Electrophysiological evidence for sequential discrimination of positive and negative facial expressions.
OBJECTIVE
To elucidate the differences in temporal processing between positive and negative facial expressions by using event-related potentials (ERPs) with spatially filtered images.


METHODS
Based on the traits of parallel visual pathways, four types of facial expression images (happiness, fear, anger and neutral) with low, high and broadband spatial frequencies (LSF, HSF and BSF, respectively) were carefully created with the consideration of luminance, contrast and emotional intensity. These images were pseudo-randomly presented to 13 healthy subjects to record ERPs. Twenty recording electrodes were placed over the scalp according to the International 10-20 system. For emotion-relevant late negative components with latencies of 190-390 ms, the amplitude differences among the four facial expressions were analyzed for sequential 20-ms time windows by ANOVA.


RESULTS
There were significant amplitude differences between positive and negative LSF facial expressions in the early time windows of 270-310 ms at the occipitotemporal region. Subsequently, the amplitudes among negative HSF facial expressions differed significantly in the later time windows of 330-390 ms.


CONCLUSIONS
Discrimination between positive and negative facial expressions precedes discrimination among different negative expressions in a sequential manner based on parallel visual channels.


CONCLUSIONS
ERPs with spatially filtered images have provided the first evidence for sequential discrimination of positive and negative facial expressions.
Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan; Japan Society for the Promotion of Science (JSPS), Tokyo, Japan. Electronic address: taisuke@med.kyushu-u.ac.jp.
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Nakashima
Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan; Department of Occupational Therapy, Faculty of Rehabilitation, International University of Health and Welfare, Okawa, Japan.
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Goto
Graduate School of Systems Life Sciences, Kyushu University, Fukuoka, Japan.
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Abe
Department of Intelligent Systems, Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan.
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Kaneko
Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan.
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Saito
Department of Information and Network Engineering, Kurume Institute of Technology, Kurume, Japan.
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Makinouchi
Department of Clinical Neurophysiology, Neurological Institute, Faculty of Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan.
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Tobimatsu
D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D004192:Discrimination, Psychological / Q000502:physiology*; D004569:Electroencephalography; D004644:Emotions / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology*; D005149:Facial Expression; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D014796:Visual Perception / Q000502:physiology