February 4, 2013
Researchers Discover Regions Of The Brain Responsible For Shape, Orientation
redOrbit Staff & Wire Reports - Your Universe Online
The areas of the human brain responsible for our perception of shape and orientation have been discovered by researchers from a pair of UK-based universities — a discovery which they call an important advance in the understanding of how our minds process visual information.
Scientists from the University of York Department of Psychology and the University of Bradford School of Optometry & Vision Science used functional magnetic resonance imaging (fMRI) equipment to discover that two adjacent areas of the cortex known as human visual field maps are responsible for processing different types of visual information independent of each other.
As the scientists explained Sunday in a statement, they used the imaging technique to subject the areas to magnetic fields for a short period of time in order to disrupt their normal activity. That work was completed at the York Neuroimaging Centre (YNiC).
In doing so, they discovered that one of the areas had “a specialized and causal role in processing orientation while neural activity in the other underpinned the processing of shape defined by differences in curvature.” Their findings have been detailed in the journal Nature Neuroscience.
"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,” said Professor Tony Morland of York's Department of Psychology, who co-designed the study along with Dr. Declan McKeefry of the University of Bradford. “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.”
That proved difficult in this case, however, because brain damage tends not to occur at the spatial scale that allows scientists to study the functions of smaller, neighboring regions of the brain to be closely analyzed, Morland said.
For that reason, his team set out to briefly disrupt regular brain activity through the application of magnetic fields — which, when applied to one tiny region of the brain, allowed them to discover that some orientation tasks became harder, and when applied to an adjacent area, interfered with a person´s ability to perceive shape.
"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,” Dr. McKeefry said. "The results that we report in this paper provide new insights into how the human brain embarks upon the complex task of analyzing 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,” he added.