Retrieval practice protects memory against acute stress

Cognitive Training Prevents Stress-Induced Working Memory Deficits

BACKGROUND

Working memory is a fundamental cognitive process that is critically involved in planning, comprehension, reasoning, and problem solving. Acute stress has been shown to impair working memory. This stress-induced working memory deficit has profound implications for cognitive functioning in everyday life as well as for stress-related mental disorders. Here, we tested whether a cognitive training intervention would make working memory more resistant to disruptive effects of acute stress.

METHODS

In a preregistered, fully crossed between-subjects design with the factors stress (vs. control) and cognitive training (vs. sham), 123 healthy men and women (ages 18-35 years) completed a daily cognitive training program targeting working memory-related processes or a sham training over a period of 6 weeks. After this 6-week training intervention, participants underwent a standardized stress or control manipulation shortly before their working memory performance was tested.

RESULTS

As expected, the exposure to acute stress led to a significant working memory impairment in the sham training group. Critically, although the subjective, autonomic, and endocrine stress responses were comparable in the 2 training groups, this stress-induced working memory impairment was abolished in the intervention training group.

CONCLUSIONS

These results are the first to show that a cognitive training intervention directed at prefrontal and hippocampal functioning can prevent the detrimental effects of stressful events on working memory performance.

Impaired free recall of neutral but not negative material tested 105 min after cortisol administration

Pharmacological studies have consistently shown memory retrieval impairment after administration of cortisol, particularly pronounced for emotional laboratory material (i.e. list of emotional words). However, it is unclear how pharmacological elevation of cortisol affects memory retrieval of ecologically-relevant emotional material (i.e. similar to a newspaper article about an emotional event). In the present study, we aimed to explore whether cortisol administration affects the recall of ecologically-relevant emotional and neutral material, and when memory retrieval occurs after a longer delay (105 min). In this double-blind, pseudo-randomized, placebo-control study, 79 participants learned a negative text and a neutral text. Twenty-four hours later, they were administrated either 10 mg of hydrocortisone or placebo. After 105 min, participants engaged in free recall of both texts. The group with cortisol administration showed significantly reduced free recall compared to the placebo group. Interestingly, this memory retrieval impairment was driven by significantly lower recall after cortisol vs. placebo administration for neutral texts, but not negative texts. The current finding suggests that cortisol administration impairs neutral ecologically-relevant material while leaving emotional material unaffected. These divergent findings, compared to existing literature, emphasize the necessity of employing more ecologically validated material to gain a more comprehensive understanding of the intricate interplay between cortisol administration and memory for ecological material.

Analyzing the determinants of beef cattle commercialization and Its market inefficiency: A case study of Pabna district, Bangladesh

The world has entered a new era of globalization and industrialization, which pose several challenges to ensuring food security. Beef cattle production is one of the fastest-growing subsectors that has the capacity to meet protein demand. Due to growing demand of meat and protein and a market-oriented production system, small-scale beef cattle production contribute most to marginal farmers as a means of rising income in many developing nations like Bangladesh. Though production and commercialization are not easier for households' due to various factors and a lack of market efficiency. To determine beef cattle commercialization and market inefficiency, the current study focused on the determinants of beef cattle commercialization and the challenges to the of market efficiency. Heckman's two-stage model used to determine the factors that influence households' commercialization decisions, and the two-stage least squares method is used to examine the constraints of market inefficiencies. However, commercialization decisions offer twofold decision of commercialization and degree of commercialization. The result showed that commercialization decisions are significantly influenced by households' age, extension services, and production costs. The degree of commercialization was affected by education, marketing costs, income from dairy, transportation costs, and training access. On the other hand, market inefficiency was influenced by formal market access, distance, extension services, and earning from cattle. As extension services worsen both commercialization decisions and market efficiency, the government should focus on extension services and offer farmers opportunities to increase their understanding and knowledge of marketing.

A Scoping Review of Retrieval Practice (Test-Enhanced Learning) in Nursing Education

AIM

The aim of this study was to determine the status of retrieval practice in original research of nursing education.

BACKGROUND

The science of learning is an emerging interdisciplinary field that offers evidence-based strategies to improve learning. One of the most highly effective strategies is retrieval practice, which involves recalling previously learned information from long-term memory prior to additional study.

METHOD

Searching PubMed, CINAHL, Scopus, Psych INFO, and ERIC, an interprofessional team followed a formal scoping review framework and utilized the PRISMA Extension for Scoping Reviews to report the findings.

RESULTS

The review included 25 research studies, with all but one at the prelicensure level. Quantitative designs were most common, and outcomes reflected objective and subjective measures. If present, terms were varied and inconsistent with supporting research. Documentation of many characteristics was lacking.

CONCLUSION

Retrieval practice is an increasingly common strategy being studied at the prelicensure level. Opportunities for improvement include consistent use of standard terminology, documentation of important characteristics, and more attention to subjective outcomes and to graduate and continuing education levels.

