THE EMERGENCE OF CONCEPT CELLS IN THE HUMAN MEDIAL TEMPORAL LOBE

Concept cells are single neurons in the human medial temporal lobe (MTL) that selectively respond to a single abstract concept, such as different visual depictions and the written or spoken name of a famous person. These neurons are thought to provide temporally stable representations that support declarative learning and memory. However, it remains unknown when and how concept cells develop their selectivity during concept acquisition.
Here, we track the emergence of concept cells during concept learning using single-neuron recordings from the MTL of epilepsy patients undergoing presurgical intracranial monitoring. Participants repeatedly performed the same concept-learning task across multiple sessions and days, in which they learned to categorize cartoon monsters into two families (the concepts) based on high-dimensional multimodal perceptual features. Before and after each feedback-based training session, conceptual knowledge was assessed by testing categorization of novel items.
Behaviorally, participants rapidly acquired abstract conceptual knowledge within the first few sessions. Preliminary neural evidence suggests that concept-selective responses in single MTL neurons emerge early during learning. In addition, population-level activity across recorded MTL neurons reflects the representational structure of the learned concepts.
Together, these findings suggest that the MTL - and concept cells in particular - are engaged during the initial acquisition of abstract conceptual knowledge. This provides new insight into how concrete experiences are transformed into generalized conceptual representations in the human brain.