title: The role of the left anterior temporal lobe in semantic composition vs. semantic memory.
abstract: The left anterior temporal lobe (LATL) is robustly implicated in semantic processing by a growing body of literature. However, these results have emerged from two distinct bodies of work, addressing two different processing levels. On the one hand, the LATL has been characterized as a 'semantic hub׳ that binds features of concepts across a distributed network, based on results from semantic dementia and hemodynamic findings on the categorization of specific compared to basic exemplars. On the other, the LATL has been implicated in combinatorial operations in language, as shown by increased activity in this region associated with the processing of sentences and of basic phrases. The present work aimed to reconcile these two literatures by independently manipulating combination and concept specificity within a minimal MEG paradigm. Participants viewed simple nouns that denoted either low specificity (fish) or high specificity categories (trout) presented in either combinatorial (spotted fish/trout) or non-combinatorial contexts (xhsl fish/trout). By combining these paradigms from the two literatures, we directly compared the engagement of the LATL in semantic memory vs. semantic composition. Our results indicate that although noun specificity subtly modulates the LATL activity elicited by single nouns, it most robustly affects the size of the composition effect when these nouns are adjectivally modified, with low specificity nouns eliciting a much larger effect. We conclude that these findings are compatible with an account in which the specificity and composition effects arise from a shared mechanism of meaning specification.
authors.affiliation: Department of Psychology, New York University, New York, NY, USA; NYUAD Institute, New York University Abu Dhabi, Abu Dhabi, UAE. Electronic address: masha.westerlund@nyu.edu.
authors.forename: Masha
authors.initials: M
authors.lastname: Westerlund
authors.affiliation: Department of Psychology, New York University, New York, NY, USA; Department of Linguistics, New York University, New York, NY, USA; NYUAD Institute, New York University Abu Dhabi, Abu Dhabi, UAE.
authors.forename: Liina
authors.initials: L
authors.lastname: Pylkkänen
mesh_terms: D000293:Adolescent; D000328:Adult; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D032882:Comprehension; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008568:Memory / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012660:Semantics; D013702:Temporal Lobe / Q000502:physiology*; D055815:Young Adult
keywords: Composition; Concept specificity; Left anterior temporal lobe; Magnetoencephalography; Semantic memory