Effects of flu on brain

Group of researchers from Germany and USA studied effects of influenza virus on brain cells. The study published in the Journal of Neuroscience finds that female mice infected with two different strains of the flu shows changes in structure and function of the hippocampus. These changes persist for one month after infection.

The long-term effect of influenza A virus infection on glial cell density and activation status within the hippocampal subregions. The neurotropic H7N7 IAV infection induced an increased microglia density in all hippocampal subregions at 30 days post-infection. Credit: Hosseini et al., JNeurosci

Influenza could present with neurological symptoms in some cases. So far research has not studied the long-term effect of the virus in the brain.

Researchers investigated three different influenza strains (H1N1, H3N2, H7N7). Two of these strains, H3N2 and H7N7, caused memory impairments that were associated with structural changes such as dendritic spine loss to neurons in the hippocampus. These changes persist up to 30 days following infection and fully recovered in 120 days.

Researchers feel that in the acute phase of influenza infection, this neuroinflammation in hippocampus alters the neuronal morphology and can cause cognitive deficits. The results also provide evidence that neuroinflammation induced by influenza virus infection can lead to longer-lasting alterations in neuronal connectivity with associated impairments in spatial memory formation.

Citation: Hosseini, Shirin, Esther Wilk, Kristin Michaelsen-Preusse, Ingo Gerhauser, Wolfgang Baumgärtner, Robert Geffers, Klaus Schughart, and Martin Korte. “Long-term neuroinflammation induced by influenza A virus infection and the impact on hippocampal neuron morphology and function.” The Journal of Neuroscience, 2018, 1740-17. doi:10.1523/jneurosci.1740-17.2018.

Research funding: Ministry of Science and Culture of Lower Saxony, Helmholtz-Association.

Adapted from press release by the Society for Neuroscience.

Research shows musicians have faster reaction to sensory stimuli

According to a new study by Université de Montréal’s School of Speech-Language Pathology and Audiology, part of UdeM’s medical faculty learning to play musical instrument help elderly to react faster and to stay alerted. The study is published in journal Brain and Cognition.  The study shows that musicians have faster reaction times to sensory stimuli than non-musicians have.

Credit: Pexels/pixabay

According to lead researcher Simon Landry, this study has implications for preventing some effects of aging. “The more we know about the impact of music on really basic sensory processes, the more we can apply musical training to individuals who might have slower reaction times,” Landry said.

In his study, co-authored with his thesis advisor, audiology associate professor François Champoux, Landry compared the reaction times of 16 musicians and 19 non-musicians. Research subjects sat in a quiet, well-lit room with one hand on a computer mouse and the index finger of the other on a vibrotactile device, a small box that vibrated intermittently. They were told to click on the mouse when they heard a sound (a burst of white noise) from the speakers in front of them, or when the box vibrated, or when both happened.

Each of the three stimulations – audio, tactile and audio-tactile – was done 180 times. The subjects wore earplugs to mask any buzzing “audio clue” when the box vibrated. “We found significantly faster reaction times with musicians for auditory, tactile and audio-tactile stimulations,” Landry writes in his study.

“These results suggest for the first time that long-term musical training reduces simple non-musical auditory, tactile and multisensory reaction times.” The musicians were recruited from UdeM’s music faculty, started playing between ages 3 and 10, and had at least seven years of training. There were eight pianists, 3 violinists, two percussionists, one double bassist, one harpist and one viola player. All but one (a violinist) also mastered a second instrument or more. The non-musicians were students at the School of Speech-Language Pathology. As with the musicians, roughly half were undergraduates and half graduates.

Landry, whose research interest is in how sound and touch interact, said his study adds to previous ones that looked at how musicians’ brains process sensory illusions. “The idea is to better understand how playing a musical instrument affects the senses in a way that is not related to music,” he said of his study.

Citation: Landry, Simon P., and François Champoux. “Musicians react faster and are better multisensory integrators.” Brain and Cognition 111 (2017): 156-162.
DOI: 10.1016/j.bandc.2016.12.001
Research funding: Canadian Institutes of Health Research, Fonds de recherche Québec – Santé, and Natural Sciences and Engineering Research Council of Canada.
Adapted from press release by the Université de Montréal.

