Potential avenues for exercise to activate episodic memory-related pathways: a narrative review

Comparing episodic memory outcomes from walking augmented reality and stationary virtual reality encoding experiences

Episodic Memory (EM) is the neurocognitive capacity to consciously recollect personally experienced events in specific spatio-temporal contexts. Although the relevance of spatial and temporal information is widely acknowledged in the EM literature, it remains unclear whether and how EM performance and organisation is modulated by self-motion, and by motor- and visually- salient environmental features (EFs) of the encoding environment. This study examines whether and how EM is modulated by locomotion and the EFs encountered in a controlled lifelike learning route within a large-scale building. Twenty-eight healthy participants took part in a museum-tour encoding task implemented in walking Augmented Reality (AR) and stationary Virtual Reality (VR) conditions. EM performance and organisation were assessed immediately and 48-hours after trials using a Remember/Familiar recognition paradigm. Results showed a significant positive modulation effect of locomotion on distinctive EM aspects. Findings highlighted a significant performance enhancement effect of stairway-adjacent locations compared to dead-end and mid-route stimuli-presentation locations. The results of this study may serve as design criteria to facilitate neurocognitive rehabilitative interventions of EM. The underlying technological framework developed for this study represents a novel and ecologically sound method for evaluating EM processes in lifelike situations, allowing researchers a naturalistic perspective into the complex nature of EM.

Lack of effects of acute exercise intensity on mnemonic discrimination

The hippocampus is thought to support episodic memory by pattern separation, thereby supporting the ability to discriminate high similarity items. Past research evaluating whether acute exercise can improve mnemonic discrimination of high similarity items is mixed. The present experiment attempts to extend these prior mixed findings by evaluating the effects of multiple exercise intensities on hippocampal-dependent, mnemonic discrimination and memory performance. Fifty-seven young adults completed a three-condition (control, moderate-intensity, and vigorous-intensity), within-subjects crossover pretest-posttest comparison. We observed no effects of acute exercise on recognition memory or mnemonic discrimination. We discuss the implications of these null findings with the broader literature by discussing the complexity of this potential exercise-mnemonic discrimination relationship, including the unique role of exercise intensity, differences in the level of processing (e.g., conceptual vs. perceptual), and unique brain regions involved in mnemonic discrimination.

Positive effects of brisk walking and Tai Chi on cognitive function in older adults: An fNIRS study

Exercise has shown to have beneficial effects on cognition in older adults. The purpose of this study was to investigate the cortical hemodynamic responses during the word-color Stroop test (WCST) prior and after acute walking and Tai Chi exercise by functional near-infrared spectroscopy (fNIRS). Twenty participants (9 males, mean age 62.8 ± 5.2), first underwent a baseline WCST test, after which they took three WCST tests in a randomized order, (a) after sitting rest (control), (b) after 6 minutes performing Tai Chi Quan, and (c) after a bout of 6 minutes brisk walking. During these four WCST tests cortical hemodynamic changes in the prefrontal area were monitored with fNIRS. Both brisk walking and Tai Chi enhanced hemodynamic activity during the Stroop incongruent tasks, leading to improved cognitive performance (quicker reaction time). Brisk walking induced a greater hemodynamic activity in the right dorsolateral prefrontal cortex (DLPFC) and ventrolateral prefrontal cortex (VLPFC) area, whereas Tai Chi induced a greater bilateral hemodynamic activity in the DLPFC and VLPFC areas. The present study provided empirical evidence of enhanced hemodynamic response in task- specific regions of the brain that can be achieved by a mere six minutes of brisk walking or Tai Chi in older adults.

Implications of Physical Exercise on Episodic Memory and Anxiety: The Role of the Serotonergic System

There is a growing interest in investigating the effects of physical exercise on cognitive performance, particularly episodic memory. Similarly, an increasing number of studies in recent decades have studied the effects of physical activity on mood and anxiety disorders. Moreover, the COVID-19 pandemic has raised awareness of the importance of regular physical activity for both mental and physical health. Nevertheless, the exact mechanisms underlying these effects are not fully understood. Interestingly, recent findings suggest that the serotonergic system may play a key role in mediating the effects of physical exercise on episodic memory and anxiety. In this review, we discuss the impact of physical exercise on both episodic memory and anxiety in human and animal models. In addition, we explore the accumulating evidence that supports a role for the serotonergic system in the effects of physical exercise on episodic memory and anxiety.

Acute evening high-intensity interval training may attenuate the detrimental effects of sleep restriction on long-term declarative memory

Recent evidence shows that a nap and acute exercise synergistically enhanced memory. Additionally, human-based cross-sectional studies and animal experiments suggest that physical exercise may mitigate the cognitive impairments of poor sleep quality and sleep restriction, respectively. We evaluated whether acute exercise may offset sleep restriction's impairment of long-term declarative memory compared to average sleep alone. A total of 92 (82% females) healthy young adults (24.6 ± 4.2 years) were randomly allocated to one of four evening groups: sleep restriction only (S5, 5-6 h/night), average sleep only (S8, 8-9 h/night), high-intensity interval training (HIIT) before restricted sleep (HIITS5), or HIIT before average sleep (HIITS8). Groups either followed a 15-min remote HIIT video or rest period in the evening (7:00 p.m.) prior to encoding 80 face-name pairs. Participants completed an immediate retrieval task in the evening. The next morning a delayed retrieval task was given after their subjectively documented sleep opportunities. Long-term declarative memory performance was assessed with the discriminability index (d') during the recall tasks. While our results showed that the d' of S8 (0.58 ± 1.37) was not significantly different from those of HIITS5 (-0.03 ± 1.64, p = 0.176) and HIITS8 (-0.20 ± 1.28, p = 0.092), there was a difference in d' compared to S5 (-0.35 ± 1.64, p = 0.038) at the delayed retrieval. These results suggest that the acute evening HIIT partially reduced the detrimental effects of sleep restriction on long-term declarative memory.

Exercise-Induced Elevated BDNF Concentration Seems to Prevent Cognitive Impairment after Acute Exposure to Moderate Normobaric Hypoxia among Young Men

Memory impairment, reduced learning ability, decreased concentration, and psychomotor performance can be all signs of deleterious impact of hypoxia on cognitive functioning. In turn, physical exercise can improve performance and enhance cognitive functions. The purpose of this study was to investigate whether the potential positive effects of exercise performed under normobaric hypoxia can counteract the negative effects of hypoxia on cognitive function, and whether these changes correlate with brain-derived neurotrophic factor (BDNF) concentrations. Seventeen healthy subjects participated in a crossover study where they performed two sessions of single breathing bouts combined with moderate intensity exercise under two conditions: normoxia (NOR EX) and normobaric hypoxia (NH EX). To assess cognitive function, Stroop test was applied. There were no significant differences in any part of the Stroop interference test regardless of the conditions (NOR, NH), despite a statistical decrease in SpO2 (p < 0.0001) under normobaric hypoxic conditions. In addition, a statistical increase (p < 0.0001) in BDNF concentration was observed after both conditions. Acute exercise under normobaric hypoxia did not impair cognitive function despite a significant decrease in SpO2. Exercise in such conditions may offset the negative effects of hypoxia alone on cognitive function. This may be related to the significant increase in BDNF concentration and, as a consequence, positively affect the executive functions.

