Frontal lobe contributions to hypnotic susceptibility: a neuropsychological screening of executive functioning

In medio stat virtus: The importance of studying mediums in hypnosis research

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.

Functional connectivity of thalamus in children with primary nocturnal enuresis: results from a resting-state fMRI study

Primary nocturnal enuresis (PNE) is characterized by a low cure rate and a high reoccurrence rate, since its underlying mechanism remains unclear. Based on the recent studies that thalamus plays an important role in waking up a sleeping person, here we further investigate the functional connectivity (FC) information between thalamus and other brain regions, in order to make better understanding of the PNE's pathogenesis. In this study, we enrolled 30 children diagnosed with PNE and 30 typically developing children that are age and sex matched, the thalamus-based FC estimates were extracted at the resting-state. Experiments showed that for children with PNE, there were four brain regions found with a reduced connection efficiency with thalamus, that were cerebellum posterior lobe, frontal lobe, parietal lobe and precentral gyrus. It can be concluded that these relevant regions might induce an arousal disorder, and therefore further lead to PNE. This finding also provides a new insight in the pathophysiology of PNE.

Shared cognitive mechanisms of hypnotizability with executive functioning and information salience

In recent years, evidence linked hypnotizability to the executive control and information salience networks, brain structures that play a role in cognitive conflict resolution and perseveration (insisting on applying a previously learned logical rule on a new set). Despite the growing body of neuroimaging evidence, the cognitive phenotype of hypnotizability is not well understood. We hypothesized that higher hypnotizability would correspond to lower perseveration and set-shifting. Seventy-two healthy adults were tested for hypnotizability and executive functions (perseveration and set-shifting). Multiple regression analyses were performed to test the relationship between hypnotizability and perseveration and set-shifting. Higher hypnotizability was associated with lower perseveration after accounting for age and education. Hypnotizability significantly predicted perseveration but not set-shifting. Our results indicate an inverse relationship between trait hypnotizability and perseveration, an executive function that utilizes regions of both the executive control and the salience systems. This suggests that hypnotizability may share a common cognitive mechanism with error evaluation and implementation of logical rules.

The interoception and imagination loop in hypnotic phenomena

We tested a working hypothesis that the ideomotor and motor-control suggestions measured by current hypnotizability scales depend on the activation of an interoception-imagination processing loop. In three experiments, participants were exposed to an induction phase, Items 3 (mosquito hallucination) and 8 (arm immobilization) of the Stanford Hypnotic Susceptibility Scale, Form C, and a new version of Item 8 involving the additional activation of imaginative and interoception processes. We found that this modified version of Item 8 elicited greater responsiveness to suggestion, irrespective of its position in the sequence of hypnotic items. We argue that this interoception-imagination loop hypothesis provides a useful information processing analysis for understanding several hypnotic phenomena.

Flexibility in processing visual information: effects of mood and hypnosis

This quasi-experiment using a real/simulator model investigated differences in cognitive flexibility in high and low hypnotizable participants. Using the variables of hypnotizability (low/high), consciousness (nonhypnotized/hypnotized), mood (happy/sad), and visual-information processing (global/local), reaction times and target detection paradigms of the subjects were evaluated during both nonhypnotic and hypnotic states. Flexibility in cognitive processing was operationalized as the ability to overcome the typical global precedence and answer quickly about the nonprevalent local features. It was observed that the low hypnotizable participants were not influenced in their preference for the global or local dimension by any manipulated variable, whereas the high hypnotizables were more flexible.

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 ([Symbol: see text]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. et al. 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 states.

Effects of age on responsiveness to adjunct hypnotic analgesia during invasive medical procedures

OBJECTIVES

To assess the effects of age on responsiveness to self-hypnotic relaxation as an analgesic adjunct in patients undergoing invasive medical procedures.

MATERIAL AND METHODS

Secondary data analysis from a prospective trial with 241 patients randomized to receive hypnosis, attention, and standard care treatment during interventional radiological procedures. Growth curve analyses, hierarchical linear regressions, and logistic regressions using orthogonal contrasts were used for analysis. Outcome measures were Hypnotic Induction Profile scores, self-reported pain and anxiety, medication use, oxygen desaturation < or =89%, and procedure time.