The Forward Testing Effect Is Resistant to Acute Psychosocial Retrieval Stress

The forward testing effect refers to the finding that testing of previously studied information improves memory for subsequently studied newer information. Recent research showed that the effect is immune to acute psychosocial encoding/retrieval stress, i.e., stress that is induced before initial encoding. The present study investigated whether the forward testing effect is also robust to acute psychosocial retrieval stress, i.e., stress that is induced after encoding but before retrieval of the critical item list. Participants (N = 128) studied three lists of words in anticipation of a final cumulative recall test. Participants were tested immediately on Lists 1 and 2 (testing condition) or restudied the two lists after initial study (restudy condition). After study of the critical List 3, psychosocial stress was induced in half of the participants (stress group), whereas no stress was induced in the other half (control group). The Trier Social Stress Test for Groups (TSST-G) was used for stress induction. Salivary cortisol, alpha amylase, and subjective stress were repeatedly measured. The results of the criterion test showed a generally detrimental effect of psychosocial retrieval stress on List 3 recall. Importantly, the forward testing effect was unaffected by retrieval stress. The findings are discussed with respect to current theories of the forward testing effect.

The benefit of retrieval practice on cued recall under stress depends on item difficulty

Retrieval practice, the act of recalling previously studied information, yields greater memory retention than repeated studying (retrieval practice effect). Retrieval practice can also protect memories against the negative effects of stress at retrieval in free recall tests. In cued-recall tests, however, retrieval practice may not provide complete protection against stress-related memory impairments. Here we ask whether these conflicting results may be explained by the relative difficulty of the study materials. Participants (59 men) first studied 40 Swahili-Portuguese word pairs. Half of the pairs were then repeatedly studied while the other half were repeatedly recalled. In each condition, half of the pairs were easy to remember (high in memorability) while the other half were more difficult to remember (low in memorability). Participants returned 1 week later for a final cued-recall test. Half of the participants underwent a stress-induction protocol (modified Socially Evaluated Cold Pressor Test) 25 min before the final test for all 40-word pairs; the other half underwent a control condition. Salivary cortisol and questionnaire responses were used to assess the efficacy of stress induction. Participants recalled more word pairs learned via retrieval practice than via repeated study, replicating previous research. More importantly, the results revealed an interaction such that stress decreased recall for easy items, but increased recall for difficult items that had been successfully retrieved during encoding (conditional analysis). The results suggest that the impact of stress on cued recall depends both on the learning strategy and on the intrinsic difficulty of the to-be-learned materials.

Hydrogeochemical characterization of groundwater and their associated potential health risks

The present study assessed the human health risk exposure from the consumption of poor quality groundwater in the Lucknow area, a part of Central Ganga alluvial plain in India. Around 27 (n = 27) groundwater samples were collected from the study area. The analytical results of the samples (n = 27) collected indicate silicate and carbonate weathering is the dominant process along with cation exchange, sulfide oxidation, and reverse ion exchange. The type of groundwater is Ca²-Na-HCO₃^- type having all cations and anions within permissible WHO limits except for iron (Fe²⁺) and nitrate (NO₃^-). The high concentrations of Fe² and NO₃^- in samples indicate the possibility of a non-geogenic point source for the same in an urban-influenced environment. The ionic concentration of dissolved constituents is used in weighted overlay analysis to generate the water quality index (WQI). WQI indicates that most urban areas (~ 98.52%) have fallen in the good to excellent category except few situated in the highly populated parts of Lucknow. The ionic concentrations of Fe²⁺ and NO₃^- have been further used to estimate human health risk by integrating regional urban population density data in Lucknow. The risk map shows alarming risks in the west-central part, where nearly ~ 35% of the total area is at moderate to high health risk.

Adult newborn granule cells confer emotional state-dependent adaptability in memory retrieval

Achieving optimal behavior requires animals to flexibly retrieve prior knowledge. Here, we show that adult newborn granule cells (anbGCs) mediate emotional state-dependent adaptability of memory retrieval. We find that acute social reward (aSR) enhances memory retrieval by increasing the reactivation of engram cells, while acute social stress (aSS) weakens retrieval and reduces the reactivation. Such bidirectional regulation relies on the activation of distinct populations of anbGCs by aSR and aSS, triggering opposing modifications of dDG activity, which is sufficient to regulate and predict the performance of memory retrieval. Concordantly, in emotional disorder models, aSR-dependent memory adaptability is impaired, while the effect of aSS remains intact. Together, our data revealed that anbGCs mediate adaptability of memory retrieval, allowing animals to flexibly retrieve memory according to the current emotional state, and suggested the essential roles of anbGCs in translating emotional information to the regulation of memory expression.

Thinking about thinking about thinking … & feeling: A model for metacognitive and meta-affective processes in task engagement

Metacognition, or thinking about thinking, is a phenomenon that has received much attention across the numerous fields of Psychological Science. The overarching goal has centered on understanding how humans monitor their internal mental processes and exert control over these processes. However, discipline-focused approaches with little generalized discussion across the field have yielded an incomplete understanding of the construct of metacognition. Consider, for example, the cognitive approach: from this perspective, researchers have developed predictive models and useful frameworks. Further, the field has produced sophisticated techniques to measure monitoring accuracy and define attributes that contribute to monitoring assessments and control process selection. However, the impact of this research has been relatively limited and isolated from metacognitive investigations that consider other important constructs such as motivation and affect. The approaches taken in subfields, such as educational psychology, emotion, and neuropsychology when combined with the cognitive approach, may result in a more complete picture and thorough understanding of metacognition. In this article, we present an argument that the study of metacognition should bridge the various subfields of psychological inquiry. We present a framework toward an integrative approach to understanding metacognition as a complementary process to meta-affect and encourage researchers to consider the study of metacognition from a broader perspective. This article is categorized under: Psychology > Memory Psychology > Emotion and Motivation.