The effects of physical activity timing and complexity on episodic memory: A randomized controlled trial

The role of two types of acute physical activity (PA) bouts were assessed on young adults' free-recall and recognition memory in two experiments, which differed in the temporal relation of PA and word encoding. Before or following training on the Rey Auditory Verbal Learning Task, participants performed a simple two-step dance, a complex four-step dance, or remained seated. Hypotheses proposed that PA prior to encoding and complex PA would enhance PA's mnemonic benefits. Memory assessed post-PA, 24 h, and 7 days after training indicated that timing and complexity of PA did not impact free-recall or recognition memory. Findings differ from a previous study showing complex PA benefited motor learning more than simple PA (Tomporowski & Pendleton, 2018). The inconsistency may be due to different working memory processes underlying consolidation and retrieval of procedural or episodic information. Theory-based explanations regarding memory storage and retrieval are proposed to elucidate this selective process.

Episodic memory training in elderly: A systematic review

Introduction:

Episodic memory is a cognitive process that allows the recall of experiences, learning, and the pursuit of future goals. During the aging process, episodic memory declines negatively, impacting social and psychological aspects in the elderly. Such intervention strategies as cognitive training are non-pharmacological ways of reducing these losses.

Objective

We systematically reviewed studies of the cognitive training of episodic memory in healthy elderly individuals and elderly individuals with clinical conditions.

Method

We systematically searched the PubMed, PsycNET, Web of Science, and SciELO databases using the descriptors “Episodic Memory” AND “Training” AND “Elderly” OR “Aging” OR “Dementia” in English and translated into Portuguese.

Results

Of the 572 articles that were identified by the search, 23 were included in the final analysis. The main variables that comprised the intervention protocols (i.e., characteristics of the sample, type of control group, mode of episodic memory training, and duration of training) were investigated, as well as the outcome variables, efficacy, and risk of bias. The main results indicated effectiveness with regard to different forms of the cognitive training of episodic memory.

Conclusion

Episodic memory training among the elderly can mitigate the negative effects of cognitive decline in dementia and healthy subjects promoting impacts at social, psychological, and economic levels. Although it is a widely studied topic, further empirical studies on the utility of episodic memory training in healthy elderly individuals and elderly individuals with clinical conditions are still needed.

Vigorous-intensity acute exercise during encoding can reduce levels of episodic and false memory

The potential benefits (veridical memory) and, importantly, costs (false memory) of acute exercise on memory in conjunction with the timing and type of exercise have not been fully studied. In Experiment 1, we employed a three-condition (15-minute vigorous-intensity acute exercise Before or During memory encoding, or a Control condition of watching a video), within-subjects, counterbalanced design. The procedures included an immediate and delayed (20-minute post encoding) free recall assessment. Veridical memory was determined by the number of studied words that were recalled, whereas false memory was determined by retrieving a non-presented, critical item. For veridical memory, Before was not different than Control (p = .42), however, During was worse than Before and Control (p's < .001). No differences occurred for false memory. Experiment 2 was conducted that included several additional exercise conditions (e.g., light-intensity exercise) during memory encoding, used a recognition task instead of a free recall task, and extended the long-term memory assessment out to 24-hours. Experiment 2 demonstrated that vigorous-intensity acute exercise during encoding reduced both veridical and false memory for related new items (p < .05). These findings demonstrate that the timing and intensity of exercise play an important role in influencing memory performance.

EXPRESS: Effects of Acute Exercise Intensity on Source Episodic Memory and Metamemory Accuracy

Prior research suggests that behavioral (e.g., exercise) and psychological factors (e.g., metamemory; monitoring and control of one's memory processes) may influence memory function. However, there is conflicting results on the optimal intensity of acute exercise to enhance memory and whether acute exercise can also enhance metamemory. Further, very limited research has evaluated whether acute exercise can influence source episodic memory. The objective of this study was to evaluate whether there is an intensity-specific effect of acute aerobic exercise on source episodic memory and metamemory accuracy. Thirty young adults participated in a three condition (Control/Moderate/Vigorous-Intensity Exercise), within-subject counterbalanced experimental study. After each intervention, participants completed source episodic memory and metamemory tasks. Results demonstrated that acute exercise, relative to control, was effective in enhancing source episodic memory, but not metamemory accuracy. Vigorous-intensity acute exercise was the most optimal intensity to enhance source episodic memory. Overall, our findings suggest that there is an intensity-specific effect of acute exercise on source episodic memory. Further, when exercise-related improvements in memory occur, young adults may be unaware of these memory benefits from exercise.

Acute and Chronic Exercise Effects on Human Memory: What We Know and Where to Go from Here

Although the acquisition, storage, and retrieval of memories was once thought to happen within a single memory system with multiple processes operating on it, it is now believed that memory is comprised of both distinct and interacting brain systems [...].

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.

Evaluation of the transient hypofrontality theory in the context of exercise: A systematic review with meta-analysis

Accumulating research suggests that, as a result of reduced neural activity in the prefrontal cortex (PFC), higher-order cognitive function may be compromised while engaging in high-intensity acute exercise, with this phenomenon referred to as the transient hypofrontality effect. However, findings in this field remain unclear and lack a thorough synthesis of the evidence. Therefore, the purpose of this meta-analysis was to evaluate the effects of in-task acute exercise on cognitive function, and further, to examine whether this effect is moderated by the specific type of cognition (i.e., PFC-dependent vs. non-PFC-dependent). Studies were identified by electronic databases in accordance with the PRISMA guidelines. In total, 22 studies met our inclusion criteria and intercept only meta-regression models with robust variance estimation were used to calculate the weighted average effect sizes across studies. Acute exercise at all intensities did not influence cognitive function (β = -0.16, 95% CI = [-0.58, 0.27], p = .45) when exercise occurred during the cognitive task, and no significant moderation effects emerged. However, there was evidence that cognitive task type (PFC-dependent vs. non-PFC-dependent) moderated the effect of high-intensity acute exercise on a concomitant cognitive performance (β = -0.81, 95% CI = [-1.60, -0.02], p = .04). Specifically, our findings suggest that PFC-dependent cognition is impaired while engaging in an acute bout of high-intensity exercise, providing support for the transient hypofrontality theory. We discuss these findings in the context of reticular-activating and cognitive-energetic perspectives.

Strenuous Exercise Habits and Spatial Mnemonic Discrimination Ability in Young Adult Men and Women

Increased physical activity has shown positive effects on various hippocampal memory functions through accumulating evidence that physical exercise and higher cardiorespiratory fitness can enhance human performance on nonspatial mnemonic discrimination tasks that rely on hippocampal pattern separation. However, there is less direct evidence of exercise effects on spatial pattern separation in humans, despite evidence for this association in rodent models. We examined the influence of strenuous exercise habits on spatial mnemonic discrimination among 176 young adults. We used a delayed match-/non-match-to-sample (same/different) task to assess pattern separation for spatial locations across varying degrees of similarity. Participants who reported regularly engaging in strenuous exercise three or more times per week performed significantly better than those who reported engaging in strenuous exercise fewer than three times per week, even when pattern separation tasks involved higher spatial similarity. These apparent exercise effects were observed for female, but not male, participants. These findings support likely benefits of strenuous exercise habits for human spatial pattern separation skills, and they suggest a need to explore potential interaction effects of exercise and gender.

