The Neuroscience of Taste

Most, if not all, of us enjoy eating. But have you ever wondered what goes on in the brain as you experience the sense of taste?

As much as I love cooking, the most satisfying moment for me of all is getting to taste the food. The combination of various spices, veggies, and protein all mixed together in this small bowl makes the effort worth it. Sitting down to slowly chew and take in the complexity of the meal is always an experience, making me wonder how much we underestimate the concept of taste. 

Taste is much more than just sweet, salty, bitter, sour, and umami (savory). It is also about texture, spice level, and whether the food is hot or cold, mostly controlled by the receptors in the tongue and various areas of the brain. It is truly a wonder how just a small drop of something sweet can bring up long-term memories, or even create a new one. A taste of a store-bought cake can make us remember our past birthday, while a bad experience with a type of soup could deter us from ever trying it again. And, these memories involving taste tend to last for a long time. 

"Taste signals are mostly split between the limbic system and the cerebral cortex"

The neuroscience of taste or gustation starts from a tiny set of molecules released while eating or drinking, which are detected by gustatory cells in the taste buds, located around the mouth and tongue. While these cells are not technically neurons, they can synapse and send information to the brain. All gustatory cells distributed around the tongue are not just in specific locations, but also use specific mechanisms. Salty and sour molecules need to pass through an ion channel before being bound to a receptor, but umami, bitter and sweet molecules do not require that step. Once this has happened for the first time, the taste nerves then “reset”, in order to better communicate the signal to the brain. This is why the first spoonful of a meal often cannot live up to the rest. When gustatory cells detect a particular taste, they send signals to the relevant brainstem regions via three cranial nerves; the vagus, glossopharyngeal and facial nerves. 

Next, these signals are sent to the ventral posterior medial nucleus of the thalamus, which relays it to other brain regions, such as the gustatory cortex located in the frontal lobe, and the insula to process other forms of taste perception. Taste signals are mostly split between the limbic system and the cerebral cortex. The limbic system, involving the hippocampus, thalamus, amygdala and hypothalamus, helps in processing emotions for forming memories. It helps us identify if what we are tasting is good, awful, nostalgic, meant to remain in our minds forever, or just bland. The cerebral cortex lets us know if we should keep eating or just stop. 

"(...) the information related to both taste and smell converges in brain regions such as the inferior frontal lobe (...)"

When discussing taste, it is also important to reference smell, as they go hand in hand. When we try to eat foods whose taste we don’t enjoy, we pinch our nose and take it all in at once. When we have a cold, everything seems to taste bland. This is because the information related to both taste and smell converges in brain regions such as the inferior frontal lobe, which caters to specific combinations of both senses. It is essential to be able to smell our food as we eat, as it adds a certain complexity to what is being taken in. 

Finally, the role that taste plays is much more than just the expected enjoyment of a meal or drink, but is also its reward value. Our relationship with something we have associated with being tasty feeds into the reward system; for example, we associate the taste of ice cream or cotton candy with good memories, and might treat it as a gift for doing something good. A mother might squeeze lime juice on something she doesn't want her child to put in their mouth to deter them from wanting to try it another time. Drugs being bitter would make us less likely to take them, in order to prevent having to relive that experience. It can also play a role in addiction - the desire to drink soda or energy drinks might not just come from the rush they bring, but that  its taste alone has activated the dopaminergic system, causing a “rush of happiness”. The need for this strengthens the more we indulge, causing this form of dependence. 

Taste is one of the things we associate with being human, and can be a way to bond with one another. Understanding how it works on a neural level is useful in letting us know what makes us love and hate certain things, and why they have such a hold on our mind.

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This article was written by Gbonjubola Ogungbangbe and edited by Julia Dabrowska, with graphics produced by Georgie Savastano. If you enjoyed this article, be the first to be notified about new posts by signing up to become a WiNUK member (top right of this page)! Interested in writing for WiNUK yourself? Contact us through the blog page and the editors will be in touch.