Mirror neurons are a particular class of visuomotor neurons, originally discovered in area F5 of the monkey premotor cortex, that discharge both when the monkey does a particular action and when it observes another individual (monkey or human) doing a similar action.
Rizzolatti G, Craighero L, “The mirror-neuron system,” in Annual Review of Neuroscience, issue 27 (2004) p. 1