Background:
The way the brain processes rewards and punishments may play a role in some disorders of the nervous system. People with chronic overlapping pain conditions (such as myalgic encephalomyelitis/chronic fatigue syndrome \[ME/CFS\]) may have heightened responses to unpleasant, punishing sensations. Some of these conditions may also cause heightened responses to effort; this is an unpleasant sensation felt during physical and mental exertion.
Objective:
To learn more about how the brain processes different unpleasant sensations.
Eligibility:
People aged 18 to 50 years with ME/CFS. Healthy volunteers are also needed.
Design:
Participants will have 3 visits in 1 to 5 weeks.
Visit 1: Participants may have a neurologic exam. They will have a mock magnetic resonance imaging (MRI) scan. They will lie on a bed in a wooden tube while they practice 2 tasks:
Thermal pain rating: A device that creates mild to moderate heat will be placed on one leg.
Physical effort rating: Participants will squeeze a plastic bar with different levels of force.
Visit 2: Participants will have a real MRI scan. They will lie on a table that slides into a large tube.
Visit 3: Participants will have another MRI scan. They will repeat the thermal pain and physical effort tasks while in the scanner. Sensors will be placed on 1 arm to measure how the muscles function as they squeeze the bar.
Their heart rate will be tested: They will hold their finger against a camera lens for 1 minute. They will do 2 other tasks: 1 requires repeatedly pressing a key on a keyboard, and the other requires squeezing a bar.
Ability of subject to understand and the willingness to sign a written informed consent document.
Stated willingness to comply with all study procedures and availability for the duration of the study.
Male or female, aged 18-50 (inclusive).
Good general health as evidenced by medical history and/or physical examination.
Any current major neurological or psychiatric disorder such as (but not limited to) stroke, Parkinson s disease, Alzheimer s disease, schizophrenia, or major depressive disorder.
Any other current major medical disorder, such as a kidney disease, liver disease, cardiovascular disease, chronic pain condition, or any other disorder which, in the opinion of the PI would make participation risky for the individual or negatively affect the individual s ability to cooperate with study procedures.
Current use of medications acting primarily on the central nervous system, such as antidepressants, stimulants, etc.
Use of opioid medications for more than two weeks within the last two years or any use in the last month.
Single group
Thermal Pain Stimulation
DeviceThermal pain will be administered during fMRI neuroimaging via a thermal stimulation device (Medoc Ltd., Advanced Medical System, Israel; 510K: K052357; K041908; K922052) to examine brain activity corresponding to the experience of this stimulus. This device and associated system carries an FDA 510 (K) clearance.
Physical Effort Stimulation
DevicePhysical effort will be administered during fMRI neuroimaging via a hand dynamometer attachment for a physiological monitoring system (BIOPAC Systems, Inc., Goleta, CA, USA) to examine brain activity corresponding to the experience of this stimulus. This device has not received pre-marked approval or 510 (K) clearance by the FDA.
Determine which regions of the SVN are specifically involved in the subjective experience of unpleasantness associated with sensations of pain.
SVN regions in which activity is significantly associated with unpleasantness of pain.
Determine which regions of the SVN are specifically involved in the subjective experience of unpleasantness associated with sensations of physical effort.
The SVN has been hypothesized to play a role in producing the unpleasantness of negative experiences including effort.
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