Sympathetic nervous system functioning during the face-to-face still-face paradigm in the first year of life.

Contemporary theories of early development and emerging child psychopathology all posit a major, if not central role for physiological responsiveness. To understand infants' potential risk for emergent psychopathology, consideration is needed to both autonomic reactivity and environmental contexts (e.g., parent-child interactions). The current study maps infants' arousal during the face-to-face still-face paradigm using skin conductance (n = 255 ethnically-diverse mother-infant dyads; 52.5% girls, mean infant age = 7.4 months; SD = 0.9 months). A novel statistical approach was designed to model the potential build-up of nonlinear counter electromotive force over the course of the task. Results showed a significant increase in infants' skin conductance between the Baseline Free-play and the Still-Face phase, and a significant decrease in skin conductance during the Reunion Play when compared to the Still-Face phase. Skin conductance during the Reunion Play phase remained significantly higher than during the Baseline Play phase; indicating that infants had not fully recovered from the mild social stressor. These results further our understanding of infant arousal during dyadic interactions, and the role of caregivers in the development of emotion regulation during infancy.

Towards Preventative Psychiatry: Concurrent and Longitudinal Predictors of Postnatal Maternal-Infant Bonding.

Maternal-infant bonding is important for children's positive development. Poor maternal-infant bonding is a risk factor for negative mother and infant outcomes. Although researchers have examined individual predictors of maternal-infant bonding, studies typically do not examine several concurrent and longitudinal predictors within the same model. This study aimed to evaluate the unique and combined predictive power of cross-sectional and longitudinal predictors of maternal-infant bonding. Participants were 372 pregnant women recruited from an Australian hospital. Data were collected from mothers at antenatal appointments (T0), following their child's birth (T1), and at a laboratory assessment when their child was 5-11-months-old (T2). Poorer bonding at T2 was predicted at T0 by younger maternal age, higher education, and higher antenatal depressive symptoms. Poorer bonding at T2 was predicted at T1 by younger maternal age, higher education, and higher postnatal depressive symptoms. Poorer bonding at T2 was predicted at T2 by younger maternal age, higher education, higher postnatal depression symptoms, higher concurrent perceived social support, and more difficult infant temperament, when controlling for child age at T2. To promote positive maternal-infant bonding, global and targeted interventions in the perinatal period may benefit from targeting maternal psychopathology, perceived lack of social support, and coping with difficult infant temperament.

Learning to like triangles: A longitudinal investigation of evaluative conditioning in infancy.

There is tentative evidence that infants can learn preferences through evaluative conditioning to socioemotional stimuli. However, the early development of evaluative conditioning and the factors that may explain infants' capacity to learn through evaluative conditioning are not well understood. Infants (N = 319; 50.2% boys) participated in a longitudinal study where an evaluative conditioning paradigm using socioemotional stimuli was conducted on two occasions (when infants were 7 and 14 months old, on average). We tested whether repeatedly pairing neutral stimuli (triangular and square shapes) with affective stimuli (angry and happy faces) affects infants' preferences for these shapes. At both timepoints, the majority of infants did not choose the shape that was paired with happy faces, indicating that, in general, learning through evaluative conditioning was not present. However, as expected, individual differences were evident such that infants who spent more time fixating on faces compared to shapes (face-preferrers) during the conditioning trials were significantly more likely than non-face-preferrers to choose the shape paired with happy faces, and this effect strengthened with increasing age.

Still connecting the dots: An investigation into infants' attentional bias to threat using an eye-tracking task.

An attentional bias toward threat has been theorized to be a normative aspect of infants' threat and safety learning, and an indicator of risk for internalizing psychopathology in older populations. To date, only four studies have examined this bias using the dot-probe task in infancy and the findings are mixed. We extended the literature by examining patterns of attention to threat in a culturally and linguistically diverse sample of infants aged 5-11 months old (N = 151) using all measures previously employed in the infant dot-probe literature. Given that an attentional bias toward threat is associated with higher risk of developing anxiety disorders later in life, we also examined how negative affect-an early correlate of later anxiety disorders-is related to attentional bias toward threat in infancy. This study was the first to use a consistent measure of negative affect across the whole sample. An eye-tracking dot-probe task was used to examine attentional bias toward threat (i.e., angry faces) relative to positive (i.e., happy faces) stimuli. Results showed that an attention bias to threat was not characteristic of infants at this age, and negative affect did not moderate the putative relationship between attention and emotional faces (angry, happy). These findings therefore suggest that attention biases to socio-emotional threat may not have emerged by 11 months old.

