Excerpt from the original CRV Manual by Paul H. Smith:

A cognitron is an assemblage of neurons, linked together by interconnecting synapses, and which when stimulated by the mind’s recall system produce a composite concept of their various subparts. Each neuron is charged with an element of the overall concept, which when combined with the elements of its fellow neurons produces the final concept which the cognitron represents. As a human learns new facts, skills or behaviors, neurons are connecting into new cognitrons, the connecting synapses of which are more and more reinforced with use.