Biology subjects

Touray, E.

Publications and source records attributed to Touray, E..

4 recordsLinked to original sources

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

Functional specialisation across the first five years of life: a longitudinal characterisation of social perception with fNIRS

Research in typically developing infants has shown robust and consistent brain activation to social versus non-social visual and auditory stimuli in a network of brain regions, including the inferior frontal, anterior temporal and posterior superior temporal cortex. However, large-scale, longitudinal neuroimaging studies across early childhood, particularly in low- and middle-income countries are rare, yet important, given that they offer a powerful means of capturing within-person changes in neurodevelopment and identifying targets for intervention and support. Here we investigated brain responses to social perception longitudinally across the first five years of life of participants in The Gambia with functional near-infrared spectroscopy (fNIRS) within the Brain Imaging for Global Health (BRIGHT) Project. We found that social visual stimuli elicited a selective right posterior temporal response across all six age points studied here (5, 8, 12, 18, 24 months and 3-5 years of age), with concurrent selective left responses at four of the six time points (5, 8, 18 months and 3-5 years of age). Inferior frontal regions showed brain activation at multiple ages, with the youngest (5 months) and oldest (24 months to 3-5 years) time points evidencing more widespread frontal social visual responses. Conversely, auditory social stimuli elicited a significantly stronger and more prolonged response than auditory non-social stimuli across all six age points from 5 months to 3-5 years across a range of frontal and temporal areas. Finally, from individual infant trajectories of brain activation, we identified different profiles of age-dependent specialisation to auditory social stimuli, with some specialising earlier than others. Future work could take advantage of such profiles to investigate the effects of adversity and resilience factors on neurodevelopment.

neuroscience↗

bioRxiv2025

Longitudinal Habituation and Novelty Detection neural responses from infancy to early childhood in The Gambia and UK

As infants and young children learn from and respond to their environment, their development is driven by their ability to filter out irrelevant stimuli and respond to salient stimuli. While sources and types of stimuli vary across cultural contexts, research to understand the neural mechanisms of these behaviors have largely focused on relatively homogeneous populations in high income settings. To address this lack of diverse representation the Brain Imaging for Global health project (BRIGHT) collected longitudinal data in The Gambia (N=204) and the UK (N=61). Here we present results of the Habituation and Novelty Detection (HaND) fNIRS neuroimaging task. Gambian infants showed persistent response suppression (Habituation) at all visits (from 5mo to 60mo) while Novelty Detection was only observed once infants reached 18 and 24mo. In the UK, infants only showed persistent habituation from 5-12mo, while the response was not evident at 18 and 24mo. Furthermore, in contrast to The Gambia, alongside the habituation patterns observed Uk infants showed novelty detection from 5-12mo. This is the first longitudinal description of the HaND response in individuals from different contextual backgrounds across such a broad age range and number of time points, revealing different patterns of specialization in The Gambia and UK. HighlightsO_LIThis is the first characterization of Habituation and Novelty Detection (HaND) responses in infants and young children from contrasting settings across low and high-income countries. C_LIO_LIIn the Gambian cohort, Habituation was typically observed from 5 to 60months; only weak patterns of Novelty Detection were observed at 18 and 24months. C_LIO_LIIn the UK cohort, HaND responses were observed up to 12months of age; but were not evident at 18 and 24months. C_LIO_LIDevelopmental trajectories of HaND responses follow different patterns of specialization from birth to five years of age in individuals living in different contexts. C_LI

neuroscience↗

bioRxiv2024

Growth in early infancy drives optimal brain functional connectivity which predicts cognitive flexibility in later childhood

Functional brain network organization, measured by functional connectivity (FC), reflects key neurodevelopmental processes for healthy development. Early exposure to adversity, e.g. undernutrition, affects neurodevelopment, observable via disrupted FC, and leads to poorer outcomes from preschool age onward. We assessed longitudinally the impact of early growth trajectories on developmental FC in a rural Gambian population from age 5 to 24 months. To investigate how these early trajectories relate to later childhood outcomes, we assessed cognitive flexibility at 3-5 years. We observed that early physical growth before the fifth month of life drove optimal developmental trajectories of FC that in turn predicted cognitive flexibility at pre-school age. In contrast to previously studied developmental populations, this Gambian sample exhibited long-range interhemispheric FC that decreased with age. Our results highlight the measurable effects that poor growth in early infancy has on brain development and the possible subsequent impact on pre-school age cognitive development, underscoring the need for early life interventions throughout global settings of adversity.

neuroscience↗