Hypnotic suggestion reduces conflict in the human brain

Abstract

Many studies have suggested that conflict monitoring involves the anterior cingulate cortex (ACC). We previously showed that a specific hypnotic suggestion reduces involuntary conflict and alters information processing in highly hypnotizable individuals. Hypothesizing that such conflict reduction would be associated with decreased ACC activation, we combined neuroimaging methods to provide high temporal and spatial resolution and studied highly and less-hypnotizable participants both with and without a suggestion to interpret visual words as nonsense strings. Functional MRI data revealed that under posthypnotic suggestion, both ACC and visual areas presented reduced activity in highly hypnotizable persons compared with either no-suggestion or less-hypnotizable controls. Scalp electrode recordings in highly hypnotizable subjects also showed reductions in posterior activation under suggestion, indicating visual system alterations. Our findings illuminate how suggestion affects cognitive control by modulating activity in specific brain areas, including early visual modules, and provide a more scientific account relating the neural effects of suggestion to placebo.anterior cingulate cortex ͉ attention ͉ hypnosis ͉ neuroimaging ͉ Stroop effect G eneral accounts of cognitive control identify the dorsal anterior cingulate cortex (ACC) as a key to the monitoring of conflict within a network of neural regions (1-3). In multiple tasks that involve a conflict between competing responses, functional MRI (fMRI) studies have measured higher signal levels at the ACC in conditions when conflict was present (1-4).One conflict task showing reliable ACC activations requires proficient readers to name the ink color of a displayed word (5). Individuals are usually slower and less accurate indicating the ink color of an incompatible color word (e.g., responding ''blue'' when the word ''RED'' is displayed in blue ink) than identifying the ink color of a congruent color name (e.g., responding ''red'' when the word ''RED'' is inked in red). This difference in performance constitutes the Stroop conflict and is one of the most robust and well-studied phenomena in attentional research (6, 7). The dominant view regards reading as a largely automatic process whereby skilled readers cannot withhold activating a word's underlying meaning despite explicit instructions to attend only to its ink color. Indeed, the standard account maintains that semantic processing of words occurs involuntarily (6,8) and that the Stroop is a benchmark experimental task of cognitive conflict (9). Nonetheless, independent researchers have challenged the robustness of the Stroop effect (10, 11), suggesting that rather than being inevitable, other factors such as attention may govern the process (12). Although critiqued (13), this approach has resulted in data showing either reduction or removal of Stroop interference (14,15).Recently, we used hypnotic suggestion as an attentional tool to manipulate conflict (16). Whereas earlier case reports (17,18) and at least one...

Dissociative Experience and Cultural Neuroscience: Narrative, Metaphor and Mechanism

“…4 Conversion symptoms, involving loss of sensory or motor functions due to psychological processes, have been viewed as examples of 'somatoform dissociation' (Nijenhuis 2004). This work is consistent with studies of hypnosis which show that, in highly hypnotizable individuals, specific suggestions can reduce conflict between ordinarily competing attentional processes (Raz 2005). Functional brain imaging in this situation shows an effective disconnection between anterior cingulate cortex, thought to be involved in monitoring cognitive conflicts and other cortical regions involved in the cognitive or perceptual task (Egner et al 2005;Raz et al 2005). Through these mechanisms, hypnotic suggestion can create a functional dissociation that reduces conflict between otherwise incompatible cognitive processes, allowing potentially contradictory streams of information processing to peacefully co-exist.…”

Discrete response patterns in the upper range of hypnotic suggestibility: A latent profile analysis

“…At the very least, some HS subtypes are clearly more responsive to particular suggestion profiles and thus more rigorous screening of participants for instrumental studies will be important in future research. For example, relative to each other, class 1 would probably be more responsive to an alexia suggestion (Raz, Fan, & Posner, 2005), class 2 would be more responsive to an amnesia suggestion (Mendelsohn, Chalamish, Solomonovich, & Dudai, 2008;Terhune & Brugger, 2011), and class 4 would probably display elevated responding to both suggestions. A more refined understanding of variegation in the upper range of hypnotic responding is likely to substantially improve the identification of participants for instrumental research.…”

Hypnosis and top-down regulation of consciousness

“…The use of hypnotic suggestion to modulate selective attention has been repeatedly demonstrated (Iani, Ricci, Gherri, & Rubichi, 2006;Raz, Fan, & Posner, 2005;Raz, Kirsch, Pollard, & Nitkin-Kaner, 2006). These and other studies have shown that suggestions for altered visual perception can be used to enhance performance in selective attention tasks such as Stroop and Flanker tasks.…”