A recent brain imaging study helps explain how we learn to copy actions through observation. Functional magnetic resonance imaging (fMRI) of participants’ brains, while they watched someone else perform a task, suggests that areas of the brain are used in a similar way to when the person is actually moving.
One of the most recently developed forms of neuroimaging, fMRI allows the observation of neural activity in the brain by tracking changes in the blood flow to neurons.
Dr. Scott Frey of the University of Oregon and his team took fMRI scans of the brain while 19 college-aged, healthy participants watched films of other people building or taking apart objects using parts of Tinker Toys.
“We’ve been looking at the process of motor learning through observation in the context of procedures,” Dr. Frey said. “Teaching a physical skill often involves someone demonstrating the essential action components after which the learner tries to reproduce what has been observed.
“This is true for behaviors ranging from learning to eat with utensils, playing an instrument or performing surgery. We wanted to know how the brain takes what is seen and translates it into a motor program for guiding skilled movements.”
In the study, brain scans of those simply watching were compared against scans from those planning to copy the actions in the correct order afterwards. Dr. Frey found that observing with the intention to copy used parts of the brain that also are used when learning by physically doing the activity. The participants’ accuracy in reproducing the actions a few minutes later was predicted by the amount of activity in the intraparietal sulcus (IPS), which is in the parietal lobe. This backs up previous findings that the IPS is involved in the processing of others’ intentions.
When the participants were asked to watch a film and copy the actions, but not necessarily in the same order, activity in these brain regions increased to a lesser extent. Dr. Frey believes that activity in the IPS may act as a “thermometer” to show how well a person is translating what they are seeing into plans for action.
“What appears vital is the intention of the observer, rather than simply the visual stimulus that is being viewed,” he said. “If the goal is to be able to do what you are seeing, then it appears that activity through your motor system is up-regulated substantially. This could prove important as a means of facilitating rehabilitation of individuals with movement impairments or paralyses.”
Brain damage long has been linked to problems using objects, with damage to different areas causing different types of problems. Sometimes a patient can perform an action properly but out of context. For example, one patient with damage to his right hemisphere tried to brush his teeth with a comb and eat with a toothbrush. This was not because he did not know what the objects were, as he was able to name them.
In a 2005 study, Dr. Frey confirmed the idea that skills in using objects can be separated from the knowledge of what they are. His team tested eight patients with a type of apraxia affecting object-related movement, five stroke patients without this type of problem, and six healthy participants.
The apraxia patients could identify objects but had problems in planning how to reach for them accurately. However, they had no problems with hand actions not involving objects, such as signaling “stop” or waving goodbye. They were also much more likely to have damage to the IPS.
Frey S. H. and Gerry V. E. Modulation of Neural Activity during Observational Learning of Actions and Their Sequential Orders. Journal of Neuroscience, Vol. 26, December 20, 2006, pp. 13194-13201.
Buxbaum L. J., Frey S. H. and Bartlett-Williams, M. Deficient internal models for planning hand-object interactions in apraxia. Neuropsychologia, Vol. 43, June 2005, pp. 917-29.
Johnson-Frey S. H. The neural bases of complex tool use in humans. Trends in Cognitive Sciences, Vol. 8, February 2004, pp. 71-78.