Can Boosting Immunity Make You Smarter?

After spending a few days in bed with the flu, you may have felt a bit stupid. It is a common sensation, that your sickness is slowing down your brain. At first blush, though, it doesn’t make much sense. For one thing, flu viruses infect the lining of the airways, not the neurons in our brains. For another, the brain is walled off from the rest of the body by a series of microscopic defenses collectively known as the blood-brain barrier. It blocks most viruses and bacteria while allowing essential molecules like glucose to slip through. What ails the body, in other words, shouldn’t interfere with our thinking.

But over the past decade, Jonathan Kipnis, a neuroimmunologist in the University of Virginia School of Medicine’s department of neuroscience, has discovered a possible link, a modern twist on the age-old notion of the body-mind connection. His research suggests that the immune system engages the brain in an intricate dialogue that can influence our thought processes, coaxing our brains to work at their best.

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Mediterranean diet may not protect brain

Hopes that a Mediterranean diet would be as good for the head as it is for the heart may have been dampened by a French study that found little benefit for aging brains from the diet rich in fruit, vegetables, whole grains, nuts, wine and olive oil.

The study, published in the American Journal of Clinical Nutrition, looked at the participants’ dietary patterns in middle age and measured their cognitive performance at around age 65, but found no connection between Mediterranean eating and mental performance.

"Our study does not support the hypothesis of a significant neuroprotective effect of a (Mediterranean diet) on cognitive function," writes study leader Emmanuelle Kesse-Guyot at the nutritional epidemiology research centre of the French national health research agency INSERM.

It’s been suggested that the “good” fats in the Mediterranean diet might benefit the brain directly, or that low saturated fats and high fiber in the diet could help stave off cognitive decline indirectly by keeping blood vessels healthy.

Previous research has seemed to uphold that premise.

One large study in the US Midwest, for example, found that people in their 60s and older who ate a mostly Mediterranean diet were less prone to mental decline as they aged. Another study of residents of Manhattan linked a Mediterranean-style diet to a 40 per cent lower risk of Alzheimer’s disease.

No significant difference

Researchers in the French study used data on 3083 people who were followed from the mid-1990s, when they were at least 45 years old.

At the beginning of the study, participants recorded what they ate over one 24-hour period every two months, for a total of six dietary record samples per year. Then, between 2007 and 2009 when the participants were about 65 years old, their memory and other mental abilities were measured.

Researchers then separated participants into three categories depending on how closely they adhered to a Mediterranean-style diet, and compared their mental ability test scores.

Overall, they found that people who ate a diet closest to the Mediterranean ideal performed about the same as those who ate a non-restricted diet.

Associate Professor Nikos Scarmeas, of New York’s Columbia University Medical Center, was not involved with the study but has researched the effects of food on brain health. He says it’s important to note that the new study had some limitations.

For instance, researchers only tested the participants’ mental abilities once, making it impossible to track whether they got better or worse over time, adds Scarmeas.

"We don’t have the strong evidence to go and tell people, ‘Listen, if you follow this diet, it will improve cognition’," he says.

(Image: mediterraneandiet.com)

Carbon nanotubes could one day enhance your brain

Swiss Federal Institute of Technology scientists found that carbon nanotubes offer the potential to establish functional links between neurons that could fight disease and enhance our brains.

The human brain contains about 10 billion neurons, each connecting to other nerve cells through 10,000 or more synapses. Neurons process signals from these connections, then produce output commands that stimulate biological functions, everything from breathing to thinking to kissing.

Many scientists consider our brain similar to a massive parallel processing system, a supercomputer. However, when that computer breaks down we can lose memory or worse, develop sicknesses such as Parkinson’s, Alzheimer’s or other forms of dementia.

Unfortunately, we can’t take our brain down to Wall Mart or Fry’s for an upgrade; however, what if we could put something in our brain that would enhance the signal processing capabilities of individual neurons. Swiss scientists say they’ve done just that with carbon nanotubes.

The forward-thinking research team; led by Michel Giugliano, now a professor at the University of Antwerp, created carbon nanotube scaffolds, which serve as electrical bypass circuitry, to not only repair faulty neural networks, but also enhance performance of healthy cells.

Although there are still some engineering hurdles to overcome, the scientists see huge potential for strengthening neural networks with carbon nanotubes. This procedure could allow brain-machine interfaces for neuroprosthetics that process sight, sound, smell and motion.

Such circuits might be used, for instance, to veto epileptic attacks before they occur, perform spinal bypasses around injuries, and repair or enhance normal cognitive functions. In the not-too-distant future, non-biological nano-neurons could enable our brains to process information much faster than today’s biological brains can.

