Specific brain waves activate in different parts of the brain based on our thoughts.
- Electrophysiological signatures specifically linked to different states of internal thought to identify whether our mind is focused or wandering.
- When thoughts wander aimlessly, there is a surge of alpha waves in the prefrontal cortex.
- P300, or P3, brain waves were observed at lower frequencies in the parietal lobe, which is a marker of inattention.
Depending on our thoughts, our brain calibrates itself differently. A team of American scientists from the University of Berkeley in California has managed to identify brain waves corresponding specifically to some of our thought states. The results, presented on January 26 in the journal Proceedings of the National Academy of Sciences (PNAS), describe electrophysiological signatures specifically related to different states of internal thought, allowing us to identify whether our mind is focused or wandering.
Four distinct states of thought
Gray areas on the brain mechanisms involved in our thought flows remain. To shed some light, the researchers conducted their study on 39 participants whom they taught to distinguish 4 distinct thought states: task-related (“task related”), wandering (“freely moving”), deliberately constrained (“deliberately constrained”) and automatically constrained (“automatically constrained”). The notion of constraint used here refers to the fact that attention is focused on something for an extended period of time. When thought is automatically constrained, it means it is directed toward personal information, and when thought is deliberately constrained, thought is directed toward a goal.
The volunteers then had to perform a task, after which they were asked to rate on a scale of 1 to 7 how well their thoughts during the sequence corresponded to each category studied previously: related to the task, wandering freely, deliberately constraints or automatically constraints. They indicated in which direction arrows presented on a screen point. During the exercise, the researchers recorded their brain activity using electroencephalography (EEG), the results of which were compared to those self-reported by the participants.
The activated area describes the state of thought
The results showed that the brain waves are different depending on the states of thought. When participants’ thoughts wandered aimlessly, the researchers observed a sharp increase in alpha waves in the prefrontal cortex. These waves are characteristic of a peaceful or creative state of thought and have oscillated at frequencies between 8.5 and 12 hertz. In addition, P300, or P3, brain waves were observed at lower frequencies in the parietal lobe, which is a marker of inattention. When participants were found to be more focused on their task, P3 waves were observed in the frontal lobe, instead of alpha waves.
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