Frank Rosenblatt's 1958 model of an artificial neuron that learns to sort inputs into categories. It was one of the first trainable neural networks.
Back with the perceptron and the artificial neuron, the very beginning of AI, it was already thinking about human neurons and how they worked, and it was already centering human intelligence.
Peter Bauman, James Bridle on Machine Intelligence
The first project that I did was adapting the perceptron and implementing backprop through a multilayer perceptron.
Ryan Murdock, Ryan Murdock on Hacking AI