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Functional Neuroimaging Studies of Hypnosis and Meditation: A Comparative Perspective
Abstract
Over the last few decades, an increasing number of functional neuroimaging studies have been performed with respect to hypnosis and meditation. The objective of this article is to review a num-ber of these studies to compare the neural substrates related to different components of hypnosis and meditation. We examine neuroimaging studies conducted to explore the impact of hypnosis on the brain regions and systems involved in color perception, hand paralysis, pain, and the default-mode network (DMN). We also review neuroimaging investigations carried out to examine the neural correlates of various meditation techniques, as well as the effects of meditation on the brain mechanisms related to emotion, pain, and the DMN. Given the discrepancy existing between the findings from neuroimaging studies of hypnosis and meditation carried out in regard to pain and the DMN, we conclude that it is premature to claim that hypnosis and meditation are mediated by similar brain systems and neural mechanisms.
... Neurophysiological studies have demonstrated that hypnosis is different from the effects brought by placebo and sleep (1). The use of Positron Emission Tomography (PET) demonstrated that during hypnosis there is an activation of the anterior cingulate cortex in the brain, capable of modifying the perceptions of a person as to reduce painful stimuli (2,3). ...
Background and aim of the study
Much evidence shows that hypnotic communication can have a pain-relieving effect and reduce complications such as anxiety, insomnia and depression. Whenever this technique was applied, the use of pharmaceuticals was reduced, there were fewer side effects, shorter hospitalization times frames and lower treatment costs. The aim of this study is to evaluate the knowledge and perceptions of nurses about hypnotic communication and the causes for which this technique is not frequently used. A secondary objective pointed to measuring the effectiveness of an educational event on hypnosis.
Method
The evaluation was done by directly administering an anonymous and voluntary survey created ad hoc, in a pre-test and post-test modality, to nurses subscribed to a four-hour formative event on hypnotic communication organized in 2019 by the Nursing Order, Province of Ravenna.
Results
78 nurses (85.7%) participated in the study. The analysis of the pre-test results shows a gap of knowledge regarding hypnotic communication. The variation of answers between the pre-test and post-test (T-Student) has shown a radical difference in knowledge (95%-100% correct answers). The main causes were found regarding the lack of use for hypnotic communication: stereotypes and prejudices related to this technique and insufficient university education.
Conclusions
The implementation of this technique, effective and efficient under various aspects, requires a preliminary creation of culture regarding this theme, capable of surpassing the stereotypes and resistances brought by a lack of theoretical elements.
... Contrary to a recent review concluding that there is little evidence for shared mechanisms of pain modulation between hypnosis and meditation ( Dumont, Martin, & Broer, 2012), in our reading of the literature there are clear points of convergence, as well as divergence. Most obvious is the involvement of the dACC in both phenomena. ...
... Similarly, reductions in stress and pain sensitivity have been associated with reductions in grey-matter density in the amygdala of Zen [16] and Western [17] meditators. Further research is required to clarify whether the mediating systems for mindfulness and hypnosis are the same [16] or different [18]. ...
Hypnosis can be defined as an altered conscious state of focused attention which involves absorption, some dissociative elements, and an increased responsiveness to suggestion. Suggestions are verbal or non-verbal communications leading to subconscious changes in perception, mood, or behaviour. The main value of hypnosis as a technique in managing pain is to assist patients as a supplement to standard clinical care. The belief that the patient can do more than he or she thinks (and more than the doctor believes is possible) is likely to generate surprising therapeutic responses.
... Similarly, reductions in stress and pain sensitivity have been associated with reductions in grey-matter density in the amygdala of Zen [16] and Western [17] meditators. Further research is required to clarify whether the mediating systems for mindfulness and hypnosis are the same [16] or different [18]. ...
Communication is an essential skill required for a clinician to practice effectively. The impact of negative types of communication on patient outcome has been demonstrated. In particular, the use of warnings or negative suggestions are associated with increased pain and anxiety in patients having potentially painful procedures. It is rare to find an opportunity arising that changes, so dramatically, health care outcomes at such little cost.
... Neurophysiologic studies demonstrate that hypnosis differs from simple imagination, placebos, and sleep (21). Research using positron emission tomography (PET) shows that hypnosis involves the anterior cingulate cortex and that actual changes occur in the brain's perception that do not occur when a suggestible person simply follows instructions (22,23). ...
