Autistic children often have trouble reading visual and emotional cues in conversation, and the social behaviors of their siblings may also be directly affected by this condition. In a study presented at the May 2007 International Meeting for Autism Research, researchers from the neuroscience division of the University of California, Los Angeles used magnetic resonance imaging (MRI) to determine that the brains of children with autism display significantly reduced functioning in the prefrontal cortex's mirror neuron system (MNS), a collection of neural pathways largely responsible for reading intent and emotion in the movements, tones and facial expressions of others.

In the experiment, which involved 16 high-functioning autistic children and 16 unaffected by the condition, faculty had each child view representations of human faces conveying different emotions, such as anger and happiness. Half of the faces depicted were focused on the viewers themselves, while the other half gazed off in another direction. Typically, the response level of the MNS decreases when confronted by individuals whose attentions are not focused on the viewer. In this study, activity in the MNS decreased across the board when the non-autistic children involved did not look directly into the eyes of the pictures facing them, but among the autistic children, the MNS was all but dormant throughout the exercise. This expected discovery goes a long way toward explaining the typical difficulties in communication and empathy experienced by so many autistic children. As the study continued, the subjects were asked to imitate the faces they saw, and the autistic children, because they had trouble discerning these expressions in the first place, scored considerably lower in their attempts to reproduce what they'd seen.

A separate study also presented at the May 2007 International Meeting for Autism Research found that the siblings of autistic children demonstrated reduced capacities for reading and reproducing emotions in faces. The heredity of autism is well-established, and siblings of autistic children are generally considered high-risk of also developing the disorder. In order to measure degrees of "social referencing," or looking for the emotional cues of others to gauge one's appropriate response to a given stimuli, researchers at the University of California, San Diego presented two groups of children with "ambiguous" toys, directing their caregivers to reinforce the nature of the toy in question with varied positive/negative facial and vocal signals. They were later shown images of the same toys while their brain activity was measured and recorded. Not surprisingly, the group of high-risk children, though they did seek emotional cues from the adults in their presence, did so less often and read the results far less accurately. Their reactions did not correspond to those of the adults, and, again, the related areas of their brains displayed significantly less activity during the entire process.

The inability to properly read and apply emotion has significant implications for an individual’s social development, and we now have a better idea how the brains of autistic individuals react in different ways to the same stimuli. This knowledge will almost certainly lead to more effective treatments. At the very least, it establishes that the communication deficits experienced by autistic children are very real and spring from significant differences in the physical functions of the brain.