Sensations need Receptors

I've decided I need to model "sensations" as well as "perceptrons" but the problem now is what picks up a sensation? Here again psychology offers some helpful terminology: receptor. Just like the receptors in the back of your retina - some sensors fire automatically in response to a stimulus. These low level sensors are important for classifying low level sensations (e.g., ___ ).

So practically speaking, in The Goo a Receptor generates Sensations which in combination with other Sensations may be picked up by a Sensor that may in turn "fire" a Perceptron (e.g., I see a red line).