Transcranial Magnetic Stimulation for Autism

Researchers are going to do a trial course of deep transcranial magnetic brain stimulation on patients who are on the autistic spectrum (either autistic or those who have asperger's disorder). They are targeting an area of the brain called the medial prefrontal cortex. I mentioned about the medial prefrontal and its potential involvement with asperger's in a previous post. The study appears to have just recently begun recruiting patients.

Theory of mind (ToM) refers to the ability to infer other's mental states. It includes a recognition that other individuals experience thoughts, feelings, intentions, and desires that may be different to our own. ToM is often impaired among individuals with an autism spectrum disorder (such as autism and Asperger's disorder), and may underlie aspects of social dysfunction in this population. Indeed, it has been suggested that impaired ToM is the core deficit of autism and Asperger's disorder.

People who have theory of the mind deficits often have difficulty reading the intentions of other people. Other people's faces carry less emotional valence and are much less meaningful. Basically this is analogous to a form of "face blindness". Facial expressions become less decipherable to the person with Asperger's due to this lack of attractive valence. People with asperger's have a reduced perceptual emotional coloring that highlights the small nuances in people's facial expressions. For normal people, faces carry a special meaning and our brain is able to differentiate various subtle shades of emotions in others. A person with aspergers may be oblivious to visualizing a certain level of detail that other people can pick up easily. The researchers, for this study, are going to use the high-frequency deep rTMS to increase activity in this medial brain region.

Based on prior imaging data, it is expected that high-frequency rTMS (compared with sham rTMS) to the medial prefrontal cortex will improve ToM ability and reduce social dysfunction among adults with autism or Asperger's disorder. Should these hypotheses be supported, it will indicate the suitability of rTMS as a neurobiological intervention designed to improve ToM and social function among individuals with autism and related disorders.

I think this area of the brain could also be targeted for negative schizophrenic symptoms such as apathy, emotional blunting and poverty of speech. There is quite a bit of overlap between those symptoms and those of asperger's disorder. People who have Williams syndrome, on the other hand, tend to have increased activity in the medial prefrontal cortex. They are also often more warm and empathetic than normal people. So stimulation of this area may be able to increase empathy towards other people. Having increased medial prefrontal cortex functioning may also lead to less social anxiety among people.

"The over-activity of the medial-prefrontal cortex may be compensatory, but the result is still an abnormal fear response. The medial-prefrontal cortex still works and in fact it is working overtime because it may be the only thing that still regulates the amygdala in Williams Syndrome."

The medial prefrontal cortex is also interesting because it can be very rewarding to an organism if certain areas are electrically stimulated. This is perhaps a lesser known reward related brain region in comparison to the more commonly known one the nucleus accumbens. Obviously reward related brain regions are distributed throughout the brain, but there are a few single hedonic hotspots that can be quite pleasurable to be stimulated. See also this article.

Some of the earliest evidence for the involvement of the medial prefrontal cortex (mPFC) in the reinforcing effects of psychostimulants derives from the demonstration that rats will self-administer cocaine directly into this region through intracranial cannulae.

Its possible that some deficits in functioning from aspergers may be due to a faulty reward mechanism of the medial prefrontal cortex. Perhaps this reward related region of the brain is just not functioning properly to increase hedonic capacity. Prefrontal dopaminergic receptors appear to be associated with certain negative symptoms. Some drugs like MDMA have the capacity to increase empathy beyond that of normal bounds perhaps partially due to the serotonin/dopamine changes in the medial prefrontal cortex. Being able to instantaneously decipher even the slightest or nuanced degree of other people's emotions in a hyper real perceptual worldview is certainly not outside the range of possible future conscious states. Perhaps it would be an ideal state when compared to a perceptual consciousness populated by indecipherable and objectified faces that hold little or no meaning.

It should definitely be an interesting region to test out different brain stimulation therapies on this region for a variety of different brain disorders. Increasing both empathy and reward capacity seems like it could be beneficial for many people. It's still too early to say for sure if this trial will be successful in its goal, but the eventual results will likely be interesting nonetheless.