An Insula View of Predictive Processing in Hypnotic Responses.

The experience of being hypnotized is closely linked to changes in bodily experience or interoceptive sensations. Progress in the neuroscience of hypnotic motor suggestions, both ideomotor and challenge, implicates changes in the comparison processes between predicted (expected) and actual proprioceptive consequences of current action models and plans in behavioral and experiential response to these suggestions. These findings are interpreted as a form of active inference, minimizing prediction errors in the motor system. Hypnotic responses are proposed to be implemented as active inference of predictions (response expectancies) contained in the multilayered hierarchical self-world models generated by the acceptance of hypnotic suggestions. Acceptance of counterfactual suggested "realities" and active inference-like responses are enabled and sustained by a process of interoceptive predictive coding in which interoceptive inference suppresses interoceptive prediction errors and hence salience network and executive control network responses (effecting a form of dissociated control). These processes are mapped to known functional networks of posterior insula, dorsal anterior insula, and ventral anterior insula. Finally, this interoceptive predictive coding model of active inference in hypnotic responses is contrasted with the Martin and Pacherie (2019) model in which attention manipulates the precision of prediction errors.