Mirror Neurons

Some scientists speculate that a mirror system in people forms the basis for social behavior, for our ability to imitate, acquire language, and show empathy and understanding. It also may have played a role in the evolution of speech. Mirror neurons were so named because, by firing both when an animal acts and when it simply watches the same action, they were thought to "mirror" movement, as though the observer itself were acting.
Advances in the past few years have newly defined different types of mirror neurons in monkeys and shown how finely tuned these subsets of mirror neurons can be. New studies also have further characterized abnormal-as well as normal-mirror activity in the brains of children with the social communication disorder known as autism, suggesting new approaches to treatment.

Other findings show that mirror neuron activity is instrumental for interpreting the facial expressions and actions of others but may not be sufficient for decoding their thoughts and intentions.
Recordings from the typically developing children showed similar patterns of suppression during the two tasks, indicating that mirror neuron activity is fully developed by age 7.
In contrast, recordings from the children with autism showed that mu rhythms were enhanced during both tasks. Enhancement is an indication that the mirror neuron system is disengaged. However, because the children still were able to perform the task, Pineda says, "we propose that children with autism develop alternative, non-mirror neuron-based coping strategies for understanding facial expressions and interpreting others' mental states." He suggests that "these compensatory strategies involve inhibition of residual mirror neuron functioning."
"This idea implies that a retraining of mirror neurons to respond appropriately to stimuli and integrate normally into wider circuits may reduce the social symptoms of autism."
Advances in recording brain activity also have made possible findings showing that mirror systems are active even when we are not observing an action with an eye to repeating it.
Suresh Muthukumaraswamy, PhD, at Cardiff University, found that the mirror system is activated when we watch specific actions, even when we are concentrating on a separate task.
Brain activity was recorded as the subjects passively watched a sequence of finger movements, watched the movements knowing they would be asked to repeat them, added up the number of fingers moved as they watched, and performed the sequence of movements themselves.
Results from these recordings showed similar activity when the subjects performed the movement sequence and when they watched someone else do it. In addition, Muthukumaraswamy noted increased activity in areas of the brain regulating motor activity when subjects observed the movements knowing they would later do them, and when they added up the number of fingers used, compared with passive watching.
"These data suggest that activity of human mirror neuron systems is generally increased by attention relative to passive observation, even if that attention is not directed toward a specific motor activity," says Muthukumaraswamy. "Our results suggest that the mirror system remains active regardless of any concurrent task and hence is probably an automatic system.
"A good scientific understanding of the properties of the mirror system in normal humans is important," he adds, "because this may help to understand clinical disorders such as autism where the mirror system may not be functioning normally."
Other findings based on EEG recordings provide the first evidence of normal mirror activity in children with autism: People familiar to children with autism may activate mirror areas of the brain in normal patterns when unfamiliar people do not.
The mirror neuron system may react to stimuli that the observer sees as "like me." If this is the case, "perhaps typical individuals apply this identification to all people (both familiar and unfamiliar), resulting in activation of these areas in response to the observed stimuli, while individuals on the autism spectrum only consider familiar individuals (including themselves) as 'like me,' " she says.
This evidence for normal mirror neuron activity in autistic children may indicate that mirror system dysfunction in these cases reflects an impairment in identifying with and assigning personal significance to unfamiliar people and things, Oberman suggests. Whether deficits in relating to unfamiliar people that are characteristic of autism are the cause or the result of a dysfunctional mirror neuron system is unclear.