Memory Recall Research Articles

Trauma and memory-A contribution to the current debate in law and psychotherapy

The recall of memories of past events, experiences and emotions is acomplex process. When experiencing traumatic events, as is the case with sexual violence, ahost of additional complexities and difficulties arise. This becomes especially important in court cases which rely mostly or exclusively on the testimony of the victim, where the problem of the fallibility of memory takes center stage. Some research studies emphasize the possibility of inducing, altering or suppressing memories, especially in the context of psychotherapy. This has led to the unfortunate reality that the testimony of victims who have undergone psychotherapy is often considered to be unreliable. This in turn can lead to the impression that adecision has to be made between treatment of the adverse effects of traumatic events and maximizing the chances for aconviction of the perpetrator in court. This article introduces some central concepts of our current understanding of memory and gives an overview of the relevant scientific literature and debate. Following this, it examines the dilemma as it pertains to the different groups of all involved parties (i.e., victims, members of the judiciary and psychotherapists). Lastly, it proposes aframework of how to approach asolution to this problem by focusing on research in critical areas, expansion of therapy guidelines and documentation procedures as well as communication of these efforts to all parties involved.

A murine model of post-acute neurological sequelae following SARS-CoV-2 variant infection.

Viral variant is one known risk factor associated with post-acute sequelae of COVID-19 (PASC), yet the pathogenesis is largely unknown. Here, we studied SARS-CoV-2 Delta variant-induced PASC in K18-hACE2 mice. The virus replicated productively, induced robust inflammatory responses in lung and brain tissues, and caused weight loss and mortality during the acute infection. Longitudinal behavior studies in surviving mice up to 4 months post-acute infection revealed persistent abnormalities in neuropsychiatric state and motor behaviors, while reflex and sensory functions recovered over time. In the brain, no detectable viral RNA and minimal residential immune cell activation was observed in the surviving mice post-acute infection. Transcriptome analysis revealed persistent activation of immune pathways, including humoral responses, complement, and phagocytosis, and gene expression levels associated with ataxia telangiectasia, impaired cognitive function and memory recall, and neuronal dysfunction and degeneration. Furthermore, surviving mice maintained potent systemic T helper 1 prone cellular immune responses and strong sera neutralizing antibodies against Delta and Omicron variants months post-acute infection. Overall, our findings suggest that infection in K18-hACE2 mice recapitulates the persistent clinical symptoms reported in long-COVID patients and provides new insights into the role of systemic and brain residential immune factors in PASC pathogenesis.

The Association Between Cardiovagal Baroreceptor Sensitivity and Hippocampal Tissue Integrity in Young and Middle-aged Adults

Prior research has investigated the association of cardiovagal baroreceptor sensitivity (BRS) with white matter neuronal integrity and cerebral perfusion using magnetic resonance imaging (MRI) techniques such as diffusion tensor imaging (DTI) and arterial spin labeling (ASL); however, less is known about the association with specific regions of gray matter (i.e, hippocampus) involved in memory formation and recall. MR elastography (MRE) has emerged as a constructive tool for assessing the viscoelastic mechanical properties of the brain which are believed to reflect the microstructural integrity of neuronal tissue. PURPOSE: To investigate the association between cardiovagal BRS and the viscoelastic properties of the brain, with a sub goal of examining how advanced age affects this association. We hypothesized that there would be a positive relation between cardiovagal BRS and hippocampal (HC) viscoelastic properties that strengthens with age, indicating a greater influence of blood pressure control on HC microstructural integrity. Methods: Ten young (Yng, 25 ± 2 years) and ten middle-aged adults (MA, 55 ± 3 years) laid in supine position for 10 minutes while arterial blood pressure (ABP) and heart rate (HR) were measured. R-R intervals and systolic blood pressures were plotted within a linear regression to calculate the spontaneous baroreflex slope. Subjects went in an MRI scanner to measure hippocampal viscoelastic properties using MRE. Results: As expected, we observed a lower cBRS in the middle-aged group compared with young (MA: 12.51±4.41 vs. Yng: 25.21±8.77 ms/mmHg, p≤0.05). There were no significant differences in HC stiffness or damping ratio when comparing between age groups (MA: 3.06±0.32 kPa vs. Yng: 3.02±0.09 kPa, p=0.69; MA: 0.2±0.02 vs. Yng: 0.2±0.03, p=0.56). However, a multiple linear regression with age included as a categorical covariate revealed a trend towards a stronger association between HC stiffness and cBRS in the middle-aged compared to the young group (p=0.07). CONCLUSION: In contrast to our hypothesis, preserved BRS was associated with lower HC stiffness in the middle-aged group; however, the physiological importance of this finding needs to be more completely explored. Our findings indicate that the association between short-term blood pressure regulation via cardiovagal BRS may be more closely linked to HC tissue integrity with advancing age. These mechanisms should be explored in a larger cohort including older individuals. Supported by UD Research Foundation 2020 Pilot Grant and P20GM113125. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Reduced digit spans and ear dominance using dichotic digits in bimodal cochlear-implant users.

