Poster F103, Tuesday, March 27, 8:00-10:00 am, Exhibit Hall C
Prefrontal Cortex Supports the Transfer of Hierarchical Task Structure to Novel Environments
Adam Eichenbaum1, Jason Scimeca1, Mark D'Esposito1; 1Helen Wills Neuroscience Institute, University of California - Berkeley
Humans can rapidly learn hierarchical rule structures. The learning and execution of hierarchical rules is supported by frontal cortex such that increasingly abstract hierarchical rules recruit increasingly rostral areas of frontal cortex. This rule learning can be bolstered by applying knowledge of previously learned rules to novel environments that share a common hierarchical structure. However, the neural systems that support this structure transfer remain unknown. In the current study, we used fMRI to characterize the contributions of frontal cortex to the transfer of hierarchical rule structure. Participants performed 4 blocks of a reinforcement-learning task in which a hierarchical rule structure could be learned from deterministic binary feedback. Stimuli were composed of features from several dimensions (shapes, colors, and textures). Each block used novel features for each dimension but shared a second-order hierarchical rule structure: shapes cued first-order rules based on either color or texture. Behavioral learning metrics showed that approximately half of participants improved learning by transferring higher-order structure across blocks. Participants whose behavior indicated a high degree of structure transfer showed increased BOLD signal in the left anterior dorsal premotor cortex (prePMd) and the more rostral left inferior frontal sulcus. Participants who failed to exhibit transfer showed robust activation only in the more caudal left dorsal premotor cortex (PMd). These results are consistent with existing models of hierarchical gradients in the frontal cortex and provide novel evidence that more rostral areas previously linked to hierarchical task execution also support the generalization of structured knowledge to novel contexts.
Topic Area: THINKING: Decision making