Association of physical activity on memory interference: Boston Puerto Rican Health Study

Background : The objective of this study was to evaluate the association between habitual physical activity engagement on memory interference. The present analysis used cross-sectional data from the Boston Puerto Rican Health Study (n=1,241; mean age= 57.2; 72.1% female).

Methods : Physical activity was evaluated via self-report. Memory interference was evaluated using a word-list paradigm. The memory task included learning a list of 16 words (List A; 5 trials), followed by a distractor list (List B), and then an immediate recall of List A. Proactive interference occurs when preceding stimuli (e.g., Trial 1 and Trial 5 of List A) interferes with performance on a subsequent stimuli (List B). Retroactive interference occurs when subsequent stimuli (List B) interferes with the recall of previously encoded stimuli (Trial 5).

Results : For proactive interference, there was no association between physical activity and the difference between performance on List B and Trial 1 of List A (β=0.00001; P =0.96). Similarly, for retroactive interference, there was no association between physical activity and the difference between the short delay recall and Trial 5 of List A (β=0.0002; P=0.50).

Conclusion : The present study did not observe an association between habitual physical activity on attenuating memory interference.

Maintenance of the Amygdala-Hippocampal Circuit Function with Safe and Feasible Shaking Exercise Therapy in SAMP-10 Mice

INTRODUCTION

Patients with dementia show reduced adaptive, behavioral, and physiological responses to environmental threats. Physical exercise is expected to delay brain aging, maintain cognitive function and, consequently, help dementia patients face threats and protect themselves skillfully.

METHODS

To confirm this, we aimed to investigate the effects of the shaking exercise on the avoidance function in the senescence-accelerated mouse-prone strain-10 (SAMP-10) model at the behavioral and tissue levels. SAMP-10 mice were randomized into 2 groups: a control group and a shaking group. The avoidance response (latency) of the mice was evaluated using a passive avoidance task. The degree of amygdala and hippocampal aging was evaluated based on the brain morphology. Subsequently, the association between avoidance response and the degree of amygdala-hippocampal aging was evaluated.

RESULTS

Regarding the passive avoidance task, the shaking group showed a longer latency period than the control group (p < 0.05), even and low intensity staining of ubiquitinated protein, and had a higher number of and larger neurons than those of the control group. The difference between the groups was more significant in the BA region of the amygdala and the CA1 region of the hippocampus (staining degree: p < 0.05, neuron size: p < 0.01, neuron counts: p < 0.01) than in other regions.

CONCLUSIONS

The shaking exercise prevents nonfunctional protein (NFP) accumulation, neuron atrophy, and neuron loss; delays the aging of the amygdala and hippocampus; and maintains the function of the amygdala-hippocampal circuit. It thus enhances emotional processing and cognition functions, the memory of threats, the skillful confrontation of threats, and proper self-protection from danger.

The Effects of Acute Exercise on Short- and Long-Term Memory: Considerations for the Timing of Exercise and Phases of Memory

The specific questions addressed from this research include: (1) Does high-intensity acute exercise improve memory?, (2) If so, do the mechanisms occur via encoding, consolidation, or retrieval? and (3) If acute exercise occurs in multiple phases of memory (e.g., before encoding and during consolidation), does this have an additive effect on memory? Three experimental, within-subject, counterbalanced studies were conducted among young adults. High-intensity exercise involved a 20-minutes bout of exercise at 75% of heart rate reserve. Memory was evaluated from a word-list task, including multiple evaluations out to 24-hours post-encoding. The timing of the exercise and memory assessments were carefully positioned to evaluate whether any improvements in memory were driven by mechanisms related to encoding, consolidation, and/or retrieval. We demonstrated that high-intensity acute exercise enhanced memory. This effect was robust (repeatable) and occurred through encoding, consolidation and retrieval-based mechanisms. Further, incorporating acute exercise into multiple phases of memory additively enhanced memory function.

One single physical exercise session improves memory persistence by hippocampal activation of D1 dopamine receptors and PKA signaling in rats

Previously, we demonstrated that one single physical exercise session could positively modulate recognition memory persistence by D1/D5 activation. Here, we aim to investigate whether the effect of physical exercise on memory occurs due to the activation of both receptors, D1 and D5, or only one of them. Adult male Wistar rats were habituated on a treadmill one week before experiments. After learning session in the object recognition task, some animals received intrahippocampal infusions of the vehicle or a D1/D5 agonist (SKF 38393, 12.5 μg/μL/side), whereas others performed a single session of physical exercise on a treadmill (30 min at an intensity of 60-70% of indirect VO₂ max.). Immediately after physical exercise, some animals received intrahippocampal infusions of vehicle or D1/D5 antagonist (SCH 23390, 1 μg/μL/side). Signaling pathways of D1 and D5 receptors in the hippocampus were evaluated by pharmacological activation or inactivation of protein kinases A (PKA) and C (PKC), respectively. According to previous findings, D1/D5 agonist and a single physical exercise session after learning promoted memory persistence, and D1/D5 block impaired physical exercise effect. Importantly, here we demonstrated for the first time that PKA inhibition, but not PKC, impairs the effect of acute physical exercise on memory persistence. Besides, PKA stimulation can promote its effects on memory. Therefore, we provide evidence that corroborates the idea that D1-like dopaminergic receptors, by activation of the PKA pathway, are involved in the effects of acute physical exercise on memory.

The Impact of Acute Exercise Timing on Memory Interference

This study evaluated whether the timing of acute exercise can attenuate a memory interference effect. Across two experiments, participants completed an AB/AC memory task. Participants studied eight word pairs; four denoted AB (e.g., Hero - Apple) and four control (DE) pairs. Following this List 1, participants studied eight additional word pairs (List 2); four denoted AC, re-using words from the AB pairs (e.g., Hero - Project) and four control (FG) pairs. Following their study of both lists, participants completed a cued recall assessment. In Experiment 1 (N = 100), an acute exercise bout occurred before the AB/AC memory interference task, and the participants' three lab visits (successive conditions) were control, moderate-intensity (50% HRR; heart rate reserve) exercise, and vigorous-intensity (80% HRR) exercise. In Experiment 2 (N = 68), the acute exercise occurred between List 1 and List 2, and the participants' two lab visits (successive conditions) were a (80% HRR) vigorous-intensity exercise visit and a control visit. Across both experiments, we observed evidence of both proactive and retroactive interference (p < .05), but acute exercise, regardless of intensity, did not attenuate this interference (p > .05). Acute moderate-intensity exercise was better than control or vigorous-intensity exercise in enhancing associative memory (p < .05), independent of interference. In Experiment 2, vigorous intensity exercise was associated with more pronounced interference (p < .05). Our results suggest that acute exercise can enhance associative memory performance, with no attenuation of interference by exercise.

