Neural responses to happy, fearful and angry faces of varying identities in 5- and 7-month-old infants.

The processing of facial emotion is an important social skill that develops throughout infancy and early childhood. Here we investigate the neural underpinnings of the ability to process facial emotion across changes in facial identity in cross-sectional groups of 5- and 7-month-old infants. We simultaneously measured neural metabolic, behavioral, and autonomic responses to happy, fearful, and angry faces of different female models using functional near-infrared spectroscopy (fNIRS), eye-tracking, and heart rate measures. We observed significant neural activation to these facial emotions in a distributed set of frontal and temporal brain regions, and longer looking to the mouth region of angry faces compared to happy and fearful faces. No differences in looking behavior or neural activations were observed between 5- and 7-month-olds, although several exploratory, age-independent associations between neural activations and looking behavior were noted. Overall, these findings suggest more developmental stability than previously thought in responses to emotional facial expressions of varying identities between 5- and 7-months of age.

Growth faltering is associated with altered brain functional connectivity and cognitive outcomes in urban Bangladeshi children exposed to early adversity.

BACKGROUND: Stunting affects more than 161 million children worldwide and can compromise cognitive development beginning early in childhood. There is a paucity of research using neuroimaging tools in conjunction with sensitive behavioral assays in low-income settings, which has hindered researchers' ability to explain how stunting impacts brain and behavioral development. We employed high-density EEG to examine associations among children's physical growth, brain functional connectivity (FC), and cognitive development. METHODS: We recruited participants from an urban impoverished neighborhood in Dhaka, Bangladesh. One infant cohort consisted of 92 infants whose height (length) was measured at 3, 4.5, and 6 months; EEG data were collected at 6 months; and cognitive outcomes were assessed using the Mullen Scales of Early Learning at 27 months. A second, older cohort consisted of 118 children whose height was measured at 24, 30, and 36 months; EEG data were collected at 36 months; and Intelligence Quotient (IQ) scores were assessed at 48 months. Height-for-age (HAZ) z-scores were calculated based on the World Health Organization standard. EEG FC in different frequency bands was calculated in the cortical source space. Linear regression and longitudinal path analysis were conducted to test the associations between variables, as well as the indirect effect of child growth on cognitive outcomes via brain FC. RESULTS: In the older cohort, we found that HAZ was negatively related to brain FC in the theta and beta frequency bands, which in turn was negatively related to children's IQ score at 48 months. Longitudinal path analysis showed an indirect effect of HAZ on children's IQ via brain FC in both the theta and beta bands. There were no associations between HAZ and brain FC or cognitive outcomes in the infant cohort. CONCLUSIONS: The association observed between child growth and brain FC may reflect a broad deleterious effect of malnutrition on children's brain development. The mediation effect of FC on the relation between child growth and later IQ provides the first evidence suggesting that brain FC may serve as a neural pathway by which biological adversity impacts cognitive development.

Rapid face processing for positive and negative emotions in 5-, 7-, and 12-month-old infants: An exploratory study.

Processing of positive and negative facial expressions in infancy follows a distinct course with a bias towards fearful facial expressions starting at 7 months of age; however, little is known about the developmental trajectory of fear processing and other facial expressions, and if this bias is driven by specific regions of the face. This study used eye tracking to examine the processing of positive and negative emotional faces in independent groups of 5- (n = 43), 7- (n = 60), and 12-month-old infants (n = 70). Methods: Infants were shown static images of female faces exhibiting happy, anger, and fear expressions, for one-second each. Total looking time and looking time for areas of interest (AOIs) including forehead and eyes (top), mouth and chin (bottom), and contour of each image were computed. Infants across all ages looked longer to fear faces than angry or happy faces. Negative emotions generally elicited greater looking times for the top of the face than did happy faces. In addition, we also found that at 12 months of age infants looked longer for the bottom of the faces than did 5-month-olds. Our study suggests that the visual bias to attend longer to fearful faces may be in place by 5 months of age, and between 5 and 12 months of age, there seems to be a developmental shift towards looking more to the bottom of the faces. STATEMENT OF CONTRIBUTION: What is already known in this subject? Bias for fear face processing is present at 7 months of age. Using older data collection systems, we have some idea about which facial features recruit infant attention. What the present study adds? Well-controlled paradigm that examines both positive and negative facial expressions, to different areas of interest in the face. Use of the same paradigm to test a cross-sectional sample of infants in distinct developmental stages - 5, 7, and 12 months.

Testing the effects of expression, intensity and age on emotional face processing in ASD.

