Excitatory synapse
![A diagram of a typical central nervous system synapse. The spheres located in the upper neuron contain neurotransmitters that fuse with the presynaptic membrane and release neurotransmitters into the synaptic cleft. These neurotransmitters bind to receptors located on the postsynaptic membrane of the lower neuron, and, in the case of an excitatory synapse, may lead to a depolarization of the postsynaptic cell.](/Images/godic/202501/12/SynapseSchematic_en.svg3556.png")
![Animation showing the function of a chemical synapse.](/Images/godic/202501/12/-Synapse.theora.ogv3556.jpg")
![Histological brain sample of the Substantia Nigra in Parkinson's disease, showing the presence of Lewy bodies and other signs of neurodegeneration.](/Images/godic/202501/12/Histological_sample_of_Substantia_nigra_in_Parkinson's_disease3556.jpg")
An excitatory synapse is a synapse in which an action potential in a presynaptic neuron increases the probability of an action potential occurring in a postsynaptic cell. Neurons form networks through which nerve impulses travel, each neuron often making numerous connections with other cells. These electrical signals may be excitatory or inhibitory, and, if the total of excitatory influences exceeds that of the inhibitory influences, the neuron will generate a new action potential at its axon hillock, thus transmitting the information to yet another cell.