Analysis of electrophysiological state patterns and changes during hypnosis induction

Gamma power and beta envelope correlation are potential neural predictors of deep hypnosis

Hypnosis is a psychological intervention that is commonly used to enhance the effectiveness of therapeutic suggestions. Despite extensive fascination and study, the neural mechanisms behind hypnosis remain elusive. In the current study, we undertook a systematic exploration of these neural correlates. We first extracted well-studied neurophysiological features from EEG sensors and source-localized data using spectral analysis and two measures of functional connectivity: weighted phase lag index (wPLI) and power envelope correlation (PEC). Next, we developed classification models that predicted self-rated hypnotic experience based on the extracted feature sets. Our findings reveal that gamma power computed on sensor-level data and beta PEC computed between source-localized brain networks are the top predictors of hypnosis depth. Further, a SHapley Additive exPlanations (SHAP) analysis suggested reduced gamma power in the midline frontal area and increased beta PEC between interhemispheric Dorsal Attention Networks (DAN) contribute to the hypnotic experience. These results broaden our understanding of the neural correlates of deep hypnosis, highlighting potential targets for future research. Moreover, this study demonstrates the potential of using predictive models in understanding the neural underpinnings of self-reported hypnotic depth, offering a template for future investigations.

Effectiveness and reliability of hypnosis in stereotaxy: a randomized study

BACKGROUND

Patients suffering from Parkinson's disease (PD) may experience pain during stereotactic frame (SF) fixation in deep brain stimulation (DBS). We assessed the role of hypnosis during the SF fixation in PD patients undergoing awake bilateral subthalamic nucleus (STN) DBS.

METHODS

N = 19 patients were included (N = 13 males, mean age 63 years; N = 10 allocated to the hypnosis and N = 9 allocated to the control groups). Patients were randomly assigned to the interventional (hypnosis and local anesthesia) or non-interventional (local anesthesia only) groups. The primary outcome was the pain perceived (the visual analogue scale (VAS)). Secondary outcomes were stress, anxiety, and depression, as measured by the perceived stress scale (PSS) and hospital anxiety and depression scale (HADS). Procedural distress was measured using the peritraumatic distress inventory (PDI-13).

RESULTS

In the hypnosis group, VASmean was 5.6 ± 2.1, versus 6.4 ± 1.2 in the control group (p = 0.31). Intervention and control groups reported similar VASmax scores (7.6 ± 2.1 versus 8.6 ± 1.6 (p = 0.28), respectively). Both groups had similar HADS scores (6.2 ± 4.3 versus 6.7 ± 1.92, p = 0.72 (HADSa) and 6.7 ± 4.2 versus 7.7 ± 3, p = 0.58 (HADSd)), so were the PSS scores (26.1 ± 6.3 versus 25.1 ± 7, p = 0.75). Evolutions of VASmean (R2 = 0.93, 95% CI [0.2245, 1.825], p = 0.03) and PDI-13 scores (R2 = 0.94, 95% CI [1.006, 6.279], p = 0.02) significantly differ over follow-up with patients in the hypnosis groups showing lower scores.

CONCLUSION

In this unblinded, randomized study, hypnosis does not influence pain, anxiety, and distress during awake SF fixation but modulates pain memory over time and may prevent the integration of awake painful procedures as a bad experience into the autobiographical memory of patients suffering from PD. A randomized controlled study with more data is necessary to confirm our findings.

Hypnosis measured with monitors of anesthetic depth - EEG changes during the test for Harvard Group Scale of Hypnotic Susceptibility

Introduction

Hypnotic trance can be defined as a non-ordinary state of consciousness that is accompanied by a number of neurophysiological changes, including brain electrophysiology. In addition to subjective measures, corresponding objective parameters are needed in experimental and clinical hypnosis research but are complex, impractical, or unspecific. A similar challenge exists for the measurement and monitoring of drug-induced hypnosis, namely general anesthesia. The observation of changes in EEG induced by narcotics has led to the development of monitors for the depth of anesthesia based on EEG parameters. We investigated whether two such monitors react to the induction and maintenance of hypnosis during a highly standardized procedure.

