Journal: bioRxiv
Article Title: Agency and Expectations in Pain Treatment: An Investigation of the Active Inference Model
doi: 10.1101/2022.07.20.500796
Figure Lengend Snippet: (a) Schematic representation of the paradigm, (b) trial design for experiment 1, and (c) trial design for experiment 2. Colored lines represent VAS50 conditioning (red), test trials (VAS30; green) and VAS10 conditioning (blue). The black line represents alterations in temperature common to all trial types, blue, green and red lines represent changes based on VAS10 conditioning, VAS30 test trials and VAS50 conditioning trials, respectively. At trial start, the thermal-heat stimulator (thermode), attached to the left radial forearm of the participant, is at the baseline temperature (set to 30°C for experiment 1 and to 28°C for experiment 2). A red bar indicates the start of the pain phase concurrent with an increase of thermode temperature to the individually calibrated pain level of VAS70. The start of the treatment phase is indicated by a cue showing whether self- or external treatment and whether highly or low effective treatment follows. This then leads to actual low (VAS10) or high (VAS50) temperatures during conditioning trials, respectively. In test trials, the final temperature is always at VAS30 regardless of the cued treatment efficacy. Arrows indicate time points for EEG data locks, i.e. the time axis of EEG time-frequency data was set to 0 according to the onset of the cue and to the treatment outcome (i.e. target treatment VAS level was reached by the thermode), respectively. In experiment 1 (b), a rating scale controlled with two buttons was presented during the whole trial. At trial start (5s), an empty bar was presented alongside the rating scale (set to 0 at the beginning) and a display of rating buttons (lighting up in green when pressed). During the following pain phase (8-10s), the empty bar was filled red as an indication for pain. After the pain phase, the treatment cue was presented. The treatment cue showed a reduction of the red bar, where a reduction to 1/3 of the total height was associated with highly effective treatment and a reduction to 2/3 of the total height was associated with a low effective treatment. Additionally, a signal word indicated self- or external treatment. After a lag of 2s, the treatment buttons appeared on the display, lighting up in green when pressed by the subject or externally. After the treatment button was pressed, the temperature was decreased to the respective pain level. An ITI (intertrial interval) of 18s followed. In experiment 2 (c), pain ratings scales and buttons were only presented during designated rating phases. Treatment could be started immediately after the onset of the treatment cue. Here, the timing of each trial was: trial start (4s), pain phase (8s), pain rating phase (6s), treatment phase (8s) and treatment rating phase (6s) with an ITI of 4s.
Article Snippet: An electrode was attached to the elbow which was connected to an electrical current stimulator (Digitimer Ltd., model DS7A).
Techniques:
Digitimer North America LLC is a verified supplier 
Digitimer North America LLC manufactures this product 
