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Grand-average waveforms of the late SEPs in the awake and hypnosis condition. Standard deviations are reported above and below the mean as a shaded area.
Source publication
A large literature indicated hypnosis as a useful tool to reduce pain perception, especially in high susceptible individuals. However, due to different methodological aspects, it was still not clear whether hypnosis modulates the early sensory processing of the stimuli or if it affects only the later stages of affective processing. In the present s...
Citations
... However, these should not be considered as strict relationships as they were not always confirmed (e.g. Perri et al. 2019), and the definition of hypnotizability such as its quantification are still under discussion in the literature (Dixon & Laurence, 1992;Perri, 2022). In fact, since its birth hypnosis has been linked to the concept of suggestibility, and the main scales used to assess hypnotizability in terms of behavioral responses to the hypnotist's suggestions (see Facco 2021 for a review), while emerging evidence describe hypnosis as a multidimensional phenomenon including both behavioral and experiential components (Acunzo & Terhune, 2021). ...
Background
Recent studies of neurostimulation reported alteration of hypnotizability and hypnotic phenomena after inhibition of the dorsolateral prefrontal cortex (DLPFC), but the different assessments of hypnosis and the stimulation parameters still left open many questions about the role of this brain region in hypnotizability. We aimed to administer inhibitory transcranial direct current stimulation (tDCS) over the left DLPFC to observe effects of stimulation on the hypnotic experience and the feeling of agency.
Methods
a procedure of hypnotic induction with suggestions was repeated twice: before and after the unilateral cathodal tDCS over the left DLPFC. The experience was assessed through a phenomenological assessment of hypnosis and sense of agency in thirty-three participants randomly assigned to the sham or the active group.
Results
active (inhibitory) tDCS enhanced the hypnotizability by 15.4% and altered a few dimensions of consciousness such as self-awareness and absorption. No changes emerged on the feeling of agency and pass rates for suggestions.
Conclusions
tDCS reflects a promising tool to alter the hypnotic phenomena and the responsiveness to hypnotic procedures. Neurocognitive implications are discussed for the construct of hypnotizability as well as for the role of the left DLPFC in the dimensions of consciousness such as self-awareness.
... This phenomenon in which the continuous positive wave looks like a ''plateau'' is different from the study of SEP in normal people and the study in this article (see Figure 4H). However, from the perspective of topographic map distribution, this research is consistent with the results in Perri et al. (2019) and the results of the contralateral healthy fingers (see Figures 4G,H), and the topographic map distribution shows a symmetrical distribution on both sides of the center. ...
... There are not many studies on the component of P150. Zeng et al. (2006) used acupuncture to induce P150 and then traced the source to infer that the anterior cingulate cortex (ACC) was the generator of this component, while Perri et al. (2019) believed in hypnosis experiments that both the ACC and the right anterior insula are the generators of P150, and studies have shown that the anterior insula plays a key role in perceptual awareness (Craig, 2010). ...
... Regarding P250, Graungaard et al. (2010) located its source in the dorsal ACC, while Perri et al. (2019) studied the medial frontal gyrus and the dorsal cingulate gyrus as generators of P250, P250 might reflect the later stage of somatosensory perception associated with affective integration of the sensory input. ...
Purpose: Sensory feedback for prosthetics is an important issue. The area of forearm stump skin that has evoked tactile sensation (ETS) of fingers is defined as the projected finger map (PFM), and the area close to the PFM region that does not have ETS is defined as the non-projected finger map (NPFM). Previous studies have confirmed that ETS can restore the tactile pathway of the lost finger, which was induced by stimulation of transcutaneous electrical nerve stimulation (TENS) on the end of stump skin. This study aims to reveal EEG features between the PFM and the NPFM regions of the stumps under the same TENS stimulation condition.
Methods: The PFM and NPFM regions of the two subjects were stimulated with the same intensity of TENS, respectively. TENS as target stimuli are modulated according to the Oddball paradigm to evoke the P300 components.
Result: The PFM regions of both subjects were able to elicit P300 components, while their NPFM regions were not able to elicit P300 components. However, this P300 appears early (249 ms for subject 1,230 ms for subject 2) and has continuous positive peaks (peak 1,139 ± 3 ms, peak 2,194 ± 0.5 ms) in front of it.
Discussion: N30 and P300 can prove that the two subjects with PFM can perceive and recognize ETS. The heteromorphisms of the P300 waveform may be related to the difficulty in subjects’ cognition of ETS or caused by the fusion of P150, P200, and P300.
