Lifetime imaging reveals long-distance non-neural bioelectric patterns on timescales from seconds to hours

Translating the bioelectric code remains one of the core challenges to widespread biomedical translation of bioelectric interventions, as well as a better evolutionary understanding of how developmental ionic signaling evolved to become the basis of neural intelligence. To advance our understanding, it is crucial to develop model systems that allow simultaneous, quantitative study of diverse bioelectric parameters in living states, which must also be linked to cell- and tissue-level outcomes. Here, we apply quantitative Fluorescent Lifetime Imaging (FLIM) optical estimation of membrane potential (V_mem^oe) to map the bioelectric dynamics of spreading Xenopus laevis neural crest explants (NCEs) over > 17 h. We identify a slow hours-scale bioelectric component and distinct faster minutes-scale and seconds-scale components. These dynamics often span multiple cells, consistent with roles in the collective behavior of NCEs. We then use information theory to show that minutes-scale NCE V_mem^oe dynamics are largely distinct from calcium dynamics. Finally, we provide a survey of diverse bioelectric events revealing a deep complexity in collective bioelectric dynamics, likely involving tunneling nanotubes in their transmission, which suggests numerous avenues for further investigation. These combined data demonstrate FLIM as a powerful tool for observing subtle bioelectric signals at the large temporal and spatial scale needed for developmental biology studies.