Hypnosis attenuates executive cost of prospective memory

Prospective memory is defined as the ability to formulate and carry out actions at the appropriate time, or in the appropriate context. The aim of this study was to identify the effect of hypnosis on prospective memory performance and to analyze the involvement of executive control processes in intention realization in a hypnotically altered state of consciousness. In one experiment, manipulating hypnotic instruction in a within-subject fashion, we explored event based prospective memory performance in three conditions – baseline, expectation and execution - of twenty-three volunteers. Our main result is that executing prospective memory responses, at the same accuracy rate, produced a significantly lower cost of ongoing responses in terms of response latency in the hypnotic state than in wake condition

The Role of Frontal Executive Functions in Hypnosis and Hypnotic Suggestibility

There is both theoretical and empirical evidence supporting a role for frontal executive functions (FEFs) in hypnosis and hypnotic suggestibility. However, the precise nature of this involvement is debated. While there is clear evidence that FEFs are impaired under hypnosis, the cause of this decreased function is unclear. Theories make differing predictions as to the role of FEFs in hypnotic suggestibility, with some arguing that decreased baseline (normal function outside of the hypnotic context) FEFs lead to greater hypnotic suggestibility and others arguing that increased baseline FEFs lead to greater hypnotic suggestibility. Other theories posit that suggestibility is more a consequence of attitude rather than aptitude. The present work provides a critical review of the involvement of FEFs in hypnosis and hypnotic suggestibility. The review considers behavioral evidence from studies employing putative frontal lobe tasks including tests of fluid intelligence and both task- and nontask-based neuroimaging evidence. It is determined that the evidence to date is inconclusive and that more work is needed to establish a necessary and sufficient role for FEFs in hypnosis or hypnotic suggestibility. Recommendations are made for future research

Now You See One Letter, Now You See Meaningless Symbols: Perceptual and Semantic Hypnotic Suggestions Reduce Stroop Errors Through Different Neurocognitive Mechanisms

4noCompelling literature has suggested the possibility of adopting hypnotic suggestions to override the Stroop interference effect. However, most of these studies mainly reported behavioral data and were conducted on highly hypnotizable individuals. Thus, the question of the neural locus of the effects and their generalizability remains open. In the present study, we used the Stroop task in a within-subject design to test the neurocognitive effects of two hypnotic suggestions: the perceptual request to focus only on the central letter of the words and the semantic request to observe meaningless symbols. Behavioral results indicated that the two types of suggestions did not alter response time (RT), but both favored more accurate performance compared to the control condition. Both types of suggestions increased sensory awareness and reduced discriminative visual attention, but the perceptual request selectively engaged more executive control of the prefrontal cortex (PFC), and the semantic request selectively suppressed the temporal cortex activity devoted to graphemic analysis of the words. The present findings demonstrated that the perceptual and the semantic hypnotic suggestions reduced Stroop errors through common and specific top-down modulations of different neurocognitive processes but left the semantic activation unaltered. Finally, as we also recruited participants with a medium level of hypnotizability, the present data might be considered potentially representative of the majority of the population.openopenPerri R.L.; Bianco V.; Facco E.; Di Russo F.Perri, R. L.; Bianco, V.; Facco, E.; Di Russo, F

Structural and functional cerebral correlates of hypnotic suggestibility

Little is known about the neural bases of hypnotic suggestibility, a cognitive trait referring to the tendency to respond to hypnotic suggestions. In the present magnetic resonance imaging study, we performed regression analyses to assess hypnotic suggestibility-related differences in local gray matter volume, using voxel-based morphometry, and in waking resting state functional connectivity of 10 resting state networks, in 37 healthy women. Hypnotic suggestibility was positively correlated with gray matter volume in portions of the left superior and medial frontal gyri, roughly overlapping with the supplementary and pre-supplementary motor area, and negatively correlated with gray matter volume in the left superior temporal gyrus and insula. In the functional connectivity analysis, hypnotic suggestibility was positively correlated with functional connectivity between medial posterior areas, including bilateral posterior cingulate cortex and precuneus, and both the lateral visual network and the left fronto-parietal network; a positive correlation was also found with functional connectivity between the executive-control network and a right postcentral/parietal area. In contrast, hypnotic suggestibility was negatively correlated with functional connectivity between the right fronto-parietal network and the right lateral thalamus. These findings demonstrate for the first time a correlation between hypnotic suggestibility, the structural features of specific cortical regions, and the functional connectivity during the normal resting state of brain structures involved in imagery and self-monitoring activity

