Agnes Volein

Neural Correlates of Eye Gaze Processing in the Infant Broader Autism Phenotype

BACKGROUND Studies of infant siblings of children diagnosed with autism have allowed for a prospective approach to study the emergence of autism in infancy and revealed early behavioral characteristics of the broader autism phenotype. In view of previous findings of atypical eye gaze processing in children and adults with autism, the aim of this study was to examine the early autism phenotype in infant siblings of children diagnosed with autism spectrum disorder (sib-ASD), focusing on the neural correlates of direct compared with averted gaze. METHODS A group of 19 sib-ASD was compared with 17 control infants with no family history of ASD (mean age=10 months) on their response to direct versus averted gaze in static stimuli. RESULTS Relative to the control group, the sib-ASD group showed prolonged latency of the occipital P400 event-related potentials component in response to direct gaze, but they did not differ in earlier components. Similarly, time-frequency analysis of high-frequency oscillatory activity in the gamma band showed group differences in response to direct gaze, where induced gamma activity was late and less persistent over the right temporal region in the sib-ASD group. CONCLUSION This study suggests that a broader autism phenotype, which includes an atypical response to direct gaze, is manifest early in infancy.

Social Perception in Infancy: A Near Infrared Spectroscopy Study

The capacity to engage and communicate in a social world is one of the defining characteristics of the human species. While the network of regions that compose the social brain have been the subject of extensive research in adults, there are limited techniques available for monitoring young infants. This study used near infrared spectroscopy to investigate functional activation in the social brain network of 36 five-month-old infants. We measured the hemodynamic responses to visually presented stimuli in the temporal lobes. A significant increase in oxyhemoglobin was localized to 2 posterior temporal sites bilaterally, indicating that these areas are involved in the social brain network in young infants.

Electrophysiological evidence of illusory audiovisual speech percept in human infants

How effortlessly and quickly infants acquire their native language remains one of the most intriguing questions of human development. Our study extends this question into the audiovisual domain, taking into consideration visual speech cues, which were recently shown to have more importance for young infants than previously anticipated [Weikum WM, Vouloumanos A, Navarra J, Soto-Faraco S, Sebastián-Gallés N, Werker JF (2007) Science 316:1159]. A particularly interesting phenomenon of audiovisual speech perception is the McGurk effect [McGurk H, MacDonald J (1976) Nature 264:746–748], an illusory speech percept resulting from integration of incongruent auditory and visual speech cues. For some phonemes, the human brain does not detect the mismatch between conflicting auditory and visual cues but automatically assimilates them into the closest legal phoneme, sometimes different from both auditory and visual ones. Measuring event-related brain potentials in 5-month-old infants, we demonstrate differential brain responses when conflicting auditory and visual speech cues can be integrated and when they cannot be fused into a single percept. This finding reveals a surprisingly early ability to perceive speech cross-modally and highlights the role of visual speech experience during early postnatal development in learning of the phonemes and phonotactics of the native language.

Investigation of depth dependent changes in cerebral haemodynamics during face perception in infants

Near-infrared spectroscopy has been used to record oxygenation changes in the visual cortex of 4 month old infants. Our in-house topography system, with 30 channels and 3 different source-detector separations, recorded changes in the concentration of oxy-, deoxy- and total haemoglobin (HbO2, HHb and HbT) in response to visual stimuli (face, scrambled visual noise and cartoons as rest). The aim of this work was to demonstrate the capability of the system to spatially localize functional activation and study the possibility of depth discrimination in the haemodynamic response. The group data show both face stimulation and visual noise stimulation induced significant increases in HbO2 from rest, but the increase in HbO2 with face stimulation was not significantly different from that seen with visual noise stimulation. The face stimuli induced increases in HbO2 were spread across a greater area across all depths than visual noise induced changes. In results from a single subject there was a significant increase of HbO2 in the inferior area of the visual cortex in response to both types of stimuli, and a larger number of channels (source-detector pairs) showed HbO2 increase to face stimuli, especially at the greatest depth. Activation maps were obtained using 3D reconstruction methods on multi source-detector separation optical topography data.

