Using the delayed spatial alternation task to assess environmentally associated changes in working memory in very young children

The role of exercise in restoring executive function: a comparison of tobacco-exposed college athletes and sedentary students

Introduction

As adolescent smoking rates rise, its impact on cognitive function has drawn greater attention. This study explores whether exercise can mitigate the negative effects of smoking on executive function in male college students.

Methods

Sixty male college students were divided into four groups (n = 15 each): sedentary smokers, sedentary nonsmokers, athletic smokers, and athletic nonsmokers. All participants completed the Eriksen flanker task, with prefrontal cortex activation measured using functional near-infrared spectroscopy. After the baseline test, all sedentary students engaged in 33 min of high-intensity interval training, followed by the same procedures as in the pre-test.

Results

In the flanker task, college athletes exhibited superior executive function compared to sedentary students, with higher accuracy (p = 0.042), faster reaction times (p = 0.002), and more pronounced brain activation (p = 0.048). Post-exercise, reaction times improved significantly in sedentary groups (p < 0.05). Smoking impaired executive function both before and after exercise, with smokers showing lower accuracy (p < 0.001), slower reaction times (p < 0.001), and diminished brain activation (p < 0.001) compared to nonsmokers.

Discussion

Engaging in acute aerobic exercise may improve executive function in sedentary smokers. Exercise may help mitigate smoking-related declines in executive function among college students.

A comprehensive analysis of children's blood lead levels in Latin America and the Caribbean over the last eight years: Progress and recommendations

In 2017 we published a review on blood lead levels (BLL) in children from Latin America and the Caribbean (LAC) for data available up to 14th of March 2014 and recommended the identification and control of "lead hot spots". In the present study, an evaluation of progress toward reducing BLL in the region was carried out. A systematic review of the latest literature on lead exposure in the LAC region held on the PubMed, Web of Science and LILACS databases (January 2014 to March 2022) was conducted using the PRISMA methodology. Only original papers published in peer-reviewed English, Spanish, or Portuguese journals were eligible. A total of 558 papers were retrieved, 77 of which met the selection criteria and 31 (40.25 %) were carried out in Mexico. The prevalence of children with BLL above 10 μg. dL-1 was 22.08 % in the previous review versus 6.78 % in the current study. In the present review, the prevalence of children with BLL above 5 μg. dL-1 was 29.62 %, and only one study reported a BLL prevalence rate between 3.3 and 5 μg. dL-1. The highest BLLs were associated with well-known sources or occupational exposures. The number of countries (n = 13) that published data on BLL in children was lower compared to the previous review (n = 16). Most studies were conducted in areas with known lead exposure sources, similar to the earlier review. The percentage of children at risk of lead poisoning in the region remains unknown because few studies have published data on environmental exposure levels and most samples were relatively small. The recommendation to identify and control sources of lead exposure was maintained, while further suggestions for establishing a systematic public health surveillance system for lead were proposed to help reduce the knowledge gap and inform public health policy-making in LAC.

The Role of Nonhuman Primates in Neurotoxicology Research: Preclinical Models and Experimental Methods

Although noteworthy progress has been made in developing alternatives to animal testing, nonhuman primates still play a critical role in advancing biomedical research and will likely do so for many years. Core similarities between monkeys and humans in genetics, physiology, reproduction, development, and behavior make them excellent models for translational studies relevant to human health. This unit is designed to specifically address the role of nonhuman primates in neurotoxicology research and outlines the specialized assessments that can be used to measure exposure-related changes at the structural, chemical, cellular, molecular, and functional levels. © 2023 Wiley Periodicals LLC.

Exposure to environmental neurotoxic substances and neurodevelopment in children from Latin America and the Caribbean

Environmental (and occupational) exposure to neurotoxic substances is a worldwide problem that can affect children's neurodevelopment (ND). In Latin American and Caribbean (LAC) countries there are over 300 million children living under the threat of neurodevelopmental delays due to toxic environmental exposure. Large industrial centers, intense mining and agricultural activities, along with changing complex ecosystems constitute a mosaic that drives contamination of air, water and the food chain. Neurotoxic contaminants such as pesticides (organochlorines, organophosphates, carbamates, pyrethroids, neonicotinoids, and manganese fungicides), chemicals of industrial use (phthalates), and metals (Hg, Pb, Al, As, F, Cd, Mo, Mn) are at the center of environmental exposure studies. Exposure to neurotoxic substances singly or in combination with other compounds or socioeconomic stressors (maternal education, socio-economic and nutritional status) intertwined with occupational and para-occupational exposure can affect ND (motor, cognition, behavior) of children. Significant negative effects of pesticides and neurotoxic elements on ND were found in all studied countries, affecting especially the less-privileged children from laboring families. Studies showed that exposures to the neurotoxicants in human milk are secondary to their more lasting effects during prenatal exposure. This review integrates exposure (prenatal and breastfeeding), metabolism, and ND effects of neurotoxicants. It highlights the overwhelming evidence showing that current levels of exposures are hazardous and detrimental to children's ND in LAC countries. The evidence indicates that a reduction in neurotoxicant exposure is essential to protect children's ND. Therefore, it is urgent to adopt policies and actions that prevent and remediate region-specific children's ND issues.