Jess Kanwal

Of her family trips to India, it’s the sensory stimulation—the colors, sounds, but especially the tastes and smells—that Jess Kanwal remembers best. “As you walk outdoors, amazing aromas draw you to street food stalls for a taste,” she describes. For Kanwal, a PhD candidate in neuroscience, this diversity of experiences is a reminder that our brains have to find ways to combine these senses in order for us to perceive the world.

Kanwal studies how two of our five senses—taste and smell—combine in the brain to produce the most delicious of gestalts: flavor. “In humans, we know that smell and taste get combined in a deep area of the brain that is part of the cortex,” she says. While the cortex is present in mammals, it is missing in the majority of animals; Kanwal was curious to discover whether cortex-less animals are also capable of combining taste and smell and, if yes, how they do it.

“I turned to the fruit fly larva,” Kanwal explains. The size of a rice grain and semi-transparent, a fruit fly larva’s main goal in life is to eat and store fat so that it can undergo metamorphosis. “Taste and smell, which help larva find food, are really important at this stage,” she says. As part of her research, she placed larva on a 9-inch by 9-inch area with varying intensity gradients of attractive smell, taste, or both and observed how they behave. “I found that they’re far better at navigating to the place with the strongest attractive smell and most delicious taste when they have both smell and taste information,” Kanwal says.

Next, she began looking for where and how taste and smell information combine in the larval brain and found flavor neurons in an area that was thought to be used only for processing smell. “Our textbook understanding of the brain is as a system that starts with separate regions, each encoding information about only one sense,” Kanwal says, but she has found that more crosstalk happens between our senses than we previously thought. “This shows that we need to study the brain in a more holistic way than we have before.”