Individuals with autism spectrum disorder (ASD) commonly show global deficits in the processing of facial emotion, including impairments in emotion recognition and slowed processing of emotional faces. Growing evidence has suggested that these challenges may increase with age, perhaps due to minimal improvement with age in individuals with ASD. In the present study, we explored the role of age, emotion type and emotion intensity in face processing for individuals with and without ASD. Twelve- and 18-22- year-old children with and without ASD participated. No significant diagnostic group differences were observed on behavioral measures of emotion processing for younger versus older individuals with and without ASD. However, there were significant group differences in neural responses to emotional faces. Relative to TD, at 12 years of age and during adulthood, individuals with ASD showed slower N170 to emotional faces. While the TD groups' P1 latency was significantly shorter in adults when compared to 12 year olds, there was no significant age-related difference in P1 latency among individuals with ASD. Findings point to potential differences in the maturation of cortical networks that support visual processing (whether of faces or stimuli more broadly), among individuals with and without ASD between late childhood and adulthood. Finally, associations between ERP amplitudes and behavioral responses on emotion processing tasks suggest possible neural markers for emotional and behavioral deficits among individuals with ASD.

Neural correlates of facial emotion processing in infancy.

In the present study we examined the neural correlates of facial emotion processing in the first year of life using ERP measures and cortical source analysis. EEG data were collected cross-sectionally from 5- (N = 49), 7- (N = 50), and 12-month-old (N = 51) infants while they were viewing images of angry, fearful, and happy faces. The N290 component was found to be larger in amplitude in response to fearful and happy than angry faces in all posterior clusters and showed largest response to fear than the other two emotions only over the right occipital area. The P400 and Nc components were found to be larger in amplitude in response to angry than happy and fearful faces over central and frontal scalp. Cortical source analysis of the N290 component revealed greater cortical activation in the right fusiform face area in response to fearful faces. This effect started to emerge at 5 months and became well established at 7 months, but it disappeared at 12 months. The P400 and Nc components were primarily localized to the PCC/Precuneus where heightened responses to angry faces were observed. The current results suggest the detection of a fearful face in infants' brain can happen shortly (~200-290 ms) after the stimulus onset, and this process may rely on the face network and develop substantially between 5 to 7 months of age. The current findings also suggest the differential processing of angry faces occurred later in the P400/Nc time window, which recruits the PCC/Precuneus and is associated with the allocation of infants' attention.

Recognition of facial emotions of varying intensities by three-year-olds.

Early facial emotion recognition is hypothesized to be critical to later social functioning. However, relatively little is known about the typical intensity thresholds for recognizing facial emotions in preschoolers, between 2 and 4 years of age. This study employed a behavioral sorting task to examine the recognition of happy, fearful, and angry expressions of varying intensity in a large sample of 3-year-old children (N = 208). Thresholds were similar for all expressions; accuracy, however, was significantly lower for fear. Fear and anger expressions above threshold were significantly more confused with one another than with other expressions. In contrast, neutral faces were significantly more often interpreted as happy than as angry or fearful. These results provide a comparison point for future studies of early facial emotion recognition in typical and atypical populations of children in this age group. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

An ERP study of recognition memory for concrete and abstract pictures in school-aged children.

Recognition memory for concrete, nameable pictures is typically faster and more accurate than for abstract pictures. A dual-coding account for these findings suggests that concrete pictures are processed into verbal and image codes, whereas abstract pictures are encoded in image codes only. Recognition memory relies on two successive and distinct processes, namely familiarity and recollection. Whether these two processes are similarly or differently affected by stimulus concreteness remains unknown. This study examined the effect of picture concreteness on visual recognition memory processes using event-related potentials (ERPs). In a sample of children involved in a longitudinal study, participants (N=96; mean age=11.3years) were assessed on a continuous visual recognition memory task in which half the pictures were easily nameable, everyday concrete objects, and the other half were three-dimensional abstract, sculpture-like objects. Behavioral performance and ERP correlates of familiarity and recollection (respectively, the FN400 and P600 repetition effects) were measured. Behavioral results indicated faster and more accurate identification of concrete pictures as "new" or "old" (i.e., previously displayed) compared to abstract pictures. ERPs were characterized by a larger repetition effect, on the P600 amplitude, for concrete than for abstract images, suggesting a graded recollection process dependent on the type of material to be recollected. Topographic differences were observed within the FN400 latency interval, especially over anterior-inferior electrodes, with the repetition effect more pronounced and localized over the left hemisphere for concrete stimuli, potentially reflecting different neural processes underlying early processing of verbal/semantic and visual material in memory.

