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Research Snapshot: U of M study examines movement preparation and brain activity

Alexander Graham Bell once said, “Before anything else, preparation is the key to success.”

Whether you’re preparing for a big presentation, a job interview or about to run a big race, your level of preparation can dramatically influence your level of success.

But did you know that most of our movements are often prepared in the brain well in advance of the time we intend to initiate an action? In some instances, the planning process in the brain begins as much as two seconds ahead of time and slowly increases until the initiation of movement.

U of M researcher Colum MacKinnon, Ph.D.

In a new study in PLOS ONE, University of Minnesota neurophysiologist Colum MacKinnon, Ph.D., demonstrates that if a loud sound occurs during the brain’s planning process, it can result in rapid and involuntary release of the intended action. In some cases, the complete movement is released as much as 1.5 seconds before the intended timing of movement initiation. The closer the timing of the loud sound got to the “go” signal, the more difficult it became to suppress the involuntary initiation.

These results show that the slow buildup of brain activity that precedes movement reflects a “releasing of the brakes before hitting the accelerator,” rather than slow construction of the bits-and-pieces of the movement.

Furthermore, when the loud sound occurred at the same time as the “go” signal, the planned movement was initiated in less than 100 milliseconds (note that the cut-off for a false start in the Olympics is 100 milliseconds). The study also showed that this “early release” phenomenon only occurred when subjects knew, with reasonable accuracy, when the “go” signal was going to occur.

“These findings have implications for movement performance when reaction times are important,” said MacKinnon. “For example, if a sprinter accurately anticipates the timing of the firing of the starter’s pistol, the loud sound can result in very rapid release of the first step.”

MacKinnon’s findings not only have practical applications in everyday activities but also with patients with neurological diseases such as Parkinson’s disease and ataxia.

“We have used this type of experiment to examine whether patients with these neurological diseases have deficits in the planning and preparation of movement,” said MacKinnon.

So far, MacKinnon and his colleagues have found that people with Parkinson’s disease retain the ability to plan and prepare actions well in advance but the disease interferes with their brain’s ability to start the movement. However, when a loud sound travels through the brain pathways that have access to the planned movement, this can result in the release of their intended action as quickly as an Olympic athlete.

Further studies are being conducted to better understand the brain regions and pathways that cause this very rapid release of prepared movements.

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