Aug. 14, 2003 New findings from a Queen's behavioural expert in eye/hand movement provide the first direct evidence that our brain patterns are similar whether we are actually doing something or simply watching someone else do it.
It's an insight that could have significant implications for the assessment of people with various movement disorders such as some stroke victims, says Dr. Randy Flanagan, who conducted the study with Dr. Roland Johansson of Umea University in Sweden.
The methods employed in the study could be used to determine whether people with impaired movement control also have problems understanding and perceiving the actions of others. The answer to this question will have implications for both diagnosis and assessment.
"This helps to explain how we understand the movements of others," Dr. Flanagan says. "We perceive an action by running it at some covert level in our own system. An example would be when sports fans watch football on TV and move in anticipation of action on the screen."
Although this theory is supported by previous neuro-physiological and brain imaging studies, until now there has been little direct, behavioural evidence.
Dr. Flanagan's findings are published this week in the current edition of Nature.
The study builds on earlier findings by other researchers showing that some brain cells fire not only when picking up an object, but also when watching an experimenter do the same thing. Rather than mere imitation, Dr. Flanagan believed that such neural activity was a way of understanding the action in anticipation of performing it.
The current Queen's study uses human subjects to examine patterns of eye-hand coordination when performing and observing a simple block-stacking task. The researchers discovered that, both in watching and performing the task, people's gaze pattern is the same.
When watching a task being performed, subjects don't simply follow the movement of hand and block with their eyes. Instead, their gaze shifts in anticipation of the next move, and the brain patterns mimic those of someone actually doing the task.
"These results indicate that eye movements while observing an action task are linked with parts of the neural processes for planning and controlling manual action," says Dr. Flanagan. "This may provide insights into how we learn to perform tasks by watching." Measuring eye movements in people while they observe skilled tasks will help us assess whether the subjects are learning the task, by determining whether their eye movements match those of the skilled performer, he adds.
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