Greenhalgh, I. | bioRxiv Science

bioRxiv2025

Examining Cross-Paradigm fNIRS Brain Activity in Neonates across The Gambia and UK

SignificanceNeonates undergo rapid development, yet the examination of emerging brain markers across paradigms, cognitive domains and diverse global populations remains limited. AimThis study investigated whether brain responses at one-month-of-age could be interrogated across paradigms to offer deeper context-specific insights into neurodevelopment. ApproachFunctional near-infrared spectroscopy (fNIRS) was used to assess frontal and temporal brain responses during natural sleep in 181 Gambian (GM) and 58 UK infants during three auditory paradigms: Social Selectivity, Habituation and Novelty Detection (HaND) and Functional Connectivity (FC). Paradigm-level brain responses were analysed using threshold-free cluster enhancement and cross-paradigm comparisons of individual responses. ResultsAt the group level, both GM and UK infants showed habituation but not novelty responses, higher inter-versus intra-hemispheric connectivity, stronger inter-hemispheric connectivity in temporal regions relative to frontal regions, stronger inter-regional connectivity between right temporal and left frontal regions, and UK infants also showed non-vocal > vocal selectivity. ConclusionsCross-cohort differences in the cross-paradigm analyses suggest context-specific developmental markers are evident within the first month of life and show high individual variability. Cross-paradigm analyses revealed that greater vocal selectivity (UK) was associated with higher inter-hemispheric connectivity, potentially allowing us to identify biomarkers of more mature neurodevelopment within the first weeks of postnatal life.

neuroscience↗

bioRxiv2025

Effect of sleep stages on patterns of fNIRS hemodynamic response to auditory paradigms in one-month-old Gambian and UK infants

SignificanceFunctional near-infrared spectroscopy (fNIRS) has advanced our understanding of early brain development, especially infant responses to social and auditory stimuli. Unlike older children and adults, very young infants are often assessed during natural sleep to reduce movement and ensure sufficient data quality. Yet the impact of sleep stage on fNIRS signals and how it might affect interpretations of early brain activation patterns remains unclear. AimThis study investigates the effect of sleep stages on fNIRS-measured hemodynamic responses to two auditory paradigms across different global populations of one-month-old infants. ApproachIn total, 46 Gambian and 40 UK infants in quiet or active sleep were tested using (1) social selectivity and (2) a habituation and novelty detection paradigms. ResultsIn the UK cohort, active sleep was associated with a stronger initial response and greater habituation compared to quiet sleep. In contrast, Gambian infants in quiet sleep showed more widespread activation and evidence of habituation, while infants in active sleep showed no habituation. No sleep stage effects were observed for response in the social selectivity paradigm in either group. ConclusionsDifferent effects of sleep stages were observed across the two cohorts and paradigms and should be carefully considered in neuroimaging studies.

neuroscience↗