State of Brain Emulation Report 2025 | Research Overview

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Key Findings

Data is the bottleneck, not hardware or algorithms

The main barrier to better brain emulation models is more and higher-quality experimental data. No organism’s full brain has been recorded at single-neuron resolution.

Small-organism brain emulation is within reach

For organisms under 1 million neurons — fruit flies, small fish, bees — capturing all aspects of the brain faithfully is increasingly plausible, potentially within the decade, at a cost in the low $100Ms.

Scale is an enormous challenge

A mouse brain has 500x more neurons than a fruit fly; a human brain has about a million times more. Mapping a mouse brain at the needed resolution is comparable in scale to a high-resolution reconstruction of Earth.

The field is tiny and underfunded

Everyone worldwide focused specifically on brain emulation could fit in a single workshop room. Total global funding for basic neuroscience has been roughly $0.5B/year — about 1% of the NIH’s annual budget.

Outsized impact is possible

Any individual or funder entering this field can have outsized impact given its small size and early stage.

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Summary<br>At a Glance

The essential summary of all materials published.

English &rarr;<br>中文 &rarr;

For Experts<br>Full Report

The complete 200+ page technical analysis with all data, figures, and methodology.

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Interactive<br>Budget Guesstimator

Estimate costs for brain emulation projects with our calculator.

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Summary

At a Glance

概览（中文）

Experts

Full Report (PDF)

Resources

Figures

Data

Budget Guesstimator

External Resources

Introductory Materials

Asimov Press

Building brains on a computer

Coming Soon

2h Guide to Brain Emulation

International

概览（中文）

Cite

DOI: 10.5281/zenodo.18377594

Authors

Niccolo Zanichelli, Maximilian Schons, Isaak Freeman, Philip K. Shiu, Anton Arkhipov

With contributions from:

Adam Glaser, Adam Marblestone, Anders Sandberg, Andrew Payne, Andy McKenzie, Anshul Kashyap, Camille Mitchell, Christian Larsen, Claire Wang, Connor Flexman, Daniel Leible, Davi Bock, Davy Deng, Ed Boyden, Florian Engert, Glenn Clayton, James Lin, Jianfeng Feng, Jordan Matelsky, Ken Hayworth, Kevin Esvelt, Konrad Kording, Lei Ma, Logan Thrasher Collins, Michael Andregg, Michael Skuhersky, Michał Januszewski, Nicolas Patzlaff, Niko McCarty, Oliver Evans, Ons M'Saad, Patrick Mineault, Quilee Simeon, Richie Kohman, Srinivas Turaga, Tomaso Poggio, Viren Jain, Yangning Lu, Zeguan Wang

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Executive Summary

Accurate brain emulations would occupy a unique position in science: combining the experimental control of computational models with the biological fidelity needed to study how neural activity gives rise to cognition, disease, and perhaps consciousness.

Building a brain emulation requires three core capabilities: 1) recording brain activity, 2) reconstructing brain wiring, and 3) digitally modelling brains with respective data. In this report, we explain how all three capabilities have advanced substantially over the past two decades, to the point where neuroscientists are collecting enough data to emulate the brains of sub-million neuron organisms, such as zebrafish larvae and fruit flies.

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Technical Overview

Neural Dynamics — Recording Brain Activity

Despite impressive progress in neuron recording capabilities, neuroscience has not yet achieved whole-brain recording (&ge; 95% of neurons and brain volume) at single-neuron resolution in any organism. The closest achievements include larval zebrafish with approximately 80% brain coverage and C. elegans with roughly 50% of nervous system neurons recorded at single-cell resolution.

Even these figures come with substantial limitations: temporal resolution is typically well below neuronal firing rates (often 1-30 Hz for calcium imaging), recording durations remain short (minutes to hours), and the need for head-fixation severely constrains behavior repertoires.

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Connectomics — Reconstructing Brain Wiring

Complete connectomes at synaptic resolution currently exist only for small organisms. C. elegans has multiple whole-nervous-system reconstructions from individual specimens, with approximately ten datasets available. Adult Drosophila has fully proofread connectomes for both the male central nervous system and the female brain.

For larger organisms, progress remains at the proof-of-concept stage. In mice, the largest densely reconstructed volume is a cubic millimeter of visual cortex, containing approximately 120,000 neurons and 523 million automatically detected synapses.

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Computational Neuroscience — Modelling Brains Faithfully

Meaningful progress toward whole-brain emulation is currently confined to small organisms where...