In order to understand how these factors affect behavior, you must understand the function of neurons in the brain. A neuron is a specialized cell that is used to send and receive messages throughout the nervous system. Neurons control all aspects of human functioning including behavior, thought, and automatic body processes. Postsynaptic potentials, synaptic transmission, and receptors all occur or exist within neurons and neuronal systems.
Postsynaptic potentials result in changes in membrane potentials, or voltage, at the postsynaptic terminal of a synapse after the release of neurotransmitters from a neuron's terminal bulbs. Their purpose is to either inhibit or initiate action potentials which serve to transmit information between neurons. As neurotransmitters attach to receptors of other neurons through synaptic transmission, information is passed between these neurons resulting in a particular behavior, thought, etc. Essentially, these processes/systems are the catalysts and instruments to all human functioning. Without them, we would be unable to think, behave, or exist.