Light Impact on Thalamo-Cortical Connectivity During an Executive Cognitive Task: Effects of Time of Day and Specificities of Teenagers

Sharifpour, R.; Campbell, I.; Paparella, I.; Balda, F.; Beckers, E.; Mortazavi, N.; Koshmanova, E.; Read, J.; Collette, F.; Phillips, C.; Talwar, P.; Lamalle, L.; Zubkov, M.; Vandewalle, G.

doi:10.1101/2025.04.03.647005

bioRxiv · 10.1101/2025.04.03.647005

Light Impact on Thalamo-Cortical Connectivity During an Executive Cognitive Task: Effects of Time of Day and Specificities of Teenagers

Sharifpour, R.·Campbell, I.·Paparella, I.·Balda, F.·Beckers, E.·Mortazavi, N.·Koshmanova, E.·Read, J.·Collette, F.·Phillips, C.·Talwar, P.·Lamalle, L.·Zubkov, M.·Vandewalle, G.

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Abstract

BackgroundLight affects not only vision but also attention, alertness, and cognition, primarily through intrinsically photosensitive retinal ganglion cells sensitive to blue-wavelength light. While previous research has shown that light influences brain regional activity, its impact on brain connectivity remains unclear. MethodsUsing 7-Tesla fMRI, this study examined how light illuminance modulates canonical left-lateralized verbal thalamo-prefrontal-parietal network connectivity during an auditory executive task. Fifty-five participants, including young adults (19-30 y, 23 Females: scanned in the morning or evening) and adolescents (15-18 y, 6 Females: scanned only in the evening), were studied. ResultsWe first found that across all the groups, moderate blue-enriched light strengthened parietal-to-frontal connectivity, while low-illuminance orange light enhanced thalamus-to-parietal connectivity. When focusing on time-of-day differences in young adults, we found that higher-illuminance blue-enriched light strengthened thalamus-to-prefrontal connectivity in the morning compared to the evening. When focusing on developmental stages differences, during the evening session only, we observe that moderate blue-enriched light enhanced thalamus-to-parietal connectivity in adolescents compared to young adults. ConclusionThese findings reinforce the view that the thalamus plays a key role in mediating the impact of light on cognition and the impact of light depends on the context of light administration, i.e. with timing and age.

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Sharifpour, R., Campbell, I., Paparella, I., Balda, F., Beckers, E., Mortazavi, N., Koshmanova, E., Read, J., Collette, F., Phillips, C., Talwar, P., Lamalle, L., Zubkov, M., Vandewalle, G.. 2025-04-03. Light Impact on Thalamo-Cortical Connectivity During an Executive Cognitive Task: Effects of Time of Day and Specificities of Teenagers. https://doi.org/10.1101/2025.04.03.647005

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