Published on: Monday, January 13, 2014

A new neuroimaging study of limb paralysis in hypnosis has been published in Neuron. Yann Cojan and colleagues looked at brain activity while participants performed a go-nogo task in 3 conditions: normal state, hypnotic left-hand paralysis, and feigned paralysis. In the task a picture of a hand would appear. It would then either turn green, in which case participants had to respond as quickly as possible, or it would turn red, and participants would have to inhibit a response. The study is neat in that it utilises an active cognitive task to probe brain activity as a result of suggestion

The authors found that motor systems prepared to move in the normal and hypnotic paralysis conditions indicating that motor intentions were preserved. However, in the hypnotic paralysis condition extra activity was seen in the precuneus - an area involved in mental imagery. Precuneus activity also seemed to be associated with decreases in motor regions which the authors suggest could indicate that motor controls are being influenced by self-related imagery. 

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Link to article in NeuronLink to page on Hypnosis And Suggestion about neuroimaging research