 At the Macy Conferences, McCulloch proposed that the firing of a neuron can be associated with an event or interaction taking place in the external world which provides sensory stimulus that is then picked up by the nervous system and processed by the neurons.But McCulloch also showed how a neural network's signal pathway could be set up reflexively with itself causing the neurons to continuously fire onto each other in a ‘reverberating’ circular feedback loop without any original ‘firing’ signal or any new additional incoming signals.McCulloch claimed this accounted for conscious phenomena in which individuals’ world view, or the reaffirmation of their senses’ perceived external stimulus, was cognitively distorted or all together missing as seen in individuals with phantom limb syndrome (claiming to feel an arm that has been amputated or lost) or hallucinations (perceived sensory stimulus without an original external signal).