Social experiences switch states of memory engrams through regulating hippocampal Rac1 activity

In pathological or artificial conditions, memory can be formed as silenced engrams that are unavailable for retrieval by presenting conditioned stimuli but can be artificially switched into the latent state so that natural recall is allowed. However, it remains unclear whether such different states of engrams bear any physiological significance and can be switched through physiological mechanisms. Here, we show that an acute social reward experience switches the silent memory engram into the latent state. Conversely, an acute social stress causes transient forgetting via turning a latent memory engram into a silent state. Such emotion-driven bidirectional switching between latent and silent states of engrams is mediated through regulation of Rac1 activity–dependent reversible forgetting in the hippocampus, as stress-activated Rac1 suppresses retrieval, while reward recovers silenced memory under amnesia by inhibiting Rac1. Thus, data presented reveal hippocampal Rac1 activity as the basis for emotion-mediated switching between latent and silent engrams to achieve emotion-driven behavioral flexibility.

Retrieval Practice Is Effective Regardless of Self-Reported Need for Cognition - Behavioral and Brain Imaging Evidence

There is an emerging consensus that retrieval practice is a powerful way to enhance long-term retention and to reduce achievement gaps in school settings. Less is known whether retrieval practice benefits performance in individuals with low intrinsic motivation to spend time and effort on a given task, as measured by self-reported need for cognition (NFC). Here, we examined retrieval practice in relation to individual differences in NFC by combining behavioral and functional magnetic resonance imaging (fMRI) data. Using a within-subject design, upper-secondary school students (N = 274) learned a language-based material (Swahili-Swedish word-pairs), with half of the items by means of retrieval practice with feedback and half by study only. One week later, the students were tested on the word-pairs either in the classroom (n = 204), or in a fMRI scanner (n = 70). In both settings, a retrieval practice effect was observed across different levels of NFC (high or low). Relatedly, comparable fMRI effects were seen in both NFC subgroups. Taken together, our findings provide behavioral and brain-imaging evidence that retrieval practice is effective also for individuals with lower levels of NFC, which is of direct relevance for educational practice.

Developing Community Co-designed Scenario-Based Training for Police Mental Health Crisis Response: a Relational Policing Approach to De-escalation

Using the current empirical landscape of police responses to people in mental health crisis as a backdrop, this methods paper makes an argument for the central role of collaborative co-design and production by diverse community experts and stakeholders to build transformative specialized training for frontline officers. Subject matter experts (SMEs) from across key domains participated in focus groups and curriculum creation, with outputs being the co-development of a conceptual approach and an innovative experiential learning training program. Part 1 unpacks the team's conceptual development of a relational policing approach. This humanized method is shaped by procedural justice, trauma-informed, person-centred, and cultural safety frameworks. Part 2 details the co-production of a novel problem-based training method for a police service in Southern Ontario, Canada. The program centres on the acquisition of core competencies related to relational policing, de-escalation, and mental health crisis response. The training was designed to bring learners through a spectrum of authentic crisis scenarios: from observer-participant scenarios informed by Forum Theatre methods and targeted SME feedback to a range of high-fidelity assessment simulations that test officers' abilities to effectively communicate, de-escalate, and make decisions under stress. This program offers repeated opportunities for officers to practice alternative crisis management strategies in scenarios that might otherwise result in the use of force.

Stress and memory encoding: What are the roles of the stress-encoding delay and stress relevance?

The effects of acute stress on memory encoding are complex. Recent work has suggested that both the delay between stress and encoding and the relevance of the information learned to the stressor may modulate the effects of stress on memory encoding, but the relative contribution of each of these two factors is unclear. Therefore, in the present study, we manipulated (1) acute stress, (2) the delay between stress and encoding, and (3) the relevance of the information learned to the stressor. The results indicated that stress during encoding led to better memory for study materials that were related to the stressor relative to memory for study materials that were unrelated to the stressor. This effect was numerically reduced for materials that were encoded 40 min after stressor onset (23 min after the stressor had ended) compared with items encoded at the time of the stressor, but this difference was not significant. These results suggest that the relevance of the information learned to the stressor may play a particularly important role in the effects of stress on memory encoding, which has important implications for theories of stress and memory.

A retrospective and correlative analysis of academic and nonacademic predictors of COMLEX level 1 performance

CONTEXT

National licensing exams (NLEs) including the Comprehensive Osteopathic Medical Licensing Examination (COMLEX) Level 1 evaluate student achievement. Scores have historically been utilized to stratify medical student applicants for residency. Grade point average (GPA), number of practice questions completed, and performance on practice exams have been shown to be predictive of NLE performance. Test anxiety and acute stress have been shown to negatively impact NLE performance. The role of study behaviors and other nonacademic factors in COMLEX Level 1 performance is unknown.

OBJECTIVES

This study aims to evaluate academic and nonacademic factors and to correlate them with COMLEX Level 1 performance. Additional analysis is conducted to associate COMLEX Level 1 performance with academic and nonacademic factors when controlling for GPA.

