Neurophysiologie de l’hypnose

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

Hypnosis and Modern Frontal-Lobe Concepts – A Sketch for a Review and an Invitation to One Particularly Promising Field

The present paper intends to briefly review the most important concepts of the modern neuropsychology of the frontal lobes, and to relate these findings to the phenomenology usually encountered in hypnosis research and practice. The frontal lobes have been studied very intensively during the last several years and some of the results, including the syndromes described in frontal-lobe lesions and psychiatric patients, demonstrate striking similarity with hypnotic phenomena. Based on these similarities, an alternative neuropsychophysiological definition of hypnosis/suggestion is proposed, viewing hypnosis/ suggestion as the process of external manipulation with frontal-lobe functions with consequent effects upon the entire brain potential of the subject

Functional Neuroimaging Studies of Hypnosis and Meditation: A Comparative Perspective

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 number 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

Pedunculopontine-Induced cortical decoupling as the neurophysiological locus of dissociation

Mounting evidence suggests an association between aberrant sleep phenomena and dissociative experiences. However, no wake-sleep boundary theory provides a compelling explanation of dissociation or specifies its physiological substrates. We present a theoretical account of dissociation that integrates theories and empirical results from multiple lines of research concerning the domain of dissociation and the regulation of rapid eye movement (REM) sleep. This theory posits that individual differences in the circuitry governing the REM sleep promoting Pedunculopontine Nucleus and Laterodorsal Tegmental Nucleus determine the degree of similarity in the cortical connectivity profiles of wakefulness and REM sleep. We propose that a latent trait characterized by elevated dissociative experiences emerges from the decoupling of frontal executive regions due to a REM sleep-like aminergic/cholinergic balance. The Pedunculopontine Induced Cortical Decoupling Account of Dissociation (PICDAD) suggests multiple fruitful lines of inquiry and provides novel insights

The Mechanisms of Psychedelic Visionary Experiences: Hypotheses from Evolutionary Psychology

abstract: Neuropharmacological effects of psychedelics have profound cognitive, emotional, and social effects that inspired the development of cultures and religions worldwide. Findings that psychedelics objectively and reliably produce mystical experiences press the question of the neuropharmacological mechanisms by which these highly significant experiences are produced by exogenous neurotransmitter analogs. Humans have a long evolutionary relationship with psychedelics, a consequence of psychedelics' selective effects for human cognitive abilities, exemplified in the information rich visionary experiences. Objective evidence that psychedelics produce classic mystical experiences, coupled with the finding that hallucinatory experiences can be induced by many non-drug mechanisms, illustrates the need for a common model of visionary effects. Several models implicate disturbances of normal regulatory processes in the brain as the underlying mechanisms responsible for the similarities of visionary experiences produced by psychedelic and other methods for altering consciousness. Similarities in psychedelic-induced visionary experiences and those produced by practices such as meditation and hypnosis and pathological conditions such as epilepsy indicate the need for a general model explaining visionary experiences. Common mechanisms underlying diverse alterations of consciousness involve the disruption of normal functions of the prefrontal cortex and default mode network (DMN). This interruption of ordinary control mechanisms allows for the release of thalamic and other lower brain discharges that stimulate a visual information representation system and release the effects of innate cognitive functions and operators. Converging forms of evidence support the hypothesis that the source of psychedelic experiences involves the emergence of these innate cognitive processes of lower brain systems, with visionary experiences resulting from the activation of innate processes based in the mirror neuron system (MNS).View the article as published at https://www.frontiersin.org/articles/10.3389/fnins.2017.00539/ful