The contrasting role of higher order awareness in hypnosis and meditation

Two key questions underpin the research presented here. Firstly, how does altered higher order awareness contribute to hypnotic experience? Secondly, how do meditation and hypnosis differ in terms of the role of higher order awareness? These questions are addressed here in the form of four papers. In the first paper I review the literatures of hypnosis and meditation in order to consider the similarities and differences between meditation and hypnosis in terms of the role of attentional skill and the neural underpinnings of each. I then draw conclusions regarding the contrasting role of higher order awareness and metacognition in meditation and hypnosis. Paper two explores higher order awareness in hypnosis by comparing the effects of alcohol, compared to placebo, on hypnotisability and associated frontal lobe executive functioning. Paper three compares meditation and hypnosis by investigating differences in higher order thoughts, mindfulness, absorption and perceptual encoding style as revealed by self-report measures. The final paper takes a broader look at higher order awareness and its relation to the experience of agency and involuntariness in hypnotic suggestion using a Libet type paradigm

Classes of Multichannel EEG Microstates in Light and Deep Hypnotic Conditions

The study assessed the brain electric mechanisms of light and deep hypnotic conditions in the framework of EEG temporal microstates. Multichannel EEG of healthy volunteers during initial resting, light hypnosis, deep hypnosis, and eventual recovery was analyzed into temporal EEG microstates of four classes. Microstates are defined by the spatial configuration of their potential distribution maps (‹potential landscapes') on the head surface. Because different potential landscapes must have been generated by different active neural assemblies, it is reasonable to assume that they also incorporate different brain functions. The observed four microstate classes were very similar to the four standard microstate classes A, B, C, D [Koenig, T. etal. Neuroimage, 2002;16: 41-8] and were labeled correspondingly. We expected a progression of microstate characteristics from initial resting to light to deep hypnosis. But, all three microstate parameters (duration, occurrence/second and %time coverage) yielded values for initial resting and final recovery that were between those of the two hypnotic conditions of light and deep hypnosis. Microstates of the classes B and D showed decreased duration, occurrence/second and %time coverage in deep hypnosis compared to light hypnosis; this was contrary to microstates of classes A and C which showed increased values of all three parameters. Reviewing the available information about microstates in other conditions, the changes from resting to light hypnosis in certain respects are reminiscent of changes to meditation states, and changes to deep hypnosis of those in schizophrenic state

Functional Brain Basis of Hypnotizability

Context Focused hypnotic concentration is a model for brain control over sensation and behavior. Pain and anxiety can be effectively alleviated by hypnotic suggestion, which modulates activity in brain regions associated with focused attention, but the specific neural network underlying this phenomenon is not known. Objective To investigate the brain basis of hypnotizability. Design Cross-sectional, in vivo neuroimaging study performed from November 2005 through July 2006. Setting Academic medical center at Stanford University School of Medicine. Patients Twelve adults with high and 12 adults with low hypnotizability. Main Outcome Measures Functional magnetic resonance imaging to measure functional connectivity networks at rest, including default-mode, salience, and executive-control networks; structural T1 magnetic resonance imaging to measure regional gray and white matter volumes; and diffusion tensor imaging to measure white matter microstructural integrity. Results High compared with low hypnotizable individuals had greater functional connectivity between the left dorsolateral prefrontal cortex, an executive-control region of the brain, and the salience network composed of the dorsal anterior cingulate cortex, anterior insula, amygdala, and ventral striatum, involved in detecting, integrating, and filtering relevant somatic, autonomic, and emotional information using independent component analysis. Seed-based analysis confirmed elevated functional coupling between the dorsal anterior cingulate cortex and the dorsolateral prefrontal cortex in high compared with low hypnotizable individuals. These functional differences were not due to any variation in brain structure in these regions, including regional gray and white matter volumes and white matter microstructure. Conclusions Our results provide novel evidence that altered functional connectivity in the dorsolateral prefrontal cortex and dorsal anterior cingulate cortex may underlie hypnotizability. Future studies focusing on how these functional networks change and interact during hypnosis are warranted

Dissociated control as a signature of typological variability in high hypnotic suggestibility

This study tested the prediction that dissociative tendencies modulate the impact of a hypnotic induction on cognitive control in different subtypes of highly suggestible individuals. Low suggestible (LS), low dissociative highly suggestible (LDHS), and high dissociative highly suggestible (HDHS) participants completed the Stroop colornaming task in control and hypnosis conditions. The magnitude of conflict adaptation (faster response times on incongruent trials preceded by an incongruent than those preceded by a congruent trial) was used as a measure of cognitive control. LS and LDHS participants displayed marginally superior up-regulation of cognitive control following a hypnotic induction, whereas HDHS participants’ performance declined. These findings indicate that dissociative tendencies modulate the influence of a hypnotic induction on cognitive control in high hypnotic suggestibility and suggest that HS individuals are comprised of distinct subtypes with dissimilar cognitive profiles