Neural nets are the third in a series of candidates for what is going on inside our heads to generate our behavioural capacity. Neural nets are like the brain in certain respects. Both the brain and nets have units that are interconnected. They may have positive or negative connections. They pass activity from one unit to another.
Connections can get stronger or weaker.
But there the resemblance stops. The neural nets that are used to model cognition do not have axons or dendrites, action potentials or graded potentials, synapses, neurotransmitters, glia, etc. I described the perceptron in the reply to Lee, Liz. Whatever state they are already in determines how that input propagates forward through the connections of the hidden layer to the output layer. Suppose the output is wrong.