... As for the specific aims of the present study, the choice of the target cortical area was guided by evidence from the present knowledge of the neurophysiology of hypnosis. In particular, a huge literature described the brain activity of individuals while receiving motor [45][46][47], cognitive [48][49][50][51] or perceptual hypnotic suggestions [52][53][54][55][56], but more relevant to this study are the neural patterns associated with the hypnotic condition, regardless of the given suggestions. One of the most authoritative papers in this field is the comprehensive meta-analysis by Landry and colleagues (2017) as the authors conducted a systematic review of brain imaging studies in order to identify the most reliable correlates of hypnotic phenomena. ...
Hypnotizability refers to the individual responsiveness to hypnosis, and literature shows that the greater the hypnotizability, the more effective the hypnotic suggestions. So far, few studies attempted to enhance hypnotizability, and only two adopted brain stimulation with magnetic pulses. In the present study, we aimed to boost hypnotizability through transcranial direct current stimulation (tDCS). To this aim, bilateral tDCS was applied over the dorsolateral prefrontal cortex (DLPFC) with the target electrode providing negative current (cathodal stimulation) over the left hemisphere. Twenty-nine subjects participated in the study and they were randomly assigned to the sham or the active group in a double-blind design. The hypnotic experience was assessed before and after the stimulation through a phenomenological measure of consciousness (the PCI-HAP). The main findings revealed that a single tDCS session enhanced the hypnotic depth by 11% and reduced the volitional control by 30%, while no differences emerged in the sham group. This is the first study adopting the electrical neurostimulation to produce an alteration of hypnotizability and sense of agency, and confirmed the key-role of the DLPFC and executive control in the hypnotic phenomena. If confirmed, these findings could have relevant implications as enhanced hypnotizability could be translated into better outcomes for many hypnotic interventions.
... Moreover, existing studies have focused primarily on non-affective matters related, for example, to sensory discrimination or object recognition via the glabrous skin of the palm. To facilitate temporal synchronization in the EEG, tactile stimuli typically comprised small square-shaped electric pulses rather than an actual mechanical stimulus (Nierhaus et al., 2015;Forschack et al., 2017;Perri et al., 2019). Popular dependent measures included a reduction in the power of Rolandic or mu rhythms (i.e. ...
Here we asked whether, similar to visual and auditory event-related potentials (ERPs), somatosensory ERPs reflect affect. Participants were stroked on hairy or glabrous skin at five stroking velocities (0.5, 1, 3, 10 and 20 cm/s). For stroking of hairy skin, pleasantness ratings related to velocity in an inverted u-shaped manner. ERPs showed a negativity at 400 ms following touch onset over somatosensory cortex contra-lateral to the stimulation site. This negativity, referred to as sN400, was larger for intermediate than for faster and slower velocities and positively predicted pleasantness ratings. For stroking of glabrous skin, pleasantness showed again an inverted u-shaped relation with velocity and, additionally, increased linearly with faster stroking. The sN400 revealed no quadratic effect and instead was larger for faster velocities. Its amplitude failed to significantly predict pleasantness. In sum, as was reported for other senses, a touch’s affective value modulates the somatosensory ERP. Notably, however, this ERP and associated subjective pleasantness dissociate between hairy and glabrous skin underscoring functional differences between the skin with which we typically receive touch and the skin with which we typically reach out to touch.
... While this prediction can be partially effective for the extreme categories of very high and very low hypnotizables, greater difficulties emerge for mediums, and this is likely due to the scoring issues discussed above. As an indirect confirmation, in a few recent studies mediums showed neither subjective nor neurophysiological differences with highs during hypnotic tasks to reduce sensory perception (Perri et al., 2020a;Perri, Rossani, & Di Russo, 2019) and cognitive conflict (Perri et al., 2020b). ...
Most of the experimental investigations on hypnosis used to compare small samples of individuals with low or high responsiveness to hypnosis by systematically excluding medium responders. The present article underlines the limitations of this methodological approach that may have partially weakened the scientific impact of hypnosis research. In fact, the mediums-neglecting bias might be one of the reasons why some investigations suffer from low replicability and generalizability. Themes such as hypnotizability scales, suggestibility, statistical power, and research design are critically reviewed with the aim of proposing a more rigorous approach that boost up impact and reliability of hypnosis research. In particular, the recruitment of medium hypnotizables and the adoption of a within-instead of a between-subjects design currently seem to be some of the best recommendations for strengthening hypnosis research, as well as to renew the dialogue between clinical and experimental hypnosis.
