“At last we have some direct experimental proof that brain waves influence behaviour in humans, in this case how fast a movement is performed,” said Peter Brown of University College London (UCL).
There are many types of brain waves, distinguished by their frequency and location, Brown explained.
In this study, researchers injected a small electrical current into the brain through the scalps of 14 people while the participants manipulated the position of a spot on a computer screen as quickly as they could with a joystick.
The electrical current used increased normal beta activity, a wave that earlier studies linked to sustained muscle activities, such as holding a book. Beta activity drops before people make a move.
Unlike most previous work, which used constant brain stimulation, the new study employed an oscillating current, more like that underlying normal brain activity. As a result, people’s fastest times on the computer task were 10 percent slower.
Brown said the researchers were surprised that the electrical currents used in the study, which were very small and imperceptible to the participants, could have such a measurable effect, said an UCL release.
“If we know what patterns of brain activity slow voluntary movement, then we can try and boost these patterns in conditions like chorea and dystonia, where there is excessive and uncontrolled movement,” Brown said.
“Conversely, we can try and suppress beta activity in conditions like Parkinson’s disease typified by slow movement.”
“The implication is that it is not just how active brain cells are that is important, but also how they couple their activity into patterns like beta activity.”
These findings were published in the October issue of Current Biology.