METHODS

An anonymous online survey was administered to third- (OMS III) and fourth-year (OMS IV) osteopathic medical students at Kansas City University that had completed the COMLEX Level 1 examination. In total, 72 students responded to the survey. Survey results were linked to student records of GPA and COMLEX Level 1 scores, resulting in 59 complete responses for analysis. Independent-sample t-tests and linear ordinary least squares regression were utilized to analyze the results.

RESULTS

The majority of participants are male (62.7%) and OMS III (98.3%) with an average age of 27.14 ± 2.58 (mean ± standard deviation). Further demographic data reveal hours per week spent for personal time during dedicated study (n=46, 19.7 ± 18.53), hours of sleep per night during dedicated study (7.34 ± 0.92), and money spent on board preparation ($1,319.12 ± $689.17). High ($1,600-$3,000), average ($1,000-$1,500), and low ($100-$900) spenders do not statistically differ and COMLEX Level 1 performance is not related to the number of resources utilized (F statistics <1; p>0.05). Pearson correlations reveal a statistically significant relationship between COMLEX Level 1 scores with GPA (0.73, p<0.001), number of practice exams completed (0.39, p<0.001), number of questions completed (0.46, p<0.001), number of weeks of study (0.55, p<0.001), and preparation cost (0.28, p<0.05). The regression analysis revealed that money spent on board preparation, number of questions completed, and time spent studying accounted for 75.8% of the variance in COMLEX Level 1 scores after controlling for GPA.

CONCLUSIONS

The data show the association of money spent on board preparation, numbers of questions competed, and time spent studying with a student's COMLEX Level 1 score. Additionally, these results highlight the amount of money students spend on extracurricular materials to prepare for COMLEX Level 1, yet the data show that the number of resources that students utilized is not related to a student's COMLEX Level 1 performance.

Abrufeffekte im Gedächtnis: Ein Überblick zur aktuellen Grundlagenforschung

Zusammenfassung. Der Frage, wie Erinnern das Gedächtnis formt, wurde in der Kognitiven Psychologie in letzter Zeit große Aufmerksamkeit gewidmet. Testungseffekte, die in einer durch Gedächtnisabruf in der Folge verbesserten Zugänglichkeit von Gedächtniseinträgen bestehen, wurden in diesem Zusammenhang insbesondere auch hinsichtlich ihres pädagogischen Potentials diskutiert. Neben erleichterter Zugänglichkeit kann Gedächtnisabruf allerdings auch Vergessen nicht abgerufener Information verursachen. Der aktuelle Stand der Grundlagenforschung zu Abrufeffekten wird in diesem Überblicksartikel dargestellt und eine integrative Betrachtung unterschiedlicher Arten von Abrufeffekten unter Berücksichtigung wichtiger Moderatorvariablen versucht.

Anatomy Terminology Performance is Improved by Combining Jigsaws, Retrieval Practice, and Cumulative Quizzing

Science courses containing English-language terminology are a common implement in "English as a foreign language" (EFL) countries across the globe. In many of these countries, licensing examinations place added significance on terminology competence by requiring health science graduates to demonstrate mastery of English-language anatomy terms. In recent years, a wealth of research has shown active learning can offer many benefits over lecture-based, didactic approaches. Despite this work, very little has been done to test the potential of active learning in improving medical terminology performance. The present study explores this potential in two human gross anatomy lecture courses in South Korea, collecting performance and survey data from 399 undergraduates over a period of four years. Jigsaws, retrieval practice, and regular cumulative quizzing were used to mitigate three learning challenges specific to the study context: high vocabulary volume, low feelings of control over learning, and difficulties with exam preparation. The results show the reforms significantly improved both performance and learning attitudes, with students overwhelmingly favoring the use of new methods over lecture when taught using a mixture of both. Given that science learning often resembles the process of learning a foreign language, this study offers broad potential for improving terminology competence across disciplines, even for non-EFL students.

Mitigating the negative effects of retrieval stress on memory: an arousal reappraisal intervention

In a preregistered experiment, we examined the efficacy of arousal reappraisal as an intervention for reducing the negative effects of stress at retrieval on memory. Participants (N = 177) were semi-randomly assigned to one of three conditions: a Stress-intervention condition, a Stress-placebo condition, and a No-stress-placebo control condition. Participants viewed four images of complex, mildly negatively valenced scenes. One day later, they received an arousal reappraisal intervention or placebo before exposure to a laboratory stressor (or a control version for the No-stress condition). Participants were then tested on their memory of the images using a free recall instruction and multiple-choice recognition questions. As expected, negative affect and blood pressure increased for the stress conditions but not the control condition. Contrary to our hypotheses, memory performance did not statistically significant differ between the Stress-placebo condition and the No-stress-placebo control condition, indicating a lack of negative effects of acute retrieval stress on memory. Furthermore, we also found no statistically significant differences between the Stress-intervention condition and Stress-placebo condition in terms of memory performance, suggesting that the intervention did not assist with enhancing memory. We integrate interpretations of the findings from this study with a discussion of avenues for future research in this area.

