# SRM Resting-state EEG

## Introduction

This EEG dataset contains resting-state EEG extracted from the experimental
paradigm used in the *Stimulus-Selective Response Modulation* (SRM) project at
the Dept. of Psychology, University of Oslo, Norway.

The data is recorded with a BioSemi ActiveTwo system, using 64 electrodes
following the positional scheme of the extended 10-20 system (10-10).
Each datafile comprises four minutes of uninterrupted EEG acquired while the
subjects were resting with their eyes closed. The dataset includes EEG from
111 healthy control subjects (the "t1" session), of which a number underwent
an additional EEG recording at a later date (the "t2" session). Thus, some
subjects have one associated EEG file, whereas others have two.

### Disclaimer

The dataset is provided "as is". Hereunder, the authors take no responsibility
with regard to data quality. The user is solely responsible for ascertaining
that the data used for publications or in other contexts fulfil the required
quality criteria.



## The data

### Raw data files

The raw EEG data signals are rereferenced to the average reference. Other than
that, no operations have been performed on the data. The files contain no
events; the whole continuous segment is resting-state data. The data signals
are unfiltered (recorded in Europe, the line noise frequency is 50 Hz). The
time points for the subject's EEG recording(s), are listed in the *_scans.tsv
file (particularly interesting for the subjects with two recordings).

Please note that the quality of the raw data has **not** been carefully
assessed. While most data files are of high quality, a few might be of poorer
quality. The data files are provided "as is", and it is the user's
esponsibility to ascertain the quality of the individual data file.


### /derivatives/cleaned_data

For convenience, a cleaned dataset is provided. The files in this derived
dataset have been preprocessed with a basic, fully automated pipeline (see
/code/s2_preprocess.m for details) directory for details. The derived files are
stored as EEGLAB .set files in a directory structure identical to that of the
raw files. Please note that the *\*_channels.tsv* files associated with the
derived files have been updated with status information about each channel
("good" or "bad"). The "bad" channels are – for the sake of consistency –
interpolated, and thus still present in the data. It might be advisable to
remove these channels in some analyses, as they (per definition) do not provide
anything to the EEG data. The cleaned data signals are referenced to the
average reference (including the interpolated channels).

Please mind the automatic nature of the employed pipeline. It might not perform
optimally on all data files (*e.g.* over-/underestimating proportion of bad
channels). For publications, we recommend implementing a more sensitive
cleaning pipeline.


### Demographic and cognitive test data

The *participants.tsv* file in the root folder contains the variables age,
sex, and a range of cognitive test scores. See the sidecar participants.json
for more information on the behavioural measures. Please note that these
measures were collected in connection with the "t1" session recording.



## How to cite

All use of this dataset in a publication context requires the following paper
to be cited:

Hatlestad-Hall, C., Rygvold, T. W., & Andersson, S. (2022). BIDS-structured
resting-state electroencephalography (EEG) data extracted from an experimental
paradigm. Data in Brief, 45, 108647. https://doi.org/10.1016/j.dib.2022.108647



## Contact

Questions regarding the EEG data may be addressed to
Christoffer Hatlestad-Hall ([email protected]).

Question regarding the project in general may be addressed to
Stein Andersson ([email protected]) or
Trine W. Rygvold ([email protected]).