Hypnosis has been used in medicine for nearly 250 years. Yet, emergency clinicians rarely use it in emergency departments or prehospital settings.
This review describes hypnosis, its historical use in medicine, several neurophysiologic studies of the procedure, its uses and potential uses in emergency care, and a simple technique for inducing hypnosis. It also discusses reasons why the technique has not been widely adopted, and suggests methods of increasing its use in emergency care, including some potential research areas.
A limited number of clinical studies and case reports suggest that hypnosis may be effective in a wide variety of conditions applicable to emergency medical care. These include providing analgesia for existing pain (e.g., fractures, burns, and lacerations), providing analgesia and sedation for painful procedures (e.g., needle sticks, laceration repair, and fracture and joint reductions), reducing acute anxiety, increasing children's cooperation for procedures, facilitating the diagnosis and treatment of acute psychiatric conditions, and providing analgesia and anxiolysis for obstetric/gynecologic problems.
Although it is safe, fast, and cost-effective, emergency clinicians rarely use hypnosis. This is due, in part, to the myths surrounding hypnosis and its association with alternative-complementary medicine. Genuine barriers to its increased clinical use include a lack of assured effectiveness and a lack of training and training requirements. Based on the results of further research, hypnosis could become a powerful and safe nonpharmacologic addition to the emergency clinician's armamentarium, with the potential to enhance patient care in emergency medicine, prehospital care, and remote medical settings.
In recent years, hypnotic suggestions have been used in several clinical conditions. This treatment is often used for anxiety treatment, somatization, and post-traumatic stress disorder. Hypnotic analgesia is one of the most clinically useful phenomena of hypnosis. The article describes the case of a patient who underwent hypnotic treatments for hypersensitivity and chronic pain. Results showed an improvement of pain control and a decrease of pain hypersensibility. In addition, during rehabilitative treatments, the patient reported a high level of compliance with the multidisciplinary team. These findings suggest that hypnosis could be a useful treatment for post-stroke pain management.
Although hypnosis and meditation represent distinct domains of practice, they appear to over-lap in phenomenology, cognitive mechanisms, neural substrates, and potential therapeutic merits. Whereas numerous studies have documented the beneficial impact of these approaches, few have harnessed these distinctive phenomena together, either clinically or as a means of illuminating cognitive questions. This paper introduces the theme of the present issue and discusses the poten-tial value of yoking empirical studies of hypnosis and meditation. The marriage of these seemingly disparate yet overlapping practices promises to improve our scientific understanding of each as well as unravel their underlying mechanisms. On the one hand, albeit largely overlooked by re-searchers studying meditation, the intimate relationship between attention and suggestion holds important implications for both theoretical models and therapeutic applications of contemplative practice. On the other hand, hypnosis and meditation serve as complementary vehicles for eluci-dating salient topics in cognitive neuroscience, including the neural underpinnings of perception and cognitive control, and the governing of deeply-ingrained processes. Binding these approaches to the science of attention and suggestion paves the road to a more nuanced appreciation of hypno-sis and meditation while fostering novel therapeutic prospects and improving our understanding of consciousness and cognition.
The subjective experience of one's environment is constructed by interactions among sensory, cognitive, and affective processes. For centuries, meditation has been thought to influence such processes by enabling a nonevaluative representation of sensory events. To better understand how meditation influences the sensory experience, we used arterial spin labeling functional magnetic resonance imaging to assess the neural mechanisms by which mindfulness meditation influences pain in healthy human participants. After 4 d of mindfulness meditation training, meditating in the presence of noxious stimulation significantly reduced pain unpleasantness by 57% and pain intensity ratings by 40% when compared to rest. A two-factor repeated-measures ANOVA was used to identify interactions between meditation and pain-related brain activation. Meditation reduced pain-related activation of the contralateral primary somato-sensory cortex. Multiple regression analysis was used to identify brain regions associated with individual differences in the magnitude of meditation-related pain reductions. Meditation-induced reductions in pain intensity ratings were associated with increased activity in the anterior cingulate cortex and anterior insula, areas involved in the cognitive regulation of nociceptive processing. Reductions in pain unpleasantness ratings were associated with orbitofrontal cortex activation, an area implicated in reframing the contextual evaluation of sensory events. Moreover, reductions in pain unpleasantness also were associated with thalamic deactivation, which may reflect a limbic gating mechanism involved in modifying interactions between afferent input and executive-order brain areas. Together, these data indicate that meditation engages multiple brain mechanisms that alter the construction of the subjectively available pain experience from afferent information.
