Pioneering Research Helps to Unravel the Brain’s Vision Secrets

Feb. 3, 2013 — A new study led by scientists at the Universities of York and Bradford has identified the two areas of the brain responsible for our perception of orientation and shape.


 

Using sophisticated imaging equipment at York Neuroimaging Centre (YNiC), the research found that the two neighbouring areas of the cortex — each about the size of a 5p coin and known as human visual field maps — process the different types of visual information independently.

The scientists, from the Department of Psychology at York and the Bradford School of Optometry & Vision Science established how the two areas worked by subjecting them to magnetic fields for a short period which disrupted their normal brain activity. The research which is reported in Nature Neuroscience represents an important step forward in understanding how the brain processes visual information.

Attention now switches to a further four areas of the extra-striate cortex which are also responsible for visual function but whose specific individual roles are unknown.

The study was designed by Professor Tony Morland, of York’s Department of Psychology and the Hull York Medical School, and Dr Declan McKeefry, of the Bradford School of Optometry and Vision Science at the University of Bradford. It was undertaken as part of a PhD by Edward Silson at York.

Researchers used functional magnetic resonance imaging (fMRI) equipment at YNiC to pinpoint the two brain areas, which they subsequently targeted with magnetic fields that temporarily disrupt neural activity. They found that one area had a specialised and causal role in processing orientation while neural activity in the other underpinned the processing of shape defined by differences in curvature.

Professor Morland said: “Measuring activity across the brain with FMRI can’t tell us what causal role different areas play in our perception. It is by disrupting brain function in specific areas that allows the causal role of that area to be assessed.

“Historically, neuropsychologists have found out a lot about the human brain by examining people who have had permanent disruption of certain parts of the brain because of injury to it. Unfortunately, brain damage seldom occurs at the spatial scale that allows the function of small neighbouring areas to be understood. Our approach is to temporarily disrupt brain activity by applying brief magnetic fields. When these fields are applied to one, small area of the brain, we find that orientation tasks are harder, while disrupting activity in this area’s nearest neighbour only affected the ability to perceive shapes.”

Dr McKeefry added: “The combination of modern brain scanning technology along with magnetic neuro-stimulation techniques provides us with a powerful means by which we can study the workings of the living human brain.

“The results that we report in this paper provide new insights into how the human brain embarks upon the complex task of analysing objects that we see in the world around us.

“Our work demonstrates how processing of different aspects of visual objects, such as orientation and shape, occurs in different brain areas that lie side by side. The ultimate challenge will be to reveal how this information is combined across these and other brain areas and how it ultimately leads to object recognition.”


Story Source:

The above story is reprinted from materials provided byUniversity of York, via AlphaGalileo.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

  1. Edward H Silson, Declan J McKeefry, Jessica Rodgers, Andre D Gouws, Mark Hymers & Antony B Morland.Specialized and independent processing of orientation and shape in visual field maps LO1 and LO2Nature Neuroscience, 2013 DOI: 10.1038/nn.3327
University of York (2013, February 3). Pioneering research helps to unravel the brain’s vision secrets. ScienceDaily. Retrieved February 4, 2013, from http://www.sciencedaily.com/releases/2013/02/130203145511.htm

Secrets of ‘SuperAger’ Brains: Elderly Super-Agers Have Brains That Look and Act Decades Younger Than Their Age

ScienceDaily (Aug. 16, 2012) — Researchers have long chronicled what goes wrong in the brains of older people with dementia. But Northwestern Medicine researcher Emily Rogalski wondered what goes right in the brains of the elderly who still have terrific memories. And, do those people — call them cognitive SuperAgers — even exist?

Dosuper-agers exist? A new study has for the first time identified an elite group of elderly people age 80 and older whose memories are as sharp as people 20 to 30 years younger than them. (Credit: © Meddy Popcorn / Fotolia)

 

Rogalski’s new study has for the first time identified an elite group of elderly people age 80 and older whose memories are as sharp as people 20 to 30 years younger than them. And on 3-D MRI scans, the SuperAger participants’ brains appear as young — and one brain region was even bigger — than the brains of the middle-aged participants.

She was astounded by the vitality of the SuperAgers’ cortex — the outer layer of the brain important for memory, attention and other thinking abilities. Theirs was much thicker than the cortex of the normal group of elderly 80 and older (whose showed significant thinning) and closely resembled the cortex size of participants ages 50 to 65, considered the middle-aged group of the study.

“These findings are remarkable given the fact that grey matter or brain cell loss is a common part of normal aging,” said Rogalski, the principal investigator of the study and an assistant research professor at the Cognitive Neurology and Alzheimer’s Disease Center at Northwestern University Feinberg School of Medicine.

Rogalski is senior author of the paper, which is published in the Journal of the International Neuropsychological Society.

By identifying older people who seem to be uniquely protected from the deterioration of memory and atrophy of brain cells that accompanies aging, Rogalski hopes to unlock the secrets of their youthful brains. Those discoveries may be applied to protect others from memory loss or even Alzheimer’s disease.

“By looking at a really healthy older brain, we can start to deduce how SuperAgers are able to maintain their good memory,” Rogalski said. “Many scientists study what’s wrong with the brain, but maybe we can ultimately help Alzheimer’s patients by figuring out what goes right in the brain of SuperAgers. What we learn from these healthy brains may inform our strategies for improving quality of life for the elderly and for combatting Alzheimer’s disease.”

By measuring the thickness of the cortex — the outer layer of the brain where neurons (brain cells) reside — Rogalski has a sense of how many brain cells are left.

“We can’t actually count them, but the thickness of the outer cortex of the brain provides an indirect measure of the health of the brain,” she said. “A thicker cortex, suggests a greater number of neurons.”

In another region deep in the brain, the anterior cingulate of SuperAger participants’ was actually thicker than in the 50 to 65 year olds.

“This is pretty incredible,” Rogalski said. “This region is important for attention. Attention supports memory. Perhaps the SuperAgers have really keen attention and that supports their exceptional memories.”

Only 10 percent of the people who “thought they had outstanding memories” met the criteria for the study. To be defined as a SuperAger, the participants needed to score at or above the norm of the 50 to 65 year olds on memory screenings.

“These are a special group of people,” Rogalski said. They aren’t growing on trees.”

For the study, Rogalski viewed the MRI scans of 12 Chicago-area Superager participants’ brains and screened their memory and other cognitive abilities. The study included 10 normally aging elderly participants who were an average age of 83.1 and 14 middle-aged participants who were an average age of 57.9. There were not significant differences in education among the groups.

Most of the SuperAger participants plan to donate their brains to the study. “By studying their brains we can link the attributes of the living person to the underlying cellular features,” Rogalski said.

 


Story Source:

The above story is reprinted from materials provided byNorthwestern University, via EurekAlert!, a service of AAAS. 


Journal Reference:

  1. Theresa M. Harrison, Sandra Weintraub, M.-Marsel Mesulam and Emily Rogalski. Superior Memory and Higher Cortical Volumes in Unusually Successful Cognitive AgingJournal of the International Neuropsychological Society, 2012 DOI:10.1017/S1355617712000847
Citation:

Northwestern University (2012, August 16). Secrets of ‘SuperAger’ brains: Elderly super-agers have brains that look and act decades younger than their age. ScienceDaily. Retrieved August 19, 2012, from http://www.sciencedaily.com/releases/2012/08/120816201620.htm