Infants' neural responses to facial emotion in the prefrontal cortex are correlated with temperament: a functional near-infrared spectroscopy study.

Accurate decoding of facial expressions is critical for human communication, particularly during infancy, before formal language has developed. Different facial emotions elicit distinct neural responses within the first months of life. However, there are broad individual differences in such responses, so that the same emotional expression can elicit different brain responses in different infants. In this study, we sought to investigate such differences in the processing of emotional faces by analyzing infants's cortical metabolic responses to face stimuli and examining whether individual differences in these responses might vary as a function of infant temperament. Seven-month-old infants (N = 24) were shown photographs of women portraying happy expressions, and neural activity was recorded using functional near-infrared spectroscopy (fNIRS). Temperament data were collected using the Revised Infant Behavior Questionnaire Short Form, which assesses the broad temperament factors of Surgency/Extraversion (S/E), Negative Emotionality (NE), and Orienting/Regulation (O/R). We observed that oxyhemoglobin (oxyHb) responses to happy face stimuli were negatively correlated with infant temperament factors in channels over the left prefrontal cortex (uncorrected for multiple comparisons). To investigate the brain activity underlying this association, and to explore the use of fNIRS in measuring cortical asymmetry, we analyzed hemispheric asymmetry with respect to temperament groups. Results showed preferential activation of the left hemisphere in low-NE infants in response to smiling faces. These results suggest that individual differences in temperament are associated with differential prefrontal oxyHb responses to faces. Overall, these analyses contribute to our current understanding of face processing during infancy, demonstrate the use of fNIRS in measuring prefrontal asymmetry, and illuminate the neural correlates of face processing as modulated by temperament.

Looking to the eyes influences the processing of emotion on face-sensitive event-related potentials in 7-month-old infants.

Previous studies in infants have shown that face-sensitive components of the ongoing electroencephalogram (the event-related potential, or ERP) are larger in amplitude to negative emotions (e.g., fear, anger) versus positive emotions (e.g., happy). However, it is still unclear whether the negative emotions linked with the face or the negative emotions alone contribute to these amplitude differences. We simultaneously recorded infant looking behaviors (via eye-tracking) and face-sensitive ERPs while 7-month-old infants viewed human faces or animals displaying happy, fear, or angry expressions. We observed that the amplitude of the N290 was greater (i.e., more negative) to angry animals compared to happy or fearful animals; no such differences were obtained for human faces. Eye-tracking data highlighted the importance of the eye region in processing emotional human faces. Infants that spent more time looking to the eye region of human faces showing fearful or angry expressions had greater N290 or P400 amplitudes, respectively.

Extraction of heart rate from functional near-infrared spectroscopy in infants.

Changes in heart rate are a useful physiological measure in infant studies. We present an algorithm for calculating the heart rate (HR) from oxyhemoglobin pulsation in functional near-infrared spectroscopy (fNIRS) signals. The algorithm is applied to data collected from 10 infants, and the HR derived from the fNIRS signals is compared against the HR as calculated by electrocardiography. We show high agreement between the two HR signals for all infants (r > 0.90), and also compare stimulus-related HR responses as measured by the two methods and find good agreement despite high levels of movement in the infants. This algorithm can be used to measure changes in HR in infants participating in fNIRS studies without the need for additional HR sensors.

Infants' experience-dependent processing of male and female faces: insights from eye tracking and event-related potentials.

The goal of the present study was to investigate infants' processing of female and male faces. We used an event-related potential (ERP) priming task, as well as a visual-paired comparison (VPC) eye tracking task to explore how 7-month-old "female expert" infants differed in their responses to faces of different genders. Female faces elicited larger N290 amplitudes than male faces. Furthermore, infants showed a priming effect for female faces only, whereby the N290 was significantly more negative for novel females compared to primed female faces. The VPC experiment was designed to test whether infants could reliably discriminate between two female and two male faces. Analyses showed that infants were able to differentiate faces of both genders. The results of the present study suggest that 7-month olds with a large amount of female face experience show a processing advantage for forming a neural representation of female faces, compared to male faces. However, the enhanced neural sensitivity to the repetition of female faces is not due to the infants' inability to discriminate male faces. Instead, the combination of results from the two tasks suggests that the differential processing for female faces may be a signature of expert-level processing.

The neural correlates of processing newborn and adult faces in 3-year-old children.

