Eligibility Criteria:
HEALTHY PARTICIPANTS
Inclusion criteria:
* Between 18 and 70 years of age (in Substudy 1: age- and sex-matched to chronic pain patients)
* Good overall health status
* Sufficient knowledge of German or English to follow instructions
* Ability to give written informed consent
Exclusion criteria:
* Pain longer than \>3 consecutive days and on more than 30 days within the last 12 months
* Major psychiatric or neurological disorders, and substance abuse
* Consumption of alcohol, illegal drugs, and analgesic drugs within 24 hours before testing
* Pregnancy
* For Substudy 2: An MR-specific safety questionnaire will be filled in to check for any contradiction to magnetic resonance imaging (MRI): wearing an electronic device, implants or prosthetics, injury from metal parts or fragments, metal parts in or on the body, surgery on the head, heart or back, tattoo or permanent makeup, problems lying still for long periods of time, claustrophobia, possible pregnancy, metal contraceptive coil
CHRONIC PAIN PATIENTS
Inclusion criteria:
* Between 18 and 70 years of age
* Unspecific musculoskeletal pain as defined according to the ICD-11 as chronic primary pain (MG30.1, e.g. chronic widespread pain, complex regional pain syndrome, chronic primary headache or orofacial pain, chronic migraine, chronic tension-type headache, trigeminal autonomic cephalalgias, burning mouth syndrome, chronic primary visceral pain, irritable bowel syndrome, chronic primary musculoskeletal pain), and which is not classified as chronic cancer related pain (MG30.2; e.g. chronic cancer pain, chronic post-cancer treatment pain), chronic postsurgical or post traumatic pain (MG30.3; e.g. chronic postsurgical pain, chronic posttraumatic pain), chronic secondary musculoskeletal pain (MG30.4; e.g. chronic musculoskeletal pain from persistent inflammation, chronic musculoskeletal pain associated with structural changes, chronic musculoskeletal pain associated with a disease of the nervous system), chronic secondary visceral pain (MG30.5; e.g. chronic visceral pain from persistent inflammation, chronic visceral pain from vascular mechanisms, chronic visceral pain from mechanical factors), chronic neuropathic pain (MG30.6; e.g. chronic peripheral neuropathic pain, trigeminal neuralgia, postherpetic neuralgia, chronic central neuropathic pain), chronic secondary headache or orofacial pain (MG30.7; e.g. chronic dental pain, chronic neuropathic orofacial pain, trigeminal neuralgia, headache or orofacial pain attributed to chronic secondary temporo-mandibular disorders), other specified chronic pain (MG30.Y), or other non-specified chronic pain (MG30.Z)
* Sufficient knowledge of German or English to follow instructions
* Ability to give written informed consent
Exclusion criteria:
* Major psychiatric or neurological disorders, and substance abuse
* Regular intake of opioids for pain (e.g. burprenorphine, codeine, fentanyl, hydromorphone, orphine, oxycodone, tapentadol, tilidine/na-loxone, tramadol)
* Consumption of alcohol, illegal drugs, and analgesic drugs within 24 hours before testing
* Pregnancy