Brain imaging is really starting to come into its own these days --- the technology is improving and scientists are getting better at interpreting the results. In addition, the NIH is emphasizing support of imagining technology, so hopefully the field will continue to advance pretty quickly.
Here is a new article in Nature Neuroscience looking at brain activity in children with autism, which may lead to a better understanding of the differences in the brains of individuals with autism. The mirror neuron system refers to the network of neurons that are important in watching and imitating, and also in understanding another's intentions â€“ all important for communication and social skills. This study shows that children with autism fail to show the usual mirror neuron activity while imitating and observing emotional expressions.
Understanding emotions in others: mirror neuron dysfunction in children with autism spectrum disorders Dapretto M, Davies MS, Pfeifer JH, Scott AA, Sigman M, Bookheimer SY, Iacoboni M. Nat Neurosci. 9(1):28-30, 2006.