Research shows new understanding on how working memory is stored in brain

Working memory is integral part of  cognitive process and it involves short term memory. Previous research shown that  it depends on sustained, elevated brain activity. However researchers at University of Wisconsin-Madison have shown that humans can hold information in working memory via “activity-silent” synaptic mechanisms. Their study is published in journal Science.

According to Brad Postle, a psychology professor at the University of Wisconsin-Madison, it’s important to note that most people feel they are able to concentrate on a lot more than their working memory can actually hold. It’s a bit like vision, in which it feels like we’re seeing everything in our field of view, but details slip away unless you re-focus on them regularly.

“The notion that you’re aware of everything all the time is a sort of illusion your consciousness creates,” says Postle. “That is true for thinking, too. You have the impression that you’re thinking of a lot of things at once, holding them all in your mind. But lots of research shows us you’re probably only actually attending to are conscious of in any given moment just a very small number of things.”

Postle’s group conducted a series of experiments in which people were asked to remember two items representing different types of information (they used words, faces and directions of motion) because they’d be tested on their memories.

When the researchers gave their subjects a cue as to the type of question coming a face, for example, instead of a word the electrical activity and blood flow in the brain associated with the word memory disappeared. But if a second cue came letting the subject know they would now be asked about that word, the brain activity would jump back up to a level indicating it was the focus of attention.

“People have always thought neurons would have to keep firing to hold something in memory. Most models of the brain assume that,” says Postle. “But we’re watching people remember things almost perfectly without showing any of the activity that would come with a neuron firing. The fact that you’re able to bring it back at all in this example proves it’s not gone. It’s just that we can’t see evidence for its active retention in the brain.”

The researchers were also able to bring the seemingly abandoned items back to mind without cueing their subjects. Using a technique called transcranial magnetic stimulation (TMS) to apply a focused electromagnetic field to a precise part of the brain involved in storing the word, they could trigger the sort of brain activity representative of focused attention.

Furthermore, if they cued their research subjects to focus on a face (causing brain activity associated with the word to drop off), a well-timed pulse of transcranial magnetic stimulation would snap the stowed memory back into attention, and prompt the subjects to incorrectly think that they had been cued to focus on the word.

“We think that memory is there, but not active,” says Postle, whose work is supported by the National Institute of Mental Health. “More than just showing us it’s there, the TMS can actually make that memory temporarily active again.”

The study conducted by Postle with Nathan Rose, a former UW-Madison postdoctoral researcher who is now a professor of psychology at the University of Notre Dame, and UW-Madison graduate students in psychology and neuroscience suggests a state of memory apart from the spotlight attention of active working memory and the deep storage of more significant things in long-term memory.

“What’s still unknown here is how the brain determines what falls away, and what enables you to retrieve things in the short-term if you need them,” Postle says.

Studying how the brain apportions attention could eventually influence the way we understand and treat mental health disorders such as schizophrenia, in which patients focus on hallucinations instead of reality, and depression, which seems strongly related to spending an unhealthy amount of time dwelling on negative things.

“We are making some interesting progress with very basic research,” says Postle. “But you can picture a point at which this work could help people control their attention, choose what they think about, and manage or overcome some very serious problems associated with a lack of control.”

Citation: “Reactivation of latent working memories with transcranial magnetic stimulation”. Nathan S. Rose, Joshua J. LaRocque, Adam C. Riggall, Olivia Gosseries, Michael J. Starrett, Emma E. Meyering & Bradley R. Postle. Science 2016 vol: 354 (6316).
DOI: 10.1126/science.aah7011
Adapted from press release by University of Wisconsin-Madison.

Research finds that better cognitive function is associated with higher physical activity and healthy eating habits (fruits and vegetables)

Findings published this week in the Journal of Public Health reveal that both younger and older Canadian adults who engage in regular physical activity, consume more fruits and vegetables and are normal weight or overweight have overall better cognitive functioning.

