According to the new study of the University of California, San Diego, recordings of ten individuals with autism show a dysfunctional mirror neuron system: their mirror neurons respond only to what they do and not to the doings of others.

The human mirror neuron system is now thought to be involved not only in the execution and observation of movement, but also in higher cognitive processes - language, for instance, or being able to imitate and learn from others' actions, or decode their intentions and empathise with their pain.

Because autism is characterised, in part, by deficits in exactly these sorts of social interaction and communication skills, previous research has suggested that a dysfunctional mirror neuron system may explain the observed pathology. The current findings, the researchers say, lend substantial support to the hypothesis.

The UC San Diego team collected EEG data in ten males with autism spectrum disorders who were considered high-functioning and ten age- and gender-matched control subjects.

The EEG data was analysed for mu rhythm suppression. Mu rhythm is suppressed or blocked when the brain is engaged in doing, seeing or imagining action, and correlates with the activity of the mirror neuron system.

As expected, mu wave suppression was recorded in the control subjects both when they moved and when they watched another human move. Their mirror neuron systems acted normally. The mirror neurons of the subjects with autism spectrum disorders, however, responded anomalously - only to their own movement.

"The findings provide evidence that individuals with autism have a dysfunctional mirror neuron system, which may contribute to many of their impairments - especially those that involve comprehending and responding appropriately to others' behaviour," said Lindsay Oberman, UCSD doctoral student and first author of the paper.; Source: University of California - San Diego