Neuroscience · interactive
A computer keeps its data in one place and does its math in another. A brain doesn't. The thickness of each connection is both the number it remembers and the thing that does the calculation. Play with it below and watch the same wire pull double duty.
Three input cells on the left feed one output cell on the right. Each connection has a thickness — that's a stored number, its weight. Hit Walk me through it, or click an input and send a signal.
The amber numbers are the memory. The cyan total is the compute. Same wires. Nudge a weight with −/+ and watch both change together.
Tip: click an input cell to switch it on or off, then send a signal. The output fires only when the total crosses the threshold.
the memory
A synapse's strength is physical — how thick and responsive the connection is. It just sits there, holding its value, even when nothing is firing. That's the "hard drive" part.
the compute
When a pulse travels through, the same thickness decides how much gets through — thick passes a lot, thin passes little. The output adds those up. Scaling-and-summing is the calculation.
the twist
The thickness was the remembered number and the multiplier applied to the signal. Change it and you change both at once — there's no separate memory to read from. Storage lives where the math happens.
In a laptop, memory and compute are separate boxes and data shuttles between them over a bus. In a brain, the number lives inside the wire that computes with it — nothing has to travel to fetch it.
von Neumann · separated
To multiply, the CPU must fetch each weight from RAM and send it back. Data is always in transit.
neuromorphic · fused
The weight is the wire's thickness. The signal computes with it as it passes. Nothing is fetched — memory and compute are one object.