The current study examines the processing of upright and inverted faces in 3-year-old children (n = 35). Event-related potentials (ERPs) were recorded during a passive looking paradigm including adult and newborn face stimuli. We observed three face-sensitive components, the P1, the N170 and the P400. Inverted faces elicited shorter P1 latency and larger P400 amplitude. P1 and N170 amplitudes were larger for adult faces. To examine the role of experience in the development of face processing, the processing of adult and newborn faces was compared for children with a younger sibling (n = 23) and children without a younger sibling (n = 12). Age of sibling at test correlated negatively with P1 amplitude for adult and newborn faces. This may indicate more efficient processing of different face ages in children with a younger sibling and potentially reflects a more flexible face representation.

Emotion recognition following early psychosocial deprivation.

An important function of the brain is to scan incoming sensory information for the presence of relevant signals and act on this information. For humans, the most salient signals are often social in nature, such as the identity and the emotional expression of the faces we encounter in our everyday lives. It can be argued that our survival as a species depends in large measure on these skills.

Iron-deficiency anemia in infancy and poorer cognitive inhibitory control at age 10 years.

AIM: The aim of this study was to assess the effects of iron-deficiency anemia (IDA) in infancy on executive functioning at age 10 years, specifically inhibitory control on the Go/No-Go task. We predicted that children who had IDA in infancy would show poorer inhibitory control. METHOD: We assessed cognitive inhibitory control in 132 Chilean children (mean [SD] age 10 y [1 mo]): 69 children had IDA in infancy (45 males, 24 females) and 63 comparison children who did not have IDA (26 males, 37 females). Participants performed the Go/No-Go task with event-related potentials. Group differences in behavioral (accuracy, reaction time) and electrophysiological outcomes (N2 and P300 components) were analyzed using repeated-measures analyses of variance. N2 and P300 are interpreted to reflect attention and resource allocation respectively. RESULTS: Relative to comparison participants, children who had IDA in infancy showed slower reaction time (mean [SE], 528.7 ms [14.2] vs 485.0 ms [15.0], 95% confidence interval [CI] for difference between groups 0.9-86.5); lower accuracy (95.4% [0.5] vs 96.9% [0.6], 95% CI -3.0 to -0.1); longer latency to N2 peak (378.9 ms [4.9] vs 356.9 ms [5.0], 95% CI 7.5-36.6); and smaller P300 amplitude (4.5 µV [0.8] vs 7.6 µV [0.9], 95% CI-5.5 to -0.5). INTERPRETATION: IDA in infancy was associated with slower reaction times and poorer inhibitory control 8 to 9 years after iron therapy. These findings are consistent with the long-lasting effects of early IDA on myelination and/or prefrontal-striatal circuits where dopamine is the major neurotransmitter.

The effect of early deprivation on executive attention in middle childhood.

BACKGROUND: Children reared in deprived environments, such as institutions for the care of orphaned or abandoned children, are at increased risk for attention and behavior regulation difficulties. This study examined the neurobehavioral correlates of executive attention in post institutionalized (PI) children. METHODS: The performance and event-related potentials (ERPs) of 10- and 11-year-old internationally adopted PI children on two executive attention tasks, go/no-go and Flanker, were compared with two groups: children internationally adopted early from foster care (PF) and nonadopted children (NA). RESULTS: Behavioral measures suggested problems with sustained attention, with PIs performing more poorly on go trials and not on no-go trials of the go/no-go and made more errors on both congruent and incongruent trials on the Flanker. ERPs suggested differences in inhibitory control and error monitoring, as PIs had smaller N2 amplitude on go/no-go and smaller error-related negativity on Flanker. CONCLUSIONS: This pattern of results raises questions regarding the nature of attention difficulties for PI children. The behavioral errors are not specific to executive attention and instead likely reflect difficulties in overall sustained attention. The ERP results are consistent with neural activity related to deficits in inhibitory control (N2) and error monitoring (error-related negativity). Questions emerge regarding the similarity of attention regulatory difficulties in PIs to those experienced by non-PI children with ADHD.

Early adversity and neural correlates of executive function: implications for academic adjustment.

Early adversity can negatively impact the development of cognitive functions, although little is known about whether such effects can be remediated later in life. The current study examined one facet of executive functioning - inhibitory control - among children who experienced institutional care and explored the impact of a foster care intervention within the context of the Bucharest Early Intervention Project (BEIP). Specifically, a go/nogo task was administered when children were eight years old and behavioral and event-related potential (ERP) measures were collected. Results revealed that children assigned to care as usual (i.e. institutional care) were less accurate and exhibited slower neural responses compared to children assigned to the foster care intervention and children who had never been institutionalized. However, children in both the care as usual and foster care groups exhibited diminished attention processing of nogo cues as assessed via P300 amplitude. Foster care children also showed differential reactivity between correct and error responses via the error-related negativity (ERN) as compared to children in the care as usual group. Combined, the results highlight perturbations in neural sources of behavioral and attention problems among children experiencing early adversity. Potential implications for academic adjustment in at risk children are discussed.

