How to store EEG data
EEG data need to be stored in a specific way to enable easy automated processing. Please follow the guidelines below.
An EEG experiment will typically entail:
1. A file containing the EEG data. These files have the extension .bdf. These files are stored on computer 1, which is located in the control area.
2. A file containing the task performance data. These files have the extension .txt. These files are stored on computer 2, which is located in the test area.
It is important that all files have the same coding, so that they can be coupled automatically. This primary code for each subject and file is: yymmdd_eeg_subjectnumber (with subjectnumber ranging from 01 to 99, and indicating the subject number you have measured that day)
To indicate different experiments for the same subject, you are required to add an experiment number: yymmdd_eeg_subjectnumber_experimentnumber
After the experiment, all files should be stored on the central storage server, in the same directory, which is named using the primary code.
The general strategy is as follows:
– all data from a subject are stored in a single directory per subject (named: yymmdd_eeg_subjectnumber)
– this code (yymmdd_eeg_subjectnumber) is the subject code and should also be entered on the EEG database form (link)
– all files collected from a single subject contain the same subject code (yymmdd_eeg_subjectnumber)
– all data from a single subject (eeg data and performance data) is transferred (from two computers) to the central storage server (\\storage.fss.uu.nl\pf_researchdata$\Matthijs_Vink\data\raw_data, see link for instructions on how to store your data on the central storage server)
– all files associated with a particular task have the same experimentnumber (named: yymmdd_eeg_subjectnumber_experimentnumber)
To store the EEG data file (.bdf file), follow the procedure outlined below. For the performance data, enter the appropriate subject code (yymmdd_eeg_subjectnumber_experimentnumber) in the Presentation box. The procedure is the same as described below, but the performance file (.txt file) is located in the ‘logfiles’ directory in the task directory.
As soon as you select ‘Start File’ in the BioSemi software, you are required to specify the filename and file location for the eeg data. Make sure that you save one eeg file (.bdf file) for each experiment.
Go to the D: drive and then go to the BDFdata directory
Make a directory named as follows:
For example, 181222_eeg_01 for the recordings of the first subject who was tested on december 22 2018.
3. Go to that directory and define a filename for each separate eeg recording / experiment. Use the following scheme:
For example, 181222_eeg_01_02 for the second recording of the first subject that was tested on december 22 2018.