For technical reasons, synaptic structure and function have been historically studied at unusually large model synapses, for example:
* Squid giant synapse
* Neuromuscular junction (NMJ), a cholinergic synapse in vertebrates, glutamatergic in insects
* Ciliary calyx in the ciliary ganglion of chicks
* Calyx of Held in the brainstem
* Ribbon synapse in the retina
* Schaffer collateral synapses in the hippocampus. These synapses are small, but their pre- and postsynaptic neurons are well separated (CA3 and CA1, respectively).