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 behaviour of the other, as though the observer were itself acting. Such neurons have been directly observed in primate and other species including birds.
Taken together, these data indicate that, in humans, in addition to the mirror system transforming observed intransitive movements into potential movements, there is a further system transforming heard phonemes in the corresponding motor representation of the same sound. There is no doubt that this system could play a fundamental role in language learning.
Two studies show that the ﬁring of mirror neurons can be modulated by the context in which an action is observed. These context effects are important because they have been interpreted as evidence that mirror neurons are precisely adapted for action understanding.
Mirror neurons can also enable you to imitate the movements of others thereby setting the stage for the complex Lamarckian or cultural inheritance that characterizes our species and liberates us from the constraints of a purely gene based evolution. Moreover, as Rizzolati has noted, these neurons may also enable you to mime — and possibly understand — the lip and tongue movements of others which, in turn, could provide the opportunity for language to evolve.
When it comes to the influence of culture, [Molnar-Szakacs and Iacoboni] found that indeed, the mirror neuron network responds differently depending on whether we are looking at someone who shares our culture, or someone who doesn't.
Recent scientific research suggests that mirror neurons can fire in ways that are dependent on spatial proximity. In a paper co-authored by Rizzolatti and published in Science in 2009, it was shown how different sets of mirror neurons fire depending on whether rhesus monkeys are witnessing actions inside or outside their peripersonal space – that is, within the range of their grasp.
The development of mirror neurons begins in infancy with eye contact with caregivers and subsequent engagement. The baby smiles we smile. We smile, the baby smiles, etc. Autistic babies tend to avoid eye contact and people with autism have low neurological mirroring responses, corresponding to the severity of their autism. People who rank high on scales measuring empathy have particularly active neurological mirror response systems.
Mirror neurons are, therefore, cells with extraordinarily complex response characteristics, closely linked to visual
observation of goal-directed actions. The excitement of their discovery is compounded by the detection of functional brain imaging activation patterns that suggest similar neurons are found in human ventral premotor and parietal cortices.
The mirror systems of two people can move in tandem. Many researchers had proposed that the brains of two people “resonate” with each other as they interact, with one person’s mirror system reflecting changes in the other. Last spring, the Proceedings of the National Academy of Sciences reported on the brain activity of people playing the game of charades. The observer and gesturer performing the charade did move neurologically in tandem
One of the more intriguing recent discoveries in brain science is the existence of “mirror neurons,” a set of neurons in the premotor area of the brain that are activated not only when performing an action oneself, but also while observing someone else perform that action. It is believed mirror neurons increase an individual's ability to understand the behaviors of others, an important skill in social species such as humans.
How do mirror neurons mediate understanding of actions done by others? The proposed mechanism is rather simple. Each time an individual sees an action done by another individual, neurons that represent that action are activated in the observer’s premotor cortex. This automatically induced, motor representation of the observed action corresponds to that which is spontaneously generated during active action and whose outcome is known to the acting individual.