Empathy for others' pain is disrupted at the neurophysiological level in schizophrenia.

OBJECTIVE: Previous research has shown that empathy for pain is disrupted at the neural level in people with schizophrenia. However, many of these studies have failed to assess key background contextual variables that have previously been linked to neurophysiological responding. Moreover, no study to date has examined the potential influence of schizotypal characteristics on neurophysiological responding in non-clinical individuals. METHODS: People with schizophrenia (N = 17) were compared to demographically matched controls (N = 19) on an event-related potential (ERP) empathy for pain paradigm. The control group also completed a measure of schizotypal personality traits. RESULTS: People with schizophrenia exhibited atypical neural responding at early, emotion-sharing (frontal N110), and late, cognitive (central late positive potential [LPP]) processing stages of pain empathy, relative to controls. In the control group, positive schizotypy traits were significantly negatively related to reduced ERP amplitude in the late, cognitive (central LPP) processing stage of empathy. CONCLUSIONS: These data cross-validate previous studies that have shown that schizophrenia is associated with atypicalities in bottom-up automatic resonance processes that likely contribute to empathic and socio-emotional processing deficits, and indicate that these findings cannot be easily attributed to background contextual differences between the two groups. The results also point to a potential relationship between positive schizotypal characteristics and neurophysiological responding. Implications for simulation theories of empathy and social functioning in schizophrenia are discussed. PRACTITIONER POINTS: Empathic processing has been consistently linked to well-being and mental health in many groups, including people with schizophrenia. Previous research has shown that, relative to controls, people with schizophrenia exhibit abnormalities in their neurophysiological empathic response, but in these prior studies, the two groups also differed in a number of potentially important background contextual variables. The current study shows that, when closely matched on background contextual variables, abnormal neural responding is still evident. These data suggest that empathy for pain is disrupted at the neurophysiological level in schizophrenia.

Greater caregiving risk, better infant memory performance?

Poor early life care often relates to cognitive difficulties. However, newer work suggests that in early-life, adversity may associate with enhanced or accelerated neurodevelopment. We examine associations between postnatal caregiving risks (i.e., higher self-reported postnatal-anxiety and lower observed maternal sensitivity) and infant relational memory (i.e., via deferred imitation and relational binding). Using subsamples of 67-181 infants (aged 433-477 post-conceptual days, or roughly five to seven months since birth) taking part in the GUSTO study, we found such postnatal caregiving risk significantly predictive of "better" performance on a relational binding task following a brief delay, after Bonferroni adjustments. Subsequent analyses suggest that the association between memory and these risks may specifically be apparent among infants spending at least 50% of their waking hours in the presence of their mothers. Our findings echo neuroimaging research concerning similar risk exposure and larger infant hippocampal volume, and likewise underscore the importance of considering developmental context in understanding early life experience. With this in mind, these findings caution against the use of cognitive outcomes as indices of experienced risk.

I like it by mere association: Conditioning preferences in infants.

Preferences have a profound impact on our behavior; however, relatively little is known about how preference formation works early in life. Evaluative conditioning occurs when the valence of an initially neutral object changes when it is paired with a positively or negatively valenced stimulus. It is possible that evaluative conditioning may account for early preference learning; however, the extent to which this kind of learning operates during infancy has not been empirically tested. The aim of the current studies was to assess whether infants' preferences for neutral objects is influenced by pairing them with affective stimuli (Experiment 1: happy vs. angry faces, N=20; Experiment 2: mother vs. stranger faces, N=22). Infants' preferences were tested using both looking time and behavioral choice measures. The results showed that infants tended to choose the object that had been paired with the positive stimulus (Experiment 1: 13/20; Experiment 2: 14/22). Gaze behavior at test did not differentiate between the two objects; however, gaze behavior during conditioning predicted infants' behavioral preference. Only infants who looked longer at the affective stimulus than at the object during learning chose the object that had been paired with positive valence more often than chance. These results suggest that infants' preferences may be influenced by learned associations between objects and affective stimuli, a process akin to evaluative conditioning in adults.

