Mirror neurons, which fire when someone either performs an action or observes it, are not defective in people with autism, scientists report today in Neuron.The findings dispute the theory, first proposed a decade ago, that flaws in the mirror neuron system give rise to the disorder."The theory is that if the system is fundamentally busted, then these individuals would follow a dramatically different developmental trajectory, and that could lead to autism — but that's not what we observed," says lead investigator David Heeger, professor of psychology and neural science at New York University.The researchers found no significant difference in the average activity of mirror neurons in participants with autism compared with healthy controls when the groups either looked at a series of hand gestures or performed them.Read more at...SFARI, May 2010.