Neural and Psychological Mechanisms of Pain Perception
National Center for Complementary and Integrative Health (NCCIH)
Summary
Background: \- Painful stimuli cause changes in a network of brain regions called the "Pain Matrix." But most of these regions respond to many other stimuli, not just pain. Researchers want to understand how different factors influence pain. They want to test what happens when people expect different levels of pain and receive treatments that can modify pain. They want to see if these factors influence decisions about pain and how the body responds to it. They also want to compare pain with responses like taste and vision. Objectives: \- To better understand how pain and emotions are processed and influenced by psychological factors. Eligibility: \- Healthy volunteers ages 18-50. Design: * This study requires 1 to 2 clinic visits that last 1 to 3 hours. * Participants will be screened with medical history and physical exam. * Some participants will have one or more magnetic resonance imaging (MRI) scans of their brain. For MRI, participants will lie on a table that slides in and out of a cylinder. The scanner makes loud knocking noises. They will get earplugs. * Participants heart activity will be recorded with electrocardiogram. Their pulse, sweating, and breathing will be monitored. * Some participants will take a taste test. Others may perform simple tasks. Others may receive pain in their arm, leg, or hand. The pain will come from heat or electric shocks. Others may judge pain using a topical pain-relieving cream. Some of these tests may be given during MRI. * Participants will fill out questionnaires. * The study will last 3 years.
Description
Objective Pain is one of the most important signals for an organism s survival. The pathways that transfer noxious input from the periphery to the central nervous system are highly conserved across human and animal models. In humans, the ultimate experience of pain is also highly influenced by psychological factors. For example, the placebo effect leads to robust pain relief and can influence responses to noxious stimuli in the human brain. However, the psychological and neurobiological mechanisms by which psychological factors influence pain remain largely unknown. Pain can be modulated by…
Eligibility
- Age range
- 18–50 years
- Sex
- All
- Healthy volunteers
- Yes
* INCLUSION CRITERIA: * Healthy * Between 18 and 50 years old * Fluent in English * Able to provide written informed consent. EXCLUSION CRITERIA (all sub-studies): * Unable to comply with study procedures or follow-up visits. * Has a major medical condition or medical history that in a clinician's assessment could affect heat sensitivity, pain thresholds, or ability to comply with study procedures. This may include cardiovascular, autonomic, or neurological conditions, including stroke, blindness, deafness, a history of brain damage, or a chronic systemic disease (e.g., diabetes). * Has a cu…
Interventions
- BehavioralInstructions
In sub-study 1, half the participants are instructed about outcomes, half learn through experience.
- BehavioralAttention
In sub-study 4, participants learn about outcomes and we manipulate attention toward or away from the pain.
- BehavioralThermal Pain
In sub-studies 2 and 3, participants are exposed to thermal stimuli and/or tastants (sugar water, salt water, neutral rinse) and we are measuring how learning varies based on the type of outcome.
- BehavioralPlacebo instructions
In sub-study 5, we test whether placebo effects and expectancy cues modulate pain through similar mechanisms.
Location
- National Institutes of Health Clinical CenterBethesda, Maryland