Bimodal stimulation, a cochlear implant (CI) in one ear and a hearing aid (HA) in the other, provides highly asymmetrical inputs. To understand how asymmetry affects perception and memory, forward and backward digit spans were measured in nine bimodal listeners. Spans were unchanged from monotic to diotic presentation; there was an average two-digit decrease for dichotic presentation with some extreme cases of decreases to zero spans. Interaurally asymmetrical decreases were not predicted based on the device or better-functioning ear. Therefore, bimodal listeners can demonstrate a strong ear dominance, diminishing memory recall dichotically even when perception was intact monaurally.

Analysing Children’s Responses from Multiple Modalities During Robot-Assisted Assessment of Mental Wellbeing

According to the World Health Organization, the early identification of mental wellbeing issues in children is extremely important for children’s growth and development. However, the available health services are not sufficient to address children’s needs in this area. Literature suggests that robots can provide the support needed to promote mental wellbeing in children, but how robots can help with the assessment of mental wellbeing is relatively unexplored. Hence, this work analyses multiple data modalities collected in an exploratory study involving 41 children (8–13 years old, 21 females and 20 males) who interacted with a Nao robot for about 30–45 min. During this session, the robot delivered four tasks: (1) happy and sad memory recall, (2) the Short Moods and Feelings Questionnaire (SMFQ), (3) the picture-based task inspired by the Children Appreciation Test (CAT), and (4) the Revised Children Anxiety and Depression Scale (RCADS). We clustered the participants into three groups based on their SMFQ scores as follows: low tertile (16 participants), med tertile (12 participants), and high tertile (13 participants). Then, we described and analysed the data collected from multiple sources (i.e., questionnaires responses, audio-visual recordings, and speech transcriptions) to gather multiple perspectives for understanding how children’s responses and behaviours differ across the three clusters (low, med, vs high) and their gender (boys vs girls) for robot-assisted assessment of mental wellbeing. Our results show that: (i) the robotised mode is the most effective in the identification of wellbeing-related concerns with respect to standardised modes of administration (self-report and parent-report); (ii) children less likely to have mental wellbeing concerns displayed more expressive responses than children who are more likely to have mental wellbeing concerns; and (iii) girls who are more likely to have mental wellbeing concerns displayed more expressive responses than boys, while boys who are less likely to have mental wellbeing concerns displayed more expressive responses than girls. Findings from this work are promising for paving the way towards automatic assessment of mental wellbeing in children via robot-assisted interactions.

