By Yağmur Başak Ören

A recent study by Kehl et al. (2024), published in Nature, has advanced our understanding of how the human brain processes smells at the single-neuron level—a breakthrough that bridges the gap between animal models and human research! 🧠👃

💡 Key Findings from the Study:

📍 Odor-Specific Neurons 

Researchers identified neurons in the piriform cortex (PC), amygdala, entorhinal cortex (EC), and hippocampus that are specifically activated by different scents. This confirms that odor identity is encoded at the level of individual neurons.

📍 The Role of Memory and Emotion

The hippocampus, known for memory processing, plays a key role in odor identification, while the amygdala encodes how we emotionally perceive scents.

📍 Cross-Modal Integration 

The study found that our brain does not process scents in isolation—neurons in the piriform cortex and amygdala also respond to related visual images. This suggests a semantic connection between scents and our broader cognitive understanding of the world.

📍 Repetition Suppression 

When participants were exposed to the same scent multiple times, their neurons gradually fired less, revealing a neural basis for olfactory habituation.

🌍 Neuromarketing & Scent Perception:

This study highlights why scent marketing is such a powerful tool for consumer engagement. Since scents activate memory- and emotion-related brain regions, brands can use signature scents to create long-lasting associations, enhance brand recall, and evoke emotional responses. This aligns with why certain retail environments, hotels, and even digital experiences leverage scent to subconsciously influence consumer behavior.

⚠️ A Note of Caution

While scent marketing is highly effective, brands must also consider olfactory habituation—the brain’s tendency to adapt to repeated smells. Over time, consumers may become desensitized to a signature scent, reducing its impact. To maintain engagement, businesses may benefit from periodically adjusting scent intensity or subtly alternating fragrance notes to refresh the sensory experience.

Kehl, M.S., Mackay, S., Ohla, K. et al. Single-neuron representations of odours in the human brain. Nature 634, 626–634 (2024). https://doi.org/10.1038/s41586-024-08016-5