Biology subjects

Wass, S. V.

Publications and source records attributed to Wass, S. V..

8 recordsLinked to original sources

bioRxiv2025

Cortical Excitability during Fixations Drives Frequency-Specific Neural Activity in Children and Adults

Extensive previous research has examined how neuronal oscillations support basic cognitive processes, from early development into adulthood. However, the question of how these oscillations originate and are maintained remains relatively underexplored. Here, we examine how transient increases in cortical excitability that occur time-locked to the offsets of spontaneous eye movements associate with frequency-specific neural activity, and how these relationships change over development and between contexts (social vs non-social). We examine two datasets of combined EEG and eye-tracking data from 24-month-old children (N=114) and adults (N=108) while they watched stimuli that were either social (an actor singing nursery rhythms) or non-social (dynamic toys). EEG data was time-locked to the offsets of eye movements and analysed using a spectrum of methods designed to highlight the progression of various neural signals across time, frequency, and space (topography). Fixation-related potentials (FRPs) manifest as a differentiable combination of eye movement-related artifact and genuine neural activity. Child FRPs are slower and unfold over longer time periods, which manifests as differences in the frequency domain. Even after removing artifact, dipoles associated with fixation-related P1 and N170 components manifest as Theta activity over fronto-central areas, along with activity in other frequencies, in children but not adults. Data sections where no fixation-related potentials are present show strongly attenuated oscillatory activity. Our results show that a variety of previously documented developmental effects in the frequency domain may be better understood as fine-grained, movement-induced brain states.

animal behavior and cognition↗

bioRxiv2023

Sing to me, baby: Infants show neural tracking and rhythmic movements to live and dynamic maternal singing

Infant-directed singing has unique acoustic characteristics that may allow even very young infants to respond to the rhythms carried through the caregivers voice. The goal of this study was to examine neural and movement responses to live and dynamic maternal singing in 7-month-old infants and their relation to linguistic development. In total, 60 mother-infant dyads were observed during two singing conditions (playsong and lullaby). In Study 1 (n = 30), we measured infant EEG and used an encoding approach utilizing ridge regressions to measure neural tracking. In Study 2 (n = 40), we coded infant rhythmic movements. In both studies, we assessed childrens vocabulary when they were 20 months old. In Study 1, we found above-threshold neural tracking of maternal singing, with superior tracking of lullabies than playsongs. We also found that the acoustic features of infant-directed singing modulated tracking. In Study 2, infants showed more rhythmic movement to playsongs than lullabies. Importantly, neural coordination (Study 1) and rhythmic movement (Study 2) to playsongs were positively related to infants expressive vocabulary at 20 months. These results highlight the importance of infants brain and movement coordination to their caregivers musical presentations, potentially as a function of musical variability.

neuroscience↗

bioRxiv2022

The development of the relationship between auditory and visual neural sensitivity and autonomic arousal from 6m to 12m

The differential sensitivity hypothesis argues that environmental sensitivity has the bivalent effect of predisposing individuals to both the risk-inducing and development-enhancing influences of early social environments. However, the hypothesis requires that this variation in environmental sensitivity be general across domains. In this study, we focused on neural sensitivity and autonomic arousal to test domain generality. Neural sensitivity can be assessed by correlating measures of perceptual sensitivity, as indexed by event-related potentials (ERP) in electrophysiology. The sensitivity of autonomic arousal can be tested via heart rate changes. Domain generality was tested by comparing associations in perceptual sensitivity across auditory and visual domains, and associations between sensitivity in sensory domains and heart rate We contrasted ERP components in auditory (P3) and visual (P1, N290 and P4) detection-of-difference tasks for N=68 infants longitudinally at 6 and 12 months of age. Domain generality should produce correlated individual differences in sensitivity across the two modalities, with higher levels of autonomic arousal associating with increased perceptual sensitivity. Having controlled for multiple comparisons, at 6 months of age, the difference in amplitude of the P3 component evoked in response to standard and deviant tones correlated with the difference in amplitude of the P1 N290 and P4 face-sensitive components evoked in response to fearful and neutral faces. However, this correlation was not found at 12 months of age. Similarly, autonomic arousal negatively correlated with neural sensitivity at 6 months but not at 12 months. The results suggest neural perceptual sensitivity is domain-general across auditory and visual domains, and is related to autonomic arousal at 6 months but not at 12 months of age. We interpret these findings within a neuroconstructivist framework and with respect to the concept of interactive specialisation. By 12 months of age, more experience of visual processing may have led to top-down endogenous attention mechanisms that process visual information in a way that no longer associates with auditory perceptual sensitivity.

neuroscience↗

bioRxiv2022

At Which Low Amplitude Modulated Frequency Do Infants Best Entrain? A Frequency Tagging Study