Effects of Exercise on Explicit Memory Function: Incidental and Intentional Encoding May Depend on Exercise Timing

The present experiment evaluated the effects of self-reported exercise behavior and an acute bout of high-intensity exercise on explicit memory function. The memory tasks were encoded either incidentally or intentionally; for intentional encoding, participants were told to focus on memorizing the stimuli (words), whereas for incidental encoding, participants were unaware that they would be subsequently asked to complete an object recognition task. Among a sample of 150 adults (M_age = 20 years), randomly assigned experimental participants engaged in the following task sequence: (a) incidentally encoded a series of objects, (b) engaged in 20 minutes of high-intensity exercise, (c) intentionally encoded a word list, and (d) completed explicit memory retrieval tasks. Control group participants viewed a time matched video in lieu of high intensity exercise. We measured self-reported exercise behavior via an exercise questionnaire. We did not observe convincing evidence of an effect of high-intensity acute exercise, when occurring during the early consolidation period, on memory function, for either incidental or intentional encoding tasks. However, self-reported engagement in moderate-to-vigorous physical activity was favorably associated with explicit memory performance.

Does exercise have a protective effect on cognitive function under hypoxia? A systematic review with meta-analysis

OBJECTIVE

This study aimed to examine (1) the independent effects of hypoxia on cognitive function and (2) the effects of exercise on cognition while under hypoxia.

METHODS

Design: Systematic review with meta-analysis.

DATA SOURCES

PubMed, Scopus, Web of Science, PsychInfo, and SPORTDiscus were searched. Eligibility criteria for selecting studies: randomized controlled trials and nonrandomized controlled studies that investigated the effects of chronic or acute exercise on cognition under hypoxia were considered (Aim 2), as were studies investigating the effects of hypoxia on cognition (Aim 1).

RESULTS

In total, 18 studies met our inclusionary criteria for the systematic review, and 12 studies were meta-analyzed. Exposure to hypoxia impaired attentional ability (standardized mean difference (SMD) = -0.4), executive function (SMD = -0.18), and memory function (SMD = -0.26), but not information processing (SMD = 0.27). Aggregated results indicated that performing exercise under a hypoxia setting had a significant effect on cognitive improvement (SMD = 0.3, 95% confidence interval: 0.14 - 0.45, I2 = 54%, p < 0.001). Various characteristics (e.g., age, cognitive task type, exercise type, exercise intensity, training type, and hypoxia level) moderated the effects of hypoxia and exercise on cognitive function.

CONCLUSION

Exercise during exposure to hypoxia improves cognitive function. This association appears to be moderated by individual and exercise/hypoxia-related characteristics.

Aerobic Fitness Unrelated to Acquisition of Spatial Relational Memory in College-Aged Adults

While compelling evidence indicates that poorer aerobic fitness relates to impairments in retrieving information from hippocampal-dependent memory, there is a paucity of research on how aerobic fitness relates to the acquisition of such relational information. Accordingly, the present investigation examined the association between aerobic fitness and the rate of encoding spatial relational memory-assessed using a maximal oxygen consumption test and a spatial configuration task-in a sample of 152 college-aged adults. The findings from this investigation revealed no association between aerobic fitness and the acquisition of spatial relational memory. These findings have implications for how aerobic fitness is characterized with regard to memory, such that aerobic fitness does not appear to relate to the rate of learning spatial-relational information; however, given previously reported evidence, aerobic fitness may be associated with a greater ability to recall relational information from memory.

Does Aerobic and Resistance Exercise Influence Episodic Memory through Unique Mechanisms?

Aerobic and resistance exercise (acute and chronic) independently and collectively induce beneficial responses in the brain that may influence memory function, including an increase in cerebral blood flow, neurogenesis, neuroelectrical alterations, and protein production. However, whether aerobic and resistance exercise improve memory via similar or distinct mechanisms has yet to be fully explained. Here, we review the unique influence of aerobic and resistance exercise on neural modulation, proteins, receptors, and ultimately, episodic memory. Resistance training may optimize neural communication, information processing and memory encoding by affecting the allocation of attentional resources. Moreover, resistance exercise can reduce inflammatory markers associated with neural communication while increasing peripheral and central BDNF (brain-derived neurotrophic factor) production. Aerobic training increases hippocampal levels of BDNF and TrkB (Tropomyosin receptor kinase B), protein kinases and glutamatergic proteins. Likewise, both aerobic and anaerobic exercise can increase CREB (cAMP response element-binding protein) phosphorylation. Thus, we suggest that aerobic and resistance exercise may influence episodic memory via similar and, potentially, distinct mechanisms.

Acute exercise, memory, and neural activation in young adults

Acute exercise benefits memory, and the temporal placement of exercise relative to exposure can affect the magnitude of benefits observed. Although the temporal placement appears to be important, there is a limited understanding as to how cognitive benefits in response to acute exercise are achieved. Hence, we conducted a two-part study including a behavioral study and a follow-up functional magnetic resonance imaging (fMRI) study to advance our understanding of the potential role of the effects of exercise on memory and neural activation. For Study One, we assessed the effect of acute exercise on memory in young adults. Participants were randomized to exercise before exposure for 20 min (before only, BO), after exposure for 20 min (After Only, AO), before and after exposure for 10 min at each time (before and after, BA), or to receive no exercise (No-exercise Control, NC). Similar to previous findings, any exercise prior to exposure (BO, BA) benefited some aspects of memory performance. Interestingly, the more consistent and larger benefits were seen with a shorter duration of exercise both before and after exposure (BA). Study Two replicated the methods of Study One comparing the BA condition (which had the most robust benefits) to the NC condition while collecting fMRI data during the memory task. Analyses assessed condition differences of activation during encoding and recall. There were no condition differences during memory encoding, however there was a condition effect on activation in occipito-temporal regions during the memory recall trials. Consistent with previous research, exercise appears to benefit memory with some exercise prior to exposure being important for the benefits achieved. Further, exercise affects neural activation and the results appear complementary to the behavior findings. Future research should use a within-subjects design to control for heterogeneity in behavior and neural activation.

Effectiveness of neurobic exercise program on memory and depression among elderly residing at old age home

Objectives This study finds out the effectiveness of neurobic exercise program on memory and depression among elderly residing in old age homes. Methods The non-probability purposive sampling technique was used for sample selection. Wechsler's memory scale (WMS-IV) and Geriatric depression scale (GDS) were the instruments used to assess the memory and depression among elderly during the pretest and posttest, respectively and the researcher had developed data sheet to collect information about the background variables using interview technique. Results The neurobic exercise program was found to be effective in reducing depression among elderly residing in old age homes. There was a significant difference (p<0.001) in the level of depression had been found during the pretest and posttest in the interventional group. There was a statistically significant difference (p<0.001) found between the study group and in the control group. There was significant correlation (r=0.417, p<0.05) found between the memory and depression during the pretest in the study group among the elderly. A statistically significant association (p<0.05) found in the mean scores of depression and marital status of the elderly during the pretest in the study group and there was a significant association (p<0.01) found in the mean scores of depression and the gender of the elderly during the pretest and posttest in the non interventional group were found. Conclusions The findings suggested that neurobic exercise program is an effective intervention in improving memory and reducing depression.

