New research published in the journal Research in Autism Spectrum Disorders titled "Relationship between brain stem volume and aggression in children diagnosed with autism spectrum disorder." Has identified a inverse proportional relationship between the size of an autistic child's brain stem and aggressive behavior.

<center>https://c1.staticflickr.com/6/5065/5653340435_e5b7118536_b.jpg</center>

# Brain Stem

The brain stem is the portion of the brain which is responsible for joining the brain to the spinal chord, it is composed of a few parts which are labeled in the image below, the [midbrain](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Blausen_0114_BrainstemAnatomy.png/768px-Blausen_0114_BrainstemAnatomy.png), [medula oblongata](https://en.wikipedia.org/wiki/Medulla_oblongata), and the [pons](https://en.wikipedia.org/wiki/Pons).

<center>http://i.imgsafe.org/e6d3465f15.png</center>
<center>[Source](https://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Blausen_0114_BrainstemAnatomy.png/768px-Blausen_0114_BrainstemAnatomy.png)</center>

Each of these sections of the brain are heavily involved in involuntary bodily control. For instance the midbrain is responsible for regulating your body temperature, your alertness, the sleep/wake cycle among other things. The pons is responsible for regulating things such as swallowing, breathing, and bladder control. While the medula oblongata... 

<center>http://i.giphy.com/eSXwGcq6OudZm.gif</center>
<center> No, my god not Hakuna Matata, Medula Oblongata</center>


it controls things like your heart rate, blood pressure, and even your sneezing. 

# The Paper

The results were determined from a joint study between workers from Brigham Young University and The University of Utah, and only involved a small sample size (150 children). The intention of the study was more to be exploratory rather than to present conclusive irrefutable results so take the information with a grain of salt.

The children were scored for aggressive behavior based on [The aberrant behavior checklist](https://www.ncbi.nlm.nih.gov/pubmed/3993694) with about half being characterized as aggressive and the other half non aggressive. Then through use of MRI imaging of the brains of the children researchers quantified the volume of various aspects of the brain. They found no statistical correlation between the sizes of any portion of the brain except the **brain stem.** 

Here the researchers noticed that the autistic children who displayed the more aggressive behaviors all had smaller brain stem volumes. This may seem surprising, however it is consistent with some prior research. Previously researchers have showed a link between the [brain stem and autism](https://www.ncbi.nlm.nih.gov/pubmed/19059284). In addition to that link, a separate study has shown an interaction between [oxytosin](http://www.jneurosci.org/content/25/29/6807) and aggression (despite the fact that oxytocin is the "love hormone") and the [amygdala (another portion of the brain which directly contacts the brain stem)](https://www.ncbi.nlm.nih.gov/pubmed/16339042).

So their is some precedence for this sort of data, still this could be more a case of correlation not equaling causation, and it is clear that significantly more study is necessary before any strong conclusions can be determined. That said, it's still (at least for me) a surprising and interesting result. I did not expect to see a correlation between this particular portion of the brain, so involved in various involuntary bodily functions and an aggressive response. Still the data is what it is, and for me at least this is just an illustration of how much more we have to learn about how the brain functions.

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If you are interested in reading more into this, check out this science daily article:

https://www.sciencedaily.com/releases/2017/02/170209142651.htm

Or Dive Into The Primary Literature (if you can get around the paywall):

http://www.sciencedirect.com/science/article/pii/S1750946716301556

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