Hypnosis changes how the brain processes information

Researchers from the University of Turku have revealed that the way the brain processes information is fundamentally altered during hypnosis, which is interesting because the extent to which hypnosis modifies neural processing has been hotly debated in the field. Published in the journal Neuroscience of Consciousness, their breakthrough helps us to understand how hypnosis produces changes in a person’s behaviour and subjective experiences.

The team’s study was conducted by tracking how a magnetically induced electrical current spread throughout the brain during hypnosis and normal waking state. This method has been previously used to measure system-level changes in the brain in various states of consciousness, such as anaesthesia, coma and sleep. This is the first time such a method has been used to assess hypnosis.

During the study, the participant sat still with eyes closed, alternatively either hypnotised or in a normal waking state. Hypnosis was induced via a single-word cue, and the different conditions were identical in every other respect.

“This allowed us to control the possible effects of the experimental set-up or other factors, such as alertness,” said Jarno Tuominen, a senior researcher at Turku.

During a normal waking state, information is processed and shared by various parts within the brain to enable flexible responses to external stimuli. The Turku researchers found that during hypnosis the brain shifted to a state where individual brain regions acted more independently of each other.

“In a normal waking state, different brain regions share information with each other, but during hypnosis this process is kind of fractured and the various brain regions are no longer similarly synchronised,” said Turku researcher Henry Railo.

The findings also help to better understand which types of changes and mechanisms may explain the experiential and behavioural alterations attributed to hypnosis, such as liability to suggestions.

The study focused on a single person who has been extensively studied earlier and been shown to react strongly to hypnotic suggestions. During hypnosis, this person can experience phenomena that are not typically possible in a normal waking state, such as vivid and controlled hallucinations.

“Even though these findings cannot be generalised before a replication has been conducted on a larger sample of participants, we have demonstrated what kind of changes happen in the neural activity of a person who reacts to hypnosis particularly strongly,” said Tuominen.

Image credit: ©stock.adobe.com/au/rck

Please follow us and share on Twitter and Facebook. You can also subscribe for FREE to our weekly newsletters and bimonthly magazine.