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Related Experiment Video

Updated: Apr 24, 2026

Visualizing Visual Adaptation

Visualizing Visual Adaptation

Published on: April 24, 2017

Negative and positive visual hypnotic hallucinations: attending inside and out.

David Spiegel¹

¹Stanford University School of Medicine, Stanford, California 94305-5718, USA. dspiegel@leland.stanford.edu

The International Journal of Clinical and Experimental Hypnosis

|August 12, 2003

Summary

Hypnosis alters brain function by changing perception and attention. Specific hypnotic suggestions modify sensory cortex responses and activate attentional systems, demonstrating measurable neural changes.

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Area of Science:

Neuroscience
Cognitive Psychology
Psychiatry

Background:

Hypnosis is a state of consciousness involving focused attention and reduced peripheral awareness.
Perceptual and attentional functions are known to be modulated by hypnotic states.
Understanding the neural underpinnings of hypnotic effects is crucial for therapeutic applications.

Purpose of the Study:

To investigate the neural mechanisms underlying hypnotic perceptual alterations.
To differentiate the brain activity associated with reduced perception versus altered attention during hypnosis.
To explore the role of specific hypnotic instructions in modulating brain function.

Main Methods:

Utilized event-related potential (ERP) amplitude to measure sensory cortex response.
Employed Positron Emission Tomography (PET) to assess regional cerebral blood flow and brain activation.
Compared brain activity under different hypnotic suggestion conditions (e.g., perceptual obstruction vs. attentional focus).

Main Results:

Hypnotic suggestions reducing perception decreased brain response in sensory cortices (lower ERP amplitude, reduced blood flow).
Hypnotic suggestions altering attention activated the anterior attentional system, particularly the anterior cingulate cortex.
Hypnosis appears to involve neural activation without arousal, potentially mediated by dopaminergic pathways.

Conclusions:

Hypnotic perceptual alteration is associated with measurable changes in specific brain regions responsible for perception and attention.
The nature of hypnotic instructions directly modulates neural activity in relevant brain networks.
Positive obstructive hallucinations may facilitate inward attention by engaging attentional systems while reducing perceptual processing.