Premium
The role of the dorsolateral prefrontal cortex in the motor placebo effect
Author(s) -
VillaSánchez Bernardo,
Emadi Andani Mehran,
Fiorio Mirta
Publication year - 2018
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.14217
Subject(s) - placebo , transcranial direct current stimulation , dorsolateral prefrontal cortex , psychology , prefrontal cortex , motor cortex , transcranial magnetic stimulation , stimulation , brain stimulation , physical medicine and rehabilitation , neuroscience , audiology , medicine , cognition , alternative medicine , pathology
The neural correlates of the placebo effect in the motor domain are still unknown. The aim of this study was to tackle the role of a frontal cortical region, the dorsolateral prefrontal cortex (dl PFC ). To this end, we stimulated the cortical site corresponding to the left dl PFC with transcranial direct current stimulation ( tDCS ) during a placebo procedure and measured any change in the motor placebo effect in all the participants and more specifically in placebo‐responders. Three different experiments were conducted in which healthy volunteers performed a force motor task with the index finger. The placebo treatment consisted of transcutaneous electrical nerve stimulation ( TENS ). In Experiment 1 (expectation alone), participants were only verbally suggested about the positive effects of TENS . In Experiment 2 (expectation and conditioning), participants were verbally suggested about TENS and conditioned with a surreptitious increase in a visual feedback of force. In Experiment 3 (control procedure), participants were told that TENS was inefficient. Each participant was tested in three different days with anodal, cathodal and sham tDCS over the dl PFC . Results showed that in Experiment 1 and 2 force increased after the procedure, independently of tDCS . By focusing on placebo‐responders, we found that in Experiment 1 force remained stable after active tDCS , whereas it increased after inactive tDCS . These findings bring new evidence on the neural underpinnings of the motor placebo effect, by showing that independently of the polarity, active tDCS over the left dl PFC may undermine the expectation‐induced enhancement of force in placebo‐responders.