Aim: 

To verify whether imagery of a sensory context induces the same motor behaviour occurring in the corresponding real context (Carli et al 2006), aim of the experiment was studying whether 1) real and imagined head rotation change vestibular reflexes (VR) similarly, with respect to the face forward position; 2) imagery of anaesthesia reduces VR amplitude; 3) the effects are modulated by hypnotizability.

Methods: 

Highly (Highs, n=12) and low hypnotizable individuals (Lows, n=12) received vestibular galvanic stimulation during 4 closed eyes conditions (2 min each): 1) head forward ; 2) head forward and suggestions for anaesthesia (AN), 3) right rotated head; 4) head forward and suggestions for imagery of head rotation. In a different group of subjects (controls: 5 Highs and 5 Lows), the effect of voluntary opposition to the VR induced movement was studied.

Results: 

Only Highs exhibited a similar VR amplitude during real and imagined head rotation; all the Highs and 8 of the Lows perceived a lower intensity of stimulation and decreased VR amplitude during AN, showing similar experience and VR decrease.Voluntary opposition to the stimulation induced movement did not modify the VR amplitude.

Conclusions: 

The results indicate a hypnotizability-related modulation of vestibular reflexes by imagery. A perceptive role of imagery is more likely and more effective in Highs than in Lows. Imagery of anaesthesia is less hypnotizability-dependent than imagery of head rotation.