We will see that their four-variable system of differential equations accurately simulates an action potential in a neuron. After we understand the basic physiology of the neuron, we can look at ways to model networks of neurons. We will build a simple nervous system which simulates perception of heat and cold. It will also simulate the parlor trick in which a blindfolded person briefly touches a very cold object and reports a sensation of heat. The following picture show the basic anatomical structure of a neuron.
Neurotransmitters arrive at the depicted neuron from efferent axons.
These neurotransmitters are either excitatory or inhibitory. The excitatory neurotransmitters tend to depolarize the neuron from its resting potential of around -70 millivolts. The inhibitory ones hyperpolarize the neuron. The cell body integrates all the depolarizing and hyperpolarizing impulses of the neurotransmitters. This action potential travels along the axon and results in the firing of a neurotransmitter at the end of the axon.