Can we fix pain bias? new study investigates

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

* INCLUSION CRITERIA: All Sub-Studies: * Healthy * Between 18 and 60 years old * Fluent in English * Able to provide written informed consent EXCLUSION CRITERIA: All Sub-Studies: * Unable to comply with study procedures * Has a major-medical condition or medical history that in a clinician's assessment could affect ability to comply with study procedures, including neurological conditions (including stroke, blindness or deafness, or a history of brain damage) * Has a current mood disorder, anxiety disorder, or substance use disorder, or has a history of psychosis, hospitalization for a mental health condition, or recurrent psychiatric episodes. * NIH staff member who is a subordinate/relative/co-worker of any investigator on the protocol * Prior completion of a different sub-study within this protocol. * Is born outside of the states or territories of the United States of America * Does not currently reside in a state or territory of the United States of America Sub-study 1: * Has a major-medical condition or medical history that in a clinician's assessment could affect heat sensitivity or pain thresholds. This may include cardiovascular, autonomic, or neurological conditions or a chronic systemic disease (e.g., diabetes) * Has a medical condition that in a clinician's assessment might affect somatosensation (e.g., Raynaud's disease, peripheral neuropathy, or circulatory disorder) * Has a current chronic pain condition or has had chronic pain in the past (painful condition lasting more than six months) * Has a dermatological condition affecting the testing region, such as scars, burns, or recent tattoos that might influence cutaneous sensibility * Regular use of prescription medication that has a significant effect on pain or heat perception. Excluded medications include central-acting agents such as opiates (morphine, tramadol), antidepressants (amitriptyline, duloxetine, milnacipran), anticonvulsants (gabapentin, pregabalin), anxiolytics (barbituates, benzodiazepines), hypnotics (zolpidem, sodium oxybate), antipsychotics (valproate, lithium, olanzapine), antimigraine agents (sumatriptan, ergotamine), and muscle relaxants (cyclobenzaprine, carisoprodol). Use of analgesic medications, such as non-steroidal anti-inflammatories, salicylates, and acetaminophen, taken on an "as needed" basis is acceptable as long as the last dose was not taken was within 5 half-lives of testing. * Is left handed Sub-study 4, FMRI participants: * Has a current chronic pain condition or has had chronic pain in the past (painful condition lasting more than six months) * Is left-handed * Any FMRI contraindications, including: * Ferromagnetic metal in the cranial cavity or eye, e.g. aneurysm clip, implanted neural stimulator, cochlear implant, ocular foreign body. * Implanted cardiac pacemaker or auto-defibrillator. * Insulin pump. * Irremovable body piercing. * Pregnant women (based on urine test completed within 24 hours prior to scan). * Those with an abnormality on a structural MRI that has functional consequences based on clinician assessment.