Autapse

An autapse is a chemical synapse from a neuron onto itself. It can also be described as a synapse formed by the axon of a neuron on its own dendrites, in vivo or in vitro.

Discovered in 1972, they were originally thought to be a biological curiosity, but are now assumed to serve some purpose (though their general function remains unknown), as they have been found to be common in some circuits of the visual cortex.