Motor behavior-induced prefrontal cortex activation and episodic memory function

BACKGROUND

The objective of this paper was to evaluate the potential individual and combined effects of acute exercise coupled with bilateral interhemispheric activation on episodic memory function. Six experiments were conducted.

METHODS

Experiment 1 was a within-subject, counterbalanced experiment. Participants completed four visits, including 1) exercise and saccadic eye movements, 2) exercise only, 3) saccadic eye movements only, and 4) no exercise and no saccadic eye movements (control). A word-list memory assessment was employed, including a long-term (20-min delay) memory evaluation. In Experiment 2, we evaluated the effects of saccadic eye movements on prefrontal cortex oxygenation, a proxy for neuronal activity. Similarly, in our third experiment, we evaluated the effects of acute exercise on prefrontal cortex oxygenation. Thus, experiments 2 and 3 were employed to provide mechanistic insights from the results shown in experiment 1. Experiment 4 replicated Experiment 1, but instead of increasing prefrontal cortex activation via saccadic eye movements, we used a fist clenching protocol. Experiment 5 evaluated the effects of fist clenching on prefrontal cortex oxygenation.

RESULTS

Collectively, these 5 experimental studies showed that acute exercise (Experiment 1), saccadic eye movements (Experiment 1), and fist clenching (Experiment 4) enhanced memory function, and that acute exercise (Experiment 3), saccadic eye movements (Experiment 2) and fist clenching (Experiment 5) all increased prefrontal cortex oxygenation. Experiment 6 demonstrated that prefrontal cortex oxygenation was positively associated with episodic memory function.

CONCLUSION

These six experiments suggest that several behaviors, such as acute exercise, saccadic eye movements and fist clenching may improve memory function and may, potentially, do so via increases in prefrontal cortex oxygenation.

Combined effects of acute exercise and hypoxia on memory

No previous studies have evaluated the potential combined effects of acute exercise and acute hypoxia exposure on memory function, which was the purpose of this study. Twenty-five participants (Mage = 21.2 years) completed two laboratory visits in a counterbalanced order, involving 1) acute exercise (a 20-min bout of moderate-intensity exercise) and then 30 min of exposure to hypoxia (FIO2 = 0.12), and 2) exposure to hypoxia alone (FIO2 = 0.12) for 30 min. Following this, participants completed a cued-recall and memory interference task (AB/AC paradigm), assessing cued-recall memory (recall 1 and recall 2) and memory interference (proactive and retroactive interference). For cued-recall memory, we observed a significant main effect for condition, with Exercise + Hypoxia condition having significantly greater cued-recall performance than Hypoxia alone. Memory interference did not differ as a function of the experimental condition. This experiment demonstrates that engaging in an acute bout of exercise prior to acute hypoxia exposure had an additive effect in enhancing cued-recall memory performance.

Baduanjin mind-body exercise improves logical memory in long-term hospitalized patients with schizophrenia: A randomized controlled trial

Neurocognitive impairment is one of the core symptoms in schizophrenia and poses a great challenge to effective treatment. Sixty-one long-term hospitalized patients with schizophrenia were recruited and randomly assigned to two groups: Baduanjin exercise and brisk walking. Patients in the Baduanjin group received 24 weeks of Baduanjin training (5 days/week, 40 min/day), while patients in the brisk walking group received 24 weeks of brisk walking (5 days/week, 40 min/day). Scores on the Wechsler Memory Scale, Digit Symbol Substitution Test (DSST), and the positive and negative syndrome scale were used to evaluate the logical memory (LM), processing speed, and clinical symptoms of all participants, while the score of Trail Making Test-A (TMT-A) was applied to assess the visual attention and graphomotor speed, at baseline and the 16th week and 24th week of intervention. The one-way repeated measures analysis of variance (ANOVA) was used to test the differences in neurocognitive changes between the two groups. Repeated measures ANOVA showed significant differences between the two groups in the LM immediate (F = 6.21, p = 0.003) and LM delayed (F=5.60, p = 0.005) scores, but not in the completion times of TMT-A (F=.22, p = 0.806) or DSST scores (F=0.97, p = 0.328). A significant effect of time was also detected in the LM immediate (F=10.24, p = 0.000) and LM delayed (F=4.93, p = 0.009) scores and in the completion time of the TMT-A (F=33.10, p = 0.000), but not in the DSST scores (F=2.12, p = 0.122). Baduanjin exercise could improve logical memory in the long-term hospitalized patients with schizophrenia.

Cognitive-Motor Dual Task Interference Effects on Declarative Memory: A Theory-Based Review

Bouts of exercise performed either prior to or immediately following study periods enhance encoding and learning. Empirical evidence supporting the benefits of interventions that simultaneously pair physical activity with material to be learned is not conclusive, however. A narrative, theory-based review of dual-task experiments evaluated studies in terms of arousal theories, attention theories, cognitive-energetic theories, and entrainment theories. The pattern of the results of these studies suggests that cognitive-motor interference can either impair or enhance memory of semantic information and the manner in which physical activity impacts working memory within executive processing appears to explain disparate outcomes. The integration and timing of physical movements in concert with the type of information to be encoded and remembered appears to be a critical requirement for learning. These observations have implications for the role of physical activity in education, rehabilitation, and gerontological settings.

Acute exercise on memory function: open vs. closed skilled exercise

Background: Previous studies suggest that acute exercise may improve memory function. Few studies, however, have investigated the differential effect of the acute exercise movement patterns on memory. Such an effect is plausible, as research demonstrates that open-skilled exercise (e.g.,racquetball) may have a greater effect on memory-related neurotrophins (e.g., brain-derived neurotrophic factors) when compared to closed-skilled exercise (e.g. treadmill exercise). A key distinction between open- and closed-skilled exercise is that open-skilled exercises are those that require an individual to react in a dynamic way to a changing, unpredictable environment. Our aim in this study was to assess wether retrospective and prospective memory are differentially influenced from open- and closed-skilled acute exercise. Methods: A within-subject design was employed. Participants (Mage = 20.6 years; 69% female)completed two visits, in a counterbalanced order. The two experimental conditions included open-skilled acute exercise (racquetball) and closed-skilled acute exercise (treadmill exercise),each lasting 30-minute at 60% of heart rate reserve (HRR). During both experimental conditions,participants completed short- and long-term assessments of retrospective and prospective memory function. Retrospective memory was evaluated across multiple word-list trials (e.g.,Trials 1-6, 20-minute delay, 24-hour delay). Results: No significant effect of exercise was found on prospective memory. For retrospective memory, there was a significant main effect for condition, F(1, 57) = 5.33, P = 0.02, η2 = 0.004,main effect for trial, F(4.12, 234.9) = 227.85, P < 0.001, η2 = 0.46, but no condition by trial interaction, F(4.63, 264.08) = 1.022, P = 0.40, η2 = 0.002. Conclusion: Retrospective memory was greater after closed-skilled exercise (treadmill) when compared to open-skilled exercise (racquetball).