Methods

A total of 56 volunteers were monitored for the bispectral index (BIS) and cerebral state index (CSI) (range 0-100, >95 considered "awake") during the Harvard Group Scale of Hypnotic Susceptibility test. For this test, trance is induced by a taped text and followed by 12 tasks performed under hypnosis. In contrast to random forms of hypnosis, this represents a standardized, worldwide-established condition. According to the resulting score, participants were classified into suggestibility groups in order to evaluate whether the electrophysiological measurements of BIS and CIS indices differ between high and low suggestible persons. Furthermore, participants were asked to rate their hypnotic depth (HD, 1-10) at every task of the test.

Results

Scores dropped significantly from a mean of 97.7 to 86.4 for BIS and from 94.6 to 77.7 for CSI with the induction of hypnosis to stay throughout hypnosis at levels of approximately 88.6 or 82.9, respectively. Results did not differ between high- and low-suggestible participants. The means of the subjective score of hypnotic depth and of the electrophysiological measurements showed a similar course. However, no correlation was found between BIS or CSI values and scores of hypnotic depths.

Conclusion

Monitors for depth of anesthesia respond to changes in consciousness, including trance states of hypnosis. However, specificity is unclear. Practically, in hypnosis research with the exclusion of drug effects or sleep, these monitors might be helpful to test and compare the efficacy of induction texts and to detect disturbances of trance state.

Loss of free will in the Iranian criminal justice system: Interdisciplinary analysis of law and neuroscience

Today, with the development of neuroscience and the discovery of new secrets of the brain, the social sciences, including law, have made significant progress with the help of new findings in this science. One of the significant applications of neuroscience in modern criminal law is the explanation of the neurological dimensions of human free will, which in addition to creating a profound and scientific approach to the definition of this important element of criminal responsibility, can help ascertain the loss of free will causes. To this end, the present study is an attempt to answer this question in the context of the Iranian criminal justice system: What are the core causes of the loss of free will from the perspective of neurolaw? The paper strives to take an appropriate step toward the development of criminal justice. In this study, we found that mental disorders, coercion, drunkenness, somnambulism, and error are the core causes that can be assessed in particular ways using EEG and fMRI techniques, however, each with limitations.

Pre-Molecular Assessment of Self-Processes in Neurotypical Subjects Using a Single Cognitive Behavioral Intervention Evoking Autobiographical Memory

In the last 20 years, several contributions have been published on what concerns the conceptual and empirical connections between self-processes. However, only a limited number of publications addressed the viability of those processes to characterize mental health in neurotypical subjects with a normative pattern of neurodevelopment. Furthermore, even fewer experiments focused explicitly on the complexity of studying neurotypical phenomenal data. On the one hand, this normative pattern is commonly associated with mental health and a multifaceted self-concept and well-being. On the other hand, well-being is often related to a healthy cognitive life. However, how such intricate and complex relation between self-processes is established in neurotypical subjects requires further evidence. The novelty of this work is thus studying the first-person experience, which is correlated with the mental events aroused by a cognitive behavioral intervention. The prior methodology that led to the complete characterization of a neurotypical sample was already published by the authors, although the materials, the methods, the sample screening, and the sample size study required further explanation and exploration. This paper's innovation is hence the phenomenological assessment of subjects' self-regulation, which is used for mental health profiling, providing the basis for subsequent molecular typing. For that matter, a convenience sample of 128 (19-25-year-old) neurotypical young adults, healthy university students at the University of Lisbon, non-medicated and with no serious, uncontrolled, or chronic diseases, are characterized according to their cognitive functioning and self-concept. The procedure comprised (i) a mental status examination (psychological assessment) and (ii) a psychological intervention, i.e., a single cognitive behavioral intervention (intervention protocol). The psychological assessment was a standardized and structured clinical interview, which comprised the use of 4 psychological scales complementary to the classical Mental Status Examination (MSE). The intervention protocol applied a combined exercise of psychophysical training and autobiographical-self memory-recalling. The results permitted identifying and isolating four different subgroups (self awareness, self consciousness, reflective self, and pre-reflective self) in neurotypical subjects with discrete self-processes. The outcome of this study is screening four different aspects of self-reflection and the isolation between various forms of self-directed attention and their interconnections in these four mental health strata. The practical implication of this study is to fulfill an a priori pre-molecular assessment of self-regulation with separate cognitive characteristics. The reliability of these mental strata, their distinct neurophysiology, and discrete molecular fingerprint will be tested in a future publication by in silico characterization, total protein profiling, and simultaneous immunodetection of the neuropeptide and neuroimmune response of the same participants.

