title: Changes in electromyographically recorded human monosynaptic reflex in relation to hypnotic susceptibility and hypnosis.
abstract: The aim of the present experiment was to study how hypnotic susceptibility and hypnosis affect motoneuron excitability. In a first trial, human subjects were selected according to their hypnotic susceptibility. In a second trial, the Hoffmann (H) reflex amplitude of the soleus muscle was studied in 3 groups: (1) highly susceptible subjects during hypnosis with standardized suggestions of simple relaxation, anesthesia, analgesia and paralysis (group I), (2) highly susceptible subjects (group II), and (3) non-susceptible subjects (group III) during long-lasting control conditions. Surface Ag/AgCl electrodes were used to stimulate the posterior tibial nerve using a constant current stimulator and to record the soleus EMG. Analysis of variance was performed on the data. The linear correlation coefficient within groups was evaluated. The H reflex amplitude decreased significantly during the recording session in groups I and II and there was no change in group III. In group I the effect of different suggestions could not be distinguished from the effect of hypnotic relaxation. The decrements in H amplitude did not differ between groups I and II, suggesting that the effect was related to personality traits rather than hypnotic induction.
authors: Istituto di Fisiologia Umana, Università di Siena, Italy.
authors: E L
authors: EL
authors: Santarcangelo
authors: K
authors: K
authors: Busse
authors: G
authors: G
authors: Carli
mesh_terms: D004558:Electric Stimulation; D004576:Electromyography; D004594:Electrophysiology; D006801:Humans; D006990:Hypnosis; D009046:Motor Neurons / Q000502:physiology*; D012023:Reflex, Monosynaptic; D013116:Spinal Cord / Q000502:physiology