Hypothesized Mechanisms Through Which Exercise May Attenuate Memory Interference

In this paper we introduce a mechanistic model through which exercise may enhance episodic memory, specifically via attenuating proactive and retroactive memory interference. We discuss the various types of memory, different stages of memory function, review the mechanisms behind forgetting, and the mechanistic role of exercise in facilitating pattern separation (to attenuate memory interference).

Experimental Effects of Acute High-Intensity Resistance Exercise on Episodic Memory Function: Consideration for Post-Exercise Recovery Period

Background

The present experiments evaluated the effects of acute high-intensity resistance exercise on episodic memory.

Methods

Two experiments were conducted. For Experiment 1, participants (N = 40; M_age = 21.0 years) were randomized into one of two groups, including an experimental exercise group and a control group (seated for 20 min). The experimental group engaged in an acute bout of resistance exercises (circuit style exercises) for 15 minutes, followed by a 5-min recovery period. Memory function was subsequently assessed using a multiple trial (immediate and delay), word-list episodic memory task (Rey Auditory Verbal Learning Test, RAVLT), and then followed by a comprehensive, computerized assessment of episodic memory (Treasure Hunt task, THT). The THT involved a spatio-temporal assessment of what, where, and when components of episodic memory. Experiment 2 evaluated if altering the recovery period would influence the potential negative effects of high-intensity resistance exercise on episodic memory function. For Experiment 2, participants (N = 51) were randomized into the same acute resistance exercise protocol but either with a 10-min recovery period, 20-min recovery period, or a control group.

Results

For Experiment 1, for RAVLT, the exercise group performed worse (F_{group × time} = 3.7, p = .001, η ²p = .09). Across nearly all THT outcomes, the exercise group had worse spatio-temporal memory than the control group. These results suggest that high-intensity resistance exercise (with a 5-min recovery) may have a detrimental effect on episodic memory function. For Experiment 2, for RAVLT, the exercise with 10-min recovery group performed better (F_{group × time} = 3.1, p = .04, η ²p = .11). Unlike Experiment 1, exercise did not impair spatio-temporal memory, with the 20-min exercise recovery group having the best "where" component of episodic memory.

Conclusion

Collectively, the results from these two experiments suggest that acute high-intensity resistance exercise may impair episodic memory when a short exercise recovery period (e.g., 5-min) is employed, but with a longer recovery period (10+ min), acute high-intensity resistance exercise may, potentially, enhance episodic memory.

Effects of Exercise on Memory Interference in Neuropsychiatric Disorders

There are several mechanisms that cause memory impairment, including motivated forgetting, active forgetting, natural decay, and memory interference. Interference occurs when one is attempting to recall something specific, but there is conflicting information making it more difficult to recall the target stimuli. In laboratory settings, it is common to measure memory interference with paired associate tasks-usually utilizing the AB-CD, AB-AC, AB-ABr, or AB-DE AC-FG method. Memory impairments are frequent among those with neuropsychiatric disorders such as depression, schizophrenia, and multiple sclerosis. The memory effects of each condition differ, but are all related to alterations in brain physiology and general memory deterioration. Exercise, or physical activity, has been demonstrated to attenuate memory interference in some cases, but the mechanisms are still being determined. Further research is needed on memory interference, in regard to exercise and neuropsychiatric disorders.

Exercise and Organ Cross Talk

Chronic heart failure, diabetes, depression, and other chronic diseases are associated with high mortality rate and low cure rate. Exercise induces muscle contraction and secretes multiple myokines, which affects the signaling pathways in skeletal muscle tissues and regulate remote organ functions. Exercise is known to be effective in treating a variety of chronic diseases. Here we summarize how exercise influences skeletal muscle, heart, brain, gut, and liver, and prevents heart failure, cognitive dysfunction, obesity, fatty liver, and other diseases. Exercise training may achieve additional benefits as compared to the present medication for these chronic diseases through cross talk among skeletal muscle and other organs.

Effects of Exercise on Long-Term Potentiation in Neuropsychiatric Disorders

Various neuropsychiatric conditions, such as depression, Alzheimer's disease, and Parkinson's disease, demonstrate evidence of impaired long-term potentiation, a cellular correlate of episodic memory function. This chapter discusses the mechanistic effects of these neuropsychiatric conditions on long-term potentiation and how exercise may help to attenuate these detrimental effects.

Experimental Investigation Examining the Effects of Acute Exercise on Implicit Memory Function

Emerging work suggests that acute exercise can enhance explicit memory function. Minimal research, however, has examined whether acute exercise is associated with implicit memory, which was the purpose of this study. Three separate experimental studies were computed (N = 120; Mean age = 21). In Experiment 1, participants were randomly assigned to either a moderate-intensity bout of acute exercise (15-minute) or engaged in a seated control task (15-minute), followed by the completion of a word-fragmentation implicit memory task. Experiment 2 replicated Experiment 1, but instead employed a higher-intensity exercise protocol. For Experiment 3, participants were randomly assigned to either a moderate-intensity bout of acute exercise (15-minute) or engaged in a seated control task (15-minute), followed by the completion of a real world, 3-dimensional implicit memory task. For Experiment 1, the exercise and control groups, respectively, had an implicit memory score of 7.0 (0.5) and 7.5 (0.6) (t(38) = 0.67, p = .51). For Experiment 2, the exercise and control groups, respectively, had an implicit memory score of 6.9 (1.9) and 7.8 (2.4) (t(38) = 1.27, p = .21). These findings suggest that exercise, and the intensity of exercise, does not alter implicit memory from a word fragmentation task. For Experiment 3, the exercise and control groups, respectively, had a discrimination implicit memory index score of 0.48 (0.18) and 0.29 (0.32) (t(38) = 2.16, p = .03). In conclusion, acute exercise does not influence a commonly used laboratory-based assessment of implicit memory but may enhance real world-related implicit memory function.

The effects of physical exercise on parahippocampal function

OBJECTIVE

The objective of this study was to examine the effects of physical exercise on parahippocampal function.

METHODS

Studies were identified using electronic databases, including PubMed, PsychInfo, Sports Discus, and Google Scholar. In total, 28 articles met the inclusionary criteria. Among these, 20 were among humans and 8 in animal models. Among the 20 human studies that examined some aspects of the parahippocampal gyrus, 5 evaluated the entorhinal cortex and 1 evaluated the perirhinal cortex. Among the 20 human studies, 3 evaluated neural activity (or BOLD-signal changes), 14 evaluated brain volume (gray or white matter), 2 examined fractional anisotropy, 1 examined glucose metabolism, and 1 examined functional connectivity between the parahippocampal gyrus and a proximal brain tissue. Among the 8 animal studies, 4 evaluated the entorhinal cortex, with the other 4 examining the perirhinal cortex.

RESULTS

The results demonstrated that, among both animal and human models, exercise had widespread effects on parahippocampal function. These effects, included, for example, increased neural excitability in the parahippocampal gyrus, increased gray/white matter, reduced volume of lesions, enhanced regional glucose metabolism, increased cerebral blood flow, augmented markers of synaptic plasticity, and increased functional connectivity with other proximal brain structures.

CONCLUSION

Exercise appears to have extensive effects on parahippocampal function.