... Oftentimes, they compromise the sense of reality. Multiple studies have explored the neural underpinnings of hypnotic hallucination in vision (Kosslyn et al., 2000;Mazzoni et al., 2009;McGeown et al., 2012;Schmidt et al., 2017;Spiegel et al., 1985), audition (Franz et al., 2020;Szechtman et al., 1998), and somatosensory processing (Derbyshire et al., 2004;Perri et al., 2019). However, the nature of hypnotic hallucinations remains poorly understood. ...
Hypnotic suggestions can produce a broad range of perceptual experiences, including hallucinations. Visual hypnotic hallucinations differ in many ways from regular mental images. For example, they are usually experienced as automatic, vivid, and real images, typically compromising the sense of reality. While both hypnotic hallucination and mental imagery are believed to mainly rely on the activation of the visual cortex via top-down mechanisms, it is unknown how they differ in the neural processes they engage. Here we used an adaptation paradigm to test and compare top-down processing between hypnotic hallucination, mental imagery, and visual perception in very highly hypnotisable individuals whose ability to hallucinate was assessed. By measuring the N170/VPP event-related complex and using multivariate decoding analysis, we found that hypnotic hallucination of faces involves greater top-down activation of sensory processing through lateralised neural mechanisms in the right hemisphere compared to mental imagery. Our findings suggest that the neural signatures that distinguish hypnotically hallucinated faces from imagined faces lie in the right brain hemisphere.
... Current density in the SI, SII, and precuneus correlated linearly with subjective chronic pain, but not in the occipital-temporal and insula-ACC regions (Figs. 3 and 4). The SI and SII cortices are known as the initial receptive cortical areas for pain stimulation and they have neural connections to pain-related cortices, according to previous electroencephalography and MEG studies (Perri et al., 2019;Peyron and Fauchon, 2019). Reduction of neural density and connectivity among pain-related cortices that show linear correlation with subjective chronic pain suggested that pain processing in these brain areas was functionally disrupted by chronic pain in patients with CRPS. ...
... Resting-state cortical activity includes not only neural activities primarily caused by chronic pain, but also neural activities related to physical and mental conditions at the time of the measurement. Chronic pain-related psychological reactions such as fatigue, irritation, or uncomfortableness might cause neural activities and connectivity among sites responsible for such emotional reactions via top-down mechanisms (Arnau et al., 2017;Bushnell et al., 2013;Chen and Heinricher, 2019;Malfliet et al., 2017;Perri et al., 2019). It is difficult to distinguish primary pain-related cortical activity from that of secondary activity modulated by chronic pain that may have been sustained for months to years in patients with CRPS. ...
Quantitative objective measurement of chronic pain is important. We elucidated chronic pain-related cortical neural activity and neural connectivity among pain-related brain regions in complex regional pain syndrome (CRPS). Resting-state magnetoencephalography recordings were performed. Cortical current density and neural connectivity, revealed by amplitude envelope correlation (AEC), were estimated on standardized brain magnetic resonance imaging. Intra-experiment pain was assessed subjectively using a visual analogue scale (VAS). The correlation between current density and VAS scores was calculated for the occipital areas and pain-related cortices. Current density in the primary (SI) and secondary (SII) somatosensory cortex and precuneus in both hemispheres was negatively correlated with the pain VAS score. The AEC and VAS values were significantly correlated for the SII and the precuneus and for the SII and insular cortex in the alpha frequency band in the right hemisphere. In the theta frequency band, the AEC and VAS values correlated for the SII and posterior cingulate cortex in the right hemisphere. Our results suggested that disruption of pain processes and functions in the default mode network occurs in CRPS. Our method targeting the neural mechanism of pain has the potential to offer a clinically objective means of evaluating it.
... Because of these differences with clinical applications, the HGSHS:A is not an optimal or even useful predictor of suggestibility outside of screening sessions. This fact is reflected in the problems of standardized hypnotic-suggestibility scales in predicting outcomes of hypnotherapy (e.g., Alladin & Alibhai, 2007;Golden, 2012;Schoenberger, 2000), interventions for pain reduction (e.g., Perri, Rossani, & Di Russo, 2019) or interventions targeting modification of food preferences (e.g., Zahedi, Luczak, et al., 2020). A suitable hypnotic-suggestibility scale for clinical purposes might focus on simulation-adaptation suggestions as (a) these suggestions measure the interaction between cognitive-simulation (i.e., imagination) and sensory-adaptation (i.e., top-down driven downregulation of sensory input), which are the essential elements of suggestibility. ...
