Researchers Mapped Whole-Body Calcium Activity in Fish
The new WHOLISTIC imaging method enables researchers to observe cellular communication throughout an entire organism.
Updated on Oct. 1, 2026 in Life Sciences
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Scientists have developed the WHOLISTIC live-imaging method to record tissue and intracellular activity across the entire body of larval zebrafish and adult Danionella cerebrum. This research-stage technique tracks time-varying calcium signals in every cell simultaneously.
Why it matters
The WHOLISTIC method was developed to enable an organism-wide view of dynamic physiology, offering a new lens into how different bodily systems coordinate. It provides a foundational approach for mapping the complex communication pathways between the brain and the rest of the body.
WHOLISTIC—which stands for WHole-Organism Live-Imaging System for recording Tissue and IntraCellular activity—uses a combination of optical and computational methods to track calcium signals. It revealed that most larval zebrafish cells exhibit calcium activity, including slow waves among ependymal cells lining the hindbrain and spinal cord during states of quiescence.
The players
Ruetten et al.
A research team specializing in optical physiology and whole-organism imaging.
Nature
A preeminent international science journal that publishes peer-reviewed research across all areas of science and technology.
The details
The system records calcium activity, a common proxy for cellular activation, by imaging the fish's entire body at high resolution. By capturing data from every cell, researchers identified that hindbrain activity is specifically linked to mesenteric arterial constriction during hypoxia, or low oxygen levels. This provides a mechanism for how central nervous system signals can directly modulate peripheral physiological responses in real time.
Timeline
The study describing the method was published in Nature in 2026.
The Tech Race
This imaging method marks a shift from focused brain-mapping initiatives toward integrated, whole-body physiological monitoring. It builds on the trajectory of the BRAIN Initiative Cell Census Network, extending its cell-specific mapping goals to encompass the dynamic interaction between central neural activity and systemic organ functions.
This development represents a high-level research tool that is currently restricted to laboratory settings for scientific analysis. It does not provide direct diagnostic capabilities for human patients but provides a new methodology for researchers to study systemic physiological responses in animal models.
The takeaway
The WHOLISTIC system proves that organism-wide calcium imaging is now technically feasible in small-vertebrate models. Future researchers should watch for studies applying this method to investigate the governing principles of brain-body communication in other model organisms.
Further reading
For more on emerging techniques in biological visualization, explore our latest coverage in Life Sciences.
More information
Read the Original research publication in Nature to see the full study data.
Source note: This article includes information reported by Nature.
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