stimMAP_2022_public

Experimental Design

Participants eligible after the calibration session were invited to complete four additional sessions. Each session included: - Four 8-minute pain tests - Social manipulation - Questionnaire on the social manipulation experience - 20-minute tDCS - Questionnaire on the tDCS experience (3 minutes) - Four additional 8-minute pain tests - Final questionnaire Treatment order in sessions 2-5 was randomized, with a 6-7 day interval between sessions.

Heat Stimulations

Noxious heat was delivered to two locations on the right forearm using the TSA-II Neurosensory Analyzer (Medoc Ltd) with a 16-mm thermode end-plate. Each session included four runs of 8-minute heat stimulations before and after the social manipulation and tDCS (8 runs total). **Trial Details**: - "Get Ready" message: 1 second - Jitter: 4-6 seconds - Heat stimulation: 13 seconds (1.5 seconds ramp up/down, 10 seconds plateau) - Jitter: 5-7 seconds - Pain rating: 7 seconds - Jitter: 6-10 seconds Each run included 12 trials with randomly applied low and high heat temperatures.

Social Manipulation

Participants were informed of two possible tDCS protocols described as being developed by DARPA. - **Analgesic Protocol**: Relieves pain, improves mood, and enhances concentration. - **Hyperalgesic Protocol**: Increases pain sensations and unpleasantness.

Participants viewed a video featuring a confederate describing their experience with the assigned tDCS protocol. Videos were randomized, with gender and identity balanced across sessions. Afterward, participants completed a questionnaire assessing their expectations for tDCS and heat stimulations.

tDCS Design

The tDCS protocol used the StarStim system (Neuroelectrics, Spain) with the following parameters: - Intensity: 2 mA for 20 minutes - Ramp-up/down: 30 seconds - Electrode Placement: C3 (anode) and FP2 (cathode) based on the 10-10 EEG system.

During tDCS, participants viewed random fractal images for potential future memory tasks. After stimulation, participants completed a questionnaire regarding sensations experienced during tDCS.

Data and Codes

Here is the link to the data and codes for this project: [Data and Codes for Experimental Sessions](https://github.com/canlab/stimMAP_2022_public)