Mirror Neurons in Children with Autism Spectrum Disorder

Approximately one in every 88 children in the US is diagnosed with autism (National Institutes of Health). Autism is a developmental disorder, characterized by several deficits. Among these is the individual’s difficulty with social interactions. Many individuals with autism have a difficult time imitating, reading, and appropriately responding to expressions of emotion.

What exactly it is that leads to these social deficits? In cognitive psychology, we learn that there are many stages that one must go through in order to appropriately process and respond to a stimulus. The individual must sense the stimulus (see it, hear it, feel it, etc.), connect it with meaning that has been previously learned, decide how to respond, and carry through with the correct response. Clearly, there are many places for errors to occur.

Some scientists suspect that humans have a mirror neuronal system (MNS), most likely located in the prefrontal cortex. These neurons are believed to be active when you perform an action, as well as when you watch someone else perform an action. It is believed that this system gives rise to theory of mind, allowing us to automatically understand the actions, as well as the emotional states of others.

Dapretto, Davies, Pfeifer, Scott, Sigman, Bookheimer, and Iacoboni (2006) examined this mirror neuronal system in high-functioning children with autism, matching them with typically developing children based on age and IQ. They used fMRI to measure brain activation while participants were asked to imitate and observe emotional expressions. They highlight the importance of the insula, found in the cortex of each hemisphere. The insula acts as a connector between the frontal lobe and the limbic system and allows for the translation and understanding of an observed emotional expression. Interestingly, Dapretto et al. (2006) found no difference in how well the children imitated facial expressions. They did, however, find significant differences in the mechanisms that allowed the children to do so. Children with ASD to had significantly less activation in the bilateral pars opercularis of the inferior frontal gyrus (Brodmann’s area 44) than typically developing children. This is important because it is the region that has been previously identified to have mirror properties. Furthermore, typically developing children showed greater activity in insular and periamygdaloid regions as well as the ventral striatum and thalamus, consistent with the theory that the insula modulates activity between the frontal component of the MNS and the limbic system.

How about children with autism who are not high-functioning? Dapretto et al. (2006) found these children to have even less activation in the pars opercularis, and that activation continued to decrease with symptom severity. Dapretto et al. (2006) concluded children with ASD to have less activation areas that are believed to include the mirror neuronal system. However, they also found these children to have more activation in certain regions of their brains than the typically developing children. Children with ASD showed greater activity in the right visual and left anterior parietal areas, which are associated with visual and motor attention. This is interesting because it indicates the possibility that children with ASD might be compensating for their lack of activity in MNS regions, like the pars opercularis. It gives us reason to think optimistically about the possibility of decreasing the severity of the social deficits in children with autism through means of different resources in the brain. However, what are the best strategies for teaching autistic children to overcome their social difficulties? Are there potential limitations to this learning?

Sources:

Dapretto, M., Davies, M., Pfeifer, J., Scott, A., Sigman, M., Bookheimer, S., and Iacoboni, M. (2006). Understanding the emotions in others: Mirror neuron dysfunction in children with autism spectrum disorders. Nature Neuroscience, 9(1), 28-30.

National Institute of Health. (2015). How many people are affected by autism spectrum disorder (ASD)? Retrieved from http://www.nichd.nih.gov/health/topics/autism/conditioninfo/Pages/at-risk.aspx.

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