Rapid facial reactions in response to happy and angry expressions in 7-month-old infants.

Humans rapidly and spontaneously activate muscles in the face when viewing emotional facial expressions in others. These rapid facial reactions (RFRs) are thought to reflect low-level, bottom-up processes, and are theorized to assist an observer to experience and share the affect of another individual. It has been assumed that RFRs are present from birth; however to date, no study has investigated this response in children younger than 3 years of age. In the present study, we used facial electromyography (EMG) to measure corrugator supercilii (brow) and zygomaticus major (cheek) muscle activity in 7-month-old infants while they viewed happy and angry facial expressions. The results showed that 7-month olds exhibited greater zygomaticus activity in response to happy expressions than angry expressions, however, we found no evidence of differential corrugator muscle activity.

Preschoolers with Down syndrome do not yet show the learning and memory impairments seen in adults with Down syndrome.

Individuals with Down syndrome (DS) exhibit a behavioral phenotype of specific strengths and weaknesses, in addition to a generalized cognitive delay. In particular, adults with DS exhibit specific deficits in learning and memory processes that depend on the hippocampus, and there is some suggestion of impairments on executive function tasks that depend on the prefrontal cortex. While these functions have been investigated in adults with DS, it is largely unclear how these processes develop in young children with DS. Here we tested preschoolers with DS and typically developing children, age-matched on either receptive language or non-verbal scores as a proxy for mental age (MA), on a battery of eye-tracking and behavioral measures that have been shown to depend on the hippocampus or the prefrontal cortex. Preschoolers with DS performed equivalently to MA-matched controls, suggesting that the disability-specific memory deficits documented in adults with DS, in addition to a cognitive delay, are not yet evident in preschoolers with DS, and likely emerge progressively with age. Our results reinforce the idea that early childhood may be a critical time frame for targeted early intervention. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=r6GUA6my22Q&list=UU3FIcom6UpITHZOIEa8Onnw.

What goes where? Eye tracking reveals spatial relational memory during infancy.

Episodic memory involves binding components of an event (who, what, when, and where) into a relational representation. The ability to encode information about the relative locations of objects (i.e., spatial relational memory) is a key component of episodic memory. Here we used eye tracking to test whether infants and toddlers learn about the spatial relations among objects. In Experiment 1, 9-, 18-, and 27-month olds were familiarized with an array of three objects. Following familiarization, they saw test arrays in which two of the objects had been replaced with novel ones (object switch condition) and arrays in which two of the objects had switched positions (location switch condition). Both 18- and 27-month olds looked significantly longer than would be predicted by chance at the objects that had switched spatial locations; however, 9-month olds did not. In Experiment 2, we showed that, given sufficient familiarization time, 9-month olds were also capable of detecting disruptions to the spatial relations among an array of objects. These results have important implications for our understanding of spatial relational memory development.

Age-related differences in memory expression during infancy: using eye-tracking to measure relational memory in 6- and 12-month-olds.

Relational memory, or the ability to bind components of an event into a network of linked representations, is a primary function of the hippocampus. Here we extend eye-tracking research showing that infants are capable of forming memories for the relation between arbitrarily paired scenes and faces, by looking at age-related changes in relational memory over the first year of life. Six- and 12-month-old infants were familiarized with pairs of faces and scenes before being tested with arrays of three familiar faces that were presented on a familiar scene. Preferential looking at the face that matches the scene is typically taken as evidence of relational memory. The results showed that while 6-month-old showed very early preferential looking when face/scene pairs were tested immediately, 12-month-old did not exhibit evidence of relational memory either immediately or after a short delay. Theoretical implications for the functional development of the hippocampus and practical implications for the use of eye tracking to measure memory during early life are discussed.

Thinking about the future early in life: the role of relational memory.

