The basic building block of neural network technology is the simulated neuron (depicted in Figure 1 as a circle). Independent neurons are of little use, however, unless they are interconnected in a network of neurons. The network processes a number of inputs from the outside world to produce an output, the network’s predictions. The neurons are connected by weights, (depicted as lines).
Neurons are grouped into layers by their connection to the outside world. For example, if a neuron receives data from outside of the network, it is considered to be in the input layer. If a neuron contains the network’s predictions, it is in the output layer. Neurons in between the input and output layers are in the hidden layer, which serves as a feature detector.
Topic of Interest:
What are Neural Networks?