Probing the neural dynamics of mnemonic representations after the initial consolidation

Memories are not stored as static engrams, but as dynamic representations affected by processes occurring after initial encoding. Previous studies revealed changes in activity and mnemonic representations in visual processing areas, parietal lobe, and hippocampus underlying repeated retrieval and suppression. However, these neural changes are usually induced by memory modulation immediately after memory formation. Here, we investigated 27 healthy participants with a two-day functional Magnetic Resonance Imaging study design to probe how established memories are dynamically modulated by retrieval and suppression 24 h after learning. Behaviorally, we demonstrated that established memories can still be strengthened by repeated retrieval. By contrast, repeated suppression had a modest negative effect, and suppression-induced forgetting was associated with individual suppression efficacy. Neurally, we demonstrated item-specific pattern reinstatements in visual processing areas, parietal lobe, and hippocampus. Then, we showed that repeated retrieval reduced activity amplitude in the ventral visual cortex and hippocampus, but enhanced the distinctiveness of activity patterns in the ventral visual cortex and parietal lobe. Critically, reduced activity was associated with enhanced representation of idiosyncratic memory traces in the ventral visual cortex and precuneus. In contrast, repeated memory suppression was associated with reduced lateral prefrontal activity, but relative intact mnemonic representations. Our results replicated most of the neural changes induced by memory retrieval and suppression immediately after learning and extended those findings to established memories after initial consolidation. Active retrieval seems to promote episode-unique mnemonic representations in the neocortex after initial encoding but also consolidation.

Stress and long-term memory retrieval: a systematic review

Introduction

The experience of stressful events can alter brain structures involved in memory encoding, storage and retrieval. Here we review experimental research assessing the impact of the stress-related hormone cortisol on long-term memory retrieval.

Method

A comprehensive literature search was conducted on PubMed, Web of Science and PsycNet databases with the following terms: “stress,” “long-term memory,” and “retrieval.” Studies were included in the review if they tested samples of healthy human participants, with at least one control group, and with the onset of the stress intervention occurring after the encoding phase and shortly (up to one hour) before the final memory test.

Results

Thirteen studies were included in the qualitative synthesis (N = 962) and were classified according to the time elapsed between stress induction and memory retrieval (stress-retrieval delay), the stress-inducing protocol (stressor), the time of day in which stress induction took place, sex, and age of participants. Most studies induced stress with the Trier Social Stress Test (TSST) between 15 and 25 minutes before the final memory (mostly recall) test and showed significant increases in cortisol levels and memory impairment.

Discussion

The reviewed studies indicate that stress does impair retrieval, particularly when induced with the TSST, in the afternoon, up to 45 minutes before the onset of the final memory test, in healthy young men. These results may inform future research on the impact of stress-induced cortisol surges on memory retrieval.

Stress Impairs Episodic Retrieval by Disrupting Hippocampal and Cortical Mechanisms of Remembering

Despite decades of science investigating the neural underpinnings of episodic memory retrieval, a critical question remains: how does stress influence remembering and the neural mechanisms of recollection in humans? Here, we used functional magnetic resonance imaging and multivariate pattern analyses to examine the effects of acute stress during retrieval. We report that stress reduced the probability of recollecting the details of past experience, and that this impairment was driven, in part, by a disruption of the relationship between hippocampal activation, cortical reinstatement, and memory performance. Moreover, even memories expressed with high confidence were less accurate under stress, and this stress-induced decline in accuracy was explained by reduced posterior hippocampal engagement despite similar levels of category-level cortical reinstatement. Finally, stress degraded the relationship between the engagement of frontoparietal control networks and retrieval decision uncertainty. Collectively, these findings demonstrate the widespread consequences of acute stress on the neural systems of remembering.

The Forward Testing Effect is Immune to Acute Psychosocial Encoding/Retrieval Stress

The forward testing effect (FTE) refers to the finding that testing of previously studied information enhances memory for subsequently studied other information. Previous research demonstrated that the FTE is a robust phenomenon that generalizes across different materials and populations. The present study examined whether the FTE is robust under acute psychosocial encoding/retrieval stress. In each of two experimental conditions, participants studied three item lists in anticipation of final cumulative recall testing. In the testing condition, participants were tested immediately on lists 1 and 2, whereas in the restudy condition, they restudied lists 1 and 2. In both conditions, participants were tested immediately on list 3. Acute psychosocial stress was induced in participants prior to the encoding of item lists using the Trier social stress test for groups protocol. No stress was induced in a control group. Salivary cortisol, alpha amylase, and subjective stress were measured repeatedly to capture the biopsychological stress response. The results showed a significant FTE on list 3 recall, that is, testing of lists 1 and 2 enhanced the recall of list 3. No significant effect of stress on the FTE was observed, suggesting that the FTE is robust under acute psychosocial encoding/retrieval stress. The discussion provides suggestions for future research directions.

