White matter fibres. Coloured 3D diffusion spectral imaging (DSI) scan of the bundles of white matter nerve fibres in the brain, depicting mirror neurons. Mirror neurons are found in the brain. They are so called because they fire when an individual carries out an action and also when an individual observes that same action being performed by another. Mirror neurons were discovered in the 1990s by researchers working with macaque monkeys. They have since been found in other primates, including humans, and some birds. It is thought these neurons could be important in social interactions, empathy and the evolution of language. Deficiencies in or of motor neurons may also be involved in brain disorders such as autism and schizophrenia.