all the characteristics of episodic memory, thus they just offer a partial measure of this complex mnemonic capacity. Nowadays, the virtual reality (VR) is a tool allowing the immersion of subjects in simulations of real situations, rich in spatial and temporal naturalistic contexts. Due to its many characteristics, the VR allows to solve several limitations of the traditional tests. The purpose of this review is to expose studies that investigated episodic memory in normal and Alzheimer's disease using VR in order to address its relevance as a new tool in the future practice of neuropsychology of aging.

Variable motor imagery training induces sleep memory consolidation and transfer improvements.

Motor-skill practice in repetitive or variable orders leads to better within-day acquisition and facilitates retention and transfer, respectively. This practice pattern effect has been robustly found for physical practice, but little is known about its effect after motor imagery (MI) practice. In the present study, we investigated the effect of constant or variable MI practice, and the consolidation following a day-time or a sleep interval. The physical performance was assessed before (pre-test) and after MI training (post-test), as well as after a night or day-time consolidation (retention test). Finally, a transfer test on an unpracticed task was further performed. Results revealed that in all participants, performance increased significantly in the post-test when compared with the pre-test, while only subjects in the variable MI training showed further gains in performance in the retention test following a night of sleep, and exhibited the best transfer of performance to a novel visuomotor sequence. In contrast, subjects in the constant MI training did not show any delayed performance gain following both day and sleep-consolidation. Overall, and for the first time, these findings partially support the practice pattern effect of motor learning with MI, and further highlight a new difference between mental and physical practice, especially on consolidation. To conclude, variable MI practice, rather than constant, seems to be the valuable condition that should be considered in the practical implications of mental training in motor learning and rehabilitation.