The effect of fish oil on social interaction memory in total sleep-deprived rats with respect to the hippocampal level of stathmin, TFEB, synaptophysin and LAMP-1 proteins

Fish oil (FO) is one of the richest natural sources of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). DHA is essential for brain functions and EPA has been approved for brain health. On the other hand, stathmin, TFEB, synaptophysin and LAMP-1 proteins are involved in synaptic plasticity, lysosome biogenesis and synaptic vesicles biogenesis. In this study, we aimed to investigate the effect of FO on social interaction memory in sleep-deprived rats with respect to level of stathmin, TFEB, synaptophysin and LAMP-1 in the hippocampus of rats. All rats received FO through oral gavage at the doses of 0.5, 0.75 and 1 mg/kg. The water box was used to induce total sleep deprivation (TSD) and the three-chamber paradigm test was used to assess social behavior. Hippocampal level of proteins was assessed using Western blot. The results showed, FO impaired social memory at the dose of 1 mg/kg in normal and sham groups. SD impaired social memory and FO did not restore this effect. Furthermore, FO at the dose of 0.75 mg/kg decreased social affiliation and social memory in all groups of normal rats, compared with related saline groups, and at the dose of 1 mg/kg impaired social memory for stranger 2 compared with saline group. In sham groups, FO at the dose of 1 mg/kg impaired social memory for stranger 2 compared with saline group. SD decreased hippocampal level of all proteins (except stathmin), and FO (1 mg/kg) restored these effects. In conclusion, FO negatively affects social interaction memory in rats.

Regression II. Development through regression

As shown in our previous paper ('Regression I. Experimental approaches to regression', JAP, 65, 2, 345-65), the common mechanism of regression can be described as reversible dedifferentiation, which is understood as a relative increase of the proportion of low-differentiated (older) systems in actualized experience. Experimental data show that regression following disease (chronic tension headache) is followed by adaptation and an increase in system differentiation in that experience domain which contains systems responsible for that adaptation. The results of mathematical modelling support the idea that reversible dedifferentiation can be one of the mechanisms for increasing the effectiveness of adaptation through learning. Reversible dedifferentiation, which is phenomenologically described as regression, is a general mechanism for restructuring the organism-environment interactions in situations where behaviours that were effective in the past become ineffective. Reversible dedifferentiation has evolved as a component of adaptation when new behaviours are formed and large-scale modifications in the existing behaviours are required in the face of changes in the external and/or internal environment. Thus, the authors believe that this article provides evidence for Jung's view that regression is not only a 'return' to past forms of thinking, affects and behaviour, but that regressive processes provide a significant impetus for psychological growth and development.

Effective forewarning requires central route processing: Theoretical improvements on the counterargumentation hypothesis and practical implications for scam prevention

Financial scams have caused tremendous financial damage globally. In Japan, the police forewarn people by equipping them with scam-prevention techniques or providing awareness regarding examples of previous scams; however, this does not appear to effectively prevent the damage, as many scam victims do not remember these warnings when faced with actual scam encounters. Considering that scammers often use appeal to emotion techniques, peripheral processing during scam attempts might disturb people’s abilities to recall the warnings on scammers’ modus operandi, thus leading to failed counter-arguing efforts. We verified this hypothesis in an experimental setting by asking 162 participants to remember given forewarnings and resist deceptive advertisements. The results showed that participants gave the advertisers’ manipulative intent a higher rating only when they processed the advertisement through a central route, in addition to being forewarned. This means that forewarning had no effect when participants processed the advertisement through a peripheral route. Moreover, forewarning recollection levels mediated the effect of processing route on this rating, which suggests that remembering forewarnings is necessary to generate counterarguments. This result expands the theory on forewarning effects and explains why people are susceptible to scam victimization. Furthermore, it provides implications for scam prevention.

Stress and cognition: A user's guide to designing and interpreting studies

Fueling the rapid growth in our understanding of how stress influences cognition, the number of studies examining the effects of stress on various cognitive processes has grown substantially over the last two decades. Despite this growth, few published guidelines exist for designing these studies, and divergent paradigm designs can diminish typical effects of stress or even reverse them. The goal of this review, therefore, is to survey necessary considerations (e.g., validating a stress induction), important considerations (e.g., specifying the timing of the stressor and cognitive task), and best practices (e.g., using Bayesian analyses) when designing a study that aims at least in part to examine the effects of acute stress on some cognitive process or function. These guidelines will also serve to help readers of these studies interpret what may otherwise be very confusing, anomalous results. Designing and interpreting studies with these considerations and practices in mind will help to move the field of stress and cognition forward by clarifying how, exactly, stress influences performance on a given cognitive task in a population of interest.

Memories of and influenced by the Trier Social Stress Test

Psychosocial stress influences cognition, affect and behavior. This current review summarizes the impact of acute stress on human long-term memory taking a neuroendocrine perspective. In this respect the stress associated increase in activity of the sympathetic nervous system (SNS) and the hypothalamus-pituitary-adrenal (HPA) axis are key. A special focus will be placed on findings obtained with the Trier Social Stress Test (TSST). This paradigm can be used to induce stress before or after a memory task. It was shown repeatedly that stress enhances long-term consolidation but impairs long term memory retrieval. However the TSST can also be used to assess memories of this stressful episode itself. The latter requires a standardized presentation of relevant stimuli during the TSST as well as a carefully designed control condition. Moreover special care has to be taken to control potential influences on visual exploration and working memory in order to correctly interpret observed effects on memory. The results obtained so far fit to the idea of enhanced encoding of salient information under stress. These findings are of relevance for educational, organizational and clinical applications.

