Brain Imaging and Pain: Analysis of Placebo Analgesia

This study is a basic science study of the mechanisms of placebo analgesia in asymptomatic healthy individuals. Each participant receives a baseline pain testing session, followed by a conditioning paradigm that results in expectation of pain relief and conditioning. They then undergo functional magnetic resonance imaging during either placebo (conditioned analgesia) or baseline. To examine order effects and habituation, the participants also either undergo a repeated placebo or a repeated baseline. The primary dependent measures in the study are the fMRI determined regions of interest, in a network of brain areas associated with pain processing. The anticipated outcome of the study is the alteration of network connectivity between sensory, affective, evaluative areas of the brain associated with placebo. Because this is not a traditional clinical trial, there are not traditional efficacy criteria, rather the outcomes are changes in brain function from manipulations of patient expectation and classical conditioning.

Asymptomatic control participants receive Natural History and Placebo instructions in a within-subject design. There are no patients, or active agents in this study. It is not a Clinical Trial.

The control condition represents a no-intervention, repeated baseline control, since the "active" intervention in this study is placebo.

There is no intervention in this study. It is not a Clinical Trial. The study is an investigation of the neural basis of placebo analgesia.

This protocol represents an investigation of the neural mechanisms of placebo analgesia. As such, it does not represent the traditional clinical trial design. Instead the "active" intervention is a placebo, and the comparison condition is a no-intervention control.

This outcomes represents the neural network underpinnings of the placebo analgesic response. It is the result of a network analysis using structural equation modeling of fMRI determined brain activations.

Inclusion Criteria: at least 18 years of age english speaking Exclusion Criteria: pain condition pregnant

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Craggs JG, Price DD, Robinson ME. Enhancing the placebo response: functional magnetic resonance imaging evidence of memory and semantic processing in placebo analgesia. J Pain. 2014 Apr;15(4):435-46. doi: 10.1016/j.jpain.2013.12.009. Epub 2014 Jan 9.