The constructive episodic simulation hypothesis suggests that we imagine possible future events by flexibly recombining details of past experiences to produce novel scenarios. Here we tested this hypothesis by determining whether episodic future thinking is related to relational memory ability during the preschool years. Children (3- to 5-year-olds) were asked to remember a past event and imagine a possible future event using an adapted version of the recombination paradigm. Relational learning and inference were assessed using a task adapted from the neuroimaging literature. The results show that preschoolers were able to describe both past and possible future events; however, they produced more specific episodic details in relation to past events relative to future events. Episodic future thinking performance was correlated with performance on the relational inference task, consistent with the idea that the ability to flexibly recombine relational knowledge is critical in episodic future thinking.

Effect of sleep on gross motor memory.

Sleep has a beneficial effect on consolidation of newly learned fine motor skills. The aim of the current study was to determine whether sleep has a similar beneficial effect on consolidation of gross motor skills. A total of 70 participants were randomly assigned to either a sleep-wake group or a wake-sleep group and were trained on an arm coordinated reaching task as a gross motor skill. Initial training occurred in the evening for the sleep-wake group and in the morning for the Wake-Sleep group. All participants attended two test sessions 12 and 24 hours following the initial training. Gross motor skill performance improved in both groups following a night of sleep but not after a day of wakefulness. These findings may have implications for learning of new gross motor skills in a range of activities from dance to motor rehabilitation.

Medial temporal lobe memory in childhood: developmental transitions.

The medial temporal lobes (MTL) support declarative memory and mature structurally and functionally during the postnatal years in humans. Although recent work has addressed the development of declarative memory in early childhood, less is known about continued development beyond this period of time. The purpose of this investigation was to explore MTL-dependent memory across middle childhood. Children (6 -10 years old) and adults completed two computerized tasks, place learning (PL) and transitive inference (TI), that each examined relational memory, as well as the flexible use of relational learning. Findings suggest that the development of relational memory precedes the development of the ability to use relational knowledge flexibly in novel situations. Implications for the development of underlying brain areas and ideas for future neuroimaging investigations are discussed.

Mapping the Specific Pathways to Early-Onset Mental Health Disorders: The "Watch Me Grow for REAL" Study Protocol.

BACKGROUND: From birth, the human propensity to selectively attend and respond to critical super-stimuli forms the basis of future socio-emotional development and health. In particular, the first super-stimuli to preferentially engage and elicit responses in the healthy newborn are the physical touch, voice and face/eyes of caregivers. From this grows selective attention and responsiveness to emotional expression, scaffolding the development of empathy, social cognition, and other higher human capacities. In this paper, the protocol for a longitudinal, prospective birth-cohort study is presented. The major aim of this study is to map the emergence of individual differences and disturbances in the system of social-Responsiveness, Emotional Attention, and Learning (REAL) through the first 3 years of life to predict the specific emergence of the major childhood mental health problems, as well as social adjustment and impairment more generally. A further aim of this study is to examine how the REAL variables interact with the quality of environment/caregiver interactions. METHODS/DESIGN: A prospective, longitudinal birth-cohort study will be conducted. Data will be collected from four assessments and mothers' electronic medical records. DISCUSSION: This study will be the first to test a clear developmental map of both the unique and specific causes of childhood psychopathology and will identify more precise early intervention targets for children with complex comorbid conditions.

Relational memory during infancy: evidence from eye tracking.

Here we report evidence from a new eye-tracking measure of relational memory that suggests that 9-month-old infants can encode memories in terms of the relations among items, a function putatively subserved by the hippocampus. Infants learned about the association between faces that were superimposed on unique scenic backgrounds. During test trials, infants were shown three faces presented on a familiar scene. All three faces were equally familiar; however, one had been presented with the test background earlier. Visual behavior was recorded continuously using a TOBII eye tracker. Infants looked preferentially at the face that matched the test background very early in the trial; however, the time course of this preferential looking effect varied as a function of delay. These results suggest that by 9 months of age infants can form memories that represent the relations among items and maintain them over short delays.

A role for affectivity in rapid facial mimicry: An electromyographic study.

Emotional expressions evoke rapid facial reactions in the perceiver that are consistent with the valence of the observed expression. We aimed to investigate whether this robust facial reaction is purely a motor matching response or instead represents underlying affective processes. Participants' (N = 60) corrugator supercilii and zygomaticus major muscle activity was quantified using facial electromyography (EMG) while they viewed three sets of images; (i) upright happy and angry facial expressions, (ii) inverted happy and angry facial expressions, and (iii) sad and happy eyes and mouth expressions. Participants displayed patterns of EMG responding that were consistent with the affective valence of the emotional expression, as opposed to merely matching the observed stimuli (i.e. a motor matching response). Using a novel methodological approach, these findings provide evidence for the contention that affective processing underlies rapid facial mimicry reactions.

