Biomedical engineer shows how people learn motor skills- Practice, practice, pra

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Biomedical engineer shows how people learn motor skills- Practice,

practice, practice

http://www.medicalnewstoday.com/medicalnews.php?newsid=31675

Practice makes perfect when people learn behaviors, from baseball

pitching to chess playing to public speaking. Biomedical engineers at

Washington University in St. Louis have now identified how people use

individual experiences to improve performance.

Kurt Thoroughman, Ph.D., Washington University assistant professor of

biomedical engineering, and Jordan , Washington University

doctoral student in biomedical engineering, tested a dozen volunteers

who played a video game that involved a robotic arm. Thoroughman and

found that the subjects learned different levels of the game

in just 20 minutes of training over different environmental

difficulties. Human subjects made reaching movements while holding a

robotic arm whose perturbing forces changed directions at the same

rate, twice as fast, or four times as fast as the direction of

movement, therefore exposing subjects to environments of increasing

complexity across movement space. Subjects learned all three

environments and learned the low and medium complexity environments

equally well. They learned the high complexity environment, too,

though not as well as the other two.

Thoroughman and also could detect how individual movements

trained people to make the next movement better. Surprisingly, people

could very quickly change the way errors in one movement induced a

learned response in the next movement. Specifically, subjects

lessened their movement-by-movement adaptation and narrowed the

spatial extent of generalization to match the environmental

complexity, showing that people can rapidly reshape the

transformation of sense into motor prediction to best learn a new

movement task.

" We've demonstrated that the richness of motor training determines

not only what we learn but how we learn, " Thoroughman said. " What we

cared about most was not only what people learned but how they

learned from trial to trial, movement to movement.

" The big picture is that in a single sitting people changed their

expectations of the complexity of the world, in that a single

movement's experience could be generalized very broadly or else

generalized very narrowly. We've shown for the first time that the

learning process itself is flexible. People can figure out that in

this particular environment: 'I need to change the way I learn,

movement to movement.' "

The researchers published their findings in the Sept. 28, 2005 issue

of Nature Neuroscience.

Ultimately, these findings can help researchers devise better

diagnostic tools for people with neurological disorders and could

lead to better neuro-prosthetic devices

Thoroughman and then modeled this adaptation using a neural

network. They found that, to mimic human behavior, the modeled

neuronal tuning of movement space needed to narrow and reduce gain

with increased environmental complexity.

According to Thoroughman, prominent theories of neural computation

have hypothesized that neuronal tuning of space, which determines

generalization, should remained fixed during learning so that a

combination of neuronal outputs can underlie adaptation simply and

flexibly. Thoroughman showed that this tuning of space is instead

flexible.

" We challenged those well-known theories with evidence that the

neuronal tuning of movement space changed within minutes of training

our subjects., " Thoroughman said.

" The overall research goal for this part of my lab is to characterize

as carefully as possible how people abstract information from single

movements to make the very next movement better. I want to understand

more about how human motor control goes right before I understand how

to help people when it goes wrong, "

Washington University in St. Louis

http://www.wustl.edu