Nature Methods has named electron microscopy-based connectomics its Method of the Year 2025, recognizing recent advances that have made large-scale reconstruction of neural wiring diagrams increasingly practical. This designation highlights progress toward one of neuroscience’s long-standing goals of understanding how neurons and synapses are organized to support brain function and behavior.
Although a complete human brain connectome is not quite within reach, breakthroughs in smaller systems suggest a decisive moment of progress. In the past year, the FlyWire Consortium reported the first full connectome of an adult fruit fly brain, while the MICrONS Project reconstructed and functionally characterized a cubic millimeter of mouse visual cortex. These studies demonstrate how electron microscopy, combined with large-scale computation, can now resolve neural circuits with unprecedented detail.
Building connectomes requires tightly integrated experimental and computational workflows. Brain tissue must be fixed, stained, and imaged across thousands of serial sections, followed by automated segmentation and extensive manual proofreading. Artificial intelligence has accelerated neuron tracing, but error correction remains a significant bottleneck, often dominating project timelines. This special issue examines the challenges and opportunities in connectomics through opinion pieces, news coverage, and related primary research articles.
The comment articles published alongside the announcement explore how connectomes are already informing neuroscience. Detailed wiring maps are being used to generate testable hypotheses about circuit function, while functional connectomics link synaptic structure to neuronal activity through combined electron microscopy and calcium imaging. Other contributions emphasize comparative connectomics, where multiple datasets allow researchers to distinguish biological variation from technical noise across individuals, development, or species.
This collection also examines future directions, including uncertainty-aware reconstruction, alternative imaging modalities that trade resolution for throughput, and strategies for scaling connectomics to larger brain volumes. Rather than focusing solely on complete brains, contributors suggest that systematic mapping of many smaller regions may offer a practical path forward for studying development, disease, and brain diversity.
Publication Details
Method of the Year 2025: electron microscopy-based connectomics. Nat Methods 22, 2463–2464 (2025). https://doi.org/10.1038/s41592-025-02988-6
Although a complete human brain connectome is not quite within reach, breakthroughs in smaller systems suggest a decisive moment of progress. In the past year, the FlyWire Consortium reported the first full connectome of an adult fruit fly brain, while the MICrONS Project reconstructed and functionally characterized a cubic millimeter of mouse visual cortex. These studies demonstrate how electron microscopy, combined with large-scale computation, can now resolve neural circuits with unprecedented detail.
Building connectomes requires tightly integrated experimental and computational workflows. Brain tissue must be fixed, stained, and imaged across thousands of serial sections, followed by automated segmentation and extensive manual proofreading. Artificial intelligence has accelerated neuron tracing, but error correction remains a significant bottleneck, often dominating project timelines. This special issue examines the challenges and opportunities in connectomics through opinion pieces, news coverage, and related primary research articles.
The comment articles published alongside the announcement explore how connectomes are already informing neuroscience. Detailed wiring maps are being used to generate testable hypotheses about circuit function, while functional connectomics link synaptic structure to neuronal activity through combined electron microscopy and calcium imaging. Other contributions emphasize comparative connectomics, where multiple datasets allow researchers to distinguish biological variation from technical noise across individuals, development, or species.
This collection also examines future directions, including uncertainty-aware reconstruction, alternative imaging modalities that trade resolution for throughput, and strategies for scaling connectomics to larger brain volumes. Rather than focusing solely on complete brains, contributors suggest that systematic mapping of many smaller regions may offer a practical path forward for studying development, disease, and brain diversity.
Publication Details
Method of the Year 2025: electron microscopy-based connectomics. Nat Methods 22, 2463–2464 (2025). https://doi.org/10.1038/s41592-025-02988-6