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bioRxiv · 10.64898/2025.12.23.696162

Multi-fiber array-based photometry system for multi-regional functional mapping in the mouse brain

Bradai, M.·Merkler, M.·Gil, G.·Davie, R.·Sakata, S.
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Abstract

Mesoscopic functional brain mapping is essential to better understanding of various brain functions and dysfunctions. However, accessing distributed neural circuits in mammalian brain regions remains a significant challenge. While fiber photometry is a versatile optical approach, existing methods often suffer from invasiveness and scalability. Here we present an affordable multi-fiber array (MFA)-based photometry system to monitor neural signals across multiple regions. Our system comprises a custom-designed MFA utilizing 50-{micro}m diameter optical fibers and off-the-shelf optical components. To demonstrate the systems versatility, we monitored GABAergic population activity using jGCaMP8s across multiple brain regions in head-fixed, awake mice. By combining with pupillometry, we identified state-dependent, region-specific GABAergic dynamics. Our MFA-based photometry system opens new avenues for investigating state-dependent neural dynamics at the mesoscopic level. To facilitate wider adoption, all codes and resources are publicly available on GitHub (https://github.com/Sakata-Lab/MFA).

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Bradai, M., Merkler, M., Gil, G., Davie, R., Sakata, S.. 2025-12-25. Multi-fiber array-based photometry system for multi-regional functional mapping in the mouse brain. https://doi.org/10.64898/2025.12.23.696162

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