BNCI 2015-004 Motor Imagery dataset

Dataset description

We provide EEG data recorded from nine users with disability (spinal cord injury and stroke) on two different days (sessions). Users performed, follow- ing a cue-guided experimental paradigm, five distinct mental tasks (MT). MTs include mental word association (condition WORD), mental subtraction (SUB), spatial navigation (NAV), right hand motor imagery (HAND) and feet motor imagery (FEET). Details on the experimental paradigm are summarized in Figure 1. The session for a single subject consisted of 8 runs resulting in 40 trials of each class for each day. One single experimental run consisted of 25 cues, with 5 of each mental task. Cues were presented in random order.

EEG was recorded from 30 electrode channels placed on the scalp according to the international 10-20 system. Electrode positions included channels AFz, F7, F3, Fz, F4, F8, FC3, FCz, FC4, T3, C3, Cz, C4, T4, CP3, CPz,CP4, P7, P5, P3, P1, Pz, P2, P4, P6, P8, PO3, PO4, O1, and O2. Reference and ground were placed at the left and right mastoid, respectively. The g.tec GAMMAsys system with g.LADYbird active electrodes and two g.USBamp biosignal amplifiers (Guger Technolgies, Graz, Austria) was used for recording. EEG was band pass filtered 0.5-100 Hz (notch filter at 50 Hz) and sampled at a rate of 256 Hz.

The duration of a single imagery trials is 10 s. At t = 0 s, a cross was presented in the middle of the screen. Participants were asked to relax and fixate the cross to avoid eye movements. At t = 3 s, a beep was sounded to get the participant’s attention. The cue indicating the requested imagery task, one out of five graphical symbols, was presented from t = 3 s to t = 4.25 s. At t = 10 s, a second beep was sounded and the fixation-cross disappeared, which indicated the end of the trial. A variable break (inter-trial-interval, ITI) lasting between 2.5 s and 3.5 s occurred before the start of the next trial. Participants were asked to avoid movements during the imagery period, and to move and blink during the ITI. Experimental runs began and ended with a blank screen (duration 4 s)

References

[1] Scherer R, Faller J, Friedrich EVC, Opisso E, Costa U, Kübler A, et al. (2015) Individually Adapted Imagery Improves Brain-Computer Interface Performance in End-Users with Disability. PLoS ONE 10(5). https://doi.org/10.1371/journal.pone.0123727