Neurons function as basic logical organs, and basically digital organs: if a neuron requires only one incoming pulse (stimulator) to produce a response, then it is an OR organ; if it requires two incoming pulses, then it is an AND organ. These two, along with simulating “no” can be combined in various ways into any complex logical operation.
It’s not simple as this, though: a neuron may have hundreds of synapses connecting it to other cells, perhaps even to one other cell, receiving an enormous number of pulse combinations, and to further complicate things, pulses may be characterized not only by frequency, but also by spatial relations to one another.
Therefore, while there is a stimulation requirement, that is, a threshold, it may be simple, or it may be very complicated. And in the case of receptors, being neurons that respond to stimuli, there may be more than a simple threshold. Further: “if the nerve cell is activated by the stimulation of certain combinations of synapses on its body and not by others, then the significant count of basic active organs must presumably be a count of synapses rather than of nerve cells.”