RESULTS

Hypnotizability did not vary with age (p = .19). Patients receiving attention and hypnosis had greater pain reduction during the procedure (p = .02), with trends toward lower pain with hypnosis (p = .07); this did not differ by age. As age increased, patients experienced more rapid pain control with hypnosis (p = .03). There was more rapid anxiety reduction with attention and hypnosis (p = .03). Trends toward lower final anxiety were also observed with attention and hypnosis versus standard care (p = .08), and with hypnosis versus attention (p = .059); these relationships did not differ by age. Patients requested and received less medication and had less oxygen desaturation < or =89% with attention and hypnosis (p < .001); this did not differ by age. However, as age increased, oxygen desaturation was greater in standard care (p = .03). Procedure time was reduced in the attention and hypnosis groups (p = .007); this did not vary by age.

CONCLUSIONS

Older patients are hypnotizable and increasing age does not appear to mitigate the usefulness of hypnotic analgesia during invasive medical procedures.

Hypnosis decouples cognitive control from conflict monitoring processes of the frontal lobe

Hypnosis can profoundly alter sensory awareness and cognitive processing. While the cognitive and behavioral phenomena associated with hypnosis have long been thought to relate to attentional processes, the neural mechanisms underlying susceptibility to hypnotic induction and the hypnotic condition are poorly understood. Here, we tested the proposal that highly hypnotizable individuals are particularly adept at focusing attention at baseline, but that their attentional control is compromised following hypnosis due to a decoupling between conflict monitoring and cognitive control processes of the frontal lobe. Employing event-related fMRI and EEG coherence measures, we compared conflict-related neural activity in the anterior cingulate cortex (ACC) and control-related activity in the lateral frontal cortex (LFC) during Stroop task performance between participants of low and high hypnotic susceptibility, at baseline and after hypnotic induction. The fMRI data revealed that conflict-related ACC activity interacted with hypnosis and hypnotic susceptibility, in that highly susceptible participants displayed increased conflict-related neural activity in the hypnosis condition compared to baseline, as well as with respect to subjects with low susceptibility. Cognitive-control-related LFC activity, on the other hand, did not differ between groups and conditions. These data were complemented by a decrease in functional connectivity (EEG gamma band coherence) between frontal midline and left lateral scalp sites in highly susceptible subjects after hypnosis. These results suggest that individual differences in hypnotic susceptibility are linked with the efficiency of the frontal attention system, and that the hypnotized condition is characterized by a functional dissociation of conflict monitoring and cognitive control processes.

Hypnotic susceptibility, baseline attentional functioning, and the Stroop task

According to the theoretical framework relating hypnosis to attention, baseline attentional functioning in highly hypnotizable individuals should be more efficient than in low hypnotizable individuals. However, previous studies did not find differences in Stroop-like tasks in which the measure indicative of the Stroop interference effect was based on response latencies. This study was designed to determine whether subjects with different levels of hypnotic susceptibility show differences in baseline attentional functioning. To assess this hypothesis, high, medium, and low hypnotizable subjects performed a Stroop task designed to evaluate accuracy performance, before being subjected to hypnotic induction. Results showed that the Stroop interference effect was smaller in high hypnotizable subjects than in low hypnotizable subjects, whereas it was not different between high, and medium hypnotizable subjects. This outcome supports the notion that baseline attentional functioning is related to hypnotic susceptibility.

Mesmer minus magic: hypnosis and modern medicine

The implications and effects of the French commission that passed judgment on Mesmer's work is examined in light of the pioneering role of hypnosis as the first Western conception of a psychotherapy, the ancient philosophical debate between idealism and empiricism, and the conflict in modern medicine between biotechnological emphasis on cure and the need for care as many previously terminal illnesses are converted to chronic diseases. The panel's report is interpreted as negative about the literal theory of animal magnetism but actually supportive of the potential therapeutic power of suggestion and "positive thinking." This aspect of hypnosis is described as a forerunner of modern cognitive therapies of depression and other illnesses. The panel exerted a constructive effect in applying scientific method and rigorous evaluation to hypnotic treatment, an application of Enlightenment philosophy that presaged the Flexner era in modern medicine. Both hypnosis and medicine ultimately benefited.

Hypnosis, the brain, and sports: Salient Findings July 2002

Three particularly noteworthy articles addressing hypnosis have been published during the early portion of 2002. All, to a degree, address biological aspects of hypnotic response. One of these articles is a thoughtful summary and synthesis of neuroscience/hypnosis research to date, describing how neuroimaging techniques offer new opportunities to use hypnosis as a manipulation and to provide a means of studying hypnosis itself. A second article focuses on the physiology of sports and the usefulness of hypnosis in the practice of sport and exercise psychology. Finally, the third article describes a study of brain activation during actual and imagined handgrip during hypnosis.