Link to the paper:
https://www.nature.com/articles/s41467-023-38190-5
We recorded single-neuron activity in the human olfactory cortex and medial temporal lobe to study how neurons encode odor identity and valence, and contribute to odor identification and cross-modal integration.
Neurons in the piriform cortex, amygdala, hippocampus, and entorhinal cortex modulate their activity based on odors presented, and they respond stronger to actual odors than odorless controls. Population activity in these regions accurately predicts odor identity.
Repeated odor presentations reduce neuronal responses, showing repetition suppression and habituation. Notably, piriform neurons show a marked first-trial effect, responding significantly stronger to the first than the second presentation of the same odor.
Our recordings show how specific brain regions contribute to distinct aspects of odor processing, with amygdala neurons adjusting their firing based on personal odor preference, and hippocampal activity predicting participants’ ability to correctly identify odors.
Presenting images matching each odor revealed explicit coding of visual information in the olfactory cortex, with individual neurons exhibiting chemosensory conceptual coding, e.g., in the form of a neuron responding to the smell, image, and written name of a banana.
A big thanks to everyone who contributed to this project.