I see that Psychological Science has published a cool new article about mirror neurons for anyone who is interested in this subject as I am, I have linked to the article.
The pace of research in this subject seems to be picking up. There was some controversy about whether or not they existed in humans as well as in monkeys and birds and other animals, since direct experimentation on humans is obviously more difficult. Of course, when neurosurgical procedures are done to help mitigate epilepsy and perhaps other conditions then experimentation is possible. Apparently last year, a study along this line of thought has suggested that these neurons exist in humans also. Prior to this there was indirect evidence that mirror neurons existed through functional magnetic resonance imaging studies. One problem with this approach is that maybe like two-thirds of the neurons in these areas are not mirror neurons so if an entire brain area lights up or fails to light up on BOLD assessment then it is hard to distinguish effects from the other neurons. Mirror neuron guru Marco Iacoboni has suggested mathematical modeling as a way around this problem. Of course perhaps someday scanning will become more sophisticated and it will be possible to tease out the effects of individual cells in living humans.
It also relates to autism as there are now probably more than 20 studies that have been done to assess mirror neuron dysfunction, in at least a limited pool of autism research subjects. Of course, one of the problems with this approach, so rampant in autism research, is the use of higher functioning autistics rather than those more severely impaired who would not sit still in a scanner or be able to use a computer. Out of all these studies, all but four of them have shown evidence of mirror neuron dysfunction in these individuals.
Another interesting item is that there are some plans to study these neurons in rhesus monkeys based on Harlow's (and perhaps other persons') research showing autistic like behaviors in these monkeys when separated from their mothers at birth, such as rocking and eye contact impairments. Going back as far back as about 1977 or 1978 I dreamed of using these monkeys as an animal model for autism when I still had my pipe dream of being a neuroscientist.
I won't comment on it further as it might spoil it for anyone else who wants to read it, but this is a good pithy article that covers some of the stuff about mirror neurons and I recommend it as an interesting read.