Frontal delta and theta power reflect strategy changes during human spatial memory retrieval in a virtual water maze task: an exploratory analysis

Brain oscillations in humans play a role in a wide range of cognitive processes, including navigation and memory. The oscillatory dynamics contributing to successful spatial memory recall in humans are not well-understood. To investigate specific oscillatory frequency bands during the recall process in human navigation, we recorded electroencephalographic (EEG) activity during a recall trial in healthy young adults (n = 15) following the learning of a goal location in a Virtual Water Maze task. We compared this to the activity during the same trial length, in a group of participants who did not learn a target location and navigated freely but were time-matched to the learning group (non-learning, n = 15). We compared relative power in Delta (2–4 Hz), Theta (5–7 Hz), Alpha (8–12 Hz), Beta (15–29 Hz), and Gamma (30–40 Hz) bands across the scalp. We found that delta and theta activity were greater during recall in our learning group, as opposed to our non-learning group. We also demonstrated clear suppression in the alpha band at posterior sites during memory-guided navigation compared to our non-learning group. Additionally, when goal-directed navigation switches to focused searching behavior, power becomes greater at the frontal region; with increases in the delta and theta bands reflecting this strategy change. There was also greater beta and gamma activity at posterior sites in our learning group. We discuss the results further in terms of the possible roles and functions of these oscillations during human navigation and hope this exploratory analysis can provide hypotheses for future spatial navigation and memory work.

Polysomnographic parameters associated with cognitive function in patients with major depression and insomnia.

To examine whether objective sleep parameters are associated with cognitive function (CF) in patients with major depressive disorder (MDD) with chronic insomnia (CI) and whether the severity of these disorders is related to CF. Thirty patients with MDD with CI attending a tertiary care institution underwent two consecutive nights of polysomnographic (PSG) recording and a battery of neuropsychological tests, which included episodic memory, sustained attention, working memory, and executive function. The severity of MDD and CI was assessed by clinical scales. We examined the relationship between PSG parameters and CF, as well as whether the severity of the disorders is related to CF. Linear regression analysis revealed that total sleep time (TST) was positively associated with higher learning and recall of episodic memory, as well as better attention. Slow-wave sleep (SWS) showed a positive association with better working memory. Furthermore, wake after sleep onset (WASO) was negatively associated with episodic memory and lower attention. No significant relationships were found between the severity of MDD or CI with CF. Both sleep duration and depth are positively associated with several aspects of CF in patients with MDD with CI. Conversely, a lack of sleep maintenance is negatively related to CF in these patients. These findings could help identify modifiable therapeutic targets to reduce CF impairment.

Positive autobiographical memory recall does not influence temporal discounting: An internal meta-analysis of experimental studies

People tend to discount the value of future rewards as the delay to receiving them increases. This phenomenon, known as temporal discounting, may underlie many impulsive behaviors, such as drug abuse and overeating. Given the potential role of temporal discounting in maladaptive behaviors, many efforts have been made to find experimental manipulations that reduce temporal discounting. One class of manipulations that has held some promise involves recalling positive autobiographical memories prior to making intertemporal choices. Just as imagining positive future events has been shown to reduce temporal discounting, a few studies have shown that recalling positive past events reduces temporal discounting, especially if memory retrieval evokes positive affective states, such as gratitude and nostalgia. However, we failed to replicate these findings. Here we present an internal meta-analysis combining data from 14 studies (n = 758) that involved within-subjects positive memory recall-based manipulations. In each study, temporal discounting was assessed using a monetary intertemporal choice task. The average effect size was not significantly different from zero. This finding helps elucidate the neurocognitive mechanisms of temporal discounting; whereas engaging the episodic memory system to imagine future events might promote more patience, engaging the episodic memory system to imagine past events does not.

In Search of Dispersed Memories: Generative Diffusion Models Are Associative Memory Networks.

Uncovering the mechanisms behind long-term memory is one of the most fascinating open problems in neuroscience and artificial intelligence. Artificial associative memory networks have been used to formalize important aspects of biological memory. Generative diffusion models are a type of generative machine learning techniques that have shown great performance in many tasks. Similar to associative memory systems, these networks define a dynamical system that converges to a set of target states. In this work, we show that generative diffusion models can be interpreted as energy-based models and that, when trained on discrete patterns, their energy function is (asymptotically) identical to that of modern Hopfield networks. This equivalence allows us to interpret the supervised training of diffusion models as a synaptic learning process that encodes the associative dynamics of a modern Hopfield network in the weight structure of a deep neural network. Leveraging this connection, we formulate a generalized framework for understanding the formation of long-term memory, where creative generation and memory recall can be seen as parts of a unified continuum.

