Healthy participants
Conditions
Interventions
Verbal suggestions: Participants are told at the start of the experiment, and again just prior to the conditioning paradigm, that pulses from an electrical stimulation device attached to their aim via
Sponsors
Leiden University, Leiden, the Netherlands
Eligibility
Inclusion criteria
Inclusion criteria: Adults ages 18-35 Strong understanding of written and spoken English Normal or corrected to normal vision
Exclusion criteria
Exclusion criteria: 1. Ever having experienced serious medical or psychiatric conditions (e.g., heart or lung disease, panic attacks, alcohol addiction, clinical depression), including any present conditions thought to increase the risk of a serious COVID-19 infection (diabetes, severe obesity, HIV, severe kidney or liver diseases) and the presence of any condition or treatment that causes a reduced resistance to infections (autoimmune disorders, blood disorders, organ or stem cell transplant recipients, people without spleens). 2. Currently experiencing or having experienced in the last 48 hours any symptoms of COVID-19 (cough, sore throat, fever, trouble breathing, muscular pain, pain behind the eyes, excessive fatigue, diarrhoea, loss of sense of smell or taste). 3. Having tested positive for COVID-19 fewer than 7 days ago. 4. After testing positive for COVID-19 more than 7 days ago, not being symptom free for at least 48 hours. 5. Having a housemate/partner test positive for COVID-19 (or an untested but suspected COVID-19 infection) in the past month. 6. Ever having experienced chronic pain complaints (pain for more than 6 months). 7. Ever having experienced persisting painful health problems in the last 6 months. 8. Ever having experienced acute physical pain (more than 1 on the 0-10-point pain Numeric Rating Scale (NRS); e.g., mild headache), on the day of testing. 9. Having used pain medication or recreational drugs in the 24 hours prior to testing. 10. Having consumed more than 3 caffeinated drinks (coffee, tea, energy drinks, etc.) on the day of testing, any alcohol the day of testing, or more than 3 units of alcohol in the 24 hours before testing. 11. (Intended) pregnancy or breastfeeding. 12. Having recent injuries to the head, wrists or arms on the day of testing. 13. Previous participation in this or similar studies (e.g., using thermal pain). 14. On the day of testing: not being able to sufficiently distinguish between the different temperatures during calibrations and nocebo acquisition, or not reporting a pain of at least 6 (0-10 pain NRS scale) with the highest temperature used during calibrations.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Stimulus preceding negativity (SPN) during evocation: The primary outcome of the study is the measurement of SPN, an event related potential (ERP) component used as a measure of anticipatory processing. Late SPN, measured in the 500ms directly prior to the onset of the thermal pain stimuli, will be compared between control and nocebo evocation phase trials to measure whether learned nocebo effects correspond with changes in anticipatory processing prior to experiencing pain. The mean signal of all evocation phase trials free of artifacts in the EEG data from included participants will be included in this analysis. | — |
Secondary
| Measure | Time frame |
|---|---|
| SPN during acquisition: In the same manner described for the primary outcome, SPN during the 500ms preceding thermal pain stimuli will be compared between control and nocebo acquisition trials. Nocebo effect on pain: Behavioral nocebo effects are measured as the mean difference between control and nocebo evocation trials during the first half of the evocation phase (first 15 control- and first 15 nocebo evocation trials). Only the first half of the evocation phase is used for the behavioral outcome as extinction is expected to progressively reduce the magnitude of the nocebo effect over the course of the evocation phase. We aim to minimize the impact of extinction on the results by analyzing only the first half of the evocation phase for this outcome. Granger Causality: Granger Causality analysis in EEG data can test whether information contained in the time series of electrode X improves the prediction accuracy of information contained in the time series of electrode Y as compared to prediction by the past time series of electrode Y alone (Friston, Moran & Seth, 2013). Should information recorded from electrode X improve the prediction accuracy of information in electrode Y, one can infer that something in the time series of electrode X Granger causes later occurrences in the time series of electrode Y. This method has previously been used on EEG data to model networks of pain processing (Tommaso et al., 2015, Ploner, Sorg & Gross, 2017). By applying this method to EEG data collected during the anticipation and evocation of nocebo effects on pain, we aim to model a network of neural activity underlying nocebo-augmented pain, and compare this model to one of pain experienced during control evocation trials, thereby developing a network model of how anticipatory processing leads to nocebo effects on pain. Specifically, we plan to test an a priori network in which EEG signal from frontal electrodes (Fp1, Fp2, F7, F3, Fz, F4, F8) Granger Causes signal in temporopar | — |
Contacts
Public ContactAndrea Evers
Leiden University
Outcome results
None listed