Human face perception traced by magneto- and electro-encephalography

Abstract

The temporal and spatial processing of face perception in normal subjects was traced by magnetoencephalography (MEG) and electroencephalography (EEG). We used 5 different visual stimuli: (1) face with opened eyes, (2) face with closed eyes, (3) eyes, (4) scrambled face, and (5) hand, and they were shown in random order. Subjects were asked to count the number of hand stimuli. To analyze the complicated brain responses to visual stimuli, we used brain electric source analysis (BESA) as the spatio-temporal multiple source model. In MEG recording, the 1M and 2M components were identified in all subjects. The 1M component was recorded to all kinds of stimuli. The 2M component was clearly identified only to face stimulation in all subjects, but to eyes stimulation in only 3 subjects with a small amplitude. The 2M component was not identified to scrambled face nor hand stimulation. The 2M component was recorded from the right hemisphere in all subjects, but in only 5 of 10 subjects from the left hemisphere. The mean peak latencies of the 1M and 2M components were approximately 132 and 179 ms, respectively. The interpeak latency between 1M and 2M was approximately 47 ms on average but the interindividual difference was large. There was no significant difference of the 2M latency between face with opened eyes and face with closed eyes. The 1M component was generated in the primary visual cortex in the bilateral hemispheres, and the 2M component was generated in the inferior temporal cortex, around the fusiform gyrus. In the EEG recording, face-specific components, positive at the vertex, P200 (Cz), and the negative at the temporal areas, N190 (T5') and N190 (T6'), were clearly recorded. The EEG results were fundamentally compatible with the MEG results. The amplitude of the component recorded from the right hemisphere was significantly larger than that from the left hemisphere. These findings suggest that the fusiform gyrus is considered to play an important role in face perception in humans, and that the right hemisphere is more dominant. Face perception takes place approximately 47 ms after the primary response to visual stimulation in the primary visual cortex, but the period of information transfer to the fusiform gyrus is variable among subjects. Detailed temporal and spatial analyses of the processing of face perception can be achieved with MEG.

Facial emotion recognition in schizophrenia:When and why does it go awry?

“…This N170 amplitude decrement was correlated with decreased fusiform gyrus gray matter volume. Since the fusiform gyrus is thought to be the source of the N170 (Watanabe et al, 1999), this finding supports the idea of a primary disturbance in the neural substrate underlying structural face encoding.…”

Familiar-face recognition and comparison: source analysis of scalp-recorded event-related potentials

“…The inferotemporal activity has been recorded in PET and fMRI studies of face processing (Haxby et al, 2000); this area is supposed to be the source for the facespecific ERP components (Allison et al, 1994;Bentin et al, 1996). Dipolar sources in the IT cortex were also modeled by Watanabe et al (1999).…”

“…This was done by developing multiple dipole source models for scalp-recorded event-related potentials (ERPs). Some aspects of face processing have been explained by dipole models elsewhere (Jemel et al, 1999;Rossion et al, 1999;Watanabe et al, 1999). Even though the non-unique nature of a solution of the inverse problem is well known, the dipolar source localization can reduce the amount of data and provide relatively robust active regions and their temporal relations during the information processing.…”

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

“…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.…”