Autistics & Brain Size

I was told that people with Autism have on average about 17.6% more brain mass than people without it. Does this apply to people with all forms of Autism (low functioning, high functioning, Asperger's) or specific types?

I assume regardless that 17.6 percent more mass doesn't mean 17.6 percent more volume as I have Asperger syndrome and my head seems to be around the same size as everybody else (maybe a little longer top to bottom, but side to side is the same as everybody else).

I understand that more isn't better btw


R.C.
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errr, quick reply here.
I've read that people who are autistic don't necessarily have greater brain mass, but some of the parts of their brains or neural wiring are unusually well developed while others are underdeveloped, so you can say they have 'specialized brains'. I think this is the most important factor that dictates the way their brains function.

This is the case for Kim Peek and Temple Grandin.

Scroll to 23:12 and you'll see a scan of Grandin's brain and a scan of a control's (age & sex) brain for comparison,
and scroll again to 23:59 to another one and you'll see what I mean. This whole video is actually worth watching if you have the time.

The computer-generated simulation of Peek's brain is in one of those super long series of documentaries that I saw some months back, I'm a bit too lazy to dig that out now sorry :P.

The study that's quoting the 17.6% only involved thirteen people (it was brain mass, btw), so it may be a lead, but a little early to tell.

From medcitynews.com:

With data adjusted for age, compared to the control brains (brains of children without autism), brains of autistic children had 67% more neurons in a region called the prefrontal cortex, which is associated with cognitive development, communication, and social and emotional function. The brains of the autistic children were also significantly heavier (by an average of 17.6%) than those of the non-autistic children, despite the fact that brain weight didn’t vary significantly among non-autistic children (average variation of 0.2%).


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While this was a preliminary study involving only 13 children, the data nevertheless reveal significant differences between the brains of autistic and non-autistic children. Total neuron number and brain weight aside, there was another difference between the autistic and non-autistic brains: those of non-autistic children showed better correlation between neuron number and brain weight. That is to say, while both neuron number and brain weight were greater in autistic children than in non-autistic children, the increased weight of the brain was less than expected based upon the greatly increased number of neurons. This suggests a neural pathology, rather than simply a “larger than normal” brain.

Cortical neurons, such as those in the prefrontal cortex, proliferate between about 10 and 20 weeks of gestation ’ that is to say, prenatally ’ and no longer proliferate once a baby has been born. As such, the study authors point out, the tremendously increased neuron count suggests that autism has its roots in prenatal development, as opposed to being caused by exposure to some causative agent (including vaccinations) during infancy or toddlerhood.

@Kayness

She had a much wider brain than normal.


@bellisaurius

I thought this study involved a much larger sample than just 13 people. Thank you for the clarification.

Out of curiousity, were there any other studies that noticed larger numbers of people or specifically focused on people with High Functioning Autism or Asperger Syndrome?

Originally Posted by RobynC

@Kayness

She had a much wider brain than normal.


@bellisaurius

I thought this study involved a much larger sample than just 13 people. Thank you for the clarification.

Out of curiousity, were there any other studies that noticed larger numbers of people or specifically focused on people with High Functioning Autism or Asperger Syndrome?

Not sure. I just looked up this study. Google Scholar might be useful here,

Fascinating

R.C.
Remember, no matter how I die: It was murder; should I be tried for a criminal offense, I probably didn't do it as I'm pretty straight laced and don't even have a speeding ticket; should I mysteriously disappear -- it wasn't voluntary…