[DSRP Evidence](https://dsrpevidence.org/) # Learning and Representation of Hierarchical Concepts in Hippocampus and Prefrontal Cortex ## Details **Authors** Theves et al. **Year** 2021 **Publisher** The Journal of Neuroscience **Discipline** Neuroscience [Read it at the publisher](https://doi.org/10.1523/JNEUROSCI.0657-21.2021) 10.1523/JNEUROSCI.0657-21.2021 ## In authors' words ### Abstract A key aspect of conceptual knowledge is that it can be flexibly applied at different levels of abstraction, implying a hierarchical organization. It is yet unclear how this hierarchical structure is acquired and represented in the brain. Here we investigate the computations underlying the acquisition and representation of the hierarchical structure of conceptual knowledge in the hippocampal-prefrontal system of 32 human participants (22 females). We assessed the hierarchical nature of learning during a novel tree-like categorization task via computational model comparisons. The winning model allowed to extract and quantify estimates for accumulation and updating of hierarchical compared with single-feature-based concepts from behavior. We find that mPFC tracks accumulation of hierarchical conceptual knowledge over time, and mPFC and hippocampus both support trial-to-trial updating. As a function of those learning parameters, mPFC and hippocampus further show connectivity changes to rostro-lateral PFC, which ultimately represented the hierarchical structure of the concept in the final stages of learning. Our results suggest that mPFC and hippocampus support the integration of accumulated evidence and instantaneous updates into hierarchical concept representations in rostro-lateral PFC. SIGNIFICANCE STATEMENT A hallmark of human cognition is the flexible use of conceptual knowledge at different levels of abstraction, ranging from a coarse category level to a fine-grained subcategory level. While previous work probed the representational geometry of long-term category knowledge, it is unclear how this hierarchical structure inherent to conceptual knowledge is acquired and represented. By combining a novel hierarchical concept learning task with computational modeling of categorization behavior and concurrent fMRI, we differentiate the roles of key concept learning regions in hippocampus and PFC in learning computations and the representation of a hierarchical category structure. ### What they set out to do (purpose) To identify how humans learn and neurally represent multi-level nested conceptual hierarchies. ### What they found (results) As people learned tree-structured nested categories, modeling showed genuinely hierarchical learning; mPFC tracked accumulated knowledge, hippocampus/mPFC coded updates, and rostrolateral PFC stored the final nested structure. ## Commentary ### In short Concepts are organized as nested part–whole hierarchies (a whole can be a part of a larger whole). ### In more detail The mind builds nested part–whole (superordinate/subordinate) category structures, and distinct brain regions accumulate, update, and store this hierarchy. Purpose: To identify how humans learn and neurally represent multi-level nested conceptual hierarchies. Finding: As people learned tree-structured nested categories, modeling showed genuinely hierarchical learning; mPFC tracked accumulated knowledge, hippocampus/mPFC coded updates, and rostrolateral PFC stored the final nested structure. [Added 2026-07-30 as new evidence beyond the original 109; DSRP structural basis: S axiom (Recursive Role): a whole can itself be a part of a larger whole — the paper directly demonstrates nested, recursive part–whole structure.] **Patterns it shows** S **Added** 2026-07-30 **How to cite this** Theves et al. (2021). Learning and Representation of Hierarchical Concepts in Hippocampus and Prefrontal Cortex. The Journal of Neuroscience.