4-class code-VEP EEG data

Participants

Twelve healthy volunteers (4 women, mean age: 30.6 years, standard deviation: 7.1), all students and staff at ISAE-SUPAERO with normal or corrected-to-normal vision took part in this study. None of the participants reported any of the exclusion criteria (neurological antecedents and being under psychoactive medication at the time of the study). The study was approved by the ethics committee of the University of Toulouse (CER approval number 2020-334) and was carried in accordance with the declaration of Helsinki. Participants gave informed written consent prior to the experiment.

Experimental protocol

EEG data were recorded using a BrainProduct LiveAmp 32 active electrodes wet-EEG setup with a refresh rate of 500Hz to record the surface brain activity. The 32 electrodes followed the 10-20 international system.  The ground electrode was placed at the FPz electrode location and all electrodes were referenced to the FCz electrode. The electrode impedances were brought below 25kOhm before the recording. EEG data and markers were synchronized during recording using Lab Streaming Layer.

Participants were comfortably sat and requested to read and sign the informed consent. Once equipped with the EEG system, volunteers were asked to focus on four targets that were cued sequentially in a random order for 0.5s, followed by a 2.2s stimulation phase, before a 0.7s inter-trial period. The cue sequence for each trial was pseudo-random and different for each block. After each block, a pause was observed and subjects had to press the space bar to continue. In total, each volunteer was presented fifteen four-trial blocks for each of the four conditions, 2 types of c-VEP codes x 2 different amplitudes depth (40% or 100%). The four flickers were all 150 pixels wide discs, without borders, and were presented on the following LCD monitor: Dell P2419HC, 1920x1080 pixels, 265cd/m2, and 60Hz refresh rate.

Preprocessing

No pre-processing was applied on these data, and they have been neither sliced or epoched, although it remains possible to do so with the help of the markers.