What's a brain?
Explore the hidden world inside a brain.
A small collection of experiences built from real connectomics data. Zoom from a whole brain to a single synapse, meet a neuron, or watch it all unfold on a museum wall. No log-in.
A free educational resource for classrooms & everyone curious about the brain.
Ways in
Inner Cosmos
The full interactive site. An eight-stage zoom from the human brain down to a single synapse, a gallery of real MICrONS neurons you can meet one by one, live neural activity, and a strip of quiet wonder.
Connectome Atlas
Follow a brain dataset from electron microscopy through alignment, segmentation, Neuroglancer, community proofreading, analysis, simulation, and the field’s expanding catalog of open maps.
Neuroscience for Kids
A gentle, illustrated tour of the brain, showing the same real neurons, told simply, one wonder at a time.
The Museum Edit
A large format edition built for museum walls and gallery screens. Run it hands on as an interactive exhibit, or let the guided zoom play as an ambient attract loop. Available to license for museums and installations.
This displays at 3628 × 1600. View it on a wide screen or rotate your phone to watch.
Meet a Neuron
Spin real, 3D reconstructed brain cells one at a time. Pyramidal neurons, chandelier cells, and more, each a true MICrONS reconstruction.
Go deeper
Fun Brain Stats
How big is a neuron, really? How far would your brain's wiring stretch if you laid it end to end? The mind-bending numbers, made tangible.
The Fly Brain
The one brain we have mapped completely: every neuron, every connection in a fruit fly. See the real FlyWire reconstruction and why it is a milestone.
Guess the Number
Five quick questions about your own brain. How many neurons? How much energy? Every answer reveals a fact that will stick with you.
For Teachers
Ways to use this in a lesson, discussion questions, and a printable guide. Free, no login, works on any device in the room.
Connectome Quest
Map the brain yourself. The Seung Lab’s hub for EyeWire II, FlyWire and BANC, where anyone can help trace real neurons one at a time — and a catalog of the datasets behind all of it.
The White Matter
Click anywhere on the cortex and the measured cables that reach it light up: named bundles averaged over a thousand human brains. Or step through a signal on the route it really takes, timed by how long each tract is.
The Whole Mouse Brain, Wired
Thousands of real neurons traced along their entire axons across a whole mouse brain, drawn where they were found. Watch a signal leave a cell body and reach every region its axon touches.
Sources & Citations
Where every number comes from — datasets, papers, and the wiring-length estimate, shown transparently.
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