Frontal functions, connectivity and neural efficiency underpinning hypnosis and hypnotic susceptibility

Abstract

An update is provided of an earlier review (Gruzelier, 1998) of the range of evidence for neurophysiological changes in frontal and lateralized functions with hypnosis, changes which have differentiated high from low hypnotically susceptible subjects, and which led to a working model and neuropsychological translation of the hypnotic induction process. New evidence is outlined from an fMRI/EEG study. This study also disclosed the importance of neural efficiency in left lateral frontal and anterior cingulate structures, and their connectivity, for distinguishing high from low hypnotic susceptibility both in hypnosis and in the everyday state. This amplifies earlier constructs such as cognitive flexibility. Though the focus will be largely on the alteration of connections with the anterior brain and its corresponding alterations of function, interhemispheric, posterior and subcortical connectivity is also considered. The practical implications for the interaction between the hypnotherapist and subject are considered, including stage hypnosis. Key words: EEG, fMRI, hypnosis, hypnotic susceptibility, neurophysiology, stage hypnosis Neurocognitive changes with hypnosis Selective inhibition, dissociation and disconnectionSince the time of Janet dissociation has been historically the dominating cognitive theory of hypnosis (Hilgard, 1965;Bowers, 1992). Now a range of evidence is showing that following instructions of hypnosis a different and unusual pattern of abilities and disabilities is brought into play in hypnotizable subjects compared with the pre-hypnosis state. These involve dissociations between cognitive processes, and disconnections between brain regions together with selective inhibition and enhancement of abilities and processes (Gruzelier, 1998;2004). The likening of hypnosis to an inhibitory process is enshrined in the term hypnosis, itself derived from Hypnos the god of sleep, and initially made popular by Pavlov's inhibitory concepts. Early electrophysiological studies found no evidence of sleep per se (Crawford and Gruzelier, 1992), nevertheless frontal inhibition may represent one dynamic of frontal involvement in hypnosis (e.g. Gruzelier, 1990;1998;Woody and Bowers, 1994;Woody and Sadler, 1998), and one which may be an alternative to disconnection, or be in parallel with it. The experimental evidence for changes in anterior brain activity will be considered in turn. Error detection and evaluation Neurophysiological fractionation of processes, to include possible inhibition, has been demonstrated between error detection processes and error evaluation processes and with the apparent inhibition or uncoupling of the latter, both of which are processes emanating from the anterior cingulate. These processes were measured with event-related potentials (ERPs) in a Stroop-like conflict task (Kaiser, Barker, Haenschel, Baldeweg and Gruzelier, 1997). The ERPs disclosed a dissociation not evident behaviourally. In the highly hypnotizable participants error detection rates decreased and reaction times (RT...

Hypnosis and top-down regulation of consciousness

“…Theories of hypnosis frequently highlight the top-down view and tend to emphasize the roles of cognitive control and executive (or metacognitive) monitoring functions based in prefrontal and anterior cingulate cortices and broader frontal-parietal networks (Dienes & Perner, 2007;Egner & Raz, 2007;Gruzelier, 2006;Jamieson & Woody, 2007;Lynn, Kirsch, & Hallquist, 2008;Woody & Sadler, 2008).…”

“…Owing to its role in monitoring and cognitive control (Fleming, Ryu, Golfinos, & Blackmon, 2014;Miller & Cohen, 2001), multiple theories of hypnosis have hypothesized a role for atypical prefrontal functioning in high hypnotic suggestibility (Dienes & Hutton, 2013;Gruzelier, 2006;Woody & Bowers, 1994). Multiple well-powered behavioural studies have suggested that highly suggestible individuals exhibit impaired performance on cognitive tasks known to depend on prefrontal cortex, such as selective attention and working memory (Farvolden & Woody, 2004;Jamieson & Sheehan, 2004;Khodaverdi-Khani & Laurence, 2016;Terhune et al, 2011c).…”

The role of frontal executive functions in hypnosis and hypnotic suggestibility.

“…Whilst some researchers have argued for a differential role for the cerebral hemispheres in producing the hypnotic experience (e.g. Gruzelier, 2006), an equally fruitful approach might be investigating functions associated with superior medial regions (BA6,8,& 9) and contrasting those with functions associated with inferior lateral regions (BA44, 45, and 46) of the PFC (see also e.g. Kallio, Revonsuo, Hämäläinen,…”

“…see Parris, Dienes & Frontal Executive Functions in Hypnosis and Hypnotic Suggestibility 16 Hodgson, 2012). This would reduce oxygenation requirements and therefore the resulting fMRI signal (Gruzelier, 2006) making it more difficult to identify the neural loci of such processes via neuroimaging. Further work is needed to identify the neural correlates of control following post-hypnotic suggestions given their potential to elucidate the contribution of FEFs to the production of suggestions.…”

Hypnosis Attenuates Executive Cost of Prospective Memory

“…This theory has received support from studies demonstrating that hypnosis reduces the connectivity between frontal lobe and other brain areas, most importantly disconnecting frontal lobe from the anterior cingular cortex, a brain structure usually associated with conflict 5 monitoring (Egner, Jamieson, & Gruzelier, 2005;Fingelkurts, Kallio, & Revonsuo, 2007;Gruzelier, 2006). Therefore, hypnosis may serve as an appropriate tool to investigate the role of executive frontal system in performing a PM task.…”