During early childhood brain development, the mind becomes wired to adapt to its surroundings. There are parts of the mind that are already hardwired at birth, but much of it develops in the first few years of life. This happens primarily in the white matter of the brain where connections are made from one brain area to another. It is my contention that the genetic difference in between autistic individuals and neurotypical individuals is that in an autistic there are fewer connections already pre-made at birth. This essentially gives the autistic a bigger “blank slate” to work with in order to adapt to the environment and create connections in response to stimuli during the first few years of life.
Scientific evidence shows that during the first few years of life, the brain development occurring in an autistic is more rapid and encompasses a larger area than any neurotypical. This has advantages since the autistic has the ability to adapt more completely to the environment, but it can also be problematic in hostile environments because the autistic is far more sensitive and far more volatile to change during this period of brain development. This period of childhood development, particularly for the autistic should be treated in exactly the same way as a foetus still in the womb. Any repeated harmful stimuli at this phase will result in major long-lasting adaptations to that stimuli, which could be problematic later in life.
Innovations in magnetic resonance imaging (MRI) technology have allowed the structure of autistic brains to be compared to that of a neurotypical brain. This is pretty exciting because it demonstrates some key differences. Before I get to talking about what those differences might be specifically, let me explain briefly the technology which allows these differences to be detected.
The technology used to perform these measurements is called diffusion tensor imaging (DTI). This technique allows measurement of the anisotropy of tissues. What does this mean? In human tissues, there are often patterns whereby tissues have individual fibres which tend to travel in a parallel direction next to one another. This is common in muscle fibres and oftentimes in certain areas of the brain known as white matter.
A good analogy to understand this concept would be looking at the internal structure of a tree. There is a grain to the wood which travels in a certain direction. Alternatively, perhaps a more apt analogy for the brain would be to look at a bundle of cables which are all grouped together and travelling from one location to another. The brain has many bundles of this sort in the white matter deep within the centre of the brain.
Let’s compare the brain to a computer network. The brain has grey matter on the surface which is analogous to a bunch of computers. There is white matter beneath the surface which contains numerous long strands of neural fibre, called axons. These axons connect one part of the grey matter to another part to relay information. So this would be like the network cables which connect individual computers together.
In a neurotypical brain there are generally many connections all bundled together between specific parts of the brain. Individual parts of the grey matter tend to activate when performing specific human functions, such as using language, or mathematics and logic etc. This allows different parts of the brain to specialize in certain types of computations. Because of this, medical science has been focussing on examining these individual parts separately to determine their specific function.
What the new studies have shown, however, is that in an autistic brain, the typical bundles of axons which connect specific parts of the brain are not laid out in the usual way that is expected to be seen in a neurotypical brain. So where a neurotypical brain has thick bundles of neural axon fibres connecting certain parts to one another, the autistic brain does not have these. The connections tend to be scattered to a lot of different areas simultaneously.
What some have hypothesized this to mean is that the autistic brain is less well connected compared to a neurotypical brain. This is true to an extent, but I believe an important upshot of this fact has been completely overlooked.
Consider a specific area of the brain, for instance Broca’s area which controls a person’s ability to speak. The connections in a neurotypical brain to this area tend to be mostly to and from the Wernicke area which allows these two specific areas to collaborate and perform their language functions while leaving the rest of the brain to perform other tasks. In an autistic brain however, the connections to Broca’s area are spread out to many different areas of the brain, rather than being primarily to the Wernicke area. This means that in order to engage in speaking, an autistic needs to engage his entire set of cognitive resources. This makes it difficult to focus on other things simultaneously, like the visual field, hearing or other senses. This makes perfect sense, considering that autistics find it very difficult to pick up non-verbal cues when they speak.
There is a benefit to having interconnections to many different areas of the brain instead of just between two specific ones. For instance, when an autistic focuses on performing a certain specific cognitive task, he will be engaging more grey matter resources simultaneously than a neurotypical can. As a result, he will appear to be more proficient at the task and be able to contemplate more aspects about that task simultaneously than a neurotypical could. The neurotypical may be using only the Broca and Wernicke areas to speak, but the autistic is using more cognitive resources to perform the same task. So his pronunciation, grammar and proper use of dictionary definitions tend to be far more precise than most neurotypicals of similar intelligence.
25 Dec 2013, 2:27 pm
