Developmental precursors of social brain networks: the emergence of attentional and cortical sensitivity to facial expressions in 5 to 7 months old infants.

Santeri Yrttiaho,Jussi Kaatiala,Linda Forssman,Jukka M Leppänen,Vincent M Reid

doi:10.1371/journal.pone.0100811

Abstract

Biases in attention towards facial cues during infancy may have an important role in the development of social brain networks. The current study used a longitudinal design to examine the stability of infants' attentional biases towards facial expressions and to elucidate how these biases relate to emerging cortical sensitivity to facial expressions. Event-related potential (ERP) and attention disengagement data were acquired in response to the presentation of fearful, happy, neutral, and phase-scrambled face stimuli from the same infants at 5 and 7 months of age. The tendency to disengage from faces was highly consistent across both ages. However, the modulation of this behavior by fearful facial expressions was uncorrelated between 5 and 7 months. In the ERP data, fear-sensitive activity was observed over posterior scalp regions, starting at the latency of the N290 wave. The scalp distribution of this sensitivity to fear in ERPs was dissociable from the topography of face-sensitive modulation within the same latency range. While attentional bias scores were independent of co-registered ERPs, attention bias towards fearful faces at 5 months of age predicted the fear-sensitivity in ERPs at 7 months of age. The current results suggest that the attention bias towards fear could be involved in the developmental tuning of cortical networks for social signals of emotion.

Highlights

While the social skills of an individual reach their full capacity after years of development, critical phases of this development may occur already during the first year of life
The analyses focused on the amplitude of the N290 component (i.e., 248–348 ms post-stimulus time) given previous research linking this component with face processing and our own preliminary analyses of the current dataset showing overlap in face- and fear-sensitivity at this latency range (Supplement S1)
Modulation of cortical activity within the same latency range by stimulus fearfulness was found already at the age of 5 months in the bootstrap analysis including all trials, but this effect became more consistent across different analyses and its scalp distribution more well-defined at 7 months of age

Summary

Introduction

While the social skills of an individual reach their full capacity after years of development, critical phases of this development may occur already during the first year of life. Studying the emergence of cortical face sensitivity in infants may provide a critical window on the ontogeny of social cognition. The preference for smiling faces at 3 months, likewise, changes into bias towards fearful faces by the age of 5 to 7 months [10,11,12]. Such early biases in attention towards facial cues have been suggested to have an important role in canalizing the development of social brain networks [13]

Objectives

Results

Conclusion