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Fig. 8.2
Screenshots from the experiment representing different steps of the experiment.
a Fixation cross. b One digit appearing in the memorization sequence. c Target digit appearing.
d Feedback report question:
'
Vous attendiez-vous
à
ce resultat
'
=
'
Did you expect this result?
'
,
'
Oui
'
=
'
Yes
'
and
'
Non
'
=
'
No
'
fatigue as well as other possible nuisance intervening during the experiment. A
random rest break was allowed between blocks, during which the boxes performed a
colorful animation chosen each time at random among four preset animations.
Between the two sessions, the screen was shut down to allow a rest break of 2
-
3 min.
8.8.3 Data Acquisition
EEG recordings were acquired from 31 silver/chloride electrodes positioned
according to the extended 10/20 system (FP1, FPz, FP2, F7, F3, Fz, F4, F8, FT7,
FC3, FCz, FC4, FT8, T7, C3, Cz, C4, T8, TP7, CP3, CPz, CP4, TP8, P7, P3, Pz,
P4, P8, O1, Oz, O2) with the aid of a standard elastic cap. Both earlobes, digitally
linked, were used as electrical reference. The ground sensor was positioned on the
forehead. The impedance of each sensor was kept below 5 k. The EEG was band-
pass-
70 Hz and digitized at 500 Hz using the Mitsar 202
DC EEG acquisition system (Mitsar Co. Ltd., Saint Petersburg, Russia). During
recording, the stimulation program continuously sent to the Mitsar system triggers
ltered in the range 0.1
-
