A virtual reality paradigm to assess episodic memory: Validation-dataset for six parallel versions and a structured behavioral assessment

In the epilepsy monitoring unit of the Department of Neurology at the University Clinic of Salzburg 20 adult patients were recruited to participate in a validation of 6 parallel versions of the virtual reality test for episodic memory. Patients were tested up to 7 times, i.e. twice a day, in the morning and evening, beginning on Monday evening. Each session consisted of learning a new town and immediate recall for this town. All sessions but the first one included also delayed recall of the previously learned town and a recognition test. Recall included the sub-scales what, details, when, egocentric where and allocentric where. Recognition memory was tested by presenting the patients 30 sentences of which 15 were true and 15 were false. While not all patients completed the full testing schedule, at immediate recall for 9 patients a full data set (7 sessions) is available. All patients were free of antiepileptic medication (N = 19) or medication was kept constant across the week (N = 1). This data can be used to demonstrate the feasibility to use the virtual reality test in the epilepsy monitoring unit e.g. to monitor effects of seizures or medication on episodic memory.Yvonne Höller's research was funded by the Austrian Science Fund (FWF) : T 798-B27 and by the Research Fund of the Paracelsus Medical University : A-16/02/021-HÖL .Peer reviewe

Virtual Reality for Assessment of Episodic Memory in Normal and Pathological Aging

Memory is one of the most important cognitive functions in a person’s life. Memory is essential for recalling personal memories and for performing many everyday tasks, such as reading, playing music, returning home, and planning future actions, and, more generally, memory is crucial for interacting with the world. Determining how humans encode, store, and retrieve memories has a long scientific history, beginning with the classical research by Ebbinghaus in the late 20th century (Ebbinghaus, 1964). Since this seminal work, the large number of papers published in the domain of memory testifies that understanding memory is one of the most important challenges in cognitive neurosciences. With population growth and population aging, understanding memory failures both in the healthy elderly and in neurological and psychiatric conditions is a major societal issue. A substantial body of evidence, mainly from double dissociations observed in neuropsychological patients, has led researchers to consider memory not as a unique entity but as comprising several forms with distinct neuroanatomical substrates (Squire, 2004). With reference to long-term memory, episodic memory may be described as the conscious recollection of personal events combined with their phenomenological and spatiotemporal encoding contexts, such as recollecting one’s wedding day with all the contextual details (Tulving, 2002). Episodic memory is typically opposed to semantic memory, which is viewed as a system dedicated to the storage of facts and general decontextualized knowledge (e.g., Paris is the capital of France), including also the mental lexicon. Episodic memory was initially defined by Tulving as a memory system specialized in storing specific experiences in terms of what happened and where and when it happened (Tulving, 1972). Later, phenomenological processes were associated with the retrieval of memories (Tulving, 2002). Episodic memory is assumed to depend on the self, and involves mental time travel and a sense of reliving the original encoding context that includes autonoetic awareness (i.e., the awareness that this experience happened to oneself, is not happening now, and is part of one’s personal history)

When a Reactivated Visual Mask Disrupts Serial Recall

Abstract. To prevent forgetting in working memory, the attentional refreshing is supposed to increase the level of activation of memory traces by focusing attention. However, the involvement of memory traces reactivation in refreshing relies in the majority on indirect evidence. The aim of this study was to show that refreshing relies on the reactivation of memory traces by investigating how the reactivation of an irrelevant trace prevents the attentional refreshing to take place, and (2) the memory traces reactivated are sensorial in nature. We used a reactivated visual mask presented during the encoding (Experiment 1) and the refreshing (Experiment 2) of pictures in a complex span task. Results showed impaired serial recall performance in both experiments when the mask was reactivated compared to a control stimulus. Experiment 3 confirmed the refreshing account of these results. We proposed that refreshing relies on the reactivation of sensory memory traces

Attentional Refreshing in the Absence of Long-Term Memory Content: Role of Short-Term and Long-Term Consolidation