An oral presentation causes stress and memory impairments

Laboratory experiments revealed the stress hormone cortisol to decrease memory retrieval of emotional material, but a translation to real-life settings is missing so far. In this study, 51 students encoded a list of neutral, positive, and negative words as well as two neutral, biographical notes one day before attendance at a seminar at the university. In the stress condition, students gave a graded oral presentation, whereas they just attended the same seminar in the control condition immediately before retrieval took place. Measures of state anxiety, salivary cortisol and alpha-amylase confirmed the oral presentation to constitute a potent stressor. Importantly, stress significantly impaired retrieval of negative words, but not retrieval of the biographical notes. These results indicate that a real-life stressor decreases memory retrieval for negative items. In contrast, delayed memory retrieval of neutral information and interrelated details of biographical notes seems to be less prone to stress effects. These results have critical implications for educational settings.

Tests improve memory - no matter if you feel good or bad while taking them

Based on studies demonstrating that testing promotes better long-term retention than restudying (i.e., the testing effect), testing has been recommended as a powerful tool to boost knowledge acquisition in educational settings. However, a factor ubiquitous in real-life learning contexts has been ignored to date: the learner's affective state. To examine whether the learner's affective state influences the testing effect, we conducted two experiments. We employed a standard testing-effect paradigm consisting of an initial study phase and a subsequent restudy/testing phase, and induced negative, neutral, or positive affective states either before participants initially studied short expository texts (Experiment 1) or before they restudied or were tested on them (Experiment 2). After one week, memory for the texts was tested. In both experiments, previously tested material was better remembered than previously restudied material. However, in none of the experiments, did the memory advantage of testing over restudying vary as a function of affect condition. Hence, the present results suggest that testing seems to benefit long-term retention independently of the learner's affective state.

Can the Testing Effect for General Knowledge Facts Be Influenced by Distraction due to Divided Attention or Experimentally Induced Anxious Mood?

Studies on testing effect have showed that a practice test on study materials leads to better performance in a final test than restudying the materials for the same amount of time. Two experiments were conducted to test how distraction, as triggered by divided attention or experimentally induced anxious mood in the practice phase, could modulate the benefit of testing (vs. restudying) on the learning of interesting and boring general knowledge facts. Two individual difference factors (trait test anxiety and working memory (WM) capacity) were measured. Under divided attention, participants restudied or recalled the missing information in visually presented general knowledge facts, while judging whether auditorily presented items were from a pre-specified category. To experimentally induce anxious mood, we instructed participants to view and interpret negative pictures with anxious music background before and during the practice phase. Immediate and two-day delayed tests were given. Regardless of item type (interesting or boring) or retention interval, the testing effect was not significantly affected by divided (vs. full) attention or anxious (vs. neutral) mood. These results remained unchanged after taking into account the influences of participants’ trait test anxiety and WM capacity. However, when analyses were restricted to the study materials that had been learnt in the divided attention condition while participants accurately responded to the concurrent distracting task, the testing effect was stronger in the divided attention condition than in the full attention condition. Contrary to previous studies (e.g., Tse and Pu, 2012), there was no WM capacity × trait test anxiety interaction in the overall testing effect. Theoretical and practical implications of these findings are discussed.

Electrode Design from "Internal" to "External" for High Stability Silicon Anodes in Lithium-Ion Batteries

Building a stable electrode structure is an effective way to promote the practical applications of Si anode, which has large volume changes during charge/discharge process, in lithium-ion batteries. Herein, we fabricated an integrated electrode structure reinforced from "internal" to "external" to boost the performance of Si nanoparticles (NPs). The electrode contains the conductive polymer of poly(3,4-ethylene dioxythiophene):poly(styrenesulphonic acid) (PEDOT:PSS) as the binder, reduced graphene oxide (rGO), and hydroxylated Si NPs, which help form the "internal" interaction between them through the hydrogen bonding, while the "external" malleable network built by the flexible polymers and two-dimensional rGO sheets as the framework endows the highly flexible network to accommodate the Si expansion and forms long-range conductive network. Thus, the built-integrated electrode by the simple casting method shows high capacity, good rate performance, and long cycling stability. It is noted that such an electrode shows a high areal capacity of 3.29 mA h cm^-2 and a high volumetric capacity of 3290 A h cm^-3 at 0.09 mA cm^-2. The integrated electrode design is promising to promote the practical use of Si anodes and can be extended to other noncarbon anodes with large volume changes.

Acute stress enhances general-knowledge semantic memory

Acute psychological stress consistently impairs episodic memory, which consists of memory for events that are associated with a specific context. However, researchers have not yet established how stress influences semantic memory, which consists of general knowledge that is devoid of context. In the present study, participants either underwent stress induction or a control task prior to taking a trivia test that was designed to measure semantic memory. In contrast to the wealth of prior research on episodic memory, we found that stress enhanced semantic-memory retrieval. Supporting this finding, higher cortisol reactivity to stress was associated with better performance on the trivia test. Together with the results from previous studies of episodic memory, our findings suggest that stress differentially influences memory retrieval, depending on the degree to which the retrieval of a given memory relies on medial-temporal, neocortical, and striatal brain regions.

