* `participant_log.csv` is a logbook with notes about participants/sessions that was kept during data collection. It contains the following columns:
* __ID__: participant number, e.g. "S01", "S28"
* __session__: session number, i.e. "1" or "2"
* __tDCS\_code\_TRIAL__: identifies which tDCS polarity (anodal or cathodal) was used during the 20-minute tDCS block in this session. See `tDCS_blinding.md` for all the possible codes and the key relating them to tDCS polarity
* __tDCS\_code\_REAL__: identifies which tDCS polarity (anodal or cathodal) was used during the 20-minute tDCS block in this session. See `tDCS_blinding.md` for all the possible codes and the key relating them to tDCS polarity
* __time\_planned__: scheduled time slot for the session, in `WEEKDAY HH.MM.YY MM:SS` format
* __duration__: time between participant entry and exit, in minutes
* __wait\_time__: time between tDCS offset and participant exit, in minutes (IRB required minimum of 30 minutes)
* __tDCS\_impedance__: value read off the tDCS device when using the manual impedance check, before onset of the trial stimulation, in kOhm
* __reward__: either €10 or 1 research credit (RC) per hour, so typically €65,- or 6.5 RCs in total (at some point entries switch to just _cash_ or _credit_)
* __notes__: notes on EEG signal quality, technical issues, participant quirks, etc.
* `study_protocol.pdf` lists all the procedures that were followed to collect the data, particularly the tDCS and EEG setup.
* `questionnaires/` contains the questionnaires (empty, see the `data/` folder for the data) that were administered.
* `tDCS_blinding.md` contains information on the participant- and experimenter blinding procedure, including the keys linking all tDCS codes used in filenames with the actual tDCS polarities (anodal and cathodal).