Iron deficiency in infancy is associated with altered neural correlates of recognition memory at 10 years.

OBJECTIVE: To determine the long-term effects of iron deficiency on the neural correlates of recognition memory. STUDY DESIGN: Non-anemic control participants (n=93) and 116 otherwise healthy formerly iron-deficient anemic Chilean children were selected from a larger longitudinal study. Participants were identified at 6, 12, or 18 months as iron-deficient anemic or non-anemic and subsequently received oral iron treatment. This follow-up was conducted when participants were 10 years old. Behavioral measures and event-related potentials from 28 scalp electrodes were measured during an new/old word recognition memory task. RESULTS: The new/old effect of the FN400 amplitude, in which new words are associated with greater amplitude than old words, was present within the control group only. The control group also showed faster FN400 latency than the formerly iron-deficient anemic group and larger mean amplitude for the P300 component. CONCLUSIONS: Although overall behavioral accuracy is comparable in groups, the results show that group differences in cognitive function have not been resolved 10 years after iron treatment. Long-lasting changes in myelination and energy metabolism, perhaps especially in the hippocampus, may account for these long-term effects on an important aspect of human cognitive development.

Shape, color and the other-race effect in the infant brain.

The 'other-race' effect describes the phenomenon in which faces are difficult to distinguish from one another if they belong to an ethnic or racial group to which the observer has had little exposure. Adult observers typically display multiple forms of recognition error for other-race faces, and infants exhibit behavioral evidence of a developing other-race effect at about 9 months of age. The neural correlates of the adult other-race effect have been identified using ERPs and fMRI, but the effects of racial category on infants' neural response to face stimuli have to date not been described. We examine two distinct components of the infant ERP response to human faces and demonstrate through the use of computer-generated 'hybrid' faces that the observed other-race effect is not the result of low-level sensitivity to 3D shape and color differences between the stimuli. Rather, differential processing depends critically on the joint encoding of race-specific features.

The effects of maternal binge drinking during pregnancy on neural correlates of response inhibition and memory in childhood.

BACKGROUND: Although an extensive literature has documented a broad range of cognitive performance deficits in children with prenatal alcohol exposure, little is known about how the neurophysiological processes underlying these deficits may be affected. Event-related potentials (ERPs), which reflect task-specific changes in brain electrical activity, provide a method for examining multiple constituents of cognitive processing at the neural level. METHODS: We recorded ERPs in 217 children from Inuit communities in Arctic Quebec (M age = 11.3 years) during 2 different tasks-Go/No-go response inhibition and continuous recognition memory. Children were classified as either alcohol-exposed (ALC) or controls (CON) depending on whether the mother reported binge drinking during pregnancy. RESULTS: Both groups performed comparably in terms of accuracy and reaction time on the tasks, and both tasks elicited the expected effects on ERPs when responses were compared across conditions. However, the ALC group showed slower P2 latencies on Go/No-go, suggesting an altered neurophysiological response associated with initial visual processing of the stimuli. On the memory task, the ALC group showed reduced FN400 amplitude to New items, known as the familiarity effect, and reduced amplitude for the late positive component, possibly reflecting impairment in memory retrieval. CONCLUSIONS: These findings show that, even in tasks in which alcohol-exposed children exhibit behavioral performance that is comparable to controls, fetal alcohol exposure is associated with altered neurophysiological processing of response inhibition and recognition memory. The data suggest that fetal alcohol exposure is associated with reduced efficiency in the initial extracting of the meaning of a stimulus, reduced allocation of attention to the task, and poorer conscious, explicit recognition memory processing.

Brain activation during upright and inverted encoding of own- and other-age faces: ERP evidence for an own-age bias.

We investigated the neural processing underlying own-age versus other-age faces among 5-year-old children and adults, as well as the effect of orientation on face processing. Upright and inverted faces of 5-year-old children, adults, and elderly adults (> 75 years of age) were presented to participants while ERPs and eye tracking patterns were recorded concurrently. We found evidence for an own-age bias in children, as well as for predicted delayed latencies and larger amplitudes for inverted faces, which replicates earlier findings. Finally, we extend recent reports about an expert-sensitive component (P2) to other-race faces to account for similar effects in regard to other-age faces. We conclude that differences in neural activity are strongly related to the amount and quality of experience that participants have with faces of various ages. Effects of orientation are discussed in relation to the holistic hypothesis and recent data that compromise this view.