Yawning may cool brain when needed

Yawning isn’t triggered because you’re bored, tired or need oxygen. Rather, yawning helps regulate the brain’s temperature, according to Gary Hack, of the University of Maryland School of Dentistry, and Andrew Gallup, of Princeton University.

"The brain is exquisitely sensitive to temperature changes and therefore must be protected from overheating," they said in a University of Maryland news release. "Brains, like computers, operate best when they are cool."

During yawning, the walls of the maxillary sinuses (located in the cheeks on each side of the nose) flex like bellows and help with brain cooling, according to the researchers.

They noted that the actual function of sinuses is still the subject of debate, and this theory may help clarify their purpose.

"Very little is understood about them, and little is agreed upon even by those who investigate them. Some scientists believe that they have no function at all," Hack said in the news release.

The researchers said their theory that yawning helps cool the brain has medical implications. For example, excessive yawning often precedes seizures in people with epilepsy and pain in people with migraine headaches.

Doctors may be able to use excessive yawning as a way to identify patients with conditions that affect temperature regulation.

"Excessive yawning appears to be symptomatic of conditions that increase brain and/or core temperature, such as central nervous system damage and sleep deprivation," Gallup said in the news release.

Smoking ‘rots’ brain, says King’s College study

Smoking “rots” the brain by damaging memory, learning and reasoning, according to researchers at King’s College London. A study of 8,800 people over 50 showed high blood pressure and being overweight also seemed to affect the brain, but to a lesser extent.

Scientists involved said people needed to be aware that lifestyles could damage the mind as well as the body. Their study was published in the journal Age and Ageing.

Researchers at King’s were investigating links between the likelihood of a heart attack or stroke and the state of the brain. Data about the health and lifestyle of a group of over-50s was collected and brain tests, such as making participants learn new words or name as many animals as they could in a minute, were also performed.

They were all tested again after four and then eight years. The results showed that the overall risk of a heart attack or stroke was “significantly associated with cognitive decline” with those at the highest risk showing the greatest decline.

It also said there was a “consistent association” between smoking and lower scores in the tests. One of the researchers, Dr Alex Dregan, said: “Cognitive decline becomes more common with ageing and for an increasing number of people interferes with daily functioning and well-being.

"We have identified a number of risk factors which could be associated with accelerated cognitive decline, all of which, could be modifiable." He added: "We need to make people aware of the need to do some lifestyle changes because of the risk of cognitive decline."

The researchers do not know how such a decline could affect people going about their daily life. They are also unsure whether the early drop in brain function could lead to conditions such as dementia.

(Image: Alamy)

A Fresh Look at Psychiatric Drugs

For several years, Henry Lester, Bren Professor of Biology at Caltech, and his colleagues have worked to understand nicotine addiction by repeatedly exposing nerve cells to the drug and studying the effects. At first glance, it’s a simple story: nicotine binds to, and activates, specific nicotine receptors on the surface of nerve cells within a few seconds of being inhaled. But nicotine addiction develops over weeks or months; and so the Caltech team wanted to know what changes in the nerve cell during that time, hidden from view.

The story that developed is that nicotine infiltrates deep into the cell, entering a protein-making structure called the endoplasmic reticulum and increasing its output of the same nicotine receptors. These receptors then travel to the cell’s surface. In other words, nicotine acts “inside out,” directing actions that ultimately fuel and support the body’s addiction to nicotine.

"That nicotine works ‘inside out’ was a surprise a few years ago," says Lester. "We originally thought that nicotine acted only from the outside in, and that a cascade of effects trickled down to the endoplasmic reticulum and the cell’s nucleus, slowly changing their function."

In a new research review paper, published in Biological Psychiatry, Lester—along with senior research fellow Julie M. Miwa and postdoctoral scholar Rahul Srinivasan—proposes that psychiatric medications may work in the same “inside-out” fashion—and that this process explains how it takes weeks rather than hours or days for patients to feel the full effect of such drugs.

"We’ve known what happens within minutes and hours after a person takes Prozac, for example," explains Lester. "The drug binds to serotonin uptake proteins on the cell surface, and prevents the neurotransmitter serotonin from being reabsorbed by the cell. That’s why we call Prozac a selective serotonin reuptake inhibitor, or SSRI." While the new hypothesis preserves that idea, it also presents several arguments for the idea that the drugs also enter into the bodies of the nerve cells themselves.

