Automatic Processing of Emotionally Salient Images Henry Schwimmer, Erica Huang, Michelle Frias, Alex Cho, Leonardo Fernandino, Allen Azizian*, & Eran Zaidel University of California, Los Angeles RESULTS Within-subjects ANOVA: 4 (Condition: frequent, infrequent neutral, infrequent positive, infrequent negative) x 3 (Electrode Laterality: left, central, right) x 3 (Electrode Location: frontal, central, parietal) •No main effect of emotional valence. • Significant interaction between laterality and emotional valence (p <.05): negative stimuli produced a larger P300 in the right electrodes while positive stimuli produced a larger P300 in the left electrodes. DISCUSSION AND CONCLUSIONS INTRODUCTION •P300 is an event related potential (ERP) associated with attentional processing in oddball detection tasks. •Discrimination of affective stimuli yields a larger P300 for negative than for positive targets. •Question: Is the effect of stimulus valence on the amplitude of the P300 attentional or is it automatic? Fig. 1. Stimuli (from left to right): Frequent Neutral, Infrequent Positive, Infrequent Negative, Infrequent Neutral. Task: •Discriminate between frequent and infrequent stimuli using manual key presses. •Frequent stimuli were presented as a large sunburst effect. • Only neutral images were presented in the background of frequent stimuli. • Infrequent stimuli were presented as a small sunburst effect. •Positive, neutral, or negative images were presented in the background of infrequent stimuli. METHODS Participants: • 17 right-handed undergraduate UCLA students Procedure: •We recorded EEG data from subjects while they performed a perceptual discrimination task. Fig. 2. ERP grand averages of all subjects: Infrequent Negative (Red), Infrequent Positive (Blue), Infrequent Neutral (Yellow), Frequent Neutral (Green). Fig. 3. Interaction between laterality and picture type * Corresponding author: [email protected] •There was no significant difference between P300 amplitudes for negative and positive stimuli. • However, there was a significant interaction between emotional valence and laterality: electrodes over the left hemisphere produced a larger P300 for positive stimuli whereas electrodes over the right hemisphere produced a larger P300 for negative stimuli. • The effect of valence on the P300 of infrequent stimuli suggest that emotional valence is processed automatically, independently of attention allocation. • Previous developmental, lesion, and other ERP studies support the valence hypothesis of hemispheric specialization of emotional stimuli (right hemisphere = negative affect, left hemisphere = REFERENCES Davidson, R. J., Fox, N.A., 1982. Asymmetrical brain activity discriminates between positive and negative affective stimuli in human infants. Science 218, 1235-1237. Olofsson, J.K., Nordin, S., Sequeria, H., Polich, J., 2008. Affective picture processing: An integrative review of ERP findings. Biological Psychology 77, 247-265. Polich, J., 2007. Updating P300: an integrative theory of P3a and P3b. Clinical Neurophysiology 118, 2128–2148. P300 P300 P300 P300 P300 P300 P300 P300 P300

Automatic Processing of Emotionally Salient Images

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Page 1: Automatic Processing of Emotionally Salient Images

Automatic Processing of Emotionally Salient ImagesHenry Schwimmer, Erica Huang, Michelle Frias, Alex Cho, Leonardo Fernandino, Allen Azizian*, & Eran Zaidel

University of California, Los Angeles

RESULTS

Within-subjects ANOVA: 4 (Condition: frequent, infrequent neutral, infrequent positive, infrequent negative) x 3 (Electrode Laterality: left, central, right) x 3 (Electrode Location: frontal, central, parietal)

•No main effect of emotional valence.• Significant interaction between laterality and emotional valence (p <.05): negative stimuli produced a larger P300 in the right electrodes while positive stimuli produced a larger P300 in the left electrodes.

DISCUSSION AND CONCLUSIONS

INTRODUCTION

•P300 is an event related potential (ERP) associated with attentional processing in oddball detection tasks.

•Discrimination of affective stimuli yields a larger P300 for negative than for positive targets.

•Question: Is the effect of stimulus valence on the amplitude of the P300 attentional or is it automatic?

Fig. 1. Stimuli (from left to right): Frequent Neutral, Infrequent Positive, Infrequent Negative, Infrequent Neutral.

Task: •Discriminate between frequent and infrequent stimuli using manual key presses. •Frequent stimuli were presented as a large sunburst effect.

• Only neutral images were presented in the background of frequent stimuli.

• Infrequent stimuli were presented as a small sunburst effect.•Positive, neutral, or negative images were presented in the background of infrequent stimuli.

METHODSParticipants: • 17 right-handed undergraduate UCLA students

Procedure:•We recorded EEG data from subjects while they performed a perceptual discrimination task.

Fig. 2. ERP grand averages of all subjects: Infrequent Negative (Red), Infrequent Positive (Blue), Infrequent Neutral (Yellow), Frequent Neutral (Green).

Fig. 3. Interaction between laterality and picture type

* Corresponding author: [email protected]

• There was no significant difference between P300 amplitudes for negative and positive stimuli.• However, there was a significant interaction between emotional valence and laterality: electrodes over the left hemisphere produced a larger P300 for positive stimuli whereas electrodes over the right hemisphere produced a larger P300 for negative stimuli.• The effect of valence on the P300 of infrequent stimuli suggest that emotional valence is

processed automatically, independently of attention allocation. • Previous developmental, lesion, and other ERP studies support the valence hypothesis of

hemispheric specialization of emotional stimuli (right hemisphere = negative affect, left hemisphere = positive affect). Our results suggest that those studies reflect automatic processes as well.

• The pattern of responses in the central electrodes is the same as in the right electrodes. This suggests dominance by the right hemisphere for processing affective stimuli.

REFERENCESDavidson, R. J., Fox, N.A., 1982. Asymmetrical brain activity discriminates between positive and negative affective stimuli in human infants. Science 218, 1235-1237.Olofsson, J.K., Nordin, S., Sequeria, H., Polich, J., 2008. Affective picture processing: An integrative review of ERP findings. Biological Psychology 77, 247-265.Polich, J., 2007. Updating P300: an integrative theory of P3a and P3b. Clinical Neurophysiology 118, 2128–2148.

P300P300 P300P300 P300P300