Dataset · 2017
Larval zebrafish whole brain
The complete brain of a larval zebrafish by serial-section EM — the first vertebrate whole brain at EM resolution, and the dataset that made whole-brain structure-and-function comparison possible in a vertebrate.
| Species | Danio rerio (larva, 5.5 days post-fertilization) |
|---|---|
| Region | Complete brain |
| Modality | Serial-section EM at multiple scales, co-registered with in vivo two-photon imaging |
| Access | Open-access resource |
| Status | Released |
Hildebrand and colleagues imaged the entire brain of a 5.5-day-old larval zebrafish by serial-section EM, using multiple rounds of targeted imaging at different scales to keep acquisition time and data volume tractable. From it they reconstructed all myelinated axons — the projectome — and found striking bilateral symmetry in reticulospinal and lateral line afferent axons. Functional reference atlases and in vivo two-photon data from the same animal were co-registered to the volume.
What it is good for. The vertebrate case. Almost everything else at EM resolution is an invertebrate or a fragment of a mammal; this is a whole vertebrate brain, small enough to hold in one volume and transparent enough to have been imaged alive first.
What it does not support. Dense synaptic connectivity. This is a projectome — myelinated axons traced across the brain — not a dense reconstruction of every synapse. Treating it as a connectome in the FlyWire sense misreads what was measured. The multi-scale imaging strategy also means resolution is not uniform across the volume.
Where these numbers come from. Hildebrand et al. (2017), Nature 10.1038/nature22356. Neuron and synapse counts are omitted: the paper reports a myelinated-axon projectome rather than a dense synaptic reconstruction, so a synapse count would misdescribe it. DOI 10.1038/nature22356.