Even the Smallest Possible Stroke Can Damage Brain Tissue and Impair Cognitive Function

Blocking a single tiny blood vessel in the brain can harm neural tissue and even alter behavior, a new study from the University of California, San Diego has shown. But these consequences can be mitigated by a drug already in use, suggesting treatment that could slow the progress of dementia associated with cumulative damage to miniscule blood vessels that feed brain cells. The team reports their results in the December 16 advance online edition of Nature Neuroscience.

"The brain is incredibly dense with vasculature. It was surprising that blocking one small vessel could have a discernable impact on the behavior of a rat," said Andy Y. Shih, lead author of the paper who completed this work as a postdoctoral fellow in physics at UC San Diego. Shih is now an assistant professor at the Medical University of South Carolina.

Working with rats, Shih and colleagues used laser light to clot blood at precise points within small blood vessels that dive from the surface of the brain to penetrate neural tissue. When they looked at the brains up to a week later, they saw tiny holes reminiscent of the widespread damage often seen when the brains of patients with dementia are examined as a part of an autopsy.

These micro-lesions are too small to be detected with conventional MRI scans, which have a resolution of about a millimeter. Nearly two dozen of these small vessels enter the brain from a square millimeter area of the surface of the brain.

"It’s controversial whether that sort of damage has consequences, although the tide of evidence has been growing as human diagnostics improve," said David Kleinfeld, professor of physics and neurobiology, who leads the research group.

To see whether such minute damage could change behavior, the scientists trained thirsty rats to leap from one platform to another in the dark to get water.

The rats readily jump if they can reach the second platform with a paw or their snout, or stretch farther to touch it with their whiskers. Many rats can be trained to rely on a single whisker if the others are clipped, but if they can’t feel the far platform, they won’t budge.

"The whiskers line up in rows and each one is linked to a specific spot in the brain," Shih said. "By training them to use just one whisker, we were able to distill a behavior down to a very small part of the brain."

When Shih blocked single microvessels feeding a column of brain cells that respond to signals from the remaining whisker, the rats still crossed to the far platform when the gap was small. But when it widened beyond the reach of their snouts, they quit.

The FDA-approved drug memantine, prescribed to slow one aspect of memory decline associated with Alzheimer’s disease, ameliorated these effects. Rats that received the drug jumped whisker-wide gaps, and their brains showed fewer signs of damage.

"This data shows us, for the first time, that even a tiny stroke can lead to disability," said Patrick D. Lyden, a co-author of the study and chair of the department of neurology at Cedars-Sinai Medical Center in Los Angeles. "I am afraid that tiny strokes in our patients contribute—over the long term—to illness such as dementia and Alzheimer’s disease," he said, adding that "better tools will be required to tell whether human patients suffer memory effects from the smallest strokes."

“We used powerful tools from biological physics, many developed in Kleinfeld’s laboratory at UC San Diego, to link stroke to dementia on the unprecedented small scale of single vessels and cells,” Shih said. “At my new position at MUSC, I plan to work on ways to improve the detection of micro-lesions in human patients with MRI. This way clinicians may be able to diagnose and treat dementia earlier.”

Aerobic exercise boosts brain power in elderly

Evidence for the importance of physical activity in keeping and potentially improving cognitive function throughout life was found in a literature review in Psychonomic Bulletin & Review by Hayley Guiney and Liana Machado from the University of Otago, New Zealand.

• Cognitive functions such as task switching, selective attention, and working memory appear to benefit from aerobic exercise. Studies in older adults reviewed by the authors consistently found that fitter individuals scored better in mental tests than their unfit peers.
  
  
• Scores in mental tests improved in participants who were assigned to an aerobic exercise regimen compared to those assigned to stretch and tone classes.
  
  
• Exercise has been found to positively affect mental tasks relating to activities such as driving, an activity where age is often seen as a limiting factor.
  
  
• MRI studies of aging have shown that, as compared with unfit, highly fit older adults exhibit less age-related atrophy in the prefrontal and temporal cortices; preserved neural tracts connecting the prefrontal cortex to other regions of the brain; superior white matter integrity in the corpus callosum; greater gray matter density in the frontal, temporal, and parietal cortices; and greater hippocampal volumes.
  
  
• Physically active older adults have both higher circulating neurotrophin levels and gray matter volumes in the prefrontal and cingulate cortex.
  
  
• These results were not replicated in children or young adults, except for memory tasks. Both the updating of working memory and the volume of information which could be held was also better in young fitter individuals or those put on an aerobic exercise regime. “Although the evidence to date supports a wider range of executive functions benefiting from regular exercise in older adults, the relative lack of supportive evidence in young adults and children may, in part, reflect a poverty of studies, especially controlled trials, in these age groups,” the authors suggest.

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.

…

“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.”