## Content of this repository
This repository contains preregistration, data, and code for the manuscript "Non-Invasive Brain Stimulation Modulates Neural Correlates of Performance Monitoring in Patients With Obsessive-Compulsive Disorder" by Luisa Balzus, Julia Klawohn, Björn Elsner, Sein Schmidt, Stephan A. Brandt, and Norbert Kathmann.
## Overview
In this preregistered study, we investigated the effects of tDCS (transcranial direct current stimulation) on performance monitoring in patients with obsessive-compulsive disorder (OCD) and healthy individuals.
Cathodal and sham tDCS was applied over the presupplementary motor area (pre-SMA) in two separate sessions, each followed by EEG recording during performance of a flanker task.
In this repository, we provide data and scripts used for statistical analyses and figure generation. For further information about the project and the data, please read the Project_and_Data_Description.md.
**For our project page with analysis code and results of statistical analyses please visit**
<https://balzuslu.github.io/modulating_performance_monitoring_in_OCD>
## Software Information
Analyses were conducted with R version 3.6.1 and R Studio version 1.2.5001.
## Data
- **./data**: The file 'Single_Trial_Data.rda' in the folder 'data' contains single-trial behavioral and EEG data used for statistical analyses (in .RData format). Information about data and variables are provided in the file 'Project_and_Data_Description.md'.
To ensure that the participants’ privacy is respected, we can only share single-trial EEG data after preprocessing and epoching since our informed consent documents did not include the possibility of sharing the continuous raw EEG data openly.
- **./response_locked_data_for_plots.csv**: The file 'response_locked_data_for_plots.csv' in the folder 'data' contains data used for figure generation (in .csv format).
## Analysis Scripts
Annotated analysis code is organized into separate R Markdown files:
- **0_Project_and_Data_Description.Rmd**: This script generates an overview over the study and the data set.
- **1_Participants.Rmd**: This script generates an overview over demographic and clinical variables.
- **2_Behavioral_Data.Rmd**: This script performs behavioral data analysis, including data cleaning, descriptive statistics, and (G)LMM analyses.
- **3_ERP_Data.Rmd**: This script performs EEG data analysis, including data cleaning, descriptive statistics, and LMM analyses.
- **4_Plots.Rmd**: This script generates figures.
The corresponding .html files display the output from running the R Markdown files in HTML format.
## Usage
To reproduce statistical analyses, download the source files, open the file 'OCD_tDCS.Rproj' and run `renv::restore()` to automatically install all required packages into the project library.
