In 1943, Warren McCulloch and Walter Pitts published a mathematical description of neurons as they were believed to operate in the brain. A neuron receives input from other neurons through connections on its dendritic tree, which are integrated to produce an output at the cell body (or soma). The output is then communicated to other neurons via a long wire (or axon), which eventually branches out to make one or more connections (at axon terminals) on the dendritic tree of other neurons.
An example neuron is shown in the following diagram:
McCulloch and Pitts described the inner workings of such a neuron as a simple logic gate that would be either on or off, depending on the input it received on its dendritic tree. Specifically, the neuron would sum up all of its inputs, and if the sum exceeded a certain threshold, an output signal would...
