Can acute resistance exercise facilitate episodic memory encoding?

Research has shown benefits of physical exercise on memory performance when carried out before or after a memory task. The effects of concurrent physical exercise and particularly resistance exercise are still inconclusive. The current study investigates the influence of resistance exercise with two intensities (fast and slow squats) on performance in a wordlist learning task using a within-subject design. Sport students (N = 58, Mage = 23 years; 26 women) were trained in a mnemonic technique to encode word lists (method of loci). In each session they were asked to encode two lists, each consisting of 20 words. During encoding, participants either performed one squat per word (fast-squat-condition), one squat every second word (slow-squat-condition), or stayed seated (control-condition). Participants performed three sessions for each condition, in counterbalanced order. Heart rates differed significantly according to exercise intensity. Memory performances in the sitting condition were better, compared to the exercise conditions. Performance in sitting and the fast squat conditions improved similarly over time, while performance in the slow squat condition increased faster, and reached the level of the fast squat condition at the end of the study phase. We conclude that light to moderate resistance exercise while working on an episodic memory task may rather represent a dual-task situation (= two tasks that compete for attentional resources). Especially doing a squat every second word may represent an inhibition task that people have to get used to. Future studies should include biochemical markers of arousal and neuronal plasticity in addition to heart rate.

Enhancing Organizational Memory Through Virtual Memoryscapes: Does It Work?

Enhancing cognitive memory through virtual reality represents an issue, that has never been investigated in organizational settings. Here, we compared a virtual memoryscape (treatment) – an immersive virtual environment used by subjects as a shared memory tool based on spatial navigation – with respect to the traditional individual-specific mnemonic tool based on the “method of loci” (control). A memory task characterized by high ecological validity was administered to 82 subjects employed by large banking group. Memory recall was measured, for both groups, immediately after the task (Phase 1) and one week later (Phase 2). Results show that (i) in Phase 1, the method of loci was more efficient in terms of recalling information than the to the virtual memoryscape; (ii) in Phase 2, there was no difference. Compared to the method of loci, the virtual memoryscape presents the advantages – relevant for organizations – of being collective, controllable, dynamic, and non-manipulable.

Optimal policies for free recall

There is rich structure in the order in which studied material is recalled in a free recall task (Howard and Kahana, 2002). Extensive effort has been directed at understanding the processes and representations that give rise to this structure; however, it remains unclear why certain types of recall organization might be favored in the first place. We provide a rational analysis of the free recall task, deriving the optimal policy for recalling items under the internal representations and processes described by the Context Maintenance and Retrieval (CMR) model of memory search (Polyn et al.,2009). We show that the optimal policy for free recall is to start from the beginning of the list and then sequentially recall forwards, providing a rational account of the primacy and forward asymmetry effects typically observed in free recall. In addition, when recall is not initiated from the beginning of list, it is optimal during recall transitions to minimize the amount of forward asymmetry. Predictions from the rational model are confirmed in human behavioral data: Top-performing human participants demonstrate a stronger tendency to initiate recall from the beginning of the list and carry forward recalls, and the amount of forward asymmetry in participants depends on whether they start recall from the beginning or end of the list. We discuss the resemblance of the optimal behavior in free recall to participants' behavior when applying mnemonic techniques such as the method of loci.

Durable memories and efficient neural coding through mnemonic training using the method of loci

Mnemonic techniques, such as the method of loci, can powerfully boost memory. We compared memory athletes ranked among the world’s top 50 in memory sports to mnemonics-naïve controls. In a second study, participants completed a 6-week memory training, working memory training, or no intervention. Behaviorally, memory training enhanced durable, longer-lasting memories. Functional magnetic resonance imaging during encoding and recognition revealed task-based activation decreases in lateral prefrontal, as well as in parahippocampal and retrosplenial cortices in both memory athletes and participants after memory training, partly associated with better performance after 4 months. This was complemented by hippocampal-neocortical coupling during consolidation, which was stronger the more durable memories participants formed. Our findings advance knowledge on how mnemonic training boosts durable memory formation through decreased task-based activation and increased consolidation thereafter. This is in line with conceptual accounts of neural efficiency and highlights a complex interplay of neural processes critical for extraordinary memory.

A Feasibility Study on the Use of the Method of Loci for Improving Episodic Memory Performance in Schizophrenia and Non-clinical Subjects

We investigated the feasibility of a short intervention using the Method of Loci (MoL), a well-known visuospatial mnemonic, to improve episodic memory recall performance in schizophrenia. The MoL training protocol comprised encoding and recall of two lists of items (words and images), a training session and practice with MoL. Then, participants had the opportunity to put into practice the newly learned MoL and were instructed to encode and recall two new lists of items using. This approach was first validated with healthy individuals (N = 71). Subsequently, five individuals with schizophrenia completed the protocol. Improvement in healthy individuals was observed for the word list (Wilcoxon effect size r = 0.15). No significant memory improvement was denoted in the schizophrenia group, possibly due to participants' difficulties using the method efficiently and due to fatigue. The MoL seems to require episodic memory, working memory monitoring and executive functions, making it suboptimal for a population with impairments in all those domains. Future research should examine the use of other strategies, better suited for individuals with cognitive impairments like those found in schizophrenia.

Dual n-back working memory training evinces superior transfer effects compared to the method of loci

Working memory (WM) training is a prevalent intervention for multiple cognitive deficits, however, the transfer effects to other cognitive tasks from gains in WM induced by different training techniques still remains controversial. Therefore, the current study recruited three groups of young adults to investigate the memory training transference, with N-back group (NBG) (n = 50) training on dual n-back task, Memory Palace group (MPG) (n = 50) on method of loci, and a blank control group (BCG) (n = 48) receiving no training. Our results showed that both training groups separately improved WM capacity on respective trained task. For untrained tasks, both training groups enhanced performance on digit-span task, while on change detection task, significant improvement was only observed in NBG. In conclusion, while both techniques can be used as effective training methods to improve WM, the dual n-back task training method, perhaps has a more prominent transfer effect than that of method of loci.

Dream to Remember

This chapter explores how the process of creating a complex, visuospatial, associative image of a pattern in experience is mnemonic, i.e. it aids remembering. Clearly, unless we retained a dream memory image it couldn’t improve our chances of survival in wake. I compare associative dream images to the associative images people use in wake to help them remember. These associative images all derive from the Ancient Art of Memory, incorporating the Method of Loci. I argue the Method of Loci works as a memory technique because it mimics the daily tour in the home range. Equally, the associative images from the Ancient Art of Memory echo the dream images retained at landmark junctions in memory networks.

Hippocampal spatial and sequential representations of event structure scaffold precise episodic temporal order memory

The hippocampus plays an important role in representing spatial locations and sequences and for transforming representations via pattern separation and completion. How these representational structures and operations support memory for the temporal order of random items is still poorly understood. We addressed this question by leveraging the method of loci (MOL), a powerful mnemonic strategy for temporal order memory that particularly recruits hippocampus-dependent computations of spatial locations and associations. Applying representational similarity analysis to fMRI activation patterns revealed that hippocampal subfields contained representations of both temporal context and multiple features of sequence structure, including location identity, distance, and sequence boundaries. Critically, the hippocampal CA1 and CA23DG exhibited spatial and sequential pattern separation, respectively, enabling the encoding of multiple items in the same location and reducing swap errors across adjacent locations. Our results suggest that the hippocampus can flexibly reconfigure multiplexed event structure representations to support accurate temporal order memory.