Open AccessNeural substrates of species‐dependent visual processing of faces: use of morphed faces
Author(s) -
Yamada Emi,
Ogata Katsuya,
Kishimoto Junji,
Tanaka Mutsuhide,
Urakawa Tomokazu,
Yamasaki Takao,
Tobimatsu Shozo
Publication year - 2015
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12387
Subject(s) - categorization , stimulus (psychology) , biological motion , perception , visual processing , psychology , morphing , event related potential , face perception , visual perception , communication , cognitive psychology , neuroscience , pattern recognition (psychology) , electroencephalography , biology , computer science , artificial intelligence
Abstract Face identification and categorization are essential for social communication. The N170 event‐related potential ( ERP ) is considered to be a biomarker of face perception. To elucidate the neural basis of species‐dependent face processing, we recorded 128‐ch high‐density ERP s in 14 healthy adults while they viewed the images of morphed faces. The morphed stimuli contained different proportions of human and monkey faces, and the species boundary was shifted away from the center of the morph continuum. Three experiments were performed to determine how task requirement, facial orientation, and spatial frequency ( SF ) of visual stimuli affected ERP s. In an equal SF condition, the latency, and amplitude of the occipital P100 for upright faces were modulated in a monotonic‐like fashion by the level of morphing. In contrast, the N170 latency for upright faces was modulated in a step‐like fashion, showing a flexion point that may reflect species discrimination. Although N170 amplitudes for upright faces were not modulated by morph level, they were modulated in a monotonic‐like fashion by inverted faces. The late positive ( LP ) component (350–550 msec) in the parietal region was modulated in a U‐shaped function by morph level during a categorization task, but not in a simple reaction task. These results suggest that P100 reflects changes in the physical properties of faces and that N170 is involved in own‐species selectivity. The LP component seems to represent species categorization that occurs 350 msec after stimulus onset.