Interhemispheric Difference for Upright and Inverted Face Perception in Humans: An Event-Related Potential Study

Abstract

We recorded event-related potentials (ERPs) to investigate the interhemispheric difference of the N170 component for upright and inverted face perception in detail in fifteen healthy subjects. This is the first ERP study focusing on interhemispheric differences for face perception by showing faces in the hemifield. The face inversion effect, the prolonged latency and enhanced amplitude were found in both hemispheres. We found that the peak latency of the N170 following both upright and inverted face stimulation showed no significant difference between each hemisphere, though the N170 latency for the inverted face in the left hemisphere was shorter than that in the right hemisphere. The N170 recorded from the hemisphere ipsilateral to the stimulated hemifield showed unique findings. The interhemispheric time difference of the N170 between the right and the left hemispheres when the inverted face was presented in the left hemifield was significantly shorter than in the other three conditions. This unique finding may indicate that the conduction time from the right to the left for inverted face perception is faster than the other conditions, or that the left hemisphere specifically processed the inverted face very rapidly after receiving signals from the right hemisphere. If the N170 was generated by some, at least two, temporally overlapping activities, the different style of a summation of these activities may cause the unique findings found in this study. In conclusion, by presenting face stimuli in the hemifields, we could identify several new findings regarding the N170 component related to the face inversion effect.

Effect of configural distortion on a face-related ERP evoked by random dots blinking

“…In previous ERP studies, the peak latency of N170 was significantly longer for configural distortions [inverted faces (Bentin et al 1996;Honda et al 2007;Itier and Taylor 2004a;Itier et al 2006;Sagiv and Bentin 2001;Watanabe et al 2003Watanabe et al , 2005, Thatcherized faces (Carbon et al 2005), and scrambled faces (George et al 1996)] than for upright faces. In addition, Latinus and Taylor (2006) found that photographic and schematic faces evoked a similar N170 when the upright face was presented, but the N170 was increased in latency when the inverted face was presented.…”

“…In previous studies using inverted faces (Bentin et al 1996;Honda et al 2007;Itier and Taylor 2004a;Itier et al 2006;Latinus and Taylor 2006;Sagiv and Bentin 2001;Watanabe et al 2003Watanabe et al , 2005, faces with scrambled features (George et al 1996;Latinus and Taylor 2006), and individual components such as the eyes and nose Taylor 2004a, Itier et al 2006;Shibata et al 2002;Watanabe et al 1999a), the N170 was longer in latency for inverted faces than for upright faces, regardless of the same low-level properties, such as luminance. These results indicate that N170 is related to differences in higher-level processing rather than changes in luminance and that its latency is affected by whether a subject easily and quickly detects a stimulus as a whole face or not.…”

“…For example, a schematic drawing consisting of a circle, two dots, and a straight line is recognized as a face, although no individual component of the drawing is part of a real face. Since Bruce and Young (1986) proposed the ''face recognition model'', there have been many studies of face perception using neuroimaging and electrophysiological methods (e.g., Bentin et al 1996;George et al 1996;Haxby et al 1996Haxby et al , 1999Honda et al 2007;Itier and Taylor 2004a;Itier et al 2006;Kanwisher et al 1998;Latinus and Taylor 2006;Miki et al 2007;Rossion and Jacques 2008;Sagiv and Bentin 2001;Shibata et al 2002;Watanabe et al 1999bWatanabe et al , 2002Watanabe et al , 2003Watanabe et al , 2005. In studies of event-related potential (ERP) using averaging electroencephalography (EEG) (e.g., Bentin et al 1996;George et al 1996), static human faces evoked a negative potential in the bilateral occipito-temporal areas peaking at around 170 ms, termed N170, which is considered to be sensitive to faces.…”

Electrophysiological study of face inversion effects in Williams syndrome

“…Visual stimuli of upright faces (upright) and inverted faces (inverted) with a neutral expression, used in our previous study [19], were presented as two stimulus conditions together with target images. The participants were asked to count the numbers of target images.…”

“…The participants were asked to count the numbers of target images. The face stimuli were similar to the ones used in Study 1 and in our previous study [19]. Each stimulus was projected onto a computer screen at the center of the visual field.…”