... (2) Do (posy)hypnotic suggestions affect perception or performance in specific tasks, such as those measuring cognitive functions (for review, see Kihlstrom, 2013;Kihlstrom, 2014)? Such studies, sometimes referred to as instrumental (Cox & Bryant, 2008;Wagstaff, 1996), ask, for instance, whether (post)hypnotic suggestions can subdue pain perception (e.g., Perri et al., 2019) or facilitate inhibition of irrelevant but intrusive information (e.g., Zahedi et al., 2019). ...
Individuals differ in their responsiveness to (post-)hypnotic suggestions. However, defining and measuring hypnotizability is contentious because standardized scales, such as the Harvard group scale (HGSHS:A), measure a mixture of general-suggestibility and its increase due to hypnotic induction (hypnotic-suggestibility). Exploratory factor analysis (FA) of standardized scales found them to be heterogeneous; however, the number and nature of latent factors are debated. We applied Confirmatory FA to HGSHS:A scores of 477 volunteers and tested several theory-driven models. Scores were best explained by a bifactor model consisting of a G-factor, tapping into hypnotizability, and three grouping factors, measuring specific suggestibilities, each requiring a unique combination of three top-down cognitive functions: cognitive-simulation, sensory-adaptation, and problem-solving. Structural equation modeling revealed that the simulation-adaptation factor (requiring cognitive-simulation and sensory-adaptation), predicts the other suggestibility factors. These results demonstrate the multifaceted structure of hypnotic-suggestibility and underscore the desideratum for developing a more differentiated scale, focusing on simulation-adaption suggestions.
... Oftentimes, they compromise the sense of reality. Multiple studies have explored the neural underpinnings of hypnotic hallucination in vision (Kosslyn et al., 2000;Mazzoni et al., 2009;McGeown et al., 2012;Schmidt et al., 2017;Spiegel et al., 1985), audition (Franz et al., 2020;Szechtman et al., 1998), and somatosensory processing (Derbyshire et al., 2004;Perri et al., 2019). However, the nature of hypnotic hallucinations remains poorly understood. ...
Hypnotic suggestions can produce a broad range of perceptual experiences, including hallucinations. Visual hypnotic hallucinations differ in many ways from regular mental images. For example, they are usually experienced as automatic, vivid, and real images, typically compromising the sense of reality. While both hypnotic hallucination and mental imagery are believed to mainly rely on the activation of the visual cortex via top-down mechanisms, it is unknown how they differ in the neural processes they engage. Here we used an adaptation paradigm to test and compare top-down processing between hypnotic hallucination, mental imagery, and visual perception in very highly hypnotisable individuals whose ability to hallucinate was assessed. By measuring the N170/VPP event-related complex and using multivariate decoding analysis, we found that hypnotic hallucination of faces involves greater top-down activation of sensory processing through lateralised mechanisms in the right hemisphere compared to mental imagery. Our findings suggest that the neural signatures that distinguish hypnotically hallucinated faces from imagined faces lie in the right brain hemisphere.
... Possible hypnotizability-related differences in the preference of visual or auditory perception, in terms of sensory thresholds and cortically evoked potentials, have not been systematically investigated, whereas somesthesia and pain have been largely studied (Perri et al., 2019). Nonetheless, current evidence indicates no significant difference between medium-highs and medium-lows in a study of visual processing speed (Friedman et al., 1986), and larger P300 amplitude and shorter N100 latency associated with auditory stimuli in highs with respect to lows (Kirenskaya et al., 2019). ...
This study investigated multisensory integration in 29 medium-to-high (mid-highs) and 24 low-to-medium (mid-lows) hypnotizable individuals , classified according to the Stanford Hypnotic Susceptibility Scale, Form A. Participants completed a simultaneity judgment (SJ) task, where an auditory and a visual stimulus were presented in close proximity to their body in a range of 11 stimulus onset asynchronies. Results show that mid-highs were prone to judge audiovisual stimuli as simultaneous over a wider range of time intervals between sensory stimuli, as expressed by a broader temporal binding window, when the visual stimulus precedes the auditory one. No significant difference was observed for response times. Findings indicate a role of hypnotizability in multisensory integration likely due to the highs' cerebellar peculiarities and/or sensory modality preference.
