1. Automa'c
Processing
of
Emo'onally
Salient
Images
Henry
Schwimmer,
Erica
Huang,
Michelle
Frias,
Alex
Cho,
Leonardo
Fernandino,
Allen
Azizian*,
&
Eran
Zaidel
University
of
California,
Los
Angeles
INTRODUCTION
RESULTS
• P300
is
an
event
related
potenNal
(ERP)
associated
with
Within-­‐subjects
ANOVA:
4
(CondiNon:
frequent,
infrequent
aenNonal
processing
in
oddball
detecNon
tasks.
neutral,
infrequent
posiNve,
infrequent
negaNve)
x
3
(Electrode
Laterality:
leS,
central,
right)
x
3
(Electrode
LocaNon:
frontal,
• DiscriminaNon
of
affecNve
sNmuli
yields
a
larger
P300
for
central,
parietal)
negaNve
than
for
posiNve
targets.
P300
P300
P300
• No
main
effect
of
emoNonal
valence.
• QuesNon:
Is
the
effect
of
sNmulus
valence
on
the
amplitude
•
Significant
interacNon
between
laterality
and
emoNonal
of
the
P300
aenNonal
or
is
it
automaNc?
valence
(p
<.05):
METHODS
negaNve
sNmuli
produced
a
larger
P300
in
the
right
electrodes
Par)cipants:
while
•
17
right-­‐handed
undergraduate
UCLA
students
posiNve
sNmuli
produced
a
larger
P300
in
the
leS
electrodes.
Procedure:
P300
P300
P300
• We
recorded
EEG
data
from
subjects
while
they
performed
a
perceptual
discriminaNon
task.
Task:
• Discriminate
between
frequent
and
infrequent
sNmuli
using
manual
key
presses.
• Frequent
sNmuli
were
presented
as
a
large
sunburst
effect.
P300
P300
P300
•
Only
neutral
images
were
presented
in
the
background
of
frequent
sNmuli.
•
Infrequent
sNmuli
were
presented
as
a
small
sunburst
Fig.
2.
ERP
grand
averages
of
all
subjects:
Infrequent
NegaNve
(Red),
Infrequent
PosiNve
(Blue),
effect.
Infrequent
Neutral
(Yellow),
Frequent
Neutral
(Green).
• PosiNve,
neutral,
or
negaNve
images
were
presented
in
Fig. 3. Interaction between laterality and picture type
the
background
of
infrequent
sNmuli.
DISCUSSION
AND
CONCLUSIONS
• There
was
no
significant
difference
between
P300
amplitudes
for
negaNve
and
posiNve
sNmuli.
• However,
there
was
a
significant
interacNon
between
emoNonal
valence
and
laterality:
electrodes
over
the
leS
hemisphere
produced
a
larger
P300
for
posiNve
sNmuli
whereas
electrodes
over
the
right
hemisphere
produced
a
larger
P300
for
negaNve
sNmuli.
• The
effect
of
valence
on
the
P300
of
infrequent
sNmuli
suggest
that
emoNonal
valence
is
processed
automaNcally,
independently
of
aenNon
allocaNon.
Fig.
1.
SNmuli
(from
leS
to
right):
Frequent
Neutral,
Infrequent
PosiNve,
Infrequent
NegaNve,
Infrequent
Neutral.
• Previous
developmental,
lesion,
and
other
ERP
studies
support
the
valence
hypothesis
of
REFERENCES
hemispheric
specializaNon
of
emoNonal
sNmuli
(right
hemisphere
=
negaNve
affect,
leS
Davidson, R. J., Fox, N.A., 1982. Asymmetrical brain activity discriminates between positive and negative affective stimuli in human infants. hemisphere
=
posiNve
affect).
Our
results
suggest
that
those
studies
reflect
automaNc
processes
as
Science 218, 1235-1237.
Olofsson, J.K., Nordin, S., Sequeria, H., Polich, J., 2008. Affective picture processing: An integrative review of ERP findings. Biological
well.
Psychology 77, 247-265.
Polich, J., 2007. Updating P300: an integrative theory of P3a and P3b. Clinical Neurophysiology 118, 2128–2148.
• The
paern
of
responses
in
the
central
electrodes
is
the
same
as
in
the
right
electrodes.
This
suggests
dominance
by
the
right
hemisphere
for
processing
affecNve
sNmuli.
* Corresponding author: aazizian@usc.edu