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
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Designer Babies May Explain Insect Sociality

Feb. 3, 2013 — Being able to choose the sex of their babies may be the key to the complex societies built by ants, bees, and wasps, according to Oxford University scientists.


 

The researchers calculated the evolutionary costs and benefits to insect mothers of choosing the sex of their offspring and showed that, if females help out with bringing up babies, then mothers prefer to have daughters rather than sons — leading to a large workforce of female helpers.

Their findings could also help to explain why termites, alone among social insects, have complex societies with a roughly equal balance of males and females: because in termite society both males and females help to raise offspring.

A report of the research is published in the March issue of the journal The American Naturalist.

‘In social ants, bees, and wasps, mothers can decide the sex of their offspring by controlling which of their eggs get fertilized by sperm,’ said Dr Andy Gardner of Oxford University’s Department of Zoology, an author of the report. ‘Fertilized eggs develop as daughters, and unfertilized eggs develop as sons. It’s the daughters who do all the work in the colony, so this special ability means that the mother can raise a female workforce without wasting resources on relatively useless males.’

Previously, the sociality of ants, bees and wasps has been attributed to the curious fact that, in these species, a female is genetically more similar to her sisters than she is to her own daughters — the so-called ‘haplodiploidy hypothesis’.

However, this genetic quirk does not occur in termites, which have also evolved elaborate societies. ‘The failure of the haplodiploidy hypothesis to explain the sociality of termites is one of the reasons why it has gradually fallen out of favour since being proposed in the 1960s’ said Dr Gardner.

Co-author Laura Ross of Oxford University’s Department of Zoology points out that termite sociality is, however, fully consistent with the new ‘sex-ratio adjustment’ hypothesis:

‘Termites are the exception that proves the rule. They can’t bias the sex ratio towards females, but they don’t need to, because the males do as much work as the females in their societies. We suggest that the ability and need for sex ratio adjustment explains why some insects have evolved advanced eusociality and why other insects have not.’


Story Source:

The above story is reprinted from materials provided byUniversity of Oxford.

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


Journal Reference:

  1. Andy Gardner, Laura Ross. Haplodiploidy, Sex-Ratio Adjustment, and EusocialityThe American Naturalist, 2013; : E000 DOI: 10.1086/669147
University of Oxford (2013, February 3). Designer babies may explain insect sociality.ScienceDaily. Retrieved February 4, 2013, from http://www.sciencedaily.com/releases/2013/02/130203085411.htm