The effects of different protocols of physical exercise and rest on long-term memory

Whilst there are many studies comparing the different effects of exercise on long-term memory, these typically adopt varying intensities, durations, and behavioural measures. Furthermore, few studies provide direct comparisons between exercise and different types of rest. Therefore, by providing a standardised methodological design, this study will ascertain the most effective intensity and protocol of exercise for the modulation of long-term memory, whilst directly comparing it to different types rest. This was achieved using the same old/new recognition memory test and an 80-90 min retention interval. Three experiments were performed (total N = 59), each with a three-armed crossover design measuring the extent to which physical exercise and wakeful rest can influence long-term memory performance. In Experiment 1, the effects of continuous moderate intensity exercise (65-75% HR_max), passive rest (no cognitive engagement) and active rest (cognitively engaged) were explored. In Experiment 2, continuous moderate intensity exercise was compared to a type of high-intensity interval training (HIIT) and passive rest. Experiment 3 observed the effects of low- (55-65% HR_max), moderate- and high-intensity (75-85% HR_max) continuous exercise. Across the three experiments moderate intensity exercise had the greatest positive impact on memory performance. Although not significant, HIIT was more effective than passive-rest, and passive rest was more effective than active rest. Our findings suggest that it is not necessary to physically overexert oneself in order to achieve observable improvements to long-term memory. By also investigating wakeful rest, we reaffirmed the importance of the cognitive engagement during consolidation for the formation of long-term memories.

The effects of sedentary behavior on memory and markers of memory function: a systematic review

Objective: To evaluate the association of sedentary behavior on memory and markers of memory among humans of all ages.Methods: PubMed, PsychInfo, Sports Discus and Google Scholar databases were searched. Inclusionary criteria included: Published in English; conducted among humans (children to older adults); employ a cross-sectional, prospective or experimental design; include a measure of sedentary behavior as the independent variable (e.g. time spent sitting or watching television); and include a memory-related outcome measure (e.g. behavioral performance on a memory task, brain tissue volume in a memory structure). Information on participant characteristics, study design, sedentary behavior measure, memory outcome measure, and hypothesized mechanisms were extracted. The relationship between sedentary behavior and memory was synthesized while considering the data extraction parameters.Results: In total, 25 articles met the inclusionary criteria, including 8 studies among children/adolescents and 17 among adults. Sedentary behavior was assessed subjectively (e.g. TV viewing, computer use, reading) and objectively (e.g. accelerometry). Outcome measures included behavioral performance on various memory tasks (e.g. episodic and working memory), BDNF levels, brain volumetric measures of the temporal lobe, and hippocampal glucose metabolism. Overall, for both the child and adult studies, findings were mixed, with studies demonstrating null, inverse, and positive associations between sedentary behavior and memory. Sedentary behavior type may play a distinct role in the relationship between sedentary behavior and memory, as computer use, in particular, appeared to favorably influence memory when compared to other sedentary types (e.g. TV viewing, which showed in inverse association with memory in select studies).Conclusion: There is conflicting evidence of the relationship between sedentary behavior and memory-related outcomes among children and adults. Future studies are needed to further disentangle these complex interrelationships. Such studies should also carefully consider how physical activity may or may not moderate these relationships.

Does brain-derived neurotrophic factor mediate the effects of exercise on memory?

Objective: Brain-derived neurotrophic factor (BDNF) has been hypothesized as a potential mechanism through which exercise may subserve memory function. The present review specifically evaluates this hypothesis.Methods: Studies were identified using electronic databases, including PubMed, PsychInfo, Sports Discus and Google Scholar.Results: In total, 52 articles met the study criteria, and among these, 36 were conducted in an animal model and 16 among humans. Among the animal experiments, 100% of them demonstrated that chronic exercise improved memory function; 97% demonstrated an exercise-induced increase in BDNF; and among the eight evaluating BDNF as a mediator, 100% provided evidence that BDNF mediated the relationship between exercise and memory. The findings in the human studies were mixed. Among the human studies, 44% demonstrated that varying exercise protocols improved memory and increased BDNF levels, and among the studies evaluating BDNF as a mediator, 40% provided evidence that BDNF mediated the relationship between exercise and memory.Conclusion: In animal models, chronic exercise training robustly increases BDNF and improves memory performance, with reasonable evidence to also suggest that BDNF may mediate the exercise-memory interaction. These interrelationships, however, are less clear among humans. Future research among humans, in particular, is needed to evaluate the extent to which BDNF may mediate the relationship between exercise and memory.

Acute exercise and mindfulness meditation on learning and memory: randomized controlled intervention

Background: The purpose of this experiment was to evaluate the potential combined effects of acute exercise and mindfulness mediation on episodic memory.

Methods: All data collection occurred in the authors’ laboratory (January to May of 2019). In this three-arm, within-subject design, participants (N=20; M_age=21.6 years) completed three counterbalanced laboratory visits, including Exercise Only, Exercise + Meditation and Control. Learning and memory were assessed from a word-list task. A one-factor repeated-measures ANOVA was computed for two memory outcomes, including the learning outcome (average performance across the 6 trials) and the long-term memory recall (10-minute delay).

Results: The exercise conditions had a greater learning effect when compared to the Control visit, M_diff = 0.68 (95% CI: 0.10, 1.25), P = 0.02. The Exercise + Memory visit had better longterm memory when compared to Exercise Only, M_diff = 0.95 (95% CI: 0.07, 1.83), P = 0.03.

Conclusion: The present experiment provides suggestive evidence that acute exercise may enhance learning and, when coupling acute exercise prior to encoding with meditation during early consolidation, long-term memory may be enhanced.

Memory-Related Encoding-Specificity Paradigm: Experimental Application to the Exercise Domain

The Encoding-Specificity Paradigm indicates that memory recall will be superior when contextual factors are congruent between memory encoding and memory retrieval. However, unlike other contextual conditions (e.g., verbal context, mental operations, global feature context, mood dependency, and physical operations), this paradigm has nearly been ignored in the exercise domain. Thus, the purpose of this study was to examine the Encoding-Specificity Paradigm in the context of exercise and rest conditions. 24 young adults (age: M = 21 years) completed a within-subject, counterbalanced experiment involving four laboratory visits, including 1) R-R (rest-rest) condition, 2) R-E (rest-exercise) condition, 3) E-R (exercise-rest) condition, or 4) E-E (exercise-exercise) condition. The exercise bout included a 15-minute moderate-intensity walk on a treadmill. Memory recall was assessed via a 15 word-list task. Memory recall was greater for R-R (8.71 ± 3.1) versus R-E (7.46 ± 2.8), and similarly, for E-E (8.63 ± 2.7) versus E-R (8.21 ± 2.7). The mean word recall for the congruent and incongruent conditions, respectively, was 8.67 (2.4) and 7.83 (2.4). There was a statistically significant condition effect (F = 5.02; P = .03; partial η² = .18). This experiment provides direct support for the Encoding-Specificity Paradigm in the exercise domain.

