Neuroscience
Latif
articalreaserch2.docxLatif Abdullah
October 29th, 2019
BIO 310
Air Pollution
Researchers indicated that living in areas of high pollution has serious long-term health effects. Living in these areas during childhood and adolescence lead to diminished mental capacity and an increased risk of brain damage. People of all ages who live in high pollution areas for extended periods place themselves at increased risk of various neurological disorder. In fact, both air pollution and heavy mental pollution have been implicated as having negative effects on central nerves system functionality. The ability of pollutants to affect the neurophislophy of individuals after the structure of the CNS has become mostly stabilized is an example of negative neuroplasticity. In addition, by permanently affecting vascular structures in the brain, air pollution can have serious effects on neural functioning and neural matter. In dogs air pollution shows to cause damage to the CNS by altering the blood–brain barrier, causing neurons in the cerebral cortex to degenerate, destroying glial cells found in white matter, and by causing neurofibrillary tangles. (scientist magazine)
Furthermore, Epidemiologists, psychologists, and neuroscientists are now working to fill in the gaps in knowledge of how air pollution might contribute to these less visible effects on human health, both by documenting the cognitive changes occurring in human populations exposed to air pollution, and by looking inside human and animal brains to try to decipher the underlying mechanisms. “This is the beginnings of a whole new field,” says Caleb Finch, a gerontologist at the University of Southern California (USC). “This is like tobacco research and cancer 70 years ago.”
According to Yale School of Public Health economist Xi Chen got interested in how poor air quality can affect the brain years ago as he started thinking about pollution’s cost to human society. To date, most researchers have focused on evaluating air pollution’s effects on mortality or respiratory health. But changes to cognition and social behavior also have profound influences on a person’s daily life, from financial decision making to relationships, Chen argues. “Society can lose even more with [this] more indirect link.
In addition, A couple years ago, Chen teamed up with colleagues in Beijing to assess such effects in adults exposed to air pollution across China. The researchers used the China Family Panel Studies—a longitudinal dataset that includes verbal and math test scores from more than 20,000 adults across the country between 2010 and 2014—and estimated air pollution exposure for each participant’s town on the days of testing using national records of nitrogen dioxide, sulfur dioxide, and particulate matter levels. They also assembled data on other variables such as daily weather and the participants’ educational background. “Air is a collective good—everyone consumes it.” (Xi Chen, Yale University). The analysis revealed that the higher a person’s estimated exposure to air pollution, the greater the decline in his test scores over the study period. Less educated men over 45 years old were the worst-affected group, and verbal scores were hit harder than math scores. The large sample size and the multiple time points suggest it’s more than just a correlation, says Chen. “We are more confident to say that our finding is a causal effect of air pollution on cognitive functioning.”
Also, the research team, led by Xiaobo Zhang of Peking University, found that exposure to increased levels of sulfur dioxide, nitrogen dioxide, and particulates smaller than 10 μm (PM10) were tied to lower verbal test scores (math scores to a lesser extent, and only when people were exposed for weeks or more). Exposure over longer periods of time correlated with larger drops in performance, and the effects were most pronounced for men and older people.
Furthermore, USC researchers reported that elderly women of European ancestry living in areas of the US with levels of particulate matter that exceeded the US Environmental Protection Agency standard of 12 μg/m3 were 81 percent more likely to experience cognitive decline generally and 92 percent more likely to suffer dementia than if they had been living with exposure below that limit. The increased risk in polluted areas—a finding that mirrors the results from cohorts in London and Taiwan—was particularly high for people with dementia- or Alzheimer’s-associated genetic variants such as APOE Ε4, hinting that air pollution might have more-severe effects in those genetically predisposed to neurodegeneration.
According to the Scientist Magazine, several labs are trying to minimize such limitations by collecting real-time pollution levels and other environmental data, rather than estimating exposure from existing datasets. ISGlobal, for example, plans to recruit 1,200 pregnant women for an in-depth look at the connections between prenatal exposure to air pollution and childhood health. Participants will monitor their surroundings with “backpacks, sensors at home, GPS, measures of physical activity, measures of noise,” and so on, Sunyer says.
In the other hand, the biological factors involved in smoking relate to how the brain responds to nicotine. When a person smokes, a dose of nicotine reaches the brain within about ten seconds. At first, nicotine improves mood and concentration, decreases anger and stress, relaxes muscles and reduces appetite.
In fact, a research has shown that exposure to secondhand smoke increases the likelihood that children will become teenage smokers and makes it more difficult for adult smokers to quit. Laboratory studies give some insight into the mechanisms at work. Nicotine, a chemical found in all tobacco products, is addictive. Long-term exposure to cigarette smoke leads to nicotine dependence in rats and an increase in nicotinic acetylcholine receptors (nAChRs) in the brain.
Furthermore, A team led by Dr. Arthur Brody of the University of California, Los Angeles, set out to study how secondhand smoke affects the human brain. They used an imaging technique to visualize when nicotine occupies brain nAChRs. The method depends on a special tracer molecule that binds specifically to nAChRs and can be detected by positron emission tomography (PET). Nicotine displaces the tracer molecule at the receptor, so the more nicotine that binds to nAChRs, the lower the tracer signals.
The scientists recruited 24 young adult participants — 11 moderately dependent cigarette smokers and 13 nonsmokers. The participants were given the tracer molecule and then asked to sit in the passenger’s seat of a car for 1 hour. They did this twice, a week apart. In 1 session, they were exposed to moderate secondhand smoke; in the other they weren’t. Afterward, they underwent PET scans. The study, which was partly funded by NIH’s National Institute on Drug Abuse (NIDA), appeared online on May 2, 2011, in Archives of General Psychiatry.
Reference:
Xi Chen, PhDAssistant Professor of Public Health (Health Policy) and Assistant Professor in the Institution for Social and Policy Studies; Affiliated Faculty, Department of Economics
Dr. Arthur Brody of the University of California, Los Angeles, Professor In-Residence, Psychiatry and Biobehavioral Sciences, Hatos Center for Neuropharmacology, Member, Brain Research Institute, Neuroscience GPB Home Area
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