Research on mirror neurons as the cause for autism has taken a surprising turn. The theory that individuals on the spectrum have a dysfunction in mirror neuron activity is being challenged by new studies.
What Are Mirror Neurons?
Specialized neurons in the brain help people learn and interact with others. Mirror neurons have been observed in two different locations of the brain, the inferior parietal cortex and the premotor cortex. What makes these neurons distinct is that they ignite while a person is performing a task but they also ignite when a person watches someone else carry out the same task.
The mirror neurons respond the same when a person simply watches someone else perform a task and when doing the action herself. This creates a dynamic between perception and experience that can lead to:
- Ability to imitate
- Develop empathy
- Feel discomfort when others are in pain
- Ability to understand social cues
Problems with mirror neuron function has been the target for "mind blindness" that is commonly associated with autistic disorders.
Research on Mirror Neurons As the Cause for Autism
Problems with empathy and the inability to understand that others have different emotions and thoughts are considerable obstacles in cases of autism spectrum disorders. Research focuses on the dysfunction of mirror neurons as the cause for autism.
Mirror Neurons Linked to Autism
It makes sense that a complex neurological condition that affects social communication and interactions connects to mirror neurons and some research supports this theory. Studies linking autism to mirror neurons include:
- University of San Diego study found that mirror neurons in individuals with autism do not fire when they are observing others but they do when they are completing the task. This apparent dysfunction in the mirror neuron system was recorded in 10 people with autism using electroencephalograph (EEG) recordings.
- A University of California in Los Angeles study found a lack of activity in mirror neuron systems in children with autism. The test measured brain activity using functional magnetic resonance imaging (fMRI) in 12 children with high functioning autism.
- Researchers from Children's Hospital of Philadelphia used diffusion tensor imaging (DTI) to track water molecules in the brain. This study found abnormalities in gray matter linked to mirror neuron systems in 13 autistic children participating in the study.
With such promising studies, it may be surprising to discover that newer research has found normally functioning mirror neuron systems in people with autism.
Normal Mirror Neuron Activity in Autism
The theory that mirror neuron dysfunction is a cause of autism is reasonable and many researchers have found evidence in brain differences in individuals on the spectrum. Neuroscientists continue their exploration of mirror neurons in autism with surprising results.
The journal Neuron reports a study that found that mirror neuron responses in autistic subjects tested were strong and normal. The study used fMRI scanning to measure brain activity in autistic participants and in neurotypical participants.
Why does this study have such different results? Ilan Dinstein is a neuroscientist who has a reasonable explanation. Testing for mirror neuron dysfunction in individuals with autism may be skewed by a delayed response. The autistic brain may experience a delay in mirror neuron activity that may be misinterpreted as a dysfunction.
Dinstein and a team of researchers from the University of Washington in Seattle and New York University found that areas associated with mirror neurons fired equally in individuals with autism and in non-autistic participants in the study. The New Scientist article, "Mirror Neurons Seen Behaving Normally in Autism" explores Dinstein's study.
The Noisy Brain
Dinstein offers an alternative theory to the mirror neuron hypothesis. The problem isn't with any particular system of the brain, but rather the connections between them. He offers the idea of a "global brain problem" affecting the autistic mind. This theory makes sense considering the wide spectrum of effects the disorder has. The newest trends in autism research may soon include the noisy brain theory.