My name is Cort Thompson and I’m one of the incredibly privileged interns working at Backyard Brains this summer. I’m an undergraduate neuroscience student at Michigan State University and this summer I am working to bring the cutting edge technique of optogenetics to the classroom while also observing the courtship behaviors and gustatory system of fruit flies as well as attempting to map the neural circuitry responsible for the regulation of the proboscis extension reflex.
First, I think a little bit of background information on optogenetics and it’s importance is necessary. Every cell in any multicellular organism has ion channels that allows it to interact with the other systems within the organism. Using genetics, certain ion channels can be swapped out for channels that have identical function but are sensitive to particular wavelengths of light. With precise placement of these light sensitive channels, key areas of the organisms biology can be controlled with millisecond precision.
In the context of my particular project though, I will be dealing with the nervous system of the fruit fly species Drosophila Melanogaster. Fruit flies are wonderfully useful in modern day science, often referred to as a “neuroscience workhorse.” Fruit flies can be easily produced and bred for genetic traits that are desirable for research purposes. Because flies are so easy to manipulate genetically, light sensitive channels can be inserted into target neurons involved with courtship and gustatory behavior so that certain neural circuits can be manipulated. For example, I can induce courtship behaviors in isolated flies and observe the behavior. Later in the summer, I hope to use green fluorescent protein to “highlight” and map the neurons involved in the drosophila proboscis extension reflex (their taste reflex, also called the gustatory system).
The part of the project that I’m currently working on to kick off rest of my experimentation is to find a way to inexpensively construct devices and materials that I can use to collect data. I already have a Backyard Brains crafted “RoachScope” that allows me to use my cell phone as a microscope to observe my flies. Before I can use the flies to collect data, the flies need to be raised. Dr. Orie Shafer of the University of Michigan and his lab have been kind enough to help me raise the flies that I need for my research. While the flies are being raised I have been building LEDs and improving the roach scope for the observation of fly behavior.
Here is a quick link to optogenetics in action (Inagaki et al. 2014)! Notice how every time the light flashes, the flies extend their proboscis free of any natural stimulus. The light is activating the neurons responsible for that particular behavior!
My setup will most likely look something like this.
So far, the project has had a few setbacks. I made the mistake of leaving some of my LED wiring setups out in the workspace, and they’ve left me for other ventures. Also, a small plague has wiped out some of the fly lines that I need to breed the light sensitive flies, so it will take longer to breed the flies that I need for my research. Even though I’ve had a couple of setbacks, I don’t think that my research will be hugely affected and I remain optimistic for the coming weeks!
For some of the experiments I will insert fruit flies into the tips of pipettes (see first image above, taken under the roach scope). I ‘m working with Alex, BYB’s designer, to create better mechanisms for holding the fruit flies and pipettes up to the roach scope. For the lights, I currently and planning on using helping hands to hold up the LEDS and to shine them on the subjects under the roach scope, where I will be recording the results with my phone. I’ve got the plan, I just need my new LED parts to arrive and for the new flies to be raised, then I can really get down to science!