Neural dynamics of accumulating and updating linguistic knowledge structures

Knowledge is acquired by generalization and integration across learning experiences, which can then be applied to future instances. This study provides novel insights into how linguistic associative knowledge is acquired by systematically tracking schematic knowledge formation while participants were learning an abstract artificial language organized by higher-order associative regularity. During learning, we found activity in the left inferior frontal gyrus in response to knowledge updating during feedback presentation, as well as in response to available accumulated knowledge during retrieval. A complementary signal was found in the caudate nucleus, where activity correlated with the availability of recently acquired knowledge during retrieval, suggesting it initially supports the retrieval of knowledge. Furthermore, we find that activity in a set of regions, including the medial prefrontal cortex and hippocampus, scaled with accumulated knowledge during feedback presentation, which might be indicative of increased generalization of features of the hierarchical knowledge structure. Together, these results provide a mechanistic insight into how linguistic associative knowledge is acquired by generalization across repeated learning experiences.