Hypnotizability May Relate to Interoceptive Ability to Accurately Perceive Sleep Depth: An Exploratory Study

When individuals score high on hypnotizability, they usually report experiencing an altered state of consciousness, physiological changes, and attentional shifts during hypnotic induction procedures as well. We hypothesize that a better interoception of such internal changes is also relevant for accurate sleep perception. We compared subjects scoring high versus low on hypnotizability to the accuracy of their estimations of Sleep Onset Latency (SOL) time awake, and sleep depth and explored their objective sleep. We sampled seven studies performed in our sleep labs across a midday nap or a night resulting in n = 231 subjects (aged 30.11 (SD = 17.02) years, range 18-82 with 15.2% males). Hypnotizability did not influence the accuracy of the perception of time needed to fall asleep or time spent awake. However, the reported sleep depth correlated significantly with the measured amount of slow-wave sleep in high hypnotizables. This pattern appeared across a nap as well as a whole night's sleep studies. We did not find any significant differences in objective sleep patterns depending on hypnotizability. Probably, high hypnotizables benefit from a better interoceptive ability for their perception of their sleep depth.

Linear and Nonlinear Quantitative EEG Analysis during Neutral Hypnosis following an Opened/Closed Eye Paradigm

Hypnotic susceptibility is a major factor influencing the study of the neural correlates of hypnosis using EEG. In this context, while its effects on the response to hypnotic suggestions are undisputed, less attention has been paid to “neutral hypnosis” (i.e., the hypnotic condition in absence of suggestions). Furthermore, although an influence of opened and closed eye condition onto hypnotizability has been reported, a systematic investigation is still missing. Here, we analyzed EEG signals from 34 healthy subjects with low (LS), medium (MS), and (HS) hypnotic susceptibility using power spectral measures (i.e., TPSD, PSD) and Lempel-Ziv-Complexity (i.e., LZC, fLZC). Indeed, LZC was found to be more suitable than other complexity measures for EEG analysis, while it has been never used in the study of hypnosis. Accordingly, for each measure, we investigated within-group differences between rest and neutral hypnosis, and between opened-eye/closed-eye conditions under both rest and neutral hypnosis. Then, we evaluated between-group differences for each experimental condition. We observed that, while power estimates did not reveal notable differences between groups, LZC and fLZC were able to distinguish between HS, MS, and LS. In particular, we found a left frontal difference between HS and LS during closed-eye rest. Moreover, we observed a symmetric pattern distinguishing HS and LS during closed-eye hypnosis. Our results suggest that LZC is better capable of discriminating subjects with different hypnotic susceptibility, as compared to standard power analysis.

No evidence for theta power as a marker of hypnotic state in highly hypnotizable subjects

EEG spectral-power density was analyzed in a group of nine highly hypnotizable subjects via ten frontal, central, parietal, and occipital electrodes under four conditions: 1) wake state, 2) neutral hypnosis, 3) hypnotic suggestion for altering perception of tones, and 4) post-hypnosis. Results indicate no theta-power changes between conditions, challenging previous findings that increased theta power is a marker of hypnosis. A decrease in gamma power under hypnotic suggestion and an almost significant decrease under neutral hypnosis were observed, compared to post-hypnosis. Anteroposterior power distribution remained stable over all conditions. The results are discussed and compared to earlier studies, which report heterogenous findings.

