Whole in One

We’ve all experienced the shock that accompanies a fight-or-flight response. Muscles contract, glands squirt out hormones, our pupils dilate. The entire body readies to react in a matter of seconds. The picture of how the autonomic nervous system coordinates so many bodily functions so quickly is usually built from pieces – different experiments focussing in different places. Here scientists take steps towards watching speedy communication around the entire body of a young zebrafish (highlighted in green) with its autonomic nervous system shown in pink. To allow experiments to zoom in on different organs and tissues, the team use an updated form of expansion microscopy, gently soaking the animal’s tissues in gel to swell its cells to allow more detailed images. Using machine learning to link momentary events in different tissues builds a picture of body-wide 'circuits' where the whole is more than the sum of its parts.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Video from work by Virginie M. S. Ruetten and colleagues
• Janelia Research Campus, HHMI, Ashburn, VA, USA
• Video originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Nature, September 2026