Previous infant entrainment research has shown neural entrainment to a wide range of stimuli and amplitude modulated frequencies. However, it is unknown if infants neurally entrain more strongly to some frequencies more than others, and to which low amplitude modulated frequency infants show the strongest entrainment. The current study seeks to address this by testing the neural entrainment of N=23 4-6-month-old infants and N=22 control group adult caregivers while they listened to a range of sinusoidally amplitude modulated beep stimuli at rest (no sound), 2, 4, 6, 8, 10 and 12 Hz. Analysis examined differences across power and phase, regions of interest predetermined by previous literature and by segmented time windows. Results showed that the strongest entrainment was at 2Hz for both adult and infant participants; that there was no significant difference in power and phase, entrainment was occipital temporal and slightly left fronto-central in adults and right fronto-central and left occipito-temporal in infants, leading to some regions of interest used in previous studies being significant in infants and all regions of interest being significant in adults. Segmenting by time window did not show any significant increase or decrease in entrainment over time, but longer time windows showed a stronger entrainment response. In conclusion, it is important to choose appropriate stimulation frequencies when investigating entrainment between stimulation frequencies or across ages; whole head recording is recommended to see the full extent of activation; there is no preference on power vs phase analyses; and longer recordings show stronger effects. Author Contribution StatementIves, J., conceptualisation, data collection and curation, formal analysis, methodology, writing - original draft; Labendzki, P., data collection and curation, formal analysis, writing - review & editing; Perapoch Amado, M., data collection and curation, writing - review & editing; Greenwood, E., data collection and curation, participant recruitment, writing - review & editing; Viswanathan, N., data collection and curation, writing - review & editing; Northrop, T., data collection and curation, participant recruitment, writing - review & editing; Wass, S., conceptualisation, funding acquisition, methodology, project administration, supervision, writing - review & editing. Highlights2Hz amplitude modulation stimulation showed the strongest neural entrainment We discuss power vs phase analyses of infant and adult frequency tagging responses We illustrate topographic differences in adult and infant neural responses

neuroscience↗

bioRxiv2022

Gaze onsets during naturalistic infant-caregiver interaction associate with 'sender' but not 'receiver' neural responses, and do not lead to changes in inter-brain synchrony.

Temporal coordination during infant-caregiver social interaction is thought to be crucial for supporting early language acquisition and cognitive development. Despite a growing prevalence of theories suggesting that increased inter-brain synchrony associates with many key aspects of social interactions such as mutual gaze, little is known about how this arises during development. Here, we investigated the role of mutual gaze onsets as a potential driver of inter-brain synchrony. We extracted dual EEG activity around naturally occurring gaze onsets during infant-caregiver social interactions in N=55 dyads (mean age 12 months). We differentiated between two types of gaze onset, depending on each partners role. Sender gaze onsets were defined at a time when either the adult or the infant made a gaze shift towards their partner at a time when their partner was either already looking at them (mutual) or not looking at them (non-mutual). Receiver gaze onsets were defined at a time when their partner made a gaze shift towards them at a time when either the adult or the infant was already looking at their partner (mutual) or not (non-mutual). Contrary to our hypothesis we found that, during a naturalistic interaction, both mutual and non-mutual gaze onsets were associated with changes in the sender, but not the receivers brain activity and were not associated with increases in inter-brain synchrony above baseline. Further, we found that mutual, compared to non-mutual gaze onsets were not associated with increased inter brain synchrony. Overall, our results suggest that the effects of mutual gaze are strongest at the intra-brain level, in the sender but not the receiver of the mutual gaze.

neuroscience↗

bioRxiv2021

Using dual EEG to analyse event-locked changes in child-adult neural connectivity

Current approaches typically measure the connectivity between interacting physiological systems as a time-invariant property. This approach obscures crucial information about how connectivity between interacting systems is established and maintained. Here, we describe methods, and present computational algorithms, that will allow researchers to address this deficit. We focus on how two different approaches to measuring connectivity, namely concurrent (e.g., power correlations, phase locking) and sequential (e.g., Granger causality), can be applied to three aspects of the brain signal, namely amplitude, power, and phase. We guide the reader through worked examples using mainly simulated data on how to leverage these methods to measure changes in interbrain connectivity between adults and children/infants relative to events identified within continuous EEG data during a free-flowing naturalistic interaction. For each, we aim to provide a detailed explanation of the interpretation of the analysis and how they can be usefully used when studying early social interactions.

neuroscience↗

bioRxiv2021

Automatic classification of ICA components from infant EEG using MARA

Automated systems for identifying and removing non-neural ICA components are growing in popularity among adult EEG researchers. Infant EEG data differs in many ways from adult EEG data, but there exists almost no specific system for automated classification of source components from paediatric populations. Here, we adapt one of the most popular systems for adult ICA component classification for use with infant EEG data. Our adapted classifier significantly outperformed the original adult classifier on samples of naturalistic free play EEG data recorded from 10 to 12-month-old infants, achieving agreement rates with the manual classification of over 75% across two validation studies (n=44, n=25). Additionally, we examined both classifiers ability to remove stereotyped ocular artifact from a basic visual processing ERP dataset, compared to manual ICA data cleaning. Here the new classifier performed on level with expert manual cleaning and was again significantly better than the adult classifier at removing artifact whilst retaining a greater amount of genuine neural signal, operationalised through comparing ERP activations in time and space. Our new system (iMARA) offers developmental EEG researchers a flexible tool for automatic identification and removal of artifactual ICA components.

neuroscience↗

bioRxiv2018

Parental neural responsivity to infants visual attention: how mature brains scaffold immature brains during social interaction.

Almost all attention and learning - in particular, most early learning - takes place in social settings. But little is known of how our brains support dynamic social interactions. We recorded dual-EEG from infants and parents during solo play and joint play. During solo play, fluctuations in infants Theta power significantly forward-predicted their subsequent attentional behaviours. But this forwards-predictiveness was lower during joint play than solo play, suggesting that infants endogenous neural control over attention is greater during solo play. Overall, however, infants were more attentive to the objects during joint play. To understand why, we examined how adult brain activity related to infant attention. We found that parents Theta power closely tracked and responded to changes in their infants attention. Further, instances in which parents showed greater neural responsivity were associated with longer sustained attention by infants. Our results offer new insights into how one partner influences another during social interaction.

neuroscience↗