Distinguishing grammatical constructions with fMRI pattern analysis.

All linguistic and psycholinguistic theories aim to provide psychologically valid analyses of particular grammatical patterns and the relationships that hold among them. Until recently, no tools were available to distinguish neural correlates of particular grammatical constructions that shared the same content words, propositional meaning, and degree of surface complexity, such as the dative (e.g., Sally gave the book to Joe) and the ditransitive (e.g., Sally gave Joe a book). We report the first fMRI data that distinguish such closely related, abstract grammatical patterns. Multi-voxel pattern analysis (MVPA) proved capable of discriminating at above-chance levels between activity patterns arising during reading of dative and ditransitive sentences. Region-of-interest analyses reveal that the union of certain language-relevant areas, anterior and posterior BA22, BA44/45 and BA47, yield classification accuracy above chance and above that of control conditions in the left hemisphere but not in the right. Looking more closely at the LH ROIs, we find that the combination of areas aBA22 and BA47 is sufficient to distinguish the two constructions better than the controls and better than chance. The fact that both of these areas-particularly BA47-have been implicated in semantics, lends support to claims that the two constructions are distinguishable semantically. More generally, the ability to distinguish closely related grammatical constructions using MVPA offers the promise of addressing traditional theoretical questions on a neuroscientifically grounded basis.