High Hypnotizability Impairs the Cerebellar Control of Pain

Abstract

In the general population, transcranial anodal direct current stimulation of the cerebellum (ctDCS) reduces pain intensity and the amplitude of nociceptive laser evoked potentials (LEPs), whereas cathodal ctDCS elicits opposite effects. Since behavioral findings suggest that the cerebellar activity of highly hypnotizable individuals (highs) differs from the general population, we investigated whether hypnotizability-related differences occur in the modulation of pain by ctDCS. Sixteen healthy highs (according to the Stanford Hypnotic Susceptibility Scale, form A) and 16 participants not selected according to hypnotizability (controls) volunteered to undergo laser nociceptive stimulation of the dorsum of the left hand before and after anodal or cathodal ctDCS. LEPs amplitudes and latencies and the subjective pain experience (Numerical Rating Scale) were analyzed. Smaller LEP amplitudes and longer latencies were observed in highs with respect to controls independently of stimulation. After anodal and cathodal cerebellar stimulation, controls reported lower and higher pain than before it, respectively. In contrast, highs did not report significant changes in the perceived pain after both stimulations. They increased significantly their N2/P2 amplitude after anodal ctDCS and did not exhibit any significant change after cathodal tDCS, whereas controls decreased the N1 and N2P2 amplitude and increased their latency after anodal cerebellar stimulation and did the opposite after cathodal ctDCS. In conclusion, the study showed impaired cerebellar pain modulation and suggested altered cerebral cortical representation of pain in subjects with high hypnotizability scores.

Spectral and topological analyses of the cortical representation of the head position: Does hypnotizability matter?

“…Indeed, the vestibular and neck proprioceptive information are conveyed to the frontoparietal, insular, and cingulate cortices which show also hypnotizability-related morphofunctional properties (Landry et al, 2017). In addition, cerebellar function, which is related to hypnotizability (Bocci et al, 2017), is required for the elaboration of sensorimotor information related to the head position (Manzoni, 2005;Kammermeier, Kleine, & Büttner, 2009). Spectral analysis of EEG signals can be used to characterize the cortical representation of the head posture.…”

“…Alterations of visual and leg proprioceptive information (Santarcangelo, Scattina, Carli, Macerata, & Manzoni, ) and asymmetric tactile feet stimulation (Solari, Orsini, & Santarcangelo, ) induce larger and/or faster body sway in highly hypnotizable individuals ( highs ), while tonic neck rotation induces changes in the velocity of body sway only in low hypnotizable subjects ( lows ) (Santarcangelo et al., ). Hypnotizability is also associated with morphofunctional differences in the cerebral cortex (Landry, Lifshitz, & Raz, ) and cerebellar cortex (Picerni et al., ; Bocci et al., ), which are structures relevant to sensorimotor integration. Indeed, the vestibular and neck proprioceptive information are conveyed to the frontoparietal, insular, and cingulate cortices which show also hypnotizability‐related morphofunctional properties (Landry et al., ).…”

Imagined and Actual Movements with and without Suggestions for anesthesia in Subjects with Different Hypnotizability

“…The highs do not exhibit learning effects due to task repetition in both postural and visuomotor tasks [2]. In contrast to the general population, reports showed increased pain perception associated with increased amplitude of cortically evoked nociceptive potentials during transcranial anodal cerebellar stimulation in highs [15]. The structural variations in the salience network, particularly in the insula, may be responsible for higher emotional intensity during imagery [16], recall of emotional events [17], and perception of the inner world and sensitivity/empathy in highs than that in lows [18].…”

Visuospatial imagery in healthy individuals with different hypnotizability levels

“…Also, it has been shown that highs receiving nociceptive stimulation after anodal cerebellar stimulation report paradoxically increased pain intensity associated with increased amplitude of the cortically evoked potentials [13], in contrast to a sample of lows and medium hypnotizable participants (mediums). Finally, reduced cerebellar inhibition of the cerebral cortex has been suggested as one of the possible factors responsible for facilitating ideomotor responses to sensorimotor suggestions [8][9][10].…”