Electrophysiological responses in mothers to their own and unfamiliar child's gaze information

Reduced gamma oscillation during visual processing of the mother's face in children with autism spectrum disorder: A pilot study

Aim

This study aimed to investigate gamma oscillations related to face processing of children with autism spectrum disorders and typically developed children using magnetoencephalography.

Methods

We developed stimuli that included naturalistic real-time eye-gaze situations between participants and their mothers. Eighteen young children with autism spectrum disorders (62-97 months) and 24 typically developed children (61-79 months) were included. The magnetoencephalography data were analyzed in the bilateral banks of the superior temporal sulcus, fusiform gyrus, and pericalcarine cortex for frequency ranges 30-59 and 61-90 Hz. The gamma oscillation normalized values were calculated to compare the face condition (children gazing at mother's face) and control measurements (baseline) using the following formula: (face - control)/(face + control).

Results

The results revealed significant differences in gamma oscillation normalized values in the low gamma band (30-59 Hz) in the right banks of the superior temporal sulcus, right fusiform gyrus, and right pericalcarine cortex between children with autism spectrum disorders and typically developed children. Furthermore, there were significant differences in gamma oscillation normalized values in the high gamma band (61-90 Hz) in the right banks of the superior temporal sulcus, bilateral fusiform gyrus, and bilateral pericalcarine cortex between the groups.

Conclusion

This report is the first magnetoencephalography study revealing atypical face processing in young children with autism spectrum disorders using relevant stimuli between participants and their mothers. Our naturalistic paradigm provides a useful assessment of social communication traits and a valuable insight into the underlying neural mechanisms in children with autism spectrum disorders.

Processing children's faces in the parental brain: A meta-analysis of ERP studies

Event-related potentials (ERPs) are an excellent tool for investigating parental neural responses to child stimuli. Using meta-analysis, we quantified the results of available studies reporting N170 or LPP/P3 ERP responses to children's faces, targeting three questions: 1) Do parents and non-parents differ in ERP responses to child faces? 2) Are parental ERP responses larger to own vs. unfamiliar child faces? 3) Are parental ERP responses to child faces associated with indicators of parenting quality, such as observed parental sensitivity? Across 23 studies (N = 1035), key findings showed 1) larger N170 amplitudes to child faces in parents than in non-parents (r = 0.19), 2) larger LPP/P3 responses to own vs. unfamiliar child faces in parents (r = 0.19), and 3) positive associations between parental LPP/P3 responses to child faces and parenting quality outcomes (r = 0.15). These results encourage further research particularly with the LPP/P3 to assess attentional-motivational processes of parenting, but also highlight the need for larger samples and more systematic assessments of associations between ERPs and parenting.

Attachment voices promote safety learning in humans: A critical role for P2

Humans have evolved to seek the proximity of attachment figures during times of threat in order to obtain a sense of safety. In this context, we examined whether or not the voice of an intimate partner (termed "attachment voice") could reduce fear-learning of conditioned stimuli (CS+) and enhance learning of safety signals (CS-). Although the ability to learn safety signals is vital for human survival, few studies have explored how attachment voices affect safety learning. To test our hypothesis, we recruited thirty-five young couples and performed a classic Pavlovian conditioning experiment, recording behavioral and electroencephalographic (EEG) data. The results showed that compared with a stranger's voice, the voices of the partners reduced expectancy of the unconditioned stimulus (a shock) during fear-conditioning, as well as the magnitude of P2 event-related potentials within the EEG responses, provided the voices were safety signals. Additionally, behavioral and EEG responses to the CS+ and CS- differed more when the participants heard their partner's voice than when they heard the stranger's voice. Thus, attachment voices, even as pure vowel sounds without any semantic information, enhanced acquisition of conditioned safety (CS-). These findings may provide implications for investigating other new techniques to improve clinical treatments for fear- and anxiety-related disorders and for psychological interventions against the mental health effects of the public health emergency.

Maternal sensitivity is associated with configural processing of infant's cues in preterm and full-term mothers

BACKGROUND

Prematurity may affect mother-infant bonding and alter maternal sensitivity to infant's cues. Efficient perception of infants' facial and bodily cues is a crucial aspect of maternal sensitivity and may be challenged by prematurity, as infants' signals may not be easily intelligible. However, it is still unexplored how premature birth impacts the maternal ability to perceive infants' signals.

AIMS

To investigate whether prematurity influences the perceptual sensitivity of mothers to infants' cues and, in particular, the configural processing of the faces and bodies of familiar and unfamiliar infants.

