In order to simplify the information which the organism handles it stores memories as representations and not as images Emotions are also stored as representations. These are states which when triggered generate a particular emotion. Yet the greatest challenge is how to handle information generated by sense organs and other receptors. Many (very many) receptors are scattered throughout the organism. They transduce touch, pressure, temperature, and more. Information is relayed to the central nervous system for additional processing.
Receptors respond only to change. Try it. Let somebody touch your hand. Initially you feel him touching you yet in a while you will not feel the touch anymore. We feel the temperature in or room only when it changes. Or, watch the fly enjoying your sandwich. As long as you stand still you do not exist. Only the movement of your hand is sensed by it and it acts while your hand lands on the sandwich obeying Newton’s laws of motion.
Then there is the Weber-Fechner law. When the intensity of a stimulus is raised it is tranduced into the logarithm of the change. The relationship between stimulus and perception is logarithmic. If the stimulus changes as a geometric progression it is transduced into an arithmetic progression. If the stimulus exceeds the transducing capacity of a receptor it is perceived as pain.
In order to be processed stimuli have to be expected or anticipated. Expectations are memory states that generate actions. Let me describe an important discovery of mirror neurons by Giacomo Rizzolatti et al. A mirror neuron in the brain fires both when an animal performs an action and when the animal observes the same action performed by another animal. When you raise your hand some neurons in your brain fire (generate action potentials), and the same happens when you watch your friend raising his hand.
You sit with your friend. As long he is still you are unaware of him. Suddenly he raises his hand (change) which is caught by your eye. The tranduced information triggers in your action memory a hand raising process by which you grasp (unconsciously) the meaning of the change that occurred in your friend. Mirror neurons indicate the state of your action memory.
His hand raising does not initiate in you an image processing of the observed change. It activates a certain state in your action memory, and if such a state does not exist you cannot interpret the change. When a change occurs your action memory anticipates its meaning.
You smile at a baby and it returns a smile which might be interpreted as follows. In order to understand that you smile, the baby has to store in its memory a face and interpret its change as a smile. Then it has to know which muscles to move in order to smile. Yet all this might be somewhat simpler. The baby observes the change in your lips which triggers in its action memory a mirror state which is followed by a smiling process.