Taste affects your sense of smell in the olfactory cortex

Professor Don Katz’s lab is interested in learning and behavior related to the gustatory system (the sense of taste). In a new paper in Journal of Neuroscience, also covered by the Washington Post website, Katz and  postdoc Joost Maier together with Univ. of Utah professor Matt Wachowiak, studied how tastes affect the processing of odors.

When any animal eats, it both smells and tastes the food, and has to make a split-second decision — is it nutritious or poisonous? Do I swallow it or spit it out? Accordingly, there has to be a processing system in the brain to integrate the information and make rapid decisions. It has been known for some time that odors affect the processing of taste in gustatory cortex. In the new article, the researchers demonstrate the effects of taste inputs on olfactory cortex. According to Maier, “this means is that the different senses are really interacting with each other at a much earlier level than previously thought,”.

To Get The Girl, You Have To Listen… No, Smell!

KC and the Sunshine band were prophetic when they wrote the song Get Down Tonight in ways that they never could have imagined. In the tiny social world of fruit fly courtship, the directive ‘do a little dance, make a little love’ is right on target. And just like in a dance club, what is said and when/how it is said are important to the success of fly hookups.

In ways not that dissimilar to humans, Drosophila melanogaster fruit flies meet at a singles bar commonly known as a fallen piece of overripe fruit. As the prospects congregate, there is a lot of information that is exchanged. Males use their wings to sing at short distances to the ladies milling about, giving persistent shouts of: (1) “Hey!” and (2) “How you doin’?”. When a female slows her pace to one of these calls from the dance floor, the male can then move in and cut out the ‘Hey’ portion of the call, and just use the more intimate “How you doin’?” signal. If she is still receptive, the male will dance a little closer, touching her butt and showing off his best moves until an eventual one-night-stand is awarded for his efforts. This interesting human/fruit fly parallel shows just how universal mating strategies are, even across 500 million years of evolution.

Also in similar fashion, when a miscommunication occurs, males have a much more difficult time obtaining a mate. The recent paper by Trott et al. (PLoS ONE, 2012) shows that the distance and timing of the two signals is critical to male mating success. Female fruit flies give off a chemical signal (like perfume!) to courting males, telling them that they’re interested, and the distance that the female lingers from the male is reinforcement to the male’s advances. Males who are deficient in their ability to smell due to an olfactory mutation also have a difficult time switching to a dominant “How you doin’?” signal. Without a functioning olfactory feedback mechanism, the male is unable to make the proper adjustments to his signal. For the female, it’s kind of like trying to have a one-on-one conversation with a male that is still trying to pick up every other female in the room. Even though the male is handsome/strong/free of parasites, interest from the female quickly wanes when he keeps giving the wrong signal. All the parts of the song are there; he just can’t read the cues.

So next time you’re out busting a move on the dance floor, think of the noble fruit fly passionately conducting it’s own miniature fandango. What is said is just as important as the moves that are made. And being able to read feedback is crucial to success. In a strange homage to Cyrano de Bergerac, it’s the male fruit fly that uses its ‘nose’ to speak sweet nothings that is best able to woo the female.

Trott AR, Donelson NC, Griffith LC, Ejima A (2012) Song Choice Is Modulated by Female Movement in Drosophila Males. PLoS ONE 7(9): e46025. doi:10.1371/journal.pone.0046025

Alexander Trott ’10 and postdocs Nathan Donelson and Aki Ejima worked on Drosophila courtship together with Prof. Leslie Griffith at Brandeis. Aki is now an Assistant Professor at Kyoto University. Alex is currently a graduate student at Harvard Medical School.

Video courtesy of Dr. Aki Ejima

The ancient insect nose

In a recent short article in The Journal of Experimental Biology titled JUMPING BRISTLETAILS – A GLIMPSE INTO THE ANCIENT INSECT NOSE“, postdoc Katherine Parisky discusses the evolution of the olfactory system in insects.

In order for aquatic organisms to have made the transition from living in water to surviving on land, mutations in several physiological processes needed to occur. For one sensory system, that of smell, olfactory brain structures that detect odors based on sensing air-borne, volatile and hydrophobic molecules evolved from structures that had the ability to detect aqueous hydrophilic solutions […]

Read more at http://jeb.biologists.org/content/214/23/vi.full

Hey – Fred ate that and lived to tell the tale

Don Katz discusses the interactions between taste, smell, and learning in a new story on BrandeisNOW.

“Rats learn what food that they like from smelling the breath of other rats,” says Katz, an associate professor of psychology and neuroscience. “A rat will essentially say, ‘Hey – Fred ate that and lived to tell the tale’ so later, when that rat is offered a choice, he will gravitate toward the food that he smelled on the other rat’s breath.”

How to tell what a rat likes: look at his face.

The importance of sniffing

Matt Wachowiak from the University of Utah’s Department of Physiology and Brain Institute will speak about Seeing what the nose tells the brain: order coding and processing in the awake animal on November 29th in the IGERT Neuroscience Seminar Series. The talk, hosted by Don Katz, will take place at 4:00 PM in Gerstenzang 121. Refreshments will be available at 3:45 PM.

This seminar will focus on understanding olfaction in the context of active sensing – in particular, on the importance of sniffing in shaping odor representations and processing. Wachowiak’s lab has found that changes in sniffing behavior can transform both temporal and identity codes for odors even at the level of sensory neurons, and that sniffing – like visual saccades – reflects directed attention towards a particular sensory target. Using a combination of awake imaging, electrophysiology, optogenetics and behavioral analyses they are investigating these bottom-up as well as top-down pathways by which sensory codes are actively shaped by the behaving animal.

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