Distributed neural encoding of binding to thematic roles

Abstract

A framework and method are proposed for the study of constituent composition in fMRI. The method produces estimates of neural patterns encoding complex linguistic structures, under the assumption that the contributions of individual constituents are additive. Like usual techniques for modeling compositional structure in fMRI, the proposed method employs pattern superposition to synthesize complex structures from their parts. Unlike these techniques, superpositions are sensitive to the structural positions of constituents, making them irreducible to structure-indiscriminate ("bag-of-words") models of composition. Using data from a study by Frankland and Greene (2015), it is shown that comparison of neural predictive models with differing specifications can illuminate aspects of neural representational contents that are not apparent when composition is not modelled. The results indicate that the neural instantiations of the binding of fillers to thematic roles in a sentence are non-orthogonal, and therefore spatially overlapping.

Electrophysiological hallmarks for event relations and event roles in working memory

“…Languages can also convey event roles through linear order as well as other structural cues, as in the English active/passive alternation "The cat chased the dog" and "The dog was chased by the cat, " where linear order of the arguments alternate but the event roles stay constant. Prior fMRI work has reported some success in decoding the binding between event roles and objects from the neural response to these kinds of alternations in English (e.g., Greene, 2015, 2020;Wang et al, 2016;Lalisse and Smolensky, 2021). However, given the poor temporal resolution of fMRI, these studies were not aimed at disentangling the extraction and maintenance processes of event roles.…”