Air pollution linked to learning and memory problems, depression
July 6, 2011
Science Daily/Ohio State University
Long-term exposure to air pollution can lead to physical changes in the brain, as well as learning and memory problems and even depression, new research in mice suggests. While other studies have shown the damaging effects of polluted air on the heart and lungs, this is one of the first long-term studies to show the negative impact on the brain.
While other studies have shown the damaging effects of polluted air on the heart and lungs, this is one of the first long-term studies to show the negative impact on the brain, said Laura Fonken, lead author of the study and a doctoral student in neuroscience at Ohio State University.
"The results suggest prolonged exposure to polluted air can have visible, negative effects on the brain, which can lead to a variety of health problems," Fonken said. "This could have important and troubling implications for people who live and work in polluted urban areas around the world."
In other studies, several of the co-authors of this study from the Davis research center found that chronic exposure to polluted air leads to widespread inflammation in the body, which is linked to a variety of health problems in humans, including depression. This new study found evidence that this low-grade inflammation is evident in the hippocampus.
http://www.sciencedaily.com/releases/2011/07/110705071735.htm
Memory May Decline Rapidly Even in Stage Before Alzheimer's Disease
March 23, 2010
Science Daily/American Academy of Neurology
Memory and thinking skills may decline rapidly for people who have mild cognitive impairment, which is the stage before Alzheimer's disease when people have mild memory problems but no dementia symptoms, and even more rapidly when dementia begins, which is when Alzheimer's disease is usually diagnosed.
"These results show that we need to pay attention to this time before Alzheimer's disease is diagnosed, when people are just starting to have problems forgetting things," said study author Robert S. Wilson, PhD, of Rush University Medical Center in Chicago.
"The changes in rate of decline occur as the brain atrophies due to the disease, first mainly in the hippocampus during the initial symptomatic stage, referred to as mild cognitive impairment, then in the temporal, parietal and frontal cortex during the dementing illness phase of Alzheimer's disease," said David S. Knopman, MD, of the Mayo Clinic in Rochester, Minn., and Fellow of the American Academy of Neurology, who wrote an editorial accompanying the article.
http://www.sciencedaily.com/releases/2010/03/100322171008.htm
Tracking the source of 'selective attention' problems in brain-injured vets
May 9, 2014
Science Daily/Acoustical Society of America (ASA)
The obvious cognitive symptoms of minor traumatic brain injury can dissipate within a few days, but blast-exposed veterans may continue to have problems focusing attention on one sound source and ignoring others, an ability known as "selective auditory attention.” According to a new study, such apparent "hearing" problems actually may be caused by diffuse injury to the brain's prefrontal lobe.
An estimated 15-20 percent of U.S. troops returning from Iraq and Afghanistan suffer from some form of traumatic brain injury (TBI) sustained during their deployment, with most injuries caused by blast waves from exploded military ordnance. The obvious cognitive symptoms of minor TBI -- including learning and memory problems -- can dissipate within just a few days. But blast-exposed veterans may continue to have problems performing simple auditory tasks that require them to focus attention on one sound source and ignore others, an ability known as "selective auditory attention."
In the task, three different melody streams, each comprised of two notes, were simultaneously presented to the subjects from three different perceived directions (this variation in directionality was achieved by differing the timing of the signals that reached the left and right ears). The subjects were then asked to identify the "shape" of the melodies (i.e., "going up," "going down," or "zig-zagging") while their brain activity was measured by electrodes on the scalp.
"Whenever a new sound begins, the auditory cortex responds, encoding the sound onset," Bressler explains. "Attentional focus, however, changes the strength of this response: when a listener is attending to a particular sound source, the neural activity in response to that sound is greater." This change of the neural response occurs because the brain's "executive control" regions, located in the brain's prefrontal cortex, send signals to the auditory sensory regions of the brain, modulating their response.
The researchers found that blast-exposed veterans with TBI performed worse on the task -- that is, they had difficulty controlling auditory attention -- "and in all of the TBI veterans who performed well enough for us to measure their neural activity, 6 out of our 10 initial subjects, the brain response showed weak or no attention-related modulation of auditory responses," Bressler says.
"Our hope is that some of our findings can be used to develop methods to assess and quantify TBI, identifying specific factors that contribute to difficulties communicating in everyday settings," he says. "By identifying these factors on an individual basis, we may be able to define rehabilitation approaches and coping strategies tailored to the individual."
http://www.sciencedaily.com/releases/2014/05/140509110159.htm