Regular engagement in physical activity and healthy eating has long been associated with a reduced risk for a range of chronic conditions. For older adults, there is a growing body of evidence that exercising may delay the onset of cognitive decline. Similarly, compounds found in fruits and vegetables have been shown to fight illnesses and help maintain healthy processes in the body. Given the increasing rates of inactivity and obesity in the world, researchers are interested in understanding the relationship between clusters of risk factors for cognitive decline, and how lifestyle factors might help prevent or delay it.

Previous studies in Spain and Korea have shown that older adults who eat more fruits and vegetables perform better in mentally stimulating activities than older adults who report eating a lower amount. However, very few studies have investigated the relationships between physical activity and eating fruit and vegetables and the effect it has on the brain for both younger and older adults.

This study examined cross-sectional data from 45,522, 30 years of age and older, participants from the 2012 annual component of the Canadian Community Health Survey. Cognitive function was assessed using a single 6-level question of the Health Utilities Index, which assessed mental processes, such as thinking, memory, and problem solving. Participants were analyzed by their age, level of physical activity, body mass index, and daily intake of fruit and vegetables. Using general linear models and mediation analyses, researchers assessed the relationship between these factors and participants’ overall cognitive function.

The results showed that higher levels of physical activity, eating more fruits and vegetables, and having a BMI in the normal weight (18.5-24.9 kg/m2) or overweight range (25.0-29.9 kg/m2) were each associated with better cognitive function in both younger and older adults. Further, by way of mediation analysis (via the Sobel test), it was determined that higher levels of physical activity may be in part responsible for the relationship between higher daily fruit and vegetable consumption and better cognitive performance.

Dr. Alina Cohen, PhD, explains: “Factors such as adhering to a healthy lifestyle including a diet that is rich in essential nutrients, regular exercise engagement, and having an adequate cardiovascular profile all seem to be effective ways by which to preserve cognitive function and delay cognitive decline.” Further that “It is pertinent that we develop a better understanding of the lifelong behaviors that may contribute to cognitive decline in late life by implementing a life-span approach whereby younger, middle-aged, and older adults are collectively studied, and where lifestyle risk factors are evaluated prior to a diagnosis of dementia.”

Citation: Alina Cohen, Chris I. Ardern, and Joseph Baker
Physical activity mediates the relationship between fruit and vegetable consumption and cognitive functioning: a cross-sectional analysis
Journal of Public Health first published online October 31, 2016
DOI: http://dx.doi.org/10.1093/pubmed/fdw113
Adapted from press release by Oxford University Press

High Body Mass Index (BMI) might affect cognitive function

Researchers from the University of Arizona have found that having a higher body mass index, or Body Mass Index, can negatively impact cognitive functioning in older adults.

“The higher your Body Mass Index (BMI), the more your inflammation goes up,” said Kyle Bourassa, lead author of the study, which is published in the journal Brain, Behavior and Immunity. “Prior research has found that inflammation — particularly in the brain — can negatively impact brain function and cognition.”

Bourassa and his co-author, UA psychology professor David Sbarra, analyzed data from the English Longitudinal Study of Aging, which includes over 12 years’ worth of information on the health, well-being and social and economic circumstances of the English population age 50 and older.

Using two separate samples from the study — one of about 9,000 people and one of about 12,500 — researchers looked at aging adults over a six-year period. They had information on study participants’ BMI, inflammation and cognition, and they found the same outcome in both samples.

“The higher participants’ body mass at the first time point in the study,” Bourassa said, “the greater the change in their CRP levels over the next four years. CRP stands for C-reactive protein, which is a marker in the blood of systemic inflammation in your body. Change in CRP over four years then predicted change in cognition six years after the start of the study. The body mass of these people predicted their cognitive decline through their levels of systemic inflammation.”

Sbarra added a word of caution in trying to understand the findings. “The findings provide a clear and integrative account of how BMI is associated with cognitive decline through systemic inflammation, but we need to remember that these are only correlational findings,” he said. “Of course, correlation does not equal causation. The findings suggest a mechanistic pathway, but we cannot confirm causality until we reduce body mass experimentally, then examine the downstream effects on inflammation and cognition.”

Publication: Body mass and cognitive decline are indirectly associated via inflammation among aging adults.
DOI: http://dx.doi.org/10.1016/j.bbi.2016.09.023
Journal: Brain, Behavior and Immunity

Adapted from press release by University of Arizona