Biology subjects

Ives, J.

Publications and source records attributed to Ives, J..

3 recordsLinked to original sources

bioRxiv2024

Examining speech-brain tracking during early bidirectional, free-flowing caregiver-infant interactions

Neural entrainment to slow modulations in the amplitude envelope of infant-directed speech is thought to drive early language learning. Most previous research with infants examining speech-brain tracking has been conducted in controlled, experimental settings, which are far from the complex environments of everyday interactions. Whilst recent work has begun to investigate speech-brain tracking to naturalistic speech, this work has been conducted in semi-structured paradigms, where infants listen to live adult speakers, without engaging in free-flowing social interactions. Here, we test the applicability of mTRF modelling to measure speech-brain tracking in naturalistic and bidirectional free-play interactions of 9-12-month-olds with their caregivers. Using a backwards modelling approach, we test individual and generic training procedures, and examine the effects of data quantity and quality on model fitting. We show model fitting is most optimal using an individual approach, trained on continuous segments of interaction data. Corresponding to previous findings, individual models showed significant speech-brain tracking at delta modulation frequencies, but not in alpha and theta bands. These findings open new methods for studying the interpersonal micro-processes that support early language learning. In future work, it will be important to develop a mechanistic framework for understanding how our brains track naturalistic speech during infancy.

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↗

bioRxiv2021

Human nasal and lung tissues infected ex vivo with SARS-CoV-2 provide insights into differential tissue-specific and virus-specific innate immune responses in the upper and lower respiratory tract

The nasal-mucosa constitutes the primary entry site for respiratory viruses including SARS-CoV-2. While the imbalanced innate immune response of end-stage COVID-19 has been extensively studied, the earliest stages of SARS-CoV-2 infection at the mucosal entry site have remained unexplored. Here we employed SARS-CoV-2 and influenza virus infection in native multi-cell-type human nasal turbinate and lung tissues ex vivo, coupled with genome-wide transcriptional analysis, to investigate viral susceptibility and early patterns of local-mucosal innate immune response in the authentic milieu of the human respiratory tract. SARS-CoV-2 productively infected the nasal turbinate tissues, predominantly targeting respiratory epithelial cells, with rapid increase in tissue-associated viral sub-genomic mRNA, and secretion of infectious viral progeny. Importantly, SARS-CoV-2 infection triggered robust antiviral and inflammatory innate immune responses in the nasal mucosa. The upregulation of interferon stimulated genes, cytokines and chemokines, related to interferon signaling and immune-cell activation pathways, was broader than that triggered by influenza virus infection. Conversely, lung tissues exhibited a restricted innate immune response to SARS-CoV-2, with a conspicuous lack of type I and III interferon upregulation, contrasting with their vigorous innate immune response to influenza virus. Our findings reveal differential tissue-specific innate immune responses in the upper and lower respiratory tract, that are distinct to SARS-CoV-2. The studies shed light on the role of the nasal-mucosa in active viral transmission and immune defense, implying a window of opportunity for early interventions, whereas the restricted innate immune response in early-SARS-CoV-2-infected lung tissues could underlie the unique uncontrolled late-phase lung damage of advanced COVID-19. IMPORTANCEIn order to reduce the late-phase morbidity and mortality of COVID-19, there is a need to better understand and target the earliest stages of SARS-CoV-2 infection in the human respiratory tract. Here we have studied the initial steps of SARS-CoV-2 infection and the consequent innate immune responses within the natural multicellular complexity of human nasal-mucosal and lung tissues. Comparing the global innate response patterns of nasal and lung tissues, infected in parallel with SARS-CoV-2 and influenza virus, we have revealed distinct virus-host interactions in the upper and lower respiratory tract, which could determine the outcome and unique pathogenesis of SARS-CoV-2 infection. Studies in the nasal-mucosal infection model can be employed to assess the impact of viral evolutionary changes, and evaluate new therapeutic and preventive measures against SARS-CoV-2 and other human respiratory pathogens.

microbiology↗