Eyewitness confidence in the interviewing context: Understanding the impact of question type and order

AbstractThe relationship between confidence and accuracy and the reliability of eyewitness identifications has attracted a lot of attention. In contrast, relatively little is known about the relationship between eyewitness confidence and the accuracy of recall memory in interview contexts. Here, we manipulated questioning approaches to investigate the impact of Free‐Recall and Cued‐Recall questions, whereby the latter were witness‐compatible (questions concerning details reported in the preceding Free‐Recall) or witness‐incompatible questions. We also manipulated the order these questions were asked. A sample of 124 mock witness participants watched a crime‐video and subsequently recalled the event to understand the impact of question type and order on confidence‐accuracy calibration. Our results show that a Free‐Recall invitation and compatible (compared to incompatible) questions promoted more stable confidence. Compatible questions yielded fewer errors, more accurate details, and promoted more reliable confidence‐accuracy calibration and discrimination, especially when they preceded the incompatible questions. Implications are discussed.

Memory control immediately improves unpleasant emotions associated with autobiographical memories of past immoral actions

ABSTRACT The ability to stop unwanted memories from coming to mind is theorised to be essential for maintaining good mental health. People can employ intentional strategies to prevent conscious intrusions of negative memories, and repeated attempts to stop retrieval both reduces the frequency of intrusions and improves subsequent emotions elicited by those memories. However, it is still unknown whether memory control can improve negative emotions immediately, at the time control is attempted. It is also not clear which strategy is most beneficial for emotion regulation; clearing the mind of any thoughts of negative memories via direct suppression, or substituting memory recall with alternative thoughts. Here, we provide novel evidence that memory control immediately regulates negative emotions associated with autobiographical memories of morally wrong actions. Repeated control significantly improved negative emotions over time, regardless of the strategy used to implement control. Thought substitution involving either positive diversionary thinking or counterfactual thinking both induced positive feelings, whereas direct suppression neutralised emotions, regardless of whether memories were positive or negative. These empirical findings have implications for clinical practice as they indicate that memory control strategies could be effective emotion regulation methods for real-world intrusive memories.

Imagery and Verbal Strategies in Spatial Memory for Route and Survey Descriptions.

Being able to represent and remember verbally-encoded information about spatial environments from different perspectives is important for numerous daily activities. The present study examined how frequently individuals spontaneously engage in visual mental imagery and verbal rehearsal strategies in memory recall of spatial descriptions, and whether using certain strategies is associated with better recall performance. Memory recall for route (person-centred) and survey (object-centred) spatial descriptions was examined in a sample of 105 neurotypical individuals, who also reported to what extent they used route- and survey-based mental imagery and verbal rehearsal strategies in each description. Results showed that participants favoured a path visualisation strategy to recall the route description and a map visualisation strategy to recall the survey description. Regression models further showed that employing both imagery and verbal strategies was associated with better recall for both route and survey descriptions, although imagery strategies held a higher predictive power. The present findings highlight the fact that the spontaneous use of internal strategies in the form of visual imagery and verbal rehearsal is ubiquitous when recalling spatial descriptions and a core part of efficient spatial memory functioning.

Guided recall of positive autobiographical memories increases anticipated pleasure and psychological resources, and reduces depressive symptoms: a replication and extension of a randomised controlled trial of brief positive cognitive-reminiscence therapy

