Effects of exercise on proactive interference in memory: potential neuroplasticity and neurochemical mechanisms

Potential Link Between Exercise and N-Methyl-D-Aspartate Glutamate Receptors in Alcohol Use Disorder: Implications for Therapeutic Strategies

Alcohol use disorder (AUD) is a significant risk factor, accounting for approximately 13% of all deaths in the US. AUD not only destroys families but also causes economic losses due to reduced productivity, absenteeism, and healthcare expenses. Statistics revealing the sustained number of individuals affected by AUD over the years underscore the need for further understanding of the underlying pathophysiology to advance novel therapeutic strategies. Previous research has implicated the limbic brain regions N-methyl-D-aspartate glutamate receptors (NMDAR) in the emotional and behavioral effects of AUD. Given that aerobic exercise can modulate NMDAR activity and sensitivity to alcohol, this review presents a summary of clinical and basic science studies on NMDAR levels induced by alcohol consumption, as well as acute and protracted withdrawal, highlighting the potential role of aerobic exercise as an adjunctive therapy for AUD. Based on our findings, the utility of exercise in the modulation of reward-linked receptors and AUD may be mediated by its effects on NMDA signaling. These data support further consideration of the potential of aerobic exercise as a promising adjunctive therapy for AUD.

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.

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.

A Brief Version of the LASSI-L Detects Prodromal Alzheimer's Disease States

BACKGROUND

The Loewenstein-Acevedo Scales for Semantic Interference and Learning (LASSI-L) is an increasingly utilized cognitive stress test designed to identify early cognitive changes associated with incipient neurodegenerative disease.

OBJECTIVE

To examine previously derived cut-points for cognitively unimpaired older adults that were suggestive of performance impairment on multiple subscales of the LASSI-L. These cut-points were applied to a new sample of older adults who were cognitive healthy controls (HC: n = 26) and those on the Alzheimer's disease (AD) continuum from early stage mild cognitive impairment (EMCI: n = 28), late stage MCI (LMCI: n = 18) to mild AD (AD: n = 27).

METHODS

All participants were administered the LASSI-L. All cognitively impaired participants were PET amyloid positive which likely reflects underlying AD neuropathology, while cognitively normal counterparts were deemed to have amyloid negative scans.

RESULTS

There was a monotonic relationship between the number of deficits on LASSI-L subscales and independent classification of study groups with greater severity of cognitive impairment. Importantly, taken together, impairment on maximum learning ability and measures of proactive semantic interference (both reflected by cued recall and intrusion errors) correctly classified 74.1% of EMCI, 94.4% of LMCI, and 96.3% of AD. Only 7.7% of HC were incorrectly classified as having impairments.

CONCLUSION

A modest number of LASSI-L subscales taking approximately 8 minutes to administer, had excellent discriminative ability using established cut-offs among individuals with presumptive stages of AD. This has potential implications for both clinical practice and clinical research settings targeting AD during early prodromal stages.

Transgenerational Effects of Traumatic Historical Events on the Incidence of Metabolic Syndrome/ Nonalcoholic Fatty Liver Disease in the Romanian Population

Concerns for successful public health management are integrated into the core business of government-responsible institutions. Diseases associated with metabolic syndrome are very common in the Romanian population. In our study, we focused on the cardiovascular and non-alcoholic fatty liver disease (NAFLD). The article starts from the hypothesis that the increased incidence of such diseases is determined today by the cumulative effect of traumatic historical events such as the famine of 1946-47 and the communist political regime specific to the 80s and 90s. This study aims to present the arguments that indicate the correlation of economic variables whose variation can be easily determined by traumatic events that affected the economy, with variables able to measure the incidence of various diseases usually associated with metabolic syndrome or NAFLD. A series of statistical data were analyzed from the official sources available in the form of consecutive value data for the 1995-2018 period. The results highlighted a direct and strong link between the variable gross domestic product (GDP) per capita in USD, 2011 purchasing power parity (PPP) and specific incidence of circulatory, nutritional endocrine and metabolic diseases, as well as a strong and inverse link between GDP and infant's deaths per 1000 live births. Conclusions highlight that the effects of traumatic historical events must be made aware through medical education of the population, supporting the idea according to which the incidence of various metabolic diseases is greater for the offspring of those who have actively suffered during such events.