A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another.[1][2][3] Thus, the neuron "mirrors" the behavior of the other, as though the observer were itself acting. Mirror neurons are not always physiologically distinct from other types of neurons in the brain; their main differentiating factor is their response patterns.[4] By this definition, such neurons have been directly observed in humans[5] and primate species,[6] and in birds.[7]
In humans, brain activity consistent with that of mirror neurons has been found in the premotor cortex, the supplementary motor area, the primary somatosensory cortex, and the inferior parietal cortex.[8] The function of the mirror system in humans is a subject of much speculation. Birds have been shown to have imitative resonance behaviors and neurological evidence suggests the presence of some form of mirroring system.[6][9]
To date, no widely accepted neural or computational models have been put forward to describe how mirror neuron activity supports cognitive functions.[10][11][12]
The subject of mirror neurons continues to generate intense debate. In 2014, Philosophical Transactions of the Royal Society B published a special issue entirely devoted to mirror neuron research.[13] Some researchers speculate that mirror systems may simulate observed actions, and thus contribute to theory of mind skills,[14][15] while others relate mirror neurons to language abilities.[16] Neuroscientists such as Marco Iacoboni have argued that mirror neuron systems in the human brain help humans understand the actions and intentions of other people. In addition, Iacoboni has argued that mirror neurons are the neural basis of the human capacity for emotions such as empathy.[17]
^Molenberghs P, Cunnington R, Mattingley JB (July 2009). "Is the mirror neuron system involved in imitation? A short review and meta-analysis". Neuroscience and Biobehavioral Reviews. 33 (7): 975–980. doi:10.1016/j.neubiorev.2009.03.010. PMID19580913. S2CID25620637.