N-of-few Study of Pain Perception (NOF)

Common and Distinct Mechanisms of Expectancy Effects Across Outcomes

A behavioral study that will examine how pain perception is affected by different types of conditioning and by context, with a few participants and multiple sessions ("N-of-few" design).

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Behavioral: Symbolic conditioning; Behavioral: Conditioning; Behavioral: Instructions; Behavioral: Counterfactual

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • New Hampshire
    • Hanover, New Hampshire, United States, 03755
      • Dartmouth College

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy participants

Exclusion Criteria:

• Cannot tolerate heat pain applied to the forearm/leg, based on a calibration task at the beginning of the experiment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: N-of-few Study of Pain

Behavioral: Symbolic conditioning; Participants will learn associations between cues and thermal stimuli with varying temperatures (low vs. high) through symbolic conditioning (no actual heat stimuli, only pictures of thermometers); Behavioral: Conditioning; Participants will learn associations between cues and thermal stimuli with varying temperatures (low vs. high) from experience (with actual heat stimuli).; Behavioral: Instructions; Participants will learn associations between cues and thermal stimuli with varying temperatures (low vs. high) from verbal instructions.; Behavioral: Counterfactual; Thermal stimuli will be either the better outcome or the worse outcome out of two possible outcomes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Within Participant Subjective Ratings of Acute Thermal Pain Following High Compared to Low Cues (Learned Via Symbolic Learning)	Each session of the experiment includes pain tasks, in which multiple thermal stimuli are delivered. Following each thermal stimulus, participants are asked to rate how painful it was, on a semi-circular computerized scale. Ratings are based on the angle (0-180), with higher angle representing higher pain ratings. In the symbolic learning procedure, cues are conditioned to different temperatures based on pictures of thermometers (instead of actual thermal stimuli as in the conditioning procedure). For the cues that were learned via symbolic learning, the investigators will compare the average rating of pain for stimuli that are preceded by high cues minus the average rating of pain for stimuli that are preceded by low cues (each averaged across sessions), within participant.	Measured repeatedly during pain tasks, in each of the 10 sessions of the experiment (up to 3 sessions per week, depending on the participants' availability), immediately after thermal stimuli. Averaged across sessions and compared across conditions.
Within Participant Subjective Ratings of Acute Thermal Pain Following High Compared to Low Cues (Learned Via Conditioning)	Each session of the experiment includes pain tasks, in which multiple thermal stimuli are delivered. Following each thermal stimulus, participants are asked to rate how painful it was, on a semi-circular computerized scale. Ratings are based on the angle (0-180), with higher angle representing higher pain ratings. In the conditioning procedure, cues are conditioned to different temperatures by delivering thermal stimuli with different temperatures after cues are presented (higher temperature following high cues and lower temperature following low cues). For the cues that were learned via conditioning, the investigators will compare the average rating of pain for stimuli that are preceded by high cues minus the average rating of pain for stimuli that are preceded by low cues (each averaged across sessions), within participant.	Measured repeatedly during pain tasks, in each of the 10 sessions of the experiment (up to 3 sessions per week, depending on the participants' availability), immediately after thermal stimuli. Averaged across sessions and compared across conditions.
Within Participant Subjective Ratings of Acute Thermal Pain Following High Compared to Low Cues (Learned Via Instructions Only)	Each session of the experiment includes pain tasks, in which multiple thermal stimuli are delivered. Following each thermal stimulus, participants are asked to rate how painful it was, on a semi-circular computerized scale. Ratings are based on the angle (0-180), with higher angle representing higher pain ratings. In the instructions only condition, cues are learned via verbal suggestion. For the cues that were learned via instructions only, the investigators will compare the average rating of pain for stimuli that are preceded by high cues minus the average rating of pain for stimuli that are preceded by low cues (each averaged across sessions), within participant.	Measured repeatedly during pain tasks, in each of the 10 sessions of the experiment (up to 3 sessions per week, depending on the participants' availability), immediately after thermal stimuli. Averaged across sessions and compared across conditions.
Within Participant Subjective Ratings of Acute Thermal Pain, When it is the Worse vs. the Better Alternative	In the counterfactual task, participants are presented with two alternatives (either two pain levels, or one pain level and either losing or gaining a certain amount of money). In these pairs of alternatives, the medium level pain is sometimes the better option (i.e., when the alternative is losing money or a more intense pain stimulus) and sometimes the worse option (i.e., when the other alternative is gaining money or a less intense pain stimulus). One of the two options is chosen by the computer (participants have no control on this choice). The investigators will compare the pain ratings (scale 0-180) within participant for the same level pain stimulus (medium intensity) when it is the worse vs. the better option.	Measured repeatedly during pain tasks, in each of the last 4 sessions of the experiment, immediately after thermal stimuli. Averaged across sessions and compared across conditions.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Within Participant Facial Expressions	The investigators will obtain continuous facial video recordings of participants during the pain tasks with a video camera. The investigators will analyze these data according to Facial Action Units (facial expressions) that are known to be related to pain, and compare them across conditions.	Measured continuously during pain stimuli in each of the 10 sessions of the experiment (up to 3 sessions per week, depending on the participants' availability). Averaged and compared across conditions.
Within Participant Thermal Imaging of the Face	The investigators will obtain thermal recordings of participant's face with an infrared camera, and compare the heat signature of the face (the temperature in different parts of the face) across conditions.	Measured continuously during pain stimuli in each of the 10 sessions of the experiment (up to 3 sessions per week, depending on the participants' availability). Averaged and compared across conditions.
Within Participant Changes in Skin Conductance Response Measured With a Biopac MP160 Device	Each session of the experiment includes pain tasks, in which multiple thermal stimuli are delivered. Skin conductance will be measured continuously. The investigators will compare the skin conductance response to pain stimuli within participant across conditions.	Measured continuously during pain stimuli in each of the 10 sessions of the experiment (up to 3 sessions per week, depending on the participants' availability). Averaged and compared across conditions.
Within Participant Changes in Subjective Ratings of Pain Expectations	Each session of the experiment includes pain tasks, in which multiple thermal stimuli are delivered. Before some of the thermal stimuli, participants are asked to rate how painful they expect the next stimulus to be, on a semi-circular computerized scale. Ratings are based on the angle (0-180), with higher angle representing higher expectations ratings. The investigators will compare the expectation ratings within participant across conditions.	Measured repeatedly during pain tasks, in each of the 10 sessions of the experiment (up to 3 sessions per week, depending on the participants' availability), immediately before thermal stimuli. Averaged and compared across conditions.