Current neuroscientific research database findings of brain activity changes after hypnosis

Using multi-modal brain imaging techniques we found pronounced changes in neuronal activity after hypnotic trance induction whereby state changes seem to occur synchronously with the specific induction instructions. In clinical patients, hypnosis proved to be a powerful method in inhibiting the reaction of the fear circuitry structures. The aim of the present paper is to critically discuss the limitations of the current neuroscientific research database in the light of a debate in defining relevant hypnotic constructs and to suggest ideas for future research projects. We discuss the role of hypnotic suggestibility (HS), the impact of hypnotic inductions and the importance of the depth of hypnotic trance. We argue that future research on brain imaging studies on the effects of hypnosis and hypnotherapy should focus on the analysis of individual cross-network activation patterns. A most promising approach is to simultaneously include physiological parameters linked to cognitive, somatic, and behavioral effects.

FUNCTIONAL CHANGES IN BRAIN ACTIVITY AFTER HYPNOSIS: Neurobiological Mechanisms and Application to Patients with a Specific Phobia-Limitations and Future Directions

Studies of brain-plasticity changes in hypnosis using functional magnetic resonance imaging (fMRI), positron-emission-tomography (PET) and electroencephalography (EEG) were reviewed. The authors found evidence in those studies that hypnosis is a powerful and successful method for inhibiting the reaction of the fear circuitry structures. Limitations of the studies were critically discussed, and implications for future research were made. The authors are currently using a portable fNIRS apparatus to integrate the scanning device into real life situations in medical practice. Their aim is to disentangle the neuronal mechanisms and physiological correlates in patients with severe fear of medical treatments when directly confronted with anxiety-provoking stimuli and to assess the effects of a brief hypnosis. Drawing on evidence from several technological modalities, neuroimaging and physiological studies pave the road to a better scientific understanding of neural mechanisms of hypnosis.

Investigation on the Neural Mechanism of Hypnosis-Based Respiratory Control Using Functional MRI

Respiratory control is essential for treatment effect of radiotherapy due to the high dose, especially for thoracic-abdomen tumor, such as lung and liver tumors. As a noninvasive and comfortable way of respiratory control, hypnosis has been proven effective as a psychological technology in clinical therapy. In this study, the neural control mechanism of hypnosis for respiration was investigated by using functional magnetic resonance imaging (fMRI). Altered spontaneous brain activity as well as neural correlation of respiratory motion was detected for eight healthy subjects in normal state (NS) and hypnosis state (HS) guided by a hypnotist. Reduced respiratory amplitude was observed in HS (mean ± SD: 14.23 ± 3.40 mm in NS, 12.79 ± 2.49 mm in HS, p=0.0350), with mean amplitude deduction of 9.2%. Interstate difference of neural activity showed activations in the visual cortex and cerebellum, while deactivations in the prefrontal cortex and precuneus/posterior cingulate cortex (PCu/PCC) in HS. Within these regions, negative correlations of neural activity and respiratory motion were observed in visual cortex in HS. Moreover, in HS, voxel-wise neural correlations of respiratory amplitude demonstrated positive correlations in cerebellum anterior lobe and insula, while negative correlations were shown in the prefrontal cortex and sensorimotor area. These findings reveal the involvement of cognitive, executive control, and sensorimotor processing in the control mechanisms of hypnosis for respiration, and shed new light on hypnosis performance in interaction of psychology, physiology, and cognitive neuroscience.

ENHANCING IMPLICIT LEARNING WITH POSTHYPNOTIC SUGGESTION: An ERP Study

Can posthypnotic suggestion (PHS) enhance cognitive abilities? The authors tested behaviorally and with event-related potentials (ERP) if sequential learning (SL), the ability to learn statistical regularities, can be enhanced with PHS. Thirty adults were assessed with the Stanford Hypnotic Susceptibility Scale (Form C) and an auditory SL task. Before this task, half the sample received a PHS to enhance SL, and the other half received the same suggestion under normal waking state. Response times and ERPs indicated a strong effect of PHS. Compared to the control group, PHS inverted, attenuated, or left unaffected the response time SL effect in low, medium, and high hypnotizability participants, respectively. These results suggest that PHS cannot be used to enhance SL.

