Student Project: Neurotransmitter Effectivity Part II

Continuing my Research

Hi Everyone!
My name is Pranav Senthilkumar and I’m a rising senior at Mission San Jose High School in California. I have previously shared my work devising a neuroprosthetic device with the help of Dr. Marzullo, and now with his excellent guidance, I am starting another major neuroscience project.

As many of you may recall, I previously created a relatively cost effective  neuroprosthetic device which successfully worked on an earthworm, as their nervous system is extremely similar to ours, and we performed numerous tests on it. Read about and replicate the experiment yourself in my previous blog post: https://blog.backyardbrains.com/2019/01/student-project-neuroprosthetic-effectivity/.?

After completing that project, I began to wonder how the chemicals already present in our brain, namely neurotransmitters, would affect the effectivity of this device.

This project hopes to utilize the neuroprosthetic device to determine the best scenarios for neuroprosthetic effectivity. Furthermore, through this project, I hope to expand this device to humans, and then use what we know about the human brain to produce more findings regarding neuroprosthetics.

This first part will serve as an introduction to my project and deal with the different neurotransmitters.

In order to modulate the amount of a certain neurotransmitter, I first obtained tablets which contained different neurotransmitters. Then, using the mass of the tablets, I determined the amount of water that would equalize the concentrations of the solutions.

Then, I carefully added 2 drops of each solution to a sample of food, which was then given to 5 different earthworms. The effectivity of the neuroprosthetic device was then tested. If you recall from my last experiment, you will know that I amputated the hind of an earthworm, and built a neuroprosthetic device.

After connecting the neuroprosthetic device to the earthworm, I was able to see the hind portion of the earthworm replicate the movements of the front. This meant that the neuroprosthetic device was working! There was a short time delay between the movements of the front of the earthworm, and that of the hind portion. In order to maximize the effectivity of the device, I tried to minimize the time delay in this experiment.

 Below I have summarized the results, and included some basic information about each neurotransmitter, as these will be quite important throughout this project.

1. Glutamate:

• Excitatory Neurotransmitter
• Important for sending signals between nerve cells
• Is known to play a part in learning and memory
• Unexpectedly, glutamate decreased neuroprosthetic effectivity significantly, changing time delay from 5.1 to nearly 12 seconds

2. Acetylcholine

• Released at the neuromuscular junction
• This means that it has a large impact on movement
• Unsurprisingly, higher ACh levels reduced the time delay from 5.1 to around 2 seconds, improving neuroprosthetic effectivity

3. GABA (Gamma AminoButyric Acid)

• Inhibitory neurotransmitter
• Blocks neurons from firing
• Effectivity was slightly hindered, though it was not significant.

Here are the final results:

Trial 1:

Trial 2:

Trial 3:

This means that the addition of acetylcholine to the earthworm made the neuroprosthetic most effective. This was somewhat expected, as acetylcholine is the neurotransmitter that is released at the neuromuscular junction, and has a large part in movement.

One of the most exciting things about this is the fact that earthworms and humans have nervous systems with remarkable similarities, so these findings could soon be applicable to humans!

Please continue to follow my projects, as I continue working on this research, and stay tuned for the next part which will be about applying this device to humans!

Until next time,

Pranav