When the brain is affected by hypnosis — a trance-like state with focused attention and reduced peripheral awareness — it faces an extreme reduction in its activities, although simple perception still takes place, according to a new study.
The findings showed that the hypnosis influences specific regions of the brain while it receives a visual stimulus and greatly impairs the brain’s deeper processing operations, such as counting.
“In our study, we are looking at how the brain makes hypnotic states possible,” said Wolfgang Miltner, Professor at the Friedrich Schiller University in Jena, Germany.
For the study, detailed in the journal Scientific Reports, the team looked more closely at the processing of visual stimuli and asked participants to look at a screen which had various symbols, such as a circle or a triangle. They were then given the task of counting a particular symbol.
At the same time, they were also told to imagine that there was a wooden board in front of their eyes. As a result of the suggested obstruction, the number of counting errors rose significantly, the researchers said.
“When we look at the neural processes that take place in the brain while processing the symbols, we see that around 400 milliseconds after the presentation of the to-be-counted symbol, there is an extreme reduction in brain activity, although it should normally be very high,” explained Barbara Schmidt, from the Friedrich Schiller University.
“However, a short time before this — up to 200 milliseconds after presentation of the stimulus — there are no differences to be seen,” Schmidt added.
This suggests that although simple perception still takes place, deeper processing operations, such as counting, are greatly impaired, the researchers noted.