ABSTRACT Reminiscence-based interventions focus on recalling autobiographical memories and reflective reasoning to develop a healthy and adaptive view of oneself and one’s life. This study aimed to replicate the effects of a three-session, group-based, positive-memory version of cognitive-reminiscence therapy (CRT) on psychological resources and mental well-being and extend the findings to anticipated pleasure. The participants (N = 75, M age = 43.7 (SD = 16.7), 60% females) were randomised to CRT or control group. Anticipated pleasure, psychological resources (schemas of positive self-esteem, self-efficacy, meaning in life, optimism), mental well-being (depression, anxiety, and stress symptoms) and theorised change processes (automatic negative thoughts, awareness of narrative identity) were assessed. Relative to the control group, the CRT group reported significantly higher anticipated pleasure (d = 0.76–0.93) and psychological resources of self-esteem, self-efficacy, and optimism (d’s = 0.58–0.99) at post-CRT and follow-up, and lower depressive symptoms post-CRT and at follow-up (d = 0.56–0.67). Findings on meaning in life and negative automatic thinking were partially replicated. This study replicates findings of the effectiveness of this intervention for improving psychological resources such as self-worth, confidence and optimism and depressive symptoms, and indicates additional effects on anticipated pleasure. CRT may serve as a standalone intervention, or as an adjunct “memory booster” for interventions focused on future thinking and related anticipated reward.

Diet switch pre-vaccination improves immune response and metabolic status in formerly obese mice.

Metabolic disease is epidemiologically linked to severe complications upon influenza virus infection, thus vaccination is a priority in this high-risk population. Yet, vaccine responses are less effective in these same hosts. Here we examined how the timing of diet switching from a high-fat diet to a control diet affected influenza vaccine efficacy in diet-induced obese mice. Our results demonstrate that the systemic meta-inflammation generated by high-fat diet exposure limited T cell maturation to the memory compartment at the time of vaccination, impacting the recall of effector memory T cells upon viral challenge. This was not improved with a diet switch post-vaccination. However, the metabolic dysfunction of T cells was reversed if weight loss occurred 4 weeks before vaccination, restoring a functional recall response. This corresponded with changes in the systemic obesity-related biomarkers leptin and adiponectin, highlighting the systemic and specific effects of diet on influenza vaccine immunogenicity.

The association between memory, COVID-19 testing, and COVID-19 incidence in middle-aged and older adults: a prospective analysis of the CLSA

ABSTRACT We investigated the association between pre-COVID-19 memory function and (a) receipt of a COVID-19 test and (b) incidence of COVID-19 using the COVID-19 Questionnaire Study (CQS) of the Canadian Longitudinal Study on Aging (CLSA). The CQS included 28,565 middle-aged and older adults. We regressed receipt of a COVID-19 test on participants’ immediate and delayed recall memory scores and re-ran the regression models with COVID-19 incidence as the outcome. All regression models were adjusted for sociodemographic, lifestyle, and health covariates. In the analytical sample (n = 21,930), higher delayed recall memory (better memory) was significantly associated with lower COVID-19 incidence. However, this association was not significant for immediate recall memory. Immediate and delayed recall memory were not associated with receipt of a COVID-19 test. Health policymakers and practitioners may viewmemory status as a potential risk for COVID-19. Memory status may not be a barrier to COVID-19 testing.

Hippocampal cholecystokinin-expressing interneurons regulate temporal coding and contextual learning

Cholecystokinin-expressing interneurons (CCKIs) are hypothesized to shape pyramidal cell-firing patterns and regulate network oscillations and related network state transitions. To directly probe their role in the CA1 region, we silenced their activity using optogenetic and chemogenetic tools in mice. Opto-tagged CCKIs revealed a heterogeneous population, and their optogenetic silencing triggered wide disinhibitory network changes affecting both pyramidal cells and other interneurons. CCKI silencing enhanced pyramidal cell burst firing and altered the temporal coding of place cells: theta phase precession was disrupted, whereas sequence reactivation was enhanced. Chemogenetic CCKI silencing did not alter the acquisition of spatial reference memories on the Morris water maze but enhanced the recall of contextual fear memories and enabled selective recall when similar environments were tested. This work suggests the key involvement of CCKIs in the control of place-cell temporal coding and the formation of contextual memories.