Brain responses to hypnotic verbal suggestions predict pain modulation

Background: The effectiveness of hypnosis in reducing pain is well supported by the scientific literature. Hypnosis typically involves verbal suggestions but the mechanisms by which verbal contents are transformed into predictive signals to modulate perceptual processes remain unclear. We hypothesized that brain activity during verbal suggestions would predict the modulation of responses to acute nociceptive stimuli. Methods: Brain activity was measured using BOLD-fMRI in healthy participants while they listened to verbal suggestions of HYPERALGESIA, HYPOALGESIA, or NORMAL sensation (control) following a standardized hypnosis induction. Immediately after the suggestions, series of noxious electrical stimuli were administered to assess pain-related responses. Brain responses measured during the suggestions were then used to predict changes in pain-related responses using delayed regression analyses. Results: Listening to suggestions of HYPERALGESIA and HYPOALGESIA produced BOLD decreases (vs. control) in the parietal operculum (PO) and in the anterior midcingulate cortex (aMCC), and increases in the left parahippocampal gyrus (lPHG). Changes in activity in PO, aMCC and PHG during the suggestions predicted larger pain-evoked responses following the HYPERALGESIA suggestions in the anterior cingulate cortex (ACC) and the anterior insula (aINS), and smaller pain-evoked responses following the HYPOALGESIA suggestions in the ACC, aMCC, posterior insula (pINS) and thalamus. These changes in pain-evoked brain responses are consistent with the changes in pain perception reported by the participants in HYPERALGESIA and HYPOALGESIA, respectively. Conclusions: The fronto-parietal network (supracallosal ACC and PO) has been associated with self-regulation and perceived self-agency. Deactivation of these regions during suggestions is predictive of the modulation of brain responses to noxious stimuli in areas previously associated with pain perception and pain modulation. The response of the hippocampal complex may reflect its role in contextual learning, memory and pain anticipation/expectations induced by verbal suggestions of pain modulation. This study provides a basis to further explore the transformation of verbal suggestions into perceptual modulatory processes fundamental to hypnosis neurophenomenology. These findings are discussed in relation to predictive coding models

Functional neuroanatomy of meditation: A review and meta-analysis of 78 functional neuroimaging investigations

Meditation is a family of mental practices that encompasses a wide array of techniques employing distinctive mental strategies. We systematically reviewed 78 functional neuroimaging (fMRI and PET) studies of meditation, and used activation likelihood estimation to meta-analyze 257 peak foci from 31 experiments involving 527 participants. We found reliably dissociable patterns of brain activation and deactivation for four common styles of meditation (focused attention, mantra recitation, open monitoring, and compassion/loving-kindness), and suggestive differences for three others (visualization, sense-withdrawal, and non-dual awareness practices). Overall, dissociable activation patterns are congruent with the psychological and behavioral aims of each practice. Some brain areas are recruited consistently across multiple techniques - including insula, pre/supplementary motor cortices, dorsal anterior cingulate cortex, and frontopolar cortex - but convergence is the exception rather than the rule. A preliminary effect-size meta-analysis found medium effects for both activations (d = .59) and deactivations (d = -.74), suggesting potential practical significance. Our meta-analysis supports the neurophysiological dissociability of meditation practices, but also raises many methodological concerns and suggests avenues for future research

HYPNOSIS FOR IMPROVEMENT OF PHYSICAL STRENGTH AND RESISTANCE

En este estudio de caso se evaluó la eficacia de la hipnosis en la mejora de la fuerza física. Participó un ciclista aficionado practicante de ciclismo, al cual se le aplicó hipnosis. El procedimiento con hipnosis consistió en la utilización de una breve técnica de relajación, una fase de inducción hipnótica, otra de hipnosis profunda, introducción de sugestión posthipnótica y fase de salida del estado hipnótico. Los resultados indicaron mejoras significativas en el progreso de la fuerza física. El rendimiento mejoraba a medida que se incrementaba el número intervenciones con hipnosis. Una de las conclusiones a destacar es que la intervención con hipnosis puede ayudar a los deportistas a resistir el agotamiento físico producido por altos niveles de esfuerzo.In this case study we assessed the effectiveness of hypnosis for the physical force in sportsmen. Participant was 1 amateur cyclist with hypnotic suggestion. The intervention with hypnosis consisted of a brief relaxation technique, a hypnotic induction phase, a deep hypnosis phase, hypnotic suggestion and a phase of exit from the hypnotic state. The results indicated an improvement of the physical force in the sportsman submitted to the treatment with hypnosis. Performance improved as number of hypnosis sessions increased. These finding suggest that hypnotic intervention can help sportsmen to withstand the physical exhaustion produced by high levels of effort