By Sarah Friedman

For parents of autistic children, the quest to know more about autism is a never-ending, often frustrating journey with few concrete answers.  Not only is there no sure explanation for what causes it, but the exact effect it takes on the brain is a topic of intense debate.  However, in this never-ending quest for information new ideas emerge based on our ever evolving science and technology that allow us to look deeper into how our brains work.  In the last few years a theory has emerged that may be a lead in the fight to understand the condition, a theory that goes to the heart of autism itself.  It’s called the Mirror Neuron theory.

The cells of the brain are called neurons.  Neurons fire out neurotransmitters, which are chemicals used by the brain cells to communicate with each other.  Measuring when, where, and how much neurotransmitter is released can demonstrate, in essence, how we think.  Mirror neurons exist in different places within the brain.  Unlike regular neurons, a mirror neuron fires both when a person is doing something, as well as when a person watches the same act being done by someone else.  For example, the mirror neurons of a normal person will fire when they clap their hands, as well as when they watch someone else clap their hands.  In the past few years several studies have been published in regard to the mirror neuron system in autistics, and the findings imply that damage to this mirroring system leads to the social ineptness and deficits in learning through imitation seen in the autistic population.

To say that most autistic individuals lack general social skills is somewhat of an understatement.  For anyone who has raised or worked with an autistic person, the idea of socialization is one of the biggest aspects of dealing with the condition.  But it’s not just the idea of being social, it’s the idea of being able to empathize, or simply register another person’s significance, as well as be able to use the wealth of information we pick up in life simply by watching others and processing what they do.

The research that led to this theory came about because of work done by neuroscientist Giacomo Rizzolatti, at the University of Parma in the 1990’s.  Rizzolatti found, inadvertently, when studying macaque monkey brain behavior, that the monkey’s neurons fired in equal amounts when it picked up peanuts, as when it watched a human pick up peanuts.  The thought was that these neurons, by acting like mirrors, provided understanding of the intent behind the action of someone else thereby producing a duplicate reaction in the monkey watching.  The same was found to be true for humans according to several studies. (Ramachandran et al. 2007)

A couple years ago a study came out which compared the brains of autistic children to non-autistic children.  The study, led by Mirella Dapretto at UCLA measured blood flow to certain areas of the brain using an MRI machine as the children watched or imitated different facial expressions.  The one major difference in brain function between the autistic kids and non-autistic kids was that every autistic child, when watching the expressions, showed far less activity in the pars opercularis of the inferior frontal gyrus, a part of the brain located near the temple which provides humans the ability to understand each other’s intentions by observing others’ actions or imitating their behavior.  The non-autistic children had equal amounts of activity whether doing or watching.  The intensity of each child’s autism was rated as well using two separate diagnostic scales.  Not only did the autistic children have far less activity in this section of the brain, but there was also a direct correlation between the intensity of the autism and the amount of activity; with the more severe cases having even less activity. (Dapretto et al. 2006)

Another study by Oberman et. al. used an electroencephalogram (EEG) to measure brain activity in certain regions by looking at mu waves, which are brain-wave patterns that are suppressed or blocked when the brain is busy either doing, seeing or imagining an action.  When a person does something voluntarily the waves are suppressed.  They are also suppressed when a person watches this same action being done by another person.  The children in the study were measured as they performed certain acts and as they watched others perform the same acts.  In the autistic children though there was suppression of mu waves when they themselves performed the action, there was little to none when watching others.  The non-autistic children showed suppression during both. (Oberman et al. 2005)

Yet another study, led by Luigi Cattaneo, used an Electromyograph (EMG) to measure muscle activity in a muscle used to open the mouth called the mylohyoid.  Both autistic and non-autistic children were measured as they watched someone else reach for and grab food, and then as they did the action themselves.  The non-autistic children had muscle activity while watching and doing the action, whereas the autistic children not only did not have muscle activity while watching someone else reach for and grasp the food, but they had no muscle activity themselves while reaching and grasping.  Their muscles only showed activity when it came time to eat the food.  The implication being that autistic children not only had an issue with the intention behind someone else grabbing the food, but also failed to make the connection between their own motor actions. (Cattaneo et al. 2007)

The term ‘broken mirror’ is often used to describe this theory because of the idea that the system in the brain that allows a person to understand another person, to mirror their actions or feelings, is broken.  It’s like a two way street with an obstruction blocking one lane making incoming information about the world around much more difficult to obtain and understand.  Think about how much in life we learn from other people simply from watching and through imitation.  Imagine the many deficits a person with an impeded ability to do this would have.  So much of what we know is dependent on others both in our ability to learn new information as well as our social relationships.  The impact of not being able to relate to or understand others can have a shattering effect on human comprehension and emotionality.  Common aspects of autism like issues with language development and speech, inability to communicate non-verbally, the inability to recognize and understand emotions and intentions in others, the general lack of desire for social relationships, and the inability to think abstractly are all things that could be a result of this faulty system.

This is not to say that the Mirror Neuron theory explains all aspects of autism.  As of yet it does not explain the repetitive ‘stimming’ behavior, the lack of eye contact, hypersensitivity to sound and touch, poor motor coordination, or the high rate of mental retardation co morbid with autism.  Along with that, most of the research comes with the limitation of being done solely on higher functioning subjects with an inability to say whether the results can be generalized to the entire autistic population.

If, however, the theory can be confirmed through further research it could open a new door in the diagnosis and treatment of autism.  Children could be diagnosed as early as infancy by looking at mu wave suppression, allowing for behavioral treatment to begin as early as possible.  If a chemical imbalance causes the disability then perhaps compounds can be found that either stimulate under working neurons or mimic what they do.  For higher functioning autistics it might be possible to use biofeedback, a method by which people are trained to improve their health by using signals from their own bodies.  Since mu waves are controllable, by visually showing a person their own lack of mu wave suppression on an EEG, they can train their bodies simply by being attuned to how they work and understanding what actually must be done to get the correct response.  Studies on this very topic are underway and it will be interesting to see how effective a method it is. (Ramachandran et al.  2007).

In the end there might not be one decisive answer to autism.  Deficits in the mirror neuron system could themselves be a side effect of some greater problem not yet identified.  Possibly something that includes the other attributes of autism not yet explained by the theory.  Or perhaps the research going on right now will expand our understanding of the system to include those aspects that don’t seem relevant now.  Whatever the next round of research shows, there is no denying that a connection exists between social understanding and deficits in particular brain function.  And though the science itself is still new, hopefully it will provide for better ways of dealing with one of life’s biggest mysteries.

Works Cited
Cattaneo L et al. (2007). Impairment of actions chains in autism and its possible role in intention understanding. Proceedings of the NationalAcademy of Sciences of the United States of America 104, 17825–17830

Dapretto M et al. (2006). Understanding emotions in others: mirror neuron dysfunction in children with autism spectrum disorders. Nature Neuroscience 9, 28–30

Oberman, L., et al. (2005). EEG Evidence for mirror neuron dysfunction in autism spectrum disorders.  Cognitive Brain Research 24, 190-8

Ramachandran V et al. (2007). Broken Mirrors A Theory of Autism. Scientific American 17(2), 20-29