Neural mechanisms of hypnosis and meditation

Hypnosis has been an elusive concept for science for a long time. However, the explosive advances in neuroscience in the last few decades have provided a "bridge of understanding" between classical neurophysiological studies and psychophysiological studies. These studies have shed new light on the neural basis of the hypnotic experience. Furthermore, an ambitious new area of research is focusing on mapping the core processes of psychotherapy and the neurobiology/underlying them. Hypnosis research offers powerful techniques to isolate psychological processes in ways that allow their neural bases to be mapped. The Hypnotic Brain can serve as a way to tap neurocognitive questions and our cognitive assays can in turn shed new light on the neural bases of hypnosis. This cross-talk should enhance research and clinical applications. An increasing body of evidence provides insight in the neural mechanisms of the Meditative Brain. Discrete meditative styles are likely to target different neurodynamic patterns. Recent findings emphasize increased attentional resources activating the attentional and salience networks with coherent perception. Cognitive and emotional equanimity gives rise to an eudaimonic state, made of calm, resilience and stability, readiness to express compassion and empathy, a main goal of Buddhist practices. Structural changes in gray matter of key areas of the brain involved in learning processes suggest that these skills can be learned through practice. Hypnosis and Meditation represent two important, historical and influential landmarks of Western and Eastern civilization and culture respectively. Neuroscience has beginning to provide a better understanding of the mechanisms of both Hypnotic and Meditative Brain, outlining similarities but also differences between the two states and processes. It is important not to view either the Eastern or the Western system as superior to the other. Cross-fertilization of the ancient Eastern meditation techniques presented with Western modern clinical hypnosis will hopefully result in each enriching the other.

Hypnotic suggestion alters the state of the motor cortex

Hypnosis often leads people to obey a suggestion of movement and to lose perceived voluntariness. This inexplicable phenomenon suggests that the state of the motor system may be altered by hypnosis; however, objective evidence for this is still lacking. Thus, we used transcranial magnetic stimulation of the primary motor cortex (M1) to investigate how hypnosis, and a concurrent suggestion that increased motivation for a force exertion task, influenced the state of the motor system. As a result, corticospinal excitability was enhanced, producing increased force exertion, only when the task-motivating suggestion was provided during hypnotic induction, showing that the hypnotic suggestion actually altered the state of M1 and the resultant behavior.

Hipnose, imobilidade tônica e eletroencefalograma

OBJETIVO: Apresentar uma revisão sobre as características da atividade elétrica cerebral que acompanha a hipnose animal, estado induzido em laboratório em mamíferos por manipulações experimentais, bem como sobre as alterações encontradas no EEG durante o estado de hipnose, visando à discussão dos resultados encontrados na busca de evidências dos fundamentos filogenéticos que possam conduzir ao entendimento dos rudimentos neurais da hipnose humana. MÉTODO: Livros e bases eletrônicas de dados foram consultados. Critério de inclusão: artigos originais publicados entre 1966-2012. Critério de exclusão: artigos que se afastavam da visão eletroneurofisiológica da hipnose. RESULTADOS: Foram encontradas 662 referências, tendo sido selecionados os artigos e livros referenciados. Além desses artigos, foi incluído no estudo o artigo de Hoagland, publicado em 1928, que é um clássico na área de imobilidade tônica em vertebrados. CONCLUSÕES: O estado de hipnose humano resulta de processamentos em inúmeros circuitos paralelos distribuídos em uma complexa rede neuronal, envolvendo, dessa forma, uma ampla área do encéfalo. Na trajetória evolutiva, a grande ampliação dos recursos corticais pode ter tornado as respostas de imobilidade tônica passíveis de modulação consciente, respostas essas ainda presentes nos humanos e que se manifestam involuntariamente em situações de grande ameaça. Vários estudos têm evidenciado mecanismos neurofisiológicos capazes de reforçar a visão da hipnose não só como um eficiente recurso para procedimentos médicos e odontológicos, funcionando como auxiliar na analgesia e sedação, mas também como excelente ferramenta psicoterapêutica.