International audienceContradictory results in the literature suggest that attentional refreshing can seemingly not operate efficiently in the absence of semantic representations, while at the same time it does not rely directly on retrieval from semantic memory. The objective of the present study was a better understanding of the bidirectional links between working memory (WM) and long-term memory (LTM), by assessing on the one hand the role of WM mechanisms in long-term recall and on the other hand how their functioning is modulated by the prior LTM content. Through two experiments, we investigated a new hypothesis: attentional refreshing requires stable WM representations independently of the presence or the absence of associated LTM traces. We manipulated this stability through short-term consolidation (Experiment 1) and multiple presentations of memoranda (Experiment 2) to evaluate how it would affect maintenance of words and pseudowords. While we found that lexicality, short-term consolidation and multiple presentations affected short-term and long-term recall, both experiments converged on the conclusion that none of these factors modulated the effect of the cognitive load of the concurrent processing task, suggesting that refreshing does not depend on LTM content nor WM representations' stability. Additionally, we found that delayed recall performance was not affected by the cognitive load, in contradiction with previous literature. These results provide new insight into the functioning of refreshing and the links between WM and LTM

The Integration of Realistic Episodic Memories Relies on Different Working Memory Processes: Evidence from Virtual Navigation

Memory is one of the most important cognitive functions in a person's life as it is essential for recalling personal memories and performing many everyday tasks. Although a huge number of studies have been conducted in the field, only a few of them investigated memory in realistic situations, due to methodological issues. The various tools that have been developed using virtual environments (VEs) have gained popularity in cognitive psychology and neuropsychology because they enable to create naturalistic and controlled situations, and are thus particularly adapted to the study of episodic memory (EM), for which an ecological evaluation is of prime importance. EM is the conscious recollection of personal events combined with their phenomenological and spatiotemporal encoding contexts. Using an original paradigm in a VE, the objective of the present study was to characterize the construction of episodic memories. While the concept of working memory has become central in the understanding of a wide range of cognitive functions, its role in the integration of episodic memories has seldom been assessed in an ecological context. This experiment aimed at filling this gap by studying how EM is affected by concurrent tasks requiring working memory resources in a realistic situation. Participants navigated in a virtual town and had to memorize as many elements in their spatiotemporal context as they could. During learning, participants had either to perform a concurrent task meant to prevent maintenance through the phonological loop, or a task aimed at preventing maintenance through the visuospatial sketchpad, or no concurrent task. EM was assessed in a recall test performed after learning through various scores measuring the what, where and when of the memories. Results showed that, compared to the control condition with no concurrent task, the prevention of maintenance through the phonological loop had a deleterious impact only on the encoding of central elements. By contrast, the prevention of visuo-spatial maintenance interfered both with the encoding of the temporal context and with the binding. These results suggest that the integration of realistic episodic memories relies on different working memory processes that depend on the nature of the traces

When motion improves working memory

International audienceIn the present study, we used a complex span task to explore how memory traces resulting from Self-Performed Task (SPT) and Verbal Task (VT) are maintained in working memory. Participants memorised series of five sentences describing an action either through SPT or VT. Between pairs of sentences, participants performed a concurrent task that varied according to its nature and its cognitive load. The concurrent task was either a verbal task, a low cognitive load motor task or a high cognitive load motor task. A control condition served as a baseline. First, we observed that performance in SPT and VT did not decrease with verbal or motor suppression, but was lower with an increase of the cognitive load. This suggests that memory traces are maintained through attentional refreshing whatever the encoding (SPT or VT). Second, while the enactment effect was replicated in the control condition, it tended to vanish with a verbal concurrent task; moreover, it was reversed with motor concurrent tasks. Surprisingly, the latter effect resulted from an increase of VT memory performance when participants repeated the same gesture between sentences. Finally, our results provide additional evidence that the enactment effect does not rely on attention

Core mechanisms underlying the long-term stability of working memory traces still work in aging

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Using More Ecological Paradigms to Investigate Working Memory: Strengths, Limitations and Recommendations

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