In the space of just a couple of years, artificial intelligence went from a subject discussed mainly by researchers to something millions of people use every day. The arrival of

How scientists are turning the brain’s chemical signals into mathematics, software, and machine learning — from dopamine and reinforcement learning to neuromorphic chips and brain-computer interfaces.

From Hodgkin-Huxley and Hubel-Wiesel to grid cells and dopamine prediction errors — how neurophysiology shaped modern AI, backed by the landmark papers behind each leap.

Living neurons playing Pong, organoid computing, and whether the brain does backpropagation — a roundup of the fast-moving link between artificial and biological neural networks, backed by recent papers.