Neurophysiology of hypnosis

We here review behavioral, neuroimaging and electrophysiological studies of hypnosis as a state, as well as hypnosis as a tool to modulate brain responses to painful stimulations. Studies have shown that hypnotic processes modify internal (self awareness) as well as external (environmental awareness) brain networks. Brain mechanisms underlying the modulation of pain perception under hypnotic conditions involve cortical as well as subcortical areas including anterior cingulate and prefrontal cortices, basal ganglia and thalami. Combined with local anesthesia and conscious sedation in patients undergoing surgery, hypnosis is associated with improved peri- and postoperative comfort of patients and surgeons. Finally, hypnosis can be considered as a useful analogue for simulating conversion and dissociation symptoms in healthy subjects, permitting better characterization of these challenging disorders by producing clinically similar experiences.

Neuro-hypnotism: prospects for hypnosis and neuroscience

The neurophysiological substrates of hypnosis have been subject to speculation since the phenomenon got its name. Until recently, much of this research has been geared toward understanding hypnosis itself, including the biological bases of individual differences in hypnotizability, state-dependent changes in cortical activity occurring with the induction of hypnosis, and the neural correlates of response to particular hypnotic suggestions (especially the clinically useful hypnotic analgesia). More recently, hypnosis has begun to be employed as a method for manipulating subjects' mental states, both cognitive and affective, to provide information about the neural substrates of experience, thought, and action. This instrumental use of hypnosis is particularly well-suited for identifying the neural correlates of conscious and unconscious perception and memory, and of voluntary and involuntary action.

The facilitating effect of clinical hypnosis on motor imagery: an fMRI study

Hypnosis is increasingly being employed in therapy of neurologically impaired patients. In fact, reports from neuropsychological practice point out that neurological patients with a loss of motor abilities achieve successful rehabilitation by means of motor imagery during hypnosis. This approach was shown to be effective even if the patients' ability to imagine movements was impaired or lost. The underlying mechanisms of "how" and "where" hypnosis affects the brain, however, are largely unknown. To identify the brain areas involved in motor imagery under hypnosis, we conducted an fMRI study in which we required healthy human subjects either to imagine or to execute repetitive finger movements during a hypnotic trance. We observed fMRI-signal increases exclusively related to hypnosis in the left superior frontal cortex, the left anterior cingulate gyrus and left thalamus. While the superior frontal cortex and the anterior cingulate were active related more to movement performance than to imagery, the thalamus was activated only during motor imagery. These areas represent central nodes of the salience network linking primary and higher motor areas. Therefore, our data substantiate the notion that hypnosis enhances motor imagery.

Single-session manualized ego state therapy (EST) for combat stress injury, PTSD, and ASD, part 1: the theory

Ego state therapy (EST) evolved from a psychodynamic understanding of personality as a product of an individual's ego states to a conceptualization of how ego-energized and object-energized elements are bound together to cope with a traumatic event. Neurobiological studies now substantiate Watkins's war neuroses conceptualizations. Because of their severity, trauma memories are encoded in the subcortical-subconscious brain regions that are accessed by the single-session manualized EST procedure but not by the popular cognitive-behavioral management therapies. The imprint of the trauma is not accessible or resolvable by such top-down verbal understanding or reframing; EST is a bottom-up therapy. Abreactive hypnosis facilitates ego state expression at physiologically and psychologically intense levels sufficient to activate subcortical processes to release affect in the presence of the therapist, who adds ego strength to the patient. This is followed by interpretation and reintegration. The result is a reconstructed personality that is adaptive and resilient.