A postsynaptic neuron is a nerve cell that receives signals from another nerve cell. When one neuron sends an electrical signal, it travels along its axon and reaches the synapse, which is a tiny gap between two neurons. The postsynaptic neuron has special receptors on its surface that catch the chemical signals (called neurotransmitters) sent across this gap. These chemical signals then trigger electrical changes in the postsynaptic neuron, which can either excite it to send its own signal or stop it from doing so, depending on the type of neurotransmitter received. This process allows communication between neurons in the brain and nervous system.