Navigation ability may be linked to genes

February 2nd, 2010 - 1:28 pm ICT by ANI  

Washington, Feb 2 (ANI): A new research has linked genes to our ability to orient ourselves to the world around us and then navigate through it.

“We found that people with a rare genetic disorder cannot use one of the very basic systems of navigation that is present in humans as early as 18 months and shared across a wide range of species,” study’s lead author Barbara Landau, the Dick and Lydia Todd Professor in the Department of Cognitive Science at The Johns Hopkins University.

“To our knowledge, this is the first evidence from human studies of a link between the missing genes and the system that we use to reorient ourselves in space,” Landau added.

For the study, Landau and colleagues involved people with a rare genetic disorder known as Williams syndrome. It is caused when a small amount of genetic material is missing from one human chromosome.

People with Williams syndrome are extremely social and verbally adept, but have difficulty with tasks such as assembling simple puzzles, copying basic patterns and navigating their bodies through the physical world. Williams syndrome occurs in one in 7,500 live births.

In the study, Landau’s team challenged people with Williams syndrome to watch while someone hid an object beneath a small cloth flap in one corner of a small rectangular room with four solid black walls that had no landmarks.

Subjects were then blindfolded and spun around for about 10 seconds to disorient them. Once the blindfold was taken off, the subjects were asked to find the hidden object.

According to Landau, the people with Williams syndrome searched the four corners randomly; indicating that their ability to mentally visualize the layout of the room and quickly find which corner held the hidden object is severely impaired.

“They searched the room for the hidden object randomly, as if they had never before seen the overall geometry of the room or the lengths of the walls and their geometric - left and right - relation to each other,” Landau said.

“If they could imagine the overall shape of the room’s layout - that there are four walls, two of them long and two of them short and that the toy was hidden in a corner that has a short wall on the right and the long wall on the left - then they should have guessed that one of the two ‘geometrically equivalent corners’ was the right place. This is what typically developing humans do, as early as 18 months of age,” she added.

Control subjects responded more typically, searching for the object in one of the two geometrically equivalent corners.

The study has been published this week in the online Early Edition of the Proceedings of the National Academy of Sciences. (ANI)

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