Researchers Find Evidence That Brain Compensates After Traumatic Injury

Researchers at Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center have found that a special magnetic resonance imaging (MRI) technique may be able to predict which patients who have experienced concussions will improve. The results, which were presented at the annual meeting of the Radiological Society of North America (RSNA), suggest that, in some patients, the brain may change to compensate for the damage caused by the injury.

“This finding could lead to strategies for preventing and repairing the damage that accompanies traumatic brain injury,” said Michael Lipton, M.D., Ph.D., who led the study and is associate director of the Gruss Magnetic Resonance Research Center at Einstein and medical director of MRI services at Montefiore, the University Hospital and academic medical center for Einstein.

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“In a traumatic brain injury, it’s not one specific area that is affected but multiple areas of the brain which are interconnected by axons,” said Dr. Lipton, who is also associate professor of radiology, of psychiatry and behavioral sciences, and in the Dominick P. Purpura Department of Neuroscience at Einstein. “Abnormally low FA within white matter has been correlated with cognitive impairment in concussion patients. We believe that high FA is evidence not of axonal injury, but of brain changes that are occurring in response to the trauma.”

Reading, Writing and Playing Games May Help Aging Brains Stay Healthy

Mental activities like reading and writing can preserve structural integrity in the brains of older people, according to a new study presented at the annual meeting of the Radiological Society of North America (RSNA).

While previous research has shown an association between late-life cognitive activity and better mental acuity, the new study from Konstantinos Arfanakis, Ph.D., and colleagues from Rush University Medical Center and Illinois Institute of Technology in Chicago studied what effect late-life cognitive activity might have on the brain’s white matter, which is composed of nerve fibers, or axons, that transmit information throughout the brain.

"Reading the newspaper, writing letters, visiting a library, attending a play or playing games, such as chess or checkers, are all simple activities that can contribute to a healthier brain," Dr. Arfanakis said.

The researchers used a magnetic resonance imaging (MRI) method known as diffusion tensor imaging (DTI) to generate data on diffusion anisotropy, a measure of how water molecules move through the brain. In white matter, diffusion anisotropy exploits the fact that water moves more easily in a direction parallel to the brain’s axons, and less easily perpendicular to the axons, because it is impeded by structures such as axonal membranes and myelin. “This difference in the diffusion rates along different directions increases diffusion anisotropy values,” Dr. Arfanakis said. “Diffusion anisotropy is higher when more diffusion is happening in one direction compared to others.”

The anisotropy values in white matter drop, however, with aging, injury and disease.

"In healthy white matter tissue, water can’t move as much in directions perpendicular to the nerve fibers," Dr. Arfanakis said. "But if, for example, you have lower neuronal density or less myelin, then the water has more freedom to move perpendicular to the fibers, so you would have reduced diffusion anisotropy. Lower diffusion anisotropy values are consistent with aging."

(Image credit: Flickr.com, Courtesy of Luis de Bethencourt)

Alzheimer’s Disease in Mice Alleviated Promising Therapeutic Approach for Humans

Pathological changes typical of Alzheimer’s disease were significantly reduced in mice by blockade of an immune system transmitter. A research team from Charité - Universitätsmedizin Berlin and the University of Zurich has just published a new therapeutic approach in fighting Alzheimer’s disease in the current issue of Nature Medicine. This approach promises potential in prevention, as well as in cases where the disease has already set in.

The accumulation of particular abnormal proteins, including amyloid-ß (Aβ) among others, in patients’ brains plays a central role in this disease. Prof. Frank Heppner from the Department of Neuropathology at Charité and his colleague Prof. Burkhard Becher from the Institute for Experimental Immunology at the University of Zurich were able to show that turning off particular cytokines (immune system signal transmitters) reduced the Alzheimer’s typical amyloid-ß deposits in mice with the disease. As a result, the strongest effects were demonstrated after reducing amyloid-ß by approximately 65 percent, when the immune molecule p40 was affected, which is a component of the cytokines interleukin (IL)-12 and -23.

Separation of a cell

This illustration shows a cell undergoing mitosis or “cell division.” The cell membrane is shown in blue, and the cell’s chromosomes are shown in yellow. Mitosis is a well-studied and well-imaged phenomenon in two-dimensional images, but it’s never before been seen quite like this. What makes this image special is the use of a new fluorescent protein called MiniSOG, shown flying out of the cell.

Image courtesy of Andrew Noske and Thomas Deerinck (National Center for Microscopy and Imaging Research, University of California, San Diego); Horng Ou and Clodagh O’Shea (Salk Institute).

(Source: MSNBC)