Collaborators and Investigators

• Sponsor: Trustees of Dartmouth College
• Collaborators: National Institute of Mental Health (NIMH)

Study record dates

Study Major Dates

• Study Start (Actual): January 22, 2021
• Primary Completion (Actual): May 24, 2021
• Study Completion (Actual): May 24, 2021

Study Registration Dates

• First Submitted: November 16, 2020
• First Submitted That Met QC Criteria: December 10, 2020
• First Posted (Actual): December 11, 2020

Study Record Updates

• Last Update Posted (Actual): April 18, 2023
• Last Update Submitted That Met QC Criteria: April 13, 2023
• Last Verified: April 1, 2023

More Information

Terms related to this study

• Other Study ID Numbers: 230134; 5R01MH076136 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All de-identified data will be publicly shared via public online platforms such as the Open Science Framework (OSF) and Github, and the NIMH Data Archive (NDA), according to the terms and conditions outlined on their website (https://ndar.nih.gov/contribute_data_sharing_regimen.html). Identifying information will not be released, including the facial videos, of which only non-identifiable features will be extracted and shared.
• IPD Sharing Time Frame: All data will be de-identified prior to sharing. Raw data will be submitted to NDA within one year from the end of data collection or 6 months from the acceptance date of the first primary study manuscript on the full dataset (excluding methods development papers), whichever is later. Analyzed data/maps of statistical results and models accompanying each paper will be submitted to NDA/OpenFMRI when the primary study manuscript is accepted.

IPD Sharing Access Criteria

These data would generally be made available to any qualified investigator for neuroimaging studies only including:

i. Research on any brain phenomenon; ii. Neuroimaging research on non-disease traits (intelligence, behavioral traits); iii. Methods development research.

The requesting investigator must provide documentation of local IRB approval.

These data would not be made available to:

i. Any criminal justice organization, because data may not be used for any criminal justice applications; ii. Any commercial entity, because use of the data is limited to not-for-profit organizations and data may not be used for any commercial purposes.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No