BETWEEN YUMMY AND YUCKY: HOW TASTE OCCURS FROM TONGUE TO BRAIN

 

Taste doesn’t stop at your tongue. 

What begins as a chemical interaction with food ends as a conscious experience in your brain, all in a matter of milliseconds.

In this post, we’ll trace the journey of taste from the receptor cells in your mouth, basically the cells that help receive tastes from food to the gustatory cortex in your brain, the place where all the information receptor cells, get from food, is processed for you to say something is yucky or yummy.

Along the way, we’ll uncover the nerves, brain regions, and signal relays that transform molecules into meaning.

Step 2: Three Cranial Nerves Carry the Signal

Unlike vision or hearing, taste doesn't use just one nerve, it uses three different cranial nerves, each responsible for a different region of the mouth and throat:

Cranial Nerve	Area Innervated	Function
Facial Nerve (VII)	Front two-thirds of the tongue	Most sensitive to sweet and salty
Glossopharyngeal Nerve (IX)	Back one-third of the tongue	More sensitive to bitter and sour
Vagus Nerve (X)	Epiglottis, pharynx	Monitors taste in deeper parts of the mouth/throat

These nerves collect input from the taste receptor cells and carry the electrical signals toward the brainstem.

Brainstem Relay: The Nucleus of the Solitary Tract (NST)

All three cranial nerves synapse at a common point in the medulla oblongata (part of the brainstem), at a structure called the Nucleus of the Solitary Tract (NST).

The NST acts like a sorting center, organizing taste input and relaying it upward for further processing. It’s also where taste signals begin integrating with visceral functions like swallowing, salivation, and digestion.

Thalamus: The Brain’s Relay Station

From the brainstem, taste signals are transmitted via secondary neurons to the ventral posteromedial nucleus (VPM) of the thalamus.

The thalamus acts as a relay hub for sensory information, and almost everything you feel, see, hear, or taste passes through it before reaching higher brain centers.

Gustatory Cortex: Where Taste Becomes Conscious

The final destination of taste signals is the primary gustatory cortex, located in the insula and frontal operculum of the cerebral cortex.

Here, taste becomes part of conscious perception, the moment you recognize a flavor, decide whether you like it, and form a memory of it.

The gustatory cortex connects with:

- The orbitofrontal cortex (reward, decision-making)

- The amygdala (emotion, fear/aversion)

- The hypothalamus (hunger, satiety)

Together, these regions shape not just what you taste, but how you feel about it, whether you crave more, and whether you remember it next time.

Bonus: Multisensory Integration

Taste doesn’t work in isolation. It's deeply tied to:

- Smell (olfaction) — Up to 80% of what we call "taste" is actually smell.

- Texture (somatosensory input) — Crunchiness, creaminess, temperature, and even pain (e.g., spiciness) come from touch and pain receptors.

- Sight — Visual cues (like color and presentation) influence taste perception.

- Hearing — Believe it or not, even sound (like crunch) affects how we perceive freshness and flavor.

These senses all converge in the orbitofrontal cortex, a brain region responsible for flavor perception, food evaluation, and decision-making about whether to keep eating.

In Summary from the Biolab desk

The neural pathways of taste are a finely tuned network that transforms chemicals in food into meaning, memory, and emotion. From your tongue to your cortex, your brain is constantly interpreting taste in the context of survival, pleasure, and behavior.

So next time you savor your favorite dish, remember, your tongue starts the story, but your brain gives it meaning.