Does an Angry Salesman Scary the Students of University of Silesia?
Visual ERP Studies
Karina Maciejewska and Zofia Drzazga
University of Silesia, Institute of Physics, Department of Medical Physics, Katowice, Poland
Keywords: Event Related Potentials, Cognitive Activity, P300.
Abstract: Three visual ERP tasks with oddball paradigm (geometric figures, picture of a nice lady and an angry
salesman, a sentence with non logic word) were performed by students of University of Silesia. Few ranges
of band-pass filters and artifact correction were examined to evaluate the optimal parameters of data
analysis. Shape, latency and amplitude of P300 in the task with a picture of angry salesman as well as in the
sentence task did not differ from the simple task with geometric figures. These results indicate that
emotional picture or a sentence with illogical word did not affect cognitive activity in studied group of
students, probably because the task was not very complex.
1 INTRODUCTION
Cognitive event related potentials (ERP) are voltage
fluctuations reflecting the deception and higher-level
processing of sensory information (Veiga, 2004).
ERP studies have revealed multiple generators
including sites in hippocampus and the temporal,
parietal and frontal lobes (Heinze, 1999).
In order to maintain reliable results, guidelines
for using event-related potentials were published
(Duncan, 2009); (Picton, 2000). However all the
parameters should be optimized individually for
every laboratory (Bayer, 2010); (Groh-Bordin,
2006). As this is preliminary ERP study, we wanted
to choose the best recommended technical
parameters for our studies as well as compare three
visual oddball tasks different in complexity.
2 MATERIAL AND METHOD
2.1 Participants
The experiment was performed among 10 healthy,
right-handed, non-smoking students of University of
Silesia (5 males and 5 females) using ASA-Lab
system (ANT) with ASA v.4.7.1 software.
2.2 Procedure and Stimuli
Three visual oddball paradigm scenarios were
performed. The scenarios included: black square on
a white background as target and white circle on a
black background as standard stimulus in the first
scenario; a picture of bad, angry salesman as target
and nice woman as standard stimulus in the second
scenario and a sentence: “I will not eat this soup,
because it is too ...” and two words: “square” as
target stimulus and “hot” as standard stimulus. The
parameters of the stimuli were: 150ms duration, 5
ms rise/fall, 1000ms interstimulus, 20% target and
80% standard stimulus probabilities.
2.3 Data Analysis
The band-pass filters were used to investigate the
proper signal analysis parameters: 0.3-30 Hz, 0.1-40
Hz, 0.3-100 Hz and artifact correction ranges: ±50
μV, ±70 μV, ±100 μV, ±150 μV, ±200 μV.
3 RESULTS AND DISCUSSION
0.3-30 Hz band-pass filter, 12 dB/oct filter steepness
and ±100 μV artifacts correction were chosen for
comparing results from three visual scenarios.
Fig. 1 presents grand-average ERPs at C3, Cz
and C4 electrode site elicited by three different
Maciejewska K. and Drzazga Z..
Does an Angry Salesman Scary the Students of University of Silesia? - Visual ERP Studies.
Copyright
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 2013 SCITEPRESS (Science and Technology Publications, Lda.)

visual tasks.
Figure 1: Grand-average ERP signals in an oddball
paradigm with geometric figures (a), angry salesman (b)
and a sentence (c) task with target and standard stimulus.
The P300 waveform looks different in each
electrode site. The signal from C3 is broad and starts
after 300 ms from the event. The waveforms from
Cz and C4 are more complex and have three local
maxima. Interesting is the fact that the P300 is
similar in all performed tasks. The values of
latencies and amplitudes of P300 waveform were
calculated and are presented in Table 1.
Table 1: P300 latencies and amplitudes for grand-average
visual oddball ERPs from target stimulus for three tasks.
Task Electrode
P300
Latency [ms]
P300
Amplitude [μV]
Figures
C3 344 4.54
Cz 391 4.56
C4 352 3.88
Salesman
C3 348 4.79
Cz 391 4.57
C4 348 3.88
Sentence
C3 340 4.80
Cz 391 4.56
C4 355 3.81
The latencies of P300 at peak maximum are in
the range 340 ms – 355 ms at C3 and C4, while at
Cz it is about 390 ms. The amplitudes of P300 are in
the range 4.54 μV – 4.80 μV at C3 and Cz, and
about 3.85 μV at C4. The values are comparable in
all tasks. These results indicate that emotional
picture of angry salesman did not influence the
changes of the processing of sensory information in
studied group of students. Latencies and amplitudes
of P300 waveform was also not affected by reading
illogical word in the sentence task. There were no
changes in latency of amplitude of P300, because the
task was not very complex.
4 CONCLUSIONS
P300 waveform obtained in visual ERP study with
oddball paradigm (target and standard stimulus)
registered at C3 was different from those at C4 and
Cz positions. It was broad and had higher amplitude
than C4 and Cz. The character of signals was
independent on kind of task, what seems that the
emotions brought out were so weak that they didn’t
activate the structures in brain responsible for
processing the emotional information. However this
research requires further studies on more
participants.
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