Francais

Neuroimaging (brain scanning) studies of hypnosis

Neuroimaging studies of hypnosis and hypnotic phenomena are a particularly interesting avenue of investigation as they can sidestep the 'demand characteristics' problem common to much hypnosis research. In the past researchers have had to rely on subjective report to confirm the effectiveness of a suggestion, but with neuroimaging technology we can look to see how a suggestion affects brain function. Like other hypnosis research, neuroimaging studies can be divided according to whether they are 'instrumental' and 'intrinsic' 1, 2, 3. Instrumental studies use hypnosis or suggestion as a research tool to investigate specific phenomenon, whereas intrinsic studies focus more on what is special about hypnosis. (The distinction in the following table between intrinsic and instrumental studies sometimes isn't clear cut, but it's a useful heuristic).

It is hard to overstate how useful brain-imaging studies have been in demonstrating the effects of hypnosis to a wider audience. They have been particularly useful in demonstrating that hypnotic subjects genuinely feel the effects of suggestions as 'real' - they are not (always) faking or trying to please the experimenter.

 

Intrinsic studies (investigating hypnosis itself)

Instrumental studies (using hypnosis as a tool)

Crawford et al 4
used Xenon inhalation to measure brain activity while hypnotised, in pain, and with suggestions for analgesia.

Rainville et al 5
conducted PET scans before and after a hypnotic induction (in the absence of suggestion), and also with hypnotic suggestions for pain modulation.

Maquet et al 6
used PET and suggestions of imagining pleasant autobiographical memories in hypnosis.

Rainville et al 7
examined perceived mental relaxation and mental absorption using PET, before and after a hypnotic induction.

Faymonville et al 8
investigate the antinociceptive mechanisms of hypnosis, during exposure to a painful stimulus.

Faymonville et al 9
conducted a connectivity analysis to examine relationships in activity between specific brain regions.

Egner et al 10
examined attentional abilities in low and high hypnotizables at baseline, and following a hypnotic induction.

Oakley et al 11
investigated the neural correlates of a hypnotic induction in fMRI.

Derbyshire et al 12
investigated the effect of hypnotic and non-hypnotic suggestions upon chronic pain in fibromyalgia patients. Hypnotic and non-hypnotic suggestions had similar behavioural effects, but differences in associated brain activity as measured by fMRI.

Cojan et al 13
Used hypnotic suggestions of limb paralysis to investigate the effects of cognitive modulation of motor systems. As well as modelling how functional limb paralysis may occur this study also informs us about how suggestions influence the interplay between brain systems.

Vanhaudenhuyse et al 14
Delivered a painful stimulus to participants in an fMRI scanner in hypnosis and in a waking state.

Rainville et al 15
used hypnotic suggestion to modulate the unpleasantness but not the intensity of a painful stimulus. Found that the anterior cingulate cortex responds to the unpleasantness component of pain.

Szechtman et al 16
used hypnotic suggestions to produce auditory hallucination.

Wik et al 17
used hypnotic suggestion in PET to modulate chronic pain in fibromyalgia patients.

Kosslyn et al 18
used hypnotic suggestion to produce positive and negative colour hallucinations.

Willoch et al 19
used hypnosis to produce phantom limb pain.

Schulz-Stübner et al 20
studied pain responses before and after a hypnotic induction.

Derbyshire et al 21
used hypnotic suggestions to generate pain in the absence of noxious stimuli. 'Real' and 'hallucinated' pain resulted in similar patterns of activity, but different from 'imagined'.

Raij et al 22
used hypnotic suggestions to generate pain in the absence of noxious stimuli

Raz et al 23
used posthypnotic suggestions affecting participants' ability to read, which knocked out the Stroop effect

Röder et al 24
used hypnosis to study the experience of pain during hypnotically produced depersonalisation. Found reduced pain related activation in the depersonalisation condition.

Mendelsohn et al 25
investigated the use of a post-hypnotic suggestion for amnesia. They found that the suggestion reduced memory for content but not context, and found brain activity which they interpreted as possibly inhibiting memory retrieval.