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A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another. Thus, the neuron "mirrors" the behavior of the other, as though the observer were itself acting. Such neurons have been directly observed in primate species. Birds have been shown to have imitative resonance behaviors and neurological evidence suggests the presence of some form of mirroring system.〔 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. The function of the mirror system is a subject of much speculation. Many researchers in cognitive neuroscience and cognitive psychology consider that this system provides the physiological mechanism for the perception/action coupling (see the common coding theory).〔 They argue that mirror neurons may be important for understanding the actions of other people, and for learning new skills by imitation. Some researchers also speculate that mirror systems may simulate observed actions, and thus contribute to theory of mind skills,〔Michael Arbib, ''(The Mirror System Hypothesis. Linking Language to Theory of Mind )'', 2005, retrieved 2006-02-17〕 while others relate mirror neurons to language abilities. Neuroscientists such as Marco Iacoboni (UCLA) have argued that mirror neuron systems in the human brain help us understand the actions and intentions of other people. In a study published in March 2005 Iacoboni and his colleagues reported that mirror neurons could discern if another person who was picking up a cup of tea planned to drink from it or clear it from the table. In addition, Iacoboni has argued that mirror neurons are the neural basis of the human capacity for emotions such as empathy. It has also been proposed that problems with the mirror neuron system may underlie cognitive disorders, particularly autism.〔Oberman LM, Hubbard EM, McCleery JP, Altschuler EL, Ramachandran VS, Pineda JA., ''(EEG evidence for mirror neuron dysfunction in autism spectral disorders )'', Brain Res Cogn Brain Res.; 24(2):190-8, 2005-06〕 However the connection between mirror neuron dysfunction and autism is tentative and it remains to be seen how mirror neurons may be related to many of the important characteristics of autism.〔 Despite the excitement generated by these findings, to date, no widely accepted neural or computational models have been put forward to describe how mirror neuron activity supports cognitive functions such as imitation. There are neuroscientists who caution that the claims being made for the role of mirror neurons are not supported by adequate research. ==Discovery== In the 1980s and 1990s, Giacomo Rizzolatti was working with Giuseppe Di Pellegrino, Luciano Fadiga, Leonardo Fogassi, and Vittorio Gallese at the University of Parma, Italy. These neurophysiologists had placed electrodes in the ventral premotor cortex of the macaque monkey to study neurons specialized for the control of hand and mouth actions; for example, taking hold of an object and manipulating it. During each experiment the researchers allowed the monkey to reach for pieces of food and recorded from a single neuron in the monkey's brain, thus measuring the neuron's response to certain movements.〔Di Pellegrino, G., Fadiga, L., Fogassi, L., Gallese, V., & Rizzolatti, G (1992). Understanding motor events: a neurophysiological study. Experimental Brain Research, 91, 176-180.〕〔Giacomo Rizzolatti et al. (1996) ''Premotor cortex and the recognition of motor actions'', Cognitive Brain Research 3 131-141〕 They found that some of the neurons they recorded from would respond when the monkey saw a person pick up a piece of food as well as when the monkey picked up the food. The discovery was initially sent to ''Nature'' but was rejected for its "lack of general interest," before being published in a less competitive journal. A few years later, the same group published another empirical paper, discussing the role of the mirror-neuron system in action recognition, and proposing that the human Broca’s region was the homologue region of the monkey ventral premotor cortex.〔 〕 While these papers reported the presence of mirror neurons responding to hand actions, a subsequent study by Pier Francesco Ferrari and colleagues〔Ferrari et al. (2003) "Mirror neurons responding to the observation of ingestive and communicative mouth actions in the ventral premotor cortex. European Journal of Neuroscience, 17 (8), 1703-1714〕 described the presence of mirror neurons responding to mouth actions and facial gestures. Further experiments confirmed that about 10% of neurons in the monkey inferior frontal and inferior parietal cortex have "mirror" properties and give similar responses to performed hand actions and observed actions. In 2002 Christian Keysers and colleagues reported that, in both humans and monkeys, the mirror system also responds to the sound of actions.〔 Reports on mirror neurons have been widely published〔 Gallese et al., ''Action recognition in the premotor cortex'', Brain, 1996 〕 and confirmed〔Fogassi et al., ''Parietal Lobe: From Action Organization to Intention Understanding'', Science, 2005〕 with mirror neurons found in both inferior frontal and inferior parietal regions of the brain. Recently, evidence from functional neuroimaging strongly suggests that humans have similar mirror neurons systems: researchers have identified brain regions which respond during both action and observation of action. Not surprisingly, these brain regions include those found in the macaque monkey〔 However, functional magnetic resonance imaging (fMRI) can examine the entire brain at once and suggests that a much wider network of brain areas shows mirror properties in humans than previously thought. These additional areas include the somatosensory cortex and are thought to make the observer feel what it feels like to move in the observed way. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mirror neuron」の詳細全文を読む スポンサード リンク
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