Cortical development and saccade planning: the ontogeny of the spike potential

The spike potential is a sharply timed positivity which precedes eye movements in adults, and is thought to indicate cortical planning of saccades. While the spike potential is observed under most conditions in adults, it has not been reported in young infants. In the present study we shed light on the ontogeny of the spike potential by demonstrating for the first time its existence in a group of older infants (12 months). This result is consistent with a relatively delayed onset of cortical control over saccades during development.

Behavioural markers for autism in infancy: Scores on the Autism Observational Scale for Infants in a prospective study of at-risk siblings

Highlights • Behavioural atypicalities in emergent ASD in infancy include both social and non-social behaviours.• Some of these atypicalities are found in HR siblings who do not go on to have ASD, supporting the notion of an early broader autism phenotype.• Understanding the interplay between different neurodevelopmental domains across the first years of life is important to understand developmental mechanisms and to develop early interventions.

Probing the Strength of Infants' Preference for Helpers over Hinderers: Two Replication Attempts of Hamlin and Wynn (2011)

Several studies indicate that infants prefer individuals who act prosocially over those who act antisocially toward unrelated third parties. In the present study, we focused on a paradigm published by Kiley Hamlin and Karen Wynn in 2011. In this study, infants were habituated to a live puppet show in which a protagonist tried to open a box to retrieve a toy placed inside. The protagonist was either helped by a second puppet (the “Helper”), or hindered by a third puppet (the “Hinderer”). At test, infants were presented with the Helper and the Hinderer, and encouraged to reach for one of them. In the original study, 75% of 9-month-olds selected the Helper, arguably demonstrating a preference for prosocial over antisocial individuals. We conducted two studies with the aim of replicating this result. Each attempt was performed by a different group of experimenters. Study 1 followed the methods of the published study as faithfully as possible. Study 2 introduced slight modifications to the stimuli and the procedure following the guidelines generously provided by Kiley Hamlin and her collaborators. Yet, in our replication attempts, 9-month-olds’ preference for helpers over hinderers did not differ significantly from chance (62.5% and 50%, respectively, in Studies 1 and 2). Two types of factors could explain why our results differed from those of Hamlin and Wynn: minor methodological dissimilarities (in procedure, materials, or the population tested), or the effect size being smaller than originally assumed. We conclude that fine methodological details that are crucial to infants’ success in this task need to be identified to ensure the replicability of the original result.

Verbal labels modulate perceptual object processing in 1-year-old children

Whether verbal labels help infants visually process and categorize objects is a contentious issue. Using electroencephalography, we investigated whether possessing familiar or novel labels for objects directly enhances 1-year-old childrens neural processes underlying the perception of those objects. We found enhanced gamma-band (20–60 Hz) oscillatory activity over the visual cortex in response to seeing objects with labels familiar to the infant (Experiment 1) and those with novel labels just taught to the infant (Experiment 2). No such effect was observed for objects that infants were familiar with but had no label for. These results demonstrate that learning verbal labels modulates how the visual system processes the images of the associated objects and suggest a possible top–down influence of semantic knowledge on object perception.

Recognition of complex object-centred spatial configurations in early infancy

In a series of experiments we tested 4- and 8-month-olds’ ability to represent the spatial layout of an object across changes in its orientation with respect to egocentric spatial coordinates. A fixed-trial familiarization procedure based on visual habituation behaviour shows that both age groups are able to discriminate between different object-centred spatial configurations. Furthermore, both age groups demonstrate the ability to make discriminations of object-centred spatial coordinates that require simultaneous reference to at least two spatial axes of the object. We discuss these findings in relation to theories of the early development of object recognition and spatial reference skills.

Near infrared topography with depth information for the detection of face perception in infants

Near infrared intensity signals were recorded from 3 different depths of the visual cortex with a 30-channel system from 12 young infants to detect subtle differences in processing stimuli with different degrees of complexity.