Autism and Mirror Neurons

Before I get to the subject of autism, I first need to explain mirror neurons. From the name you can start to gather what these neurons are involved in: imitations, mimicking, and theory of mind (empathy/understanding other peoples feelings/actions). when we pick up a book for instance, certain neurons fire in our brain (motor cortex, etc.) Simple and straight to the point. This is expected. Well, we don't even have to directly be involved in this action to have these neurons fire. Just watching someone else pick up a book causes the same neurons to fire. These are mirror neurons. That is why when someone smiles we smile back without thinking about it. Mirror neurons allow us to imitate others and learn new skills from them. Growing up, we learn a lot of things by watching others - mirror neurons make this possible. One thing unique to humans is the theory of mind. Not only can we "look" into our own mind and try to understand why we do the things we do, we can also miraculously feel the pain of others, put ourselves in their shoes, and try to understand why they do things similar or different than us. We can do this with minimal conscious cognitive effort, but mirror neurons allow this functioning to take place that other animals are not capable of. As well as returning the niceties of a wave or smile, mirror neurons also fire when you see someone in pain. Now, if the same neurons are firing, why don't we feel the pain and only sympathize with what they are going through? Our brains take care of that for us. Our executive functioning skills tell ourselves that it is not happening to us and inhibit the brain from sending the message to our bodies saying that we're in pain. The visual feedback you get from your own body that you see is not hurt, inhibits the signal from actually experiencing pain. One other abstract area that mirror neurons are found to have a role in is understanding metaphors. This is derived from patients with left supramarginal gyrus damage who have apraxia - which is an inability to mime skilled voluntary actions. These patients also have a difficult time understanding action metaphors. This region also has mirror neurons, thus why this connection was made.

Now that you have got a sense of how mirror neurons operate, let me switch back to how this relates to autism.
For those who have autism, they experience difficulty with social skills and interacting with others. They have a hard time processing facial expressing and empathizing with others. Neuroscientists are learning towards a deficiency of mirror neurons as a part of the explanation of what abnormality is taking place in an autistic brain. Researchers have done tests that have supported this hypothesis. There was a study done using EEG (electroencephalography) which picks up brain waves from placing electrodes on the scalp. It is found that the mu wave is suppressed int he brain when you make a conscious movement. Similarly, the mu wave was found to also be suppressed when someone watches another person performing the same movement. When the EEG was done on a child with autism, they had the same suppression of the mu wave when they performed the movement themselves; however, the suppression did not occur normally normally when they were watching the other person. This study has been replicated and supported many times, increasing reliability of this hypothesis. A more recent study has found less connectivity between the visual cortex in the occipital lobe and the mirror neuron region in the prefrontal cortex in patients with autism using fMRI (functional magnetic resonance imaging). Other research has tested the mirror neuron hypothesis with another form of testing using transcranial magnetic stimulation (TMS). TMS creates electrical signals in the brain, creating activity. Researchers stimulated the motor cortex (right before the central sulcus, separating the frontal lobe from the parietal lobe) and then recorded the electromuscular activation in the participants while they watch other people perform movements. Usually, when people watch someone perform movement such as squeezing a ball, the activation in the participant's same hand will go up. The same muscles they would use if they were actually squeezing the ball become "ready" as if they were going to do it. Sustaining the mirror neuron deficiency hypothesis, participants with autism had no increased activation in their muscles when watching other people's movements.

This is some interesting insight to what things in the brain are what neuroscientists think to be linked to autism. This obviously does not explain the reason why their brains are like this in the first place, but it is a step in the direction of finding out in the future. I will continue in a future post on more about mirror neurons and its likely role in autism, but for now this is enough to get you all started. And to reiterate from other posts, these are none of my own personal thoughts or research, I have gotten most of my information from the Tell-Tale Brain by V.S. Ramachandran, which I had mentioned in a previous post on phantom limbs. I'm not trying to say any of this information is my own, I just would like to share what I'm learning :)