Mirror Neurons: Autism’s Neurological Basis?

Jane Goodall, The Chimpanzee Lady

Mirror neurons were discovered late in the 80s, and they hinted at the ability to be stimulated not just by performing a certain action, but also by observing someone else do the very same action.

Originally thought to include simple motor actions and goal-oriented tasks, mirror neuron systems (MNS) have been implicated in several other cortical regions and hence, several more complex phenomena like empathy, emotions, theory of mind and maybe even autism.

The act of mimicking someone else is an ability inherent in monkeys and primates starting at a very young age, as you can see below:

I’m sure you’ve all had this experience (at least with someone’s baby if not a macaque monkey =P)

This is a fairly simple task, yet, autistic individuals exhibit difficulty in mimicking others’ facial expressions. The activation needs more time, and involves more brain regions. This probably means that normal individuals rely on the MNS present in the cortical region that control facial expressions, and thus can almost instantaneously comprehend and replicate a certain facial expression.

In individuals with autism spectrum disorder though, different strategies are employed in order to accomplish this fairly simple task. These strategies include utilizing different brain regions, such as visual cortices and learning and memory centers in order to execute a the expression. Imagine having to think about how to smile, or give a disgusted look…

This phenomenon observed in autistic individuals might seem a motor cortex dysfunction to some of you. Well, as a matter of fact, several studies have pointed out that individuals with autism have a normal cortical motor area. In an experiment involving simple finger movements, both the control group and the autistic group expressed similar brain activation when moving the fingers. What is remarkable though, is that in individuals with autism, when observing the finger movements of others, they only registered brain activity when the fingers were pointed towards them. So, the problem here was not motor-cortex activation upon observing others move their thumb and index, but in fact a problem with self-other perception.

Therefore, it is very plausible that the neurons that allow us to understand the states of others can malfunction, and as a result, cause autism. Yet, the question remains, does MSN dysfunction cause autism, or is MNS is a result of autism and abnormal neural development?