Retrieval practice improves item memory but not source memory in the context of stress

Smith, Floerke, and Thomas (2016) demonstrated that learning by repeated testing, or retrieval practice, reduced stress-related memory impairment when compared to learning by repeatedly studying material. In the present experiment, we tested whether, relative to study practice, retrieval practice would improve post-stress memory by increasing access to both item and source information. Participants learned two wordlists, which were temporally segregated to facilitate distinction between the two lists. Participants returned one week later for stress induction and two memory tests. Each test featured a recognition test that was given to assess item memory accessibility, and a list-discrimination task that was given to assess source memory. Relative to study practice, successful retrieval practice during learning reduced false alarms but did not improve source memory on the post-stress test. Results are discussed as they relate to current theories surrounding stress effects and retrieval practice effects.

Making Memories: Why Time Matters

In the last decade advances in human neuroscience have identified the critical importance of time in creating long-term memories. Circadian neuroscience has established biological time functions via cellular clocks regulated by photosensitive retinal ganglion cells and the suprachiasmatic nuclei. Individuals have different circadian clocks depending on their chronotypes that vary with genetic, age, and sex. In contrast, social time is determined by time zones, daylight savings time, and education and employment hours. Social time and circadian time differences can lead to circadian desynchronization, sleep deprivation, health problems, and poor cognitive performance. Synchronizing social time to circadian biology leads to better health and learning, as demonstrated in adolescent education. In-day making memories of complex bodies of structured information in education is organized in social time and uses many different learning techniques. Research in the neuroscience of long-term memory (LTM) has demonstrated in-day time spaced learning patterns of three repetitions of information separated by two rest periods are effective in making memories in mammals and humans. This time pattern is based on the intracellular processes required in synaptic plasticity. Circadian desynchronization, sleep deprivation, and memory consolidation in sleep are less well-understood, though there has been considerable progress in neuroscience research in the last decade. The interplay of circadian, in-day and sleep neuroscience research are creating an understanding of making memories in the first 24-h that has already led to interventions that can improve health and learning.

Reducing Lethal Force Errors by Modulating Police Physiology

OBJECTIVES

The aim of this study was to test an intervention modifying officer physiology to reduce lethal force errors and improve health.

METHODS

A longitudinal, within-subjects intervention study was conducted with urban front-line police officers (n = 57). The physiological intervention applied an empirically validated method of enhancing parasympathetic engagement (ie, heart rate variability biofeedback) during stressful training that required lethal force decision-making.

RESULTS

Significant post-intervention reductions in lethal force errors, and in the extent and duration of autonomic arousal, were maintained across 12 months. Results at 18 months begin to return to pre-intervention levels.

CONCLUSION

We provide objective evidence for a physiologically focused intervention in reducing errors in lethal force decision-making, improving health and safety for both police and the public. Results provide a timeline of skill retention, suggesting annual retraining to maintain health and safety gains.

Teaching the science of learning

The science of learning has made a considerable contribution to our understanding of effective teaching and learning strategies. However, few instructors outside of the field are privy to this research. In this tutorial review, we focus on six specific cognitive strategies that have received robust support from decades of research: spaced practice, interleaving, retrieval practice, elaboration, concrete examples, and dual coding. We describe the basic research behind each strategy and relevant applied research, present examples of existing and suggested implementation, and make recommendations for further research that would broaden the reach of these strategies.

Recent life stress exposure is associated with poorer long-term memory, working memory, and self-reported memory

Although substantial research has examined the effects of stress on cognition, much of this research has focused on acute stress (e.g. manipulated in the laboratory) or chronic stress (e.g. persistent interpersonal or financial difficulties). In contrast, the effects of recent life stress on cognition have been relatively understudied. To address this issue, we examined how recent life stress is associated with long-term, working memory, and self-reported memory in a sample of 142 healthy young adults who were assessed at two time points over a two-week period. Recent life stress was measured using the newly-developed Stress and Adversity Inventory for Daily Stress (Daily STRAIN), which assesses the frequency of relatively common stressful life events and difficulties over the preceding two weeks. To assess memory performance, participants completed both long-term and working memory tasks. Participants also provided self-reports of memory problems. As hypothesized, greater recent life stress exposure was associated with worse performance on measures of long-term and working memory, as well as more self-reported memory problems. These associations were largely robust while controlling for possible confounds, including participants' age, sex, and negative affect. The findings indicate that recent life stress exposure is broadly associated with worse memory. Future studies should thus consider assessing recent life stress as a potential predictor, moderator, or covariate of memory performance.

Acute Stress Time-dependently Modulates Multiple Memory Systems

Acute stress has been shown to modulate the engagement of different memory systems, leading to preferential expression of stimulus-response (SR) rather than episodic context memory when both types of memory can be used. However, questions remain regarding the cognitive mechanism that underlies this bias in humans-specifically, how each form of memory is individually influenced by stress in order for SR memory to be dominant. Here we separately measured context and SR memory and investigated how each was influenced by acute stress after learning (Experiment 1) and before retrieval (Experiment 2). We found that postlearning stress, in tandem with increased adrenergic activity during learning, impaired consolidation of context memory and led to preferential expression of SR rather than context memory. Preretrieval stress also impaired context memory, albeit transiently. Neither postlearning nor preretrieval stress changed the expression of SR memory. However, individual differences in cortisol reactivity immediately after learning were associated with variability in initial SR learning. These results reveal novel cognitive mechanisms by which stress can modulate multiple memory systems.