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Fig. 9.4
Photograph that represents the conditions during an EEG recording
2. Attentional task devoted to collect contingent negative variation (CNV): the
participant was instructed to press the space bar as quickly as possible after each
time the cross was replaced by a square on the screen. For each appearance of
this square, a warning sound (beep), presented 2.5 s before, allowed the par-
ticipant to prepare his response. The experimental session included 50 pairs of
stimuli (S1: beep, S2: square), with a random amount of time elapsing between
each pair. The purpose of this task is speci
ed in Sect.
9.3.1
.
3. Relaxation session: the participant was fully guided by a soundtrack broadcast
through loudspeakers placed in the room. The soundtrack suggested the par-
ticipant to perform three successive exercises of self-relaxation, based on
muscular relaxation and mental visualization. The
first exercise is the autogenic
training (Schultz
1958
). In this exercise, the participant has to mentally repeating
some sentences such as
The
second exercise is the progressive relaxation (Jacobson
1974
). It consists in
tense and un
“
I am calm
”
or
“
my arms and legs are heavy.
”
ex some muscles of the body. The last exercise is the mental
visualization. The participant imagines that he is moving in a familiar and lovely
place. The purpose of this relaxation session is to try to bring the participant to a
lower level of vigilance, quali
state.
4. Second EEG recording: 3 min of EEG were recorded with the same protocol as
in the step 1. This second recording should re
ed as the
“
relaxed
”
ect the relaxed state of the
s brain if it was reached in the prior step.
5. Second CNV task: CNV is collected using exactly the same protocol as in step 2.
participant
'
