Synaesthesia-type associations and perceptual changes induced by hypnotic suggestion

Beyond words: Conceptual framework for the study and practice of hypnotherapeutic imagery

This paper provides a conceptual framework for the study and clinical application of hypnotherapeutic imagery (HTI). Using the grounded theory method of conceptual analysis, a unified theoretical framework is constructed from a multidisciplinary review of literature (i.e., this new theory is based on the collection and analysis of independently sourced data). The aim is to enumerate the chorographical features of HTI simulations within the mental landscape, rather than seeking to predict them. This is achieved using a combination of ontological, epistemological, and methodological inquires. Because mental simulation is both symptomatic of mental disorders and a psychotherapeutic agent, used across various treatment modalities, an attempt is made to isolate those variables that differentiate HTI from other instances of mental simulation. Lastly, applied principles from multiple disciplines are used to formulate HTI methodology designed to effectively enhance intuitive understanding and unconscious problem-solving.

Segregated brain state during hypnosis

Can the brain be shifted into a different state using a simple social cue, as tests on highly hypnotizable subjects would suggest? Demonstrating an altered global brain state is difficult. Brain activation varies greatly during wakefulness and can be voluntarily influenced. We measured the complexity of electrophysiological response to transcranial magnetic stimulation in one 'hypnotic virtuoso'. Such a measure produces a response arguably outside the subject's voluntary control and has been proven adequate for discriminating conscious from unconscious brain states. We show that a single-word hypnotic induction robustly shifted global neural connectivity into a state where activity remained sustained but failed to ignite strong, coherent activity in frontoparietal cortices. Changes in perturbational complexity indicate a similar move towards a more segregated state. We interpret these findings to suggest a shift in the underlying state of the brain, likely moderating subsequent hypnotic responding.

Time to update our suggestibility scales

Oakley and colleagues (2021) suggest that a classic scale - HGSHS:A, aiming to measure hypnotic suggestibility - can be used to measure direct verbal suggestibility (DVS). According to the authors, DVS is a trait that can be measured both with and without hypnosis. I find this initiative highly welcome. However, I wish to give several examples why it is time to develop entirely new scales instead. Rather than trying to explain more phenomena with a single scale or concept, researchers should take a cue from research that points to a far more nuanced picture of suggestibility than a construct like DVS allows. There may be no single, unified phenomenon that can be measured with a single scale. The old, time-tested scales should be treated neither as sacred nor final. They require up-to-date, critical analysis of what exactly they measure, with an eye to how they can be further improved.

Difficult Turned Easy: Suggestion Renders a Challenging Visual Task Simple

Suggestions can cause some individuals to miss or disregard existing visual stimuli, but can they infuse sensory input with nonexistent information? Although several prominent theories of hypnotic suggestion propose that mental imagery can change our perceptual experience, data to support this stance remain sparse. The present study addressed this lacuna, showing how suggesting the presence of physically absent, yet critical, visual information transforms an otherwise difficult task into an easy one. Here, we show how adult participants who are highly susceptible to hypnotic suggestion successfully hallucinated visual occluders on top of moving objects. Our findings support the idea that, at least in some people, suggestions can add perceptual information to sensory input. This observation adds meaningful weight to theoretical, clinical, and applied aspects of the brain and psychological sciences.

Substantiating synesthesia: a novel aid in a case of grapheme-colour synesthesia and concomitant dyscalculia

Here we present the case of SP, a 21-year-old female with life-long dyscalculia. SP was subsequently diagnosed with grapheme-color synesthesia, a diagnosis that serendipitously catalyzed our development of a novel aid:The digit-color calculator (DCC). The DCC substantiates SP's color concurrents, dramatically ameliorating her difficulties with basic calculations. We envisage the DCC and its analogues may assist others in educational settings, particularly if they experience difficulties with the acquisition of literacy and numeracy. Further devices that leverage synesthesia may also have the potential to improve the quality of life for others with trait synesthesia regardless of concomitant disorder.

Neurophenomenology of induced and natural synaesthesia

People with synaesthesia have additional perceptual experiences, which are automatically and consistently triggered by specific inducing stimuli. Synaesthesia therefore offers a unique window into the neurocognitive mechanisms underlying conscious perception. A long-standing question in synaesthesia research is whether it is possible to artificially induce non-synaesthetic individuals to have synaesthesia-like experiences. Although synaesthesia is widely considered a congenital condition, increasing evidence points to the potential of a variety of approaches to induce synaesthesia-like experiences, even in adulthood. Here, we summarize a range of methods for artificially inducing synaesthesia-like experiences, comparing the resulting experiences to the key hallmarks of natural synaesthesia which include consistency, automaticity and a lack of 'perceptual presence'. We conclude that a number of aspects of synaesthesia can be artificially induced in non-synaesthetes. These data suggest the involvement of developmental and/or learning components in the acquisition of synaesthesia, and they extend previous reports of perceptual plasticity leading to dramatic changes in perceptual phenomenology in adults. This article is part of a discussion meeting issue 'Bridging senses: novel insights from synaesthesia'.

THE EFFECTS OF HYPNOSIS AND HYPNOTIC SUGGESTIONS ON THE MISMATCH NEGATIVITY IN HIGHLY HYPNOTIZABLE SUBJECTS

The neural mechanisms associated with hypnosis were investigated in a group of 9 high hypnotizable subjects by measuring the mismatch negativity (MMN) component of the auditory event-related potential (ERP). ERPs were recorded using a passive oddball paradigm to sinusoidal standard and deviant tone stimuli of 500 and 520 Hz, respectively, in four conditions: prehypnosis, neutral hypnosis, hypnotic suggestion for altering the tone perception, and posthypnotic conditions. Earlier studies have indicated that hypnosis and hypnotic suggestions might have an effect on MMN, but the results of our study contradict these results: No statistically significant differences were found between the conditions in the MMN amplitudes.