An ERP Study of Emotional Face Processing in the Adult and Infant Brain

Abstract

To examine the ontogeny of emotional face processing, event-related potentials (ERPs) were recorded from adults and 7-month-old infants while viewing pictures of fearful, happy, and neutral faces. Face-sensitive ERPs at occipital-temporal scalp regions differentiated between fearful and neutral/happy faces in both adults (N170 was larger for fear) and infants (P400 was larger for fear). Behavioral measures showed no overt attentional bias toward fearful faces in adults, but in infants, the duration of the first fixation was longer for fearful than happy faces. Together, these results suggest that the neural systems underlying the differential processing of fearful and happy/neutral faces are functional early in life, and that affective factors may play an important role in modulating infants' face processing. KeywordsBrain Development; Electrophysiology; Emotion; Face Perception Humans glean a wealth of behaviorally and biologically significant information from others' facial expressions. Infants will crawl over a visual cliff to approach a novel toy if their mother's face displays a happy expression, whereas they avoid the cliff if their mother poses a fearful facial expression (Sorce, Emde, Campos, & Klinnert, 1985). Investigation into the neural mechanisms that underlie the processing of facial expressions may, therefore, provide a useful model as to how behaviorally and emotionally significant stimuli are processed in the human brain, and how the processing of such stimuli differs from the processing of other types of visual stimuli.Recording of event-related potentials (ERPs) provides one tool to examine the neural mechanisms of facial expression processing. ERP studies of face processing in adults have revealed that, compared to other visual objects, faces typically elicit a larger negative deflection at occipital-temporal recording sites approximately 170 ms after the stimulus onset (Bentin,

Unconscious discrimination of social cues from eye whites in infants

“…This is in contrast to prior ERP work with infants using face stimuli presented above the perceptual threshold (for at least 500 ms) that found a larger Nc for fearful than for happy faces (38,39). This discrepancy might be related to methodological differences across studies concerning the duration of presentation (subliminal, supraliminal), the nature of the stimulus (face, eyes), or a combination of the two.…”

“…However, it is not until the age of 7 mo that they show a robust attentional bias to fear, as reflected in their neural and behavioral responses (37)(38)(39)(40)(41). The developmental emergence of this fear bias has been linked to the maturation of frontolimbic circuits (42)(43)(44)(45) and occurs at a point in development when infants begin to first experience fear themselves (46,47).…”

Motherhood and oxytocin receptor genetic variation are associated with selective changes in electrocortical responses to infant facial expressions.

“…Indeed, the late stages of pregnancy (Pearson, Lightman, & Evans, 2009;Roos et al, 2012) and increased OT levels following intranasal OT administration (Van IJzendoorn & Bakermans-Kranenburg, 2012) are associated with increased sensitivity to adults' facial expressions, suggesting a generalized bias. To address the infant specificity, we measured responses also to adults' fearful and happy expressions which have been consistently associated with distinct ERP effects (i.e., larger responses to fearful vs. happy faces; Batty & Taylor, 2003;Leppänen, Moulson, Vogel-Farley, & Nelson, 2007). EEG was recorded while mothers and non-mothers were MOTHERHOOD, OXTR, AND INFANT FACIAL EXPRESSIONS 5 presented with a stream of infant and adult facial expression stimuli.…”

Neural bases of the non-conscious perception of emotional signals

“…Electroencephalography (EEG) and magnetoencephalography (MEG) studies have provided mixed results regarding the speed of processing in the subcortical system, with some studies showing fast processing of emotional stimuli before any fine-grained analysis or attentional modulation can occur 98,99 , and others showing longer latencies 100 . A recent study that combined MEG and MRI methods reported early, event-related synchronization in the posterior thalamus (probably in the pulvinar), as fast as 10-20 ms after onset of the presentation of fearful facial expressions, followed by eventrelated synchronization in the amygdala at 20-30 ms after onset 101 .…”