Unlocking the past: efficacy of guided self-compassion and benefit-focused online interventions for managing negative personal memories

ABSTRACT Positive reappraisal strategies have been found to reduce negative affect following the recall of negative personal events. This study examined the restorative effect of two mood-repair instructions (self-compassion vs benefit-focused reappraisal) and a control condition with no instructions following a negative Mood Induction Procedure by using the guided recall of a negative autobiographical event. A total of 112 university students participated in the online study (81% women, Mage: 21.0 years). Immediately following the negative memory recall, participants were randomised to each condition [(self-compassion: n = 36, benefit-focused: n = 39) or a control condition (n = 37)]. Repeated measures ANOVAs 3 (Repair condition) × 3 (Time of mood assessment: pre-recall, post-recall, post-regulation) showed that, as expected, negative mood (sadness, shame, and guilt) worsened significantly after the guided recall in all groups (p < .001). After the mood-repair intervention, participants in the self-compassion and benefit-focused conditions showed a significant reduction in negative mood (p < .019), while such improvement was not observed in the control group. Self-compassion and benefit-focused reappraisal functioned similarly as mood repair strategies after experiencing negative affect induced by the recall of negative personal memories. Implications in the context of autobiographical memory biases are discussed.

Influence of Primary Colors on Memory Retention of Student Gamers

The intricate relationship between colors and memory has been a widespread interest in human psychology. The present study sought to better understand the influence of primary colors on memory retention among student gamers in Higher Education Institutions (HEIs). Applying a quantitative research approach, specifically an experimental research design, examined two independent variables and a control condition. Respondents were composed of 30 student gamers. Most of them were undergraduate students who were exposed to video game experiments and were chosen purposively. In analyzing the collected data, one-way ANOVA and Mauchly’s Test of Sphericity were utilized. Results revealed that primary colors do not significantly influence memory recall. This implies that better memory performance cannot be attributed to the facets of primary colors. Limitations were acknowledged regarding the chosen sample size and the research instruments’ procedural use. Hence, further studies may be conducted by minimizing the confounding variables and other external distractors in the same environment.

Memory enhancement for emotional words is attributed to both valence and arousal

We do not memorize items in our surroundings with equal priority. Previous literature has widely shown that emotional stimuli are better remembered than neutral stimuli. However, given emotional stimuli and neutral stimuli often differ in both valence and arousal dimensions, it remains unclear whether the enhancement effects can be attributed to valence, or just to arousal. Importantly, most prior studies relied on a relatively small number of stimuli and non-emotional factors such as word length, imageability and other confounds were hard to control. To address these challenges, we analyzed multiple large databases of recognition memory and free recall tasks from previous research by items with many lexical and semantic covariates included, examining the effects of valence or arousal when controlling for each other. Our results showed a U-shaped relationship between valence and memory performance for both recognition and free recall, and a linear relationship between arousal and memory performance for both tasks. These findings showed that the memory enhancement effects can be attributed to both valence and arousal. We demonstrated these effects with generalizability across many stimuli and controlled for non-emotional factors. Together, these findings disentangle the contribution of valence and arousal in emotional memory enhancement effects and provide insights for current major theories of emotional memory.

Cognitive performance and mortality among patients receiving autologous hematopoietic stem cell transplant

Objectives Patients undergoing autologous hematopoietic stem cell transplant (HCT) are at risk for death and remain understudied relative to those undergoing allogeneic HCT. Cognitive functioning may be a useful indicator of mortality risk. We examined cognition among patients who underwent autologous HCT and its relationship to mortality. Methods Participants (N = 51; 11 patients deceased) completed tasks of processing speed, working memory, executive-mediated learning, and visual recall using the computerized CogState battery prior to HCT, 30 days post-autologous HCT, and 100 days post-autologous HCT. Results Slower processing speed (HR = 3.00) and more errors on an executive-mediated visual learning task (HR = 2.78) prior to HCT were associated with an increased risk of death following HCT. Our sample size limited longitudinal analyses of whether cognitive change predicted survival, however descriptive cognitive data of the deceased versus living patient’s performances over time suggested different patterns of performance across groups. Conclusions Pre-HCT cognition may have utility as an indicator of mortality risk following autologous HCT. More research is needed to examine whether cognitive changes after HCT could also predict mortality.