The Brain under Self-Control: Modulation of Inhibitory and Monitoring Cortical Networks during Hypnotic Paralysis

Abstract

Brain mechanisms of hypnosis are poorly known. Cognitive accounts proposed that executive attentional systems may cause selective inhibition or disconnection of some mental operations. To assess motor and inhibitory brain circuits during hypnotic paralysis, we designed a go-no-go task while volunteers underwent functional magnetic resonance imaging (fMRI) in three conditions: normal state, hypnotic left-hand paralysis, and feigned paralysis. Preparatory activation arose in right motor cortex despite left hypnotic paralysis, indicating preserved motor intentions, but with concomitant increases in precuneus regions that normally mediate imagery and self-awareness. Precuneus also showed enhanced functional connectivity with right motor cortex. Right frontal areas subserving inhibition were activated by no-go trials in normal state and by feigned paralysis, but irrespective of motor blockade or execution during hypnosis. These results suggest that hypnosis may enhance self-monitoring processes to allow internal representations generated by the suggestion to guide behavior but does not act through direct motor inhibition.

Discrete response patterns in the upper range of hypnotic suggestibility: A latent profile analysis

“…In recent years, considerable attention has been devoted to the possibility of using hypnosis to model different psychological and neurological phenomena (Oakley & Halligan, 2009, 2013 , and motor paralysis (Cojan et al, 2009). The value of such research is closely tied to the assumption that HS individuals respond to hypnotic suggestions through uniform mechanisms.…”

Brain circuits implicated in psychogenic paralysis in conversion disorders and hypnosis

“…These abnormalities in basal ganglia and thalamus disappeared when scanning was repeated after [16,18,19]. This allowed testing for brain activity during failure to move on Go trials with the paralyzed hand and comparison with inhibitory control activity during NoGo trials, in addition to motor preparation.…”

“…To do so, we designed a modified Go/NoGo paradigm allowing us to probe brain activity related to various motor control stages including motor intention, execution, and inhibition. Two patients with left motor conversion were examined using slightly different versions of the same paradigm [18,49], as well as a group of healthy controls [18,19]. In this task (Fig.…”

“…As expected, however, a loss of motor activation was seen in the right motor cortex at the time of the instructed movement execution with the left/paralyzed hand (in accordance with the lack of movement, but in In the patient, left paralysis was not associated with increased activity in right IFG as seen during voluntary inhibition of simulation; whereas activation in VMPFC was selective for preparing or attempting to move the left/paralyzed hand. Adapted from Cojan et al, [18,19].…”

“…Our Go/NoGo paradigm also enabled us to directly test for a role of active inhibition and comparison of conversion disorder with voluntary simulation of paralysis. On NoGo trials, when a prepared movement had to be cancelled, healthy participants showed robust increases in a network known to be associated with motor inhibition and cognitive control, including right inferior frontal gyrus (rIFG) and right inferior parietal lobule (rIPL) [3,19,111]. Moreover, this right fronto-parietal network is similarly recruited for left or right hand motor inhibition [19].…”