What can we learn about ADHD from fruit flies?

What can we learn about ADHD from fruit flies? I love this TED talk by David Anderson which discusses ADHD, and the way that neurotransmitters work in the brain. They are releases in specific locations to act on specific synapses, so to treat brain disorders we need to be able to pinpoint these locations.

We can then activate or inhibit the activity of specific neurons in model organisms like the fruit fly, and see if behaviour changes. David found that flies with mutant dopamine receptors took longer to calm down after being irritated by blowing air at them. We can therefore infer that the normal function of dopamine and its receptor is to cause flies to calm down. If we increase dopamine levels in normal flies, we see that they do, in fact, calm down more quickly.

In humans, ADHD has also been linked to disorders in the dopamine system, as well as to learning disabilities. Flies are also capable of learning, and interestingly experiments show that the flies with mutant dopamine receptors were unable to learn.

David also discusses whether the hyperactivity and the learning disability have a causal relationship, and this can be tested in flies. They can restore the dopamine receptors in specific parts of the brain of mutant flies, which shows that there is no causal relationship whatsoever. If we restore dopamine receptors in the Central Complex the flies are no longer hyperactive, but are still unable to learn. If we restore dopamine receptors in the Mushroom Body the flies can learn but are still hyperactive.

These experiments show that dopamine controls two different functions on two different neural circuits, in two different areas of the brain. Whether this is also true in humans with ADHD, we don’t know.

As David says, in future we need to design new treatments that are targeted to specific neurons and areas of the brain.

Project 365

I set up this website after deciding that I want to build a more creative life for myself, so I can give up my job and be in control of my own destiny.

I have set myself a goal of publishing an article on my website every day this year, to document my journey from employment to self-employment.

The name I chose was Project 365 because I see this as a year that I have dedicated to learning and self-development, as I countdown to freedom. It started on 1st January 2021, so I have 225 days to go!