In 2005, Pierre Rainville and I proposed that hypnosis be included in an early mechanistic model of meditation (Grant & Rainville, 2005) put forth by Newberg and Iversen (2003). The proposal was prompted by the substantial overlap we saw, experientially and in terms of associated brain networks, between the two phenomena. In the years that have followed a flurry of studies of meditation, from various research domains, have emerged. The articles in this special issue survey the current state of that proposal, offering clear points of
review current findings and related concepts on the nature of "ordinary" conscious experiences and how it changes during a typical hypnotic event / propose that changes in cognitive processing during hypnosis facilitate the influence of suggestive communications through a diminution of alternative and self-reflective ideation (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Functional imaging studies reveal that the dorsolateral prefrontal cortex (DLPFC) is more active when we select one from a number of possible responses. The same region is activated whether the choice is between limb movements or words. The magnitude of the activity does not increase with increasing rate of response selection, although the activity decreases when performance starts to break down at high rates. In a sentence completion task, the more constrained the response is by the sentence, the less activity is seen in DLPFC. These observations suggest that DLPFC biases possible responses top-down, thereby creating an arbitrary and temporary category of responses appropriate to the task in hand. This biasing depends on interactions between DLPFC and more posterior brain regions where responses are represented; the location of these regions depends on response modality, and their activity varies with response rate.
Phenomenological analyses and questionnaire studies have shown that changes in time experience are a prominent feature of mystical states of consciousness. Spiritual traditions employ a variety of methods to induce these states. Research on meditation and psychedelic drugs can help to identify involved brain mechanisms and neural correlates of mystical states. A theory is presented that explains the experience of unity and timelessness with a phase transition to extended coherent EEG gamma activity. Based on this theory, ascetic and meditative practices can be understood as rational methods to enable qualitative shifts in the large-scale organization of brain dynamics. Some supporting evidence for the theory comes from a study with Buddhist monks. Research on mystical experiences has to deal with many methodological challenges and requires a close collaboration of scientists and religious practitioners. Research of this kind can yield important insights into the relativity of reality and its relation to brain functioning.
Background and purpose:
A noxious stimulus does not necessarily cause pain. Nociceptive signals arising from a noxious stimulus are subject to modulation via endogenous inhibitory and facilitatory mechanisms as they travel from the periphery to the dorsal horn or brainstem and on to higher brain sites. Research on the neural structures underlying endogenous pain modulation has largely been restricted to animal research due to the invasiveness of such studies (e.g., spinal cord transection, brain lesioning, brain site stimulation). Neuroimaging techniques (e.g., magnetoencephalography (MEG), positron emission tomography (PET) and functional magnetic resonance imaging (fMRI)) provide non-invasive means to study neural structures in humans. The aim is to provide a narrative review of neuroimaging studies related to human pain control mechanisms.
Methods:
The approach taken is to summarise specific pain modulation mechanisms within the somatosensory (diffuse noxious inhibitory controls, acupuncture, movement), affective (depression, anxiety, catastrophizing, stress) and cognitive (anticipation/placebo, attention/distraction, hypnosis)domains with emphasis on the contribution of neuroimaging studies.
Results and conclusions:
Findings from imaging studies are complex reflecting activation or deactivation in numerous brain areas. Despite this, neuroimaging techniques have clarified supraspinal sites involved in a number of pain control mechanisms. The periaqueductal grey (PAG) is one area that has consistently been shown to be activated across the majority of pain mechanisms. Activity in the rostral ventromedial medulla known to relay descending modulation from the PAG, has also been observed both during acupuncture analgesia and anxiety-induced hyperalgesia. Other brain areas that appear to be involved in a number of mechanisms are the anterior cingulate cortex, prefrontal cortex, orbitofrontal cortex and nucleus accumbens, but their exact role is less clear.
Implications:
Neuroimaging studies have provided essential information about the pain modulatory pathways under normal conditions, but much is still to be determined. Understanding the mechanisms of pain control is important for understanding the mechanisms that contribute to failed pain control in chronic pain. Applying fMRI outside the brain, such as in the trigeminal nucleus caudalis of the spinotrigeminal pathway and in the dorsal horn of the spinal cord, and coupling brain activity with activity at these sites may help improve our understanding of the function of brain sites and shed light on functional connectivity in the pain pathway. © 2011 Scandinavian Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.