Effects of Acute Exercise and Learning Strategy Implementation on Memory Function

Background and Objectives: Long-term potentiation (LTP), the functional connectivity among neurons, is considered a mechanism of episodic memory. Both acute exercise and learning are thought to influence memory via an LTP-related mechanism. Limited research has evaluated the individual and combined effects of acute exercise and learning strategy implementation (e.g., 3-R technique, cue-integration) on memory, which was the purpose of this study. Materials and Methods: For Experiment 1, participants (n = 80; M_age = 20.9 years) were randomized into one of four experimental groups, including Exercise + Learning (E + L), Learning Only (L), Exercise Only (E), and Control Group (C; no exercise and no learning strategy implementation). The exercise stimulus involved an acute 15-min bout of lower-intensity (60% of heart rate max) walking exercise and the learning strategy involved the implementation of the 3-R technique. Experiment 2 (n = 77; M_age = 21.1 years) replicated Experiment 1 but addressed limitations (e.g., exposure level of the memory task) from Experiment 1 and employed a higher-intensity bout of exercise (77% of heart rate max). Experiment 3 (n = 80; M_age = 21.0 years) evaluated these same four experimental conditions but employed a cue-integration learning strategy and a moderate-intensity bout of acute exercise (64% of heart rate max). Results: These three experiments demonstrate that both learning techniques were effective in enhancing memory and we also provided evidence of a main effect for acute exercise (Experiment 3). However, we did not observe consistent evidence of a learning by exercise interaction effect. Conclusions: We demonstrate that both acute exercise and different learning techniques are effective in enhancing long-term memory function.

Cognitive resources moderate the adverse impact of poor perceived neighborhood conditions on self-reported physical activity of older adults

Poor neighborhood conditions are associated with lower levels of physical activity for older adults but socio-ecological models posit that physical activity depends on both environmental and individual factors. Older adults' ability to overcome environmental barriers to physical activity may partially rely on cognitive resources. However, evidence on the moderating role of these cognitive resources in the associations between environmental barriers and physical activity is still lacking. We analyzed cross-national and longitudinal data on 28,393 adults aged 50 to 96 years as part of the SHARE. Lack of access to services and neighborhood nuisances were used as indicators of poor neighborhood conditions. Delayed recall and verbal fluency were used as indicators of cognitive resources. Confounder-adjusted generalized estimation equations were conducted to test associations between neighborhood conditions and self-reported moderate physical activity, as well as the moderating role of cognitive resources. Results showed that poor neighborhood conditions reduced the odds of engagement in physical activity. Cognitive resources robustly reduced the adverse influence of poor neighborhood conditions on physical activity. Participants with lower cognitive resource scores showed lower odds of engaging in physical activity when neighborhood conditions were poorer, whereas these conditions were not related to this engagement for participants with higher cognitive resource scores. These findings suggest that cognitive resources can temper the detrimental effect of poor neighborhood conditions on physical activity. Public policies should target both individual and environmental factors to tackle the current pandemic of physical inactivity more comprehensively.

Association of physical activity on the functional connectivity of the hippocampal-orbitofrontal pathway

Objective: The objective of the study is to examine the association between physical activity and hippocampal-orbitofrontal functional connectivity. Methods: Data from the Nathan Kline Institute-Rockland Sample was utilized, which consisted of 366 participants (M_age = 43 years; 63% female). Physical activity was self-reported using the International Physical Activity Questionnaire. Hippocampal-orbitofrontal functional connectivity was assessed from magnetic resonance imaging. Results: Moderate-intensity physical activity was not statistically significantly associated with left hippocampal-orbitofrontal connectivity (β = 0.001; 95% CI: -0.02, 0.03; P = 0.90) or right hippocampal-orbitofrontal connectivity (β = 0.01; 95% CI: -0.01, 0.04; P = 0.22). However, vigorous-intensity physical activity was statistically significantly associated with right hippocampal-orbitofrontal connectivity (β = 0.01; 95% CI: 0.004, 0.02; P = 0.002). Discussion: Habitual engagement in intense physical activity was associated with greater hippocampal-orbitofrontal connectivity, while moderate activity engagement was not. This may have important implications for the exercise neurobiology field in the context of exercise and memory function, suggesting that intense activity may facilitate cognitive/memory functions. However, our findings should be interpreted with caution given the relatively weak associations that were observed.

Acute Exercise on Memory Reconsolidation

Background and Objective: Once a memory is reactivated, it enters a labile state and, thus, is vulnerable to memory decay and/or distortion. Recent research demonstrates that acute, high-intensity exercise is associated with enhanced episodic memory function. Very limited research, however, has evaluated whether acute exercise can attenuate memory distortion from memory reactivation, which was the purpose of this study. Methods: A between-subject randomized controlled intervention was employed. Participants (N = 80) were randomly assigned to one of four groups, including (1) reminder with exercise, (2) reminder, (3) no reminder, and (4) interference control. For the groups, participants completed three visits (Visit 1, 2, and 3), which all occurred 48 hours apart. An exception to this was the interference control group, which did not complete Visit 2. On Visit 2, the reminder with exercise group engaged in a 15 min bout of high-intensity exercise (80% of heart rate reserve) immediately after memory reactivation. On Visit 3, participants engaged in a free recall (4 trials) of the memory task encoded on Visit 1. Results: In a 4 (groups) × 4 (learning trials) mixed-measures ANOVA, with the group as the between-subjects variable and the learning trials (1–4) as the within-subject variable, there was a significant main effect group, F(3, 76) = 4.18, p = 0.008, η²_p = 0.14, and a significant main effect for the learning trials, F(2.40, 182.59) = 49.25, p < 0.001, η²_p = 0.39, but there was no group by learning trials interaction, F(7.20, 182.59) = 1.07, p = 0.38, η²_p = 0.04. Conclusion: Our findings suggest that exercise may, potentially, attenuate memory distortion from memory reactivation. However, future work is needed to confirm these findings before any strong conclusions can be reached.

High-Intensity Acute Exercise and Directed Forgetting on Memory Function

Background and Objectives: Despite accumulating research demonstrating that acute exercise may enhance memory function, very little research has evaluated whether acute exercise can effectuate intentional directed forgetting (DF), an adaptative strategy to facilitate subsequent memory performance. Materials and Methods: A three-arm parallel-group randomized controlled intervention was employed. Participants were randomized into one of three groups, including: (1) exercise plus DF (Ex + DF), (2) DF (directed forgetting) only (DF) and (3) R (remember) only (R). The acute bout of exercise included 15 min of high-intensity treadmill exercise. The memory assessment involved the presentation of two-word lists. After encoding the first word list, participants were either instructed to forget all of those words (DF) or to remember them. Following this, participants encoded the second word list. Results: We observed a statistically significant main effect for list F(1, 57) = 12.27, p < 0.001, η²_p = 0.18, but no main effect for group F(2, 57) = 1.32, p = 0.27, η²_p = 0.04, or list by group interaction, F(2, 57) = 2.89, p = 0.06, η²_p = 0.09. Conclusions: This study demonstrates a directed forgetting effect in that cueing an individual to forget a previously encoded list of items facilitates memory performance on a subsequent list of items. However, we failed to demonstrate any beneficial effect of acute exercise in facilitating directed forgetting. These findings are discussed in the context of directed forgetting theories, particularly the attention inhibition mechanism, as well as the timing of the acute bout of exercise.