STUDY DESIGN

The inversion effect paradigm was used to evaluate the configural vs. detail-based processing of the face and body of own or others' infants. Preterm mothers were compared to full-term mothers with either low or high maternal sensitivity.

PARTICIPANTS

Forty-three healthy full-term and twenty-one preterm mothers of infants aged about six months.

OUTCOME MEASURES

Maternal sensitivity during dyadic interaction, gestational age, accuracy and reaction time in a delayed matching-to-sample task of upright vs. inverted body and face stimuli (i.e., inversion effect).

RESULTS

Preterm mothers were found to be less sensitive than the full-term ones. Higher maternal sensitivity during dyadic interaction was associated with lower inversion effect for unfamiliar as compared to own infants' bodies. However, preterm mothers and full-term mothers with low sensitivity showed comparable inversion effect in perceiving unfamiliar infants' faces or bodies.

CONCLUSIONS

Preterm birth per se does not directly affect body configural processing, but it may be associated to reduced maternal sensitivity, ultimately leading to a less refined perception of own infant's cues.

CPS-referred mothers' psychophysiological responses to own versus other child predict sensitivity to child distress

Maltreating mothers often struggle to respond sensitively to their children's distress. Examining psychophysiological processing of own child cues may offer insight into neurobiological mechanisms that promote sensitive parenting among high-risk mothers. The current study used event-related potential (ERP) methodology to examine associations between mothers' neural responses to their own child versus other children and observed sensitivity to distress. Participants included 73 mothers: 42 with histories of child protective services (CPS) involvement and 31 low-risk comparison mothers. Maternal sensitivity to child distress was coded from observations of children's blood sample collection. Late positive potential (LPP) ERP responses, which reflect sustained attention to emotionally salient stimuli, were measured when mothers viewed photos of their own child and other children. An own-other LPP difference score (own-other LPP) was computed by regressing the mean amplitude of mothers' LPP to their own child on the mean amplitude of mothers' LPP to other children. CPS-referred mothers and low-risk mothers did not differ in their LPP responses to own child, other children, or the own-other LPP. However, there was a significant interaction between group (CPS-referred vs. low-risk) and own-other LPP in predicting maternal sensitivity. Among the CPS-referred mothers, own-other LPP was significantly correlated with maternal sensitivity, with greater LPP amplitude to own versus other child associated with higher maternal sensitivity. In contrast, among the low-risk group, own-other LPP was not significantly correlated with maternal sensitivity. Findings add to our understanding of the neurobiology of sensitive parenting among high-risk mothers. (PsycINFO Database Record

Early and late cortical responses to directly gazing faces are task dependent

Gender categorisation of human faces is facilitated when gaze is directed toward the observer (i.e., a direct gaze), compared with situations where gaze is averted or the eyes are closed (Macrae, Hood, Milne, Rowe, & Mason, Psychological Science, 13(5), 460-464, 2002). However, the temporal dynamics underlying this phenomenon remain to some extent unknown. Here, we used electroencephalography (EEG) to assess the neural correlates of this effect, focusing on the event-related potential (ERP) components known to be sensitive to gaze perception (i.e., P1, N170, and P3b). We first replicated the seminal findings of Macrae et al. (2002, Experiment 1) regarding facilitated gender discrimination, and subsequently measured the underlying neural responses. Our data revealed an early preferential processing of direct gaze as compared with averted gaze and closed eyes at the P1, which reverberated at the P3b (Experiment 2). Critically, using the same material, we failed to reproduce these effects when gender categorisation was not required (Experiment 3). Taken together, our data confirm that direct gaze enhances the early P1, as well as later cortical responses to face processing, although the effect appears to be task dependent.

Parental reflective functioning and the neural correlates of processing infant affective cues

Parental reflective functioning refers to the capacity for a parent to understand their own and their infant's mental states, and how these mental states relate to behavior. Higher levels of parental reflective functioning may be associated with greater sensitivity to infant emotional signals in fostering adaptive and responsive caregiving. We investigated this hypothesis by examining associations between parental reflective functioning and neural correlates of infant face and cry perception using event-related potentials (ERPs) in a sample of recent mothers. We found both early and late ERPs were associated with different components of reflective functioning. These findings suggest that parental reflective functioning may be associated with the neural correlates of infant cue perception and further support the value of enhancing reflective functioning as a mechanism in parenting intervention programs.

