Greetings Earthlings! 🙂
Today I’m going to dive into the physiology of the autistic brain to explain what’s actually going on at the neurological level. I’ve touched on aspects of the science in previous posts, but I wanted to give you a quick overview post where the main points in the one place 🙂
So let’s get down to some science! 🙂
Hyper-connected Neurons:
Scientific evidence suggests that neurons in the autistic brain are hyper-connected. Specifically, studies indicate that autists have too many synapses in the brain. The synapse is basically a gap or a junction between two neurons where chemical messengers (neurotransmitters) carry information like a ferry from one neuron to the next. It looks a little bit like this:
During normal brain development, about half of the synapses we are born with are “pruned” off. In autism, this process is slowed down, and so autistic children have an excessive amount of synapses compared with their neurotypical peers. As these connections are essential to communication between neurons, this can greatly effect how the brain works and processes information.
Dysfunction at the Junction:
In addition to possessing an excessive number of synapses, communication at these neuronal junctions is also impaired in the autistic brain.
Animal studies have indicated that synapses function differently in the autistic brain as a result of genetic mutation. Mutations cause certain proteins to be absent in autism- proteins that are essential to the normal functioning of the synapse. As a consequence of this, the transmission of information between neurons is affected, resulting in a number of social and behavioral issues.
Think of physical junctions on a busy road- if something goes wrong at the junction, a chain of chaos will ensue!
Hyper-excitable Neurons:
Research shows that in many cases of autism, neurons in certain regions of the brain are more excitable than others. This means that these neurons are more sensitive to stimulation. For example, the neurons located in the sensory cortex of the brain (which processes sensory information such as smell), are more sensitive and excitable than other neurons. This is kind of like how a person can be more ticklish in some parts of the body than another- the nerves in the underarm are more excitable than those of the arm.
This sensitizes the autistic brain to all kinds of stimuli as discussed here.
Dysregulated Neurotransmitter levels:
As previously mentioned, information travels across the synapses in the brain via chemical messengers known as neurotransmitters. In the autistic brain, the levels of these neurotransmitters are dysregulated- or out of sync. Research indicates that individuals with autism tend to have higher levels of excitatory neurotransmitters (e.g. glutamic acid) and lower levels of calming neurotransmitters (e.g. GABA, serotonin) causing neurons in the autistic brain to fire excessively. In addition to this, levels of the neurohormone (a chemical that acts as both a hormone and neurotransmitter) oxytocin, which plays an influential role in trust and social behaviours, are also out of balance. Moreover, dopamine (a neurotransmitter which can both calm and excite) is also dysregulated in autism. Together, the action of biochemicals like these influences a number of autistic behaviours and issues such as ADHD, mood, appetite, sleep, anxiety, sensory processing, social behaviours, learning, memory and emotional responses.
Male vs Female Brain
Perhaps one of the most fascinating things that I have discovered about autism are the anatomical differences between the brains of the male and female autist. Brain imaging studies have revealed that autistic women have brains that are anatomically similar to neurotypical male brains, and the brains of male autists share anatomical similarities to those of neurotypical female brains.
In short- this indicates that men with autism have feminine brains, and women with autism have masculine brains!!!
I know!!!!
It sounds weird, but it makes a world of sense. Oftentimes I’ve felt like I had a male brain growing up- my tomboyish interests, my fashion sense, my preference for male company, my inability to walk in heels; it all fits!
Strange but true! 🙂
There we have it Earthlings- hope you enjoyed this brief insight into the physiology of the autistic brain 🙂 There is no clear mechanism through which autism acts, these are just some of the likely pathways involved. I’ll explore other possible mechanisms in a later post.
Have a good week everyone! 🙂
Aoife
A Is For Aoife Not Autism 