Before both real and imagined movement, a precursor signal appears in the cerebral cortex. However, during real movement it occurs in the hemisphere opposite the moving hand, and during illusory movement it has no clear connection to a specific hemisphere. This was shown by a study published in the journal by scientists from the Skolkovo Institute of Science and Technology. meninges.
Before we pick up a pen or put down a glass, a complete picture of this action is formed in the brain. Such visuomotor transformations ensure precision of movements. However, a person can imagine making a movement without moving. In this case, visual information also enters the areas of the brain responsible for movement, but the initiation of the reaction is blocked at some point and the mental effort does not end with muscle activation.
Scientists from Skoltech and Moscow State University conducted an experiment in which 17 volunteers participated. Their average age was 23. Subjects placed their hands on a panel with two buttons that were periodically illuminated. When a button lit, volunteers had to press that button or imagine doing so. During this time, researchers recorded the volunteers’ electroencephalograms.
Flashing the button during both imagined and real movement caused a signal to appear in the brain’s motor cortex, which plays a key role in controlling movements. But during actual movement, this activity was observed mainly in one hemisphere: If a person pressed a button with their right hand, signals appeared in the left hemisphere and vice versa. At the same time, the duration of this previous signal increased if the person reacted more slowly to the light of the button and pressed the button with a delay.
The study means that the formation of a mental image differs between real and imagined movement. Stroke can disrupt the processes scientists have identified. Therefore, the study authors believe that movement-related signals from the cerebral cortex can be used to evaluate the rehabilitation of stroke patients. Nikolai Syrov, a senior researcher at Skoltech and one of the study participants, said this approach would be extremely sensitive because it would allow us to record developments in the brain’s motor systems before they manifest themselves in movements.
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