By Lisa Qu
Beer and neuroscience -- an unlikely combination, you might think, for anything other than a collegiate shooting the breeze over drinks. But in my field of study -- olfaction -- they can be tightly intertwined.
I work to uncover the neural mechanisms of how we learn about a new odor. The parallels between olfactory research and beer start with some basics: They have overlapping chemistry terminology ("esters", "volatile compounds"), and the craft of brewing beer camouflages as one application of the scientific method, with plenty of trial-and-error and hypothesis testing.
No, it's not your imagination. Beer isn't something that smells good to most people at first. In fact, just a few years ago, I actually disliked beer. But since then, I've slowly amassed a mental library of styles and flavors that I've encountered, those I like, and those I'll pass on next time. These learning experiences are not unlike the ones of brewers or chefs or perfumists. Important to my work, we know that even things that once smelled or tasted repulsive can come to be pleasurable. So how do we form new odor representations, and how are they affected by learning and experience?
Three ingredients (besides water) make up your average beer: grain, yeast, and hops. Grains are prepared before you brew, yeast is added as you brew, and hops can be added while or after your brew. At each of these stages, a brewer relies heavily on his or her senses. Many scientific experiments, along with anecdotal evidence, have revealed mixed findings.
You have people like Richard Paterson, also called "The Nose", who purportedly can identify the region of Scotland a whisky is from just by smell alone. A study from my lab showed that prolonged exposure to a particular odor improved differentiation among related odors. For example, repeated experiences with a floral-like smell allowed the subjects to become floral "experts." This finding was underscored by neural activity changes in brain regions involved in olfaction.
But our sense of smell does not operate in a vacuum. Consider another study in which 54 wine students at the University of Bordeaux were asked to describe the odor qualities of a red wine. They used an overwhelming number of red wine descriptors, such as "prune", "raspberry", or "red currant". As it turns out, the red wine was simply a white wine that had been dyed red, revealing just how much our other senses can affect olfaction, even in trained experts. Another study found that participants rated the same odor differently depending on whether it had been labeled "cheddar cheese" or "body odor". These results highlight the magnitude of sensory and cognitive interactions on stimulus perception.
Work from various olfaction labs has suggested that odor representations exist as brain activity patterns, with different odors evoking unique patterns of activity. These representations are malleable according to this research, but a key question remains: How do these patterns form and encode learned information?
My current research looks at the development of novel odor representations by pairing ambiguous odors (mixtures that we have created) with pictures of similarly unfamiliar fruits and flowers (such as dragon fruit or silver vase plant). By creating these original representations through category associations, we can examine how the brain learns and codes olfactory information through activity patterns. Results of this study will help us understand how we learn about olfactory associations, and how this information is shaped through experience. It also provides a basis for how we learn to categorize information from a complex and dynamic environment.
From this work, I hope to gain insight into how the brain incorporates newly learned information to guide behavior. It might help us to understand the abilities of a whisky or wine expert, but it also sheds light on how important smell is for any kind of learning, whether it's in the lab, or in the bar.
Lisa Qu is a neuroscience Ph.D. student at Northwestern University in the laboratory of Dr. Jay Gottfried. She received her BA in Behavioral Biology from Johns Hopkins University and currently serves as the Student Life Chair for Northwestern's Chicago Graduate Student Association.
This post is part of a HuffPost Science series exploring the surge of new research on the human brain. Are you a neuroscientist with an insight to share? Tell us about it by emailing firstname.lastname@example.org.