Ainul Huda stands next to three people from her lab. The Center for Communicating Science banner is behind them and to the left.
Ainul Huda (second from left) with her labmates and advisor Lina Ni (third from left). Photo by Bria Weisz for Virginia Tech.

How can we demonstrate an understanding of how the brain works? That’s one of the questions that neuroscience graduate student Ainul Huda addressed at the September 25, 2025, Science on Tap event “Shining a Light on the Brain: Guiding Animal Behavior Using Light.” During the interactive event, Huda demonstrated how neuroscientists are learning to manipulate fruit fly behavior with light.

Ainul Huda stands and speaks, hands gesturing around her torso.
Ainul Huda speaks about fruit fly brains at Science on Tap. Photo by Bria Weisz for Virginia Tech.

    Huda’s lab studies thermosensation – in other words, she’s answering the question, “How do we respond to changes in temperature?” In humans, we can do this through thermoreceptors in our hands, which can tell us to stop touching a hot stovetop. Distinguishing changes in temperature is especially important for cold-blooded animals, since they can only survive in warm temperatures. The mosquito is a cold-blooded animal, meaning that temperature control is a possible avenue for controlling mosquito-borne illnesses.

Two of Ainul Huda's lab mates stand, holding boxes.
Huda's labmates prepare to distribute Petri dishes containing live fruit flies. Photo by Bria Weisz for Virginia Tech.

    Mosquitos and fruit flies are both part of the Diptera family of insects. Fruit flies, in particular, have become a valuable animal for neuroscience research. They have short life spans, meaning that scientists can conduct generational studies on the insects. Fruit flies also share 60 percent of their DNA with humans, which can include 75 percent of human disease genes. For neuroscientists, fruit flies are much simpler to study than humans: While humans have 86 billion neurons, fruit flies have a little over 100,000 neurons.

Ainul Huda holds up a test tube and smiles at the camera.
Huda shows the audience her fruit flies. Photo by Bria Weisz for Virginia Tech.

    After showing the audience her research subjects in a test tube, Huda explained that, to fully understand how the brain works, neuroscientists must be able to quickly manipulate it. Previous research had demonstrated that a protein in a single-celled alga caused it to move towards nearby light, introducing the concept of optogenetics — or, as Huda defined, using light and genetics to understand how cells work. 

    Since the initial research on algae, neuroscientists have engineered proteins that respond to all sorts of light levels and temperatures. At the same time,  scientists have sequenced the entirety of a fruit fly’s DNA, also called its genome.

     “We have the book, but now we need to know what the words mean,” Huda said. Optogenetics can act like a “dictionary” — a new way of seeing how each “word” in the fruit fly’s genome affects its behavior and brain.

A man shines a laser into a petri dish of fruit flies while a woman looks on from the right. The man is leaning over a pizza.
Participants use light to manipulate a Petri dish of fruit flies. Photo by Bria Weisz for Virginia Tech.

    Huda passed out lasers, Petri dishes of fruit flies, and cheat sheets explaining which genetic lines of fruit flies the participants were working with. Each genetic line had been engineered so that red light could activate specific neurons through optogenetics, allowing the audience to observe different behaviors. Using the red-light lasers, participants made their flies stop moving, jump, spin, and even “moonwalk.” After participants had a chance to make their flies do tricks, they posed questions to Huda. Most pressing was Huda’s advice for dealing with a fruit fly infestation. She suggested electronic fly zappers, blue light lanterns, or a paper plate with a bit of oil in a pinch. 

A petri dish of fruit flies. There is a piece of green tape around the dish with the word "Moonwalking" on it. There is a red spot from a laser shining into the petri dish.
A Petri dish of "moonwalking" fruit flies. Photo by Bria Weisz for Virginia Tech.

    Thank you to Ainul Huda for sharing fruit fly neuroscience and to Rising Silo Brewery for hosting! Science on Tap is a monthly event sponsored and supported by the Center for Communicating Science and by Virginia Tech's chapter of Sigma Xi. 

By Bria Weisz, Center for Communicating Science graduate assistant