Poster #163 - The Development of Face-sensitive Cortical Processing in Early Infancy

• In Event: 2-163 - Poster Session 08
  In Poster Session: PS 08 Section - Perceptual, Sensory, Motor

Integrative Statement

Human faces have unique biological structures that convey a variety of complex social messages. Multiple lines of research suggest that, in adults, faces are a class of stimuli that receives high priority from attention (for review, see Palermo & Rhodes, 2007). Information concerning the time course of neural mechanisms for face processing has been provided by electrophysiological studies through the analyses of Event-Related Potentials (ERPs). The N290 has been identified as a face-sensitive ERP component in infancy. Its activity is systematically modulated by faces and not by non-face objects (De Haan, Johnson, & Halit, 2002). Greater N290 amplitudes have been reported in response to faces than toys in 4.5-, 6-, 7.5- and 12-month old infants (Guy, Richards, Tonnesen, & Roberts, 2018; Guy, Zieber, & Richards, 2016). The face inversion effect occurs when faces are presented vertically inverted. It has been considered a marker for expert perceptual processing, since results in an impairment in perceptual recognition of the inverted face stimuli (Valentine, 1988). A selective inversion effect for human faces has been reported to modulate the amplitude of the N290 in 12-month-old infants (Halit, de Haan, & Johnson, 2003). We hypothesized that faces would elicit larger N290 responses compared to houses and that a possible developmental change would occur in the scalp distribution of the N290 responses to faces. Moreover, an inversion effect on N290 amplitude would be elicited by faces but not houses.

We examined the N290 responses to faces and houses, presented with upright and inverted orientation, in a cross-sectional study with infants at 4.5 (n=7, mean age =144 days) and 12 months (n=10, mean age=379 days) of age. N290 amplitude values over left and right posterior-lateral channels were analyzed as a function Stimulus Type, Stimulus Orientation, and Hemisphere. Separate univariate ANOVAs were performed for the two age groups, considering Type (Face, House), Orientation (Upright, Inverted), Hemisphere (Left, Right) and Electrode (Parietal (P7/P9/P8/P10), Parietal-Occipital (PO7/PO9/PO8/PO10), Temporo-Parietal (TP7/TP9/TP8/TP10) electrodes) as within-subjects factors.

Results showed a significant interaction between Type and Electrode in both 4.5- (F (5,30) = 7.38, p = .0001) and 12-month-old group of participants (F (5,45) = 3.18, p = .0152). Figure 1a displays the results of the 4.5 month old group. There was a larger N290 amplitude for faces than houses over PO8 (p = .043), and for houses than faces over TP7 (p = .040), TP9 (p = .023), and TP8 (p = .050). Figure 1b displays the results of 12-month-old participants. There was a larger N290 amplitude for faces than houses in the right hemisphere over PO8 (p = .027), PO10 (p = .005), P8 (p = .012), P10 (p = .011), and TP10 (p = .001) electrodes (Figure 2). Overall at 12 months, the N290 was larger to faces and showed face-specific activity in the right hemisphere.

These results suggest that the N290 component becomes more sensitive to faces and shows right lateralized responses in 12-month old infants. However, we did not find a significant inversion effect expected from prior work.

Authors

• Stefania Conte, University of South Carolina
  Presenting Author

• John Richards, University of South Carolina
  Non-Presenting Author