Intact spontaneous emotional expressivity to non-facial but not facial stimuli in schizophrenia: An electromyographic study.

Emotional stimuli, such as facial expressions, reliably evoke rapid, spontaneous and covert facial reactions in the perceiver that reflect the affective valence of the observed stimulus. These physiological reactions have been linked to a variety of social cognitive processes known to be disrupted in schizophrenia, such as emotion recognition and affective empathy. Moreover, individuals with schizophrenia exhibit atypical rapid facial reactions when observing emotional expressions. The current study aimed to determine if the disruption in schizophrenia is specific to facial expressions, or instead reflects more generalised emotional or motor impairments in the elicitation of this rapid facial response. Here we quantified activity in the corrugator supercilii and zygomaticus major muscle regions using electromyography while individuals with schizophrenia (n = 24) and controls (n = 21) viewed images of facial and non-facial emotional stimuli. The results indicate that schizophrenia is marked by a disruption in rapid facial responding to facial expressions, but intact responding to non-facial emotional stimuli. This dissociation between the processing of facial and non-facial emotional stimuli points to the need for a greater understanding of the degree to which facial emotion processing impairments contribute to disruptions in mimetic responding in this population.

Variations in habitual sleep and relational memory in 6-month-olds.

OBJECTIVES: Adequate sleep duration and good sleep quality are considered essential for development, especially during periods of major neurodevelopmental change. Still, relations between parent-reported habitual sleep and emerging cognitive abilities within the first year of life are not well studied. Here, we examined relations between habitual sleep measures and an aspect of cognitive functioning, relational memory, which emerges as early as 6 months of age, as compared to other abilities (ie, recognition memory and attentional orienting), both of which are considered to emerge earlier in development. PARTICIPANTS: Participants were a subset of 267 healthy typically developing 6-month-olds taking part in the Growing Up in Singapore towards Healthy Outcomes cohort study. MEASUREMENTS: Sleep duration, sleep latency, and number and duration of night awakenings were derived from the Brief Infant Sleep Questionnaire (BISQ). Short sleep was defined as <10 hours per day, categorized as "not recommended" based on the National Sleep Foundation recommendations. Associations between sleep variables and infants' performance on 2 relational memory tests (deferred imitation and relational binding) were examined independently using hierarchical (blockwise entry) linear regression. Associations between sleep and recognition memory and attentional orienting were also explored. RESULTS: Habitual short sleepers had poorer relational memory recall in the deferred imitation task compared with 'typical' sleepers (10-18 hours per day). Shorter sleep latency was related to a greater proportion of correct responses for certain aspects of relational binding. There were no associations between sleep and recognition memory or attention. CONCLUSIONS: Our findings suggest that habitual sleep duration and short sleep latency associate with 6-month-olds' relational memory, suggesting a preferential association with memory tasks that are sensitive to development during the second half of the first year.

Interpreting visual preferences in the visual paired-comparison task.

Performance on the visual paired-comparison (VPC) task has typically been interpreted with E. Sokolov's (1963) comparator model of the orienting response; novelty preferences are interpreted as evidence of retention, whereas null preferences are interpreted as evidence of forgetting. Here the authors capitalized on the verbal nature of human adults to clarify the interpretation of visual preferences in VPC performance. In 2 experiments, adults were tested on either the VPC task or a forced-choice recognition task after delays of 3 min to 12 months. In Experiment 1, adults tested on the VPC task exhibited novelty preferences after short delays, null preferences after intermediate delays, and familiarity preferences after long delays. In Experiment 2, adults tested on the forced-choice recognition task exhibited high levels of accuracy irrespective of delay, but the latency with which they recognized the stimuli increased systematically over the retention interval. These data are inconsistent with a simple Sokolovian interpretation of VPC performance and instead suggest that memory may be expressed as a novelty preference, null preference, or familiarity preference depending on the accessibility of the representation.