Attachment representation modulates oxytocin effects on the processing of own-child faces in fathers

Oxytocin (OT) plays a crucial role in parental-infant bonding and attachment. Recent functional imaging studies reveal specific attachment and reward related brain regions in individuals or within the parent-child dyad. However, the time course and functional stage of modulatory effects of OT on attachment-related processing, especially in fathers, are poorly understood. To elucidate the functional and neural mechanisms underlying the role of OT in paternal-child attachment, we performed an event-related potential study in 24 healthy fathers who received intranasal OT in a double-blind, placebo-controlled, within-subject experimental design. Participants passively viewed pictures of their own child (oC), a familiar (fC) and an unfamiliar child (ufC) while event-related potentials were recorded. Familiarity of the child's face modulated a broad negativity at occipital and temporo-parietal electrodes within a time window of 300-400ms, presumably reflecting a modulation of the N250 and N300 ERP components. The oC condition elicited a more negative potential compared to the other familiarity conditions suggesting different activation of perceptual memory representations and assignment of emotional valence. Most importantly, this familiarity effect was only observed under placebo (PL) and was abolished under OT, in particular at left temporo-parietal electrodes. This OT induced attenuation of ERP responses was related to habitual attachment representations in fathers. In summary, our results demonstrate an OT-specific effect at later stages of attachment-related face processing presumably reflecting both activation of perceptual memory representations and assignment of emotional value.

Neural systems and hormones mediating attraction to infant and child faces

We find infant faces highly attractive as a result of specific features which Konrad Lorenz termed “Kindchenschema” or “baby schema,” and this is considered to be an important adaptive trait for promoting protective and caregiving behaviors in adults, thereby increasing the chances of infant survival. This review first examines the behavioral support for this effect and physical and behavioral factors which can influence it. It then provides details of the increasing number of neuroimaging and electrophysiological studies investigating the neural circuitry underlying this baby schema effect in parents and non-parents of both sexes. Next it considers potential hormonal contributions to the baby schema effect in both sexes and the neural effects associated with reduced responses to infant cues in post-partum depression, anxiety and drug taking. Overall the findings reviewed reveal a very extensive neural circuitry involved in our perception of cuteness in infant faces, with enhanced activation compared to adult faces being found in brain regions involved in face perception, attention, emotion, empathy, memory, reward and attachment, theory of mind and also control of motor responses. Both mothers and fathers also show evidence for enhanced responses in these same neural systems when viewing their own as opposed to another child. Furthermore, responses to infant cues in many of these neural systems are reduced in mothers with post-partum depression or anxiety or have taken addictive drugs throughout pregnancy. In general reproductively active women tend to rate infant faces as cuter than men, which may reflect both heightened attention to relevant cues and a stronger activation in their brain reward circuitry. Perception of infant cuteness may also be influenced by reproductive hormones with the hypothalamic neuropeptide oxytocin being most strongly associated to date with increased attention and attraction to infant cues in both sexes.

Immediate and selective maternal brain responses to own infant faces

Infant faces elicit caregiving in adults. In previous research on brain responses to images of infant faces, the faces were unknown to participants. This study investigated EEG in primiparous mothers of 3- to 6-month-old infants viewing their own infant's face compared to an unfamiliar but appearance-matched infant's face. Spectral power was calculated and compared, and power at three EEG bands (delta, theta, and gamma) was found to differ between faces. Brain responses among primiparous mothers distinguish images of their own versus unfamiliar infants.

Understanding the human parental brain: a critical role of the orbitofrontal cortex

The bond between a parent and an infant often appears to form effortlessly and intuitively, and this relationship is fundamental to infant survival and development. Parenting is considered to depend on specific brain networks that are largely conserved across species and in place even before parenthood. Efforts to understand the neural basis of parenting in humans have focused on the overlapping networks implicated in reward and social cognition, within which the orbitofrontal cortex (OFC) is considered to be a crucial hub. This review examines emerging evidence that the OFC may be engaged in several phases of parent-infant interactions, from early, privileged orienting to infant cues, to ongoing monitoring of interactions and subsequent learning. Specifically, we review evidence suggesting that the OFC rapidly responds to a range of infant communicative cues, such as faces and voices, supporting their efficient processing. Crucially, this early orienting response may be fundamental in supporting adults to respond rapidly and appropriately to infant needs. We suggest a number of avenues for future research, including investigating neural activity in disrupted parenting, exploring multimodal cues, and consideration of neuroendocrine involvement in responsivity to infant cues. An increased understanding of the brain basis of caregiving will provide insight into our greatest challenge: parenting our young.