BrainPainLongit/dataset

## Overview

- Data acqusition ran from the years 2020-2021

- Brief experiment overview
The aim of the study was to determine which brain areas are preferentially activated when healthy participants learned to activate their descending pain inhibition via a cognitive strategy. We compared participants brain activity with fMRI before and after learning a cognitive strategy via RIII-biofeedback-training. This experiment was a longitudinal MRI study with two MRI scans: MRI1: pre-intervention and MRI2: post-intervention. Intervention was a previously published feedback training (see doi:10:1002/ejp.570) to teach participants a cognitive strategy to reduce their spinal nociception.

MRI1 -> feedback training -> MRI2

- Contents of the dataset


- Dependent Variables

1)BOLD signal
2)Pain ratings and RIII-reflex size during fMRI
3)Pain- and RIII-reduction achieved under application of cognitive strategy during feedback training

## Methods

### Subjects
Subjects were healthy and recruited via advertisements at the University Hospital Munich and the LMU Munich.

- Inclusion criteria:
1) >= 18 years of age
2) no severe internal, neurological or psychiatric conditions
3) no history of chronic pain
4) no alcohol, nicotine or drug abuse
5) no regular medication (except hormonal contraception or thyroid hormones)
6) no pregnancy or breastfeeding at time of participation
7) no contrainidication for MRI scans

### Task organization

Before task-based fMRI, T1 and resting state fMRI were acquired. DWI measures were acquired after the task-based fMRI measurement.

- Task-based fMRI
Task condition was organized in 8 randomized blocks (4 control, 4 strategy) of 5 trials each. Task instructions and experimental run-down was identical in MRI1 and MRI2, save for the instruction given for the "strategy" condition (see task details below)

### Task details

Each round commenced with presentation of a visual cue (green arrow = strategy, white bar = control) to inform the participant which cognitive task to perform. Instructions given were "think of nothing in particular" for control, condition "think of a safe and happy place" for strategy condition during MRI1 and "apply the cognitive strategy you developed during feedback trianing" for strategy condition during MRI2. Participants were asked to engage in the given cognitive task for the entire duration during which the visual cue was present (22-28s).

After a 12-16s pseudorandom delay, the RIII reflex was evoked by painful electrical stimulation of the left n. suralis and recorded for offline processing using MRI-safe ExG recording hardware. After an additional 10-12s delay participants rated the pain intensity on a scale of 0-100 (0 = no pain, 100 = strongest pain imaginable) using a sliding scale. A pseudorandom gap of 4-6s was placed between all trials.

### Experimental location

Institiute for Stroke and Dementia Reserch in Munich, Germany.

### Data abnormalities

For two subjects (sub-1344 and sub-1404), the BIDS structure contains additional sessions. This is due to hardware failute during the specific session and the inability to perform the fMRI task. fMRI task was repeated at the next possible time.