The priming of basic combinatory responses in MEG

Esti Blanco-Elorrieta, Victor S. Ferreira, Paul Del Prato, Liina Pylkkänen
2018 Cognition  
Priming has been a powerful tool for the study of human memory and especially the memory representations relevant for language. However, although it is well established that lexical access can be primed, we do not know exactly what types of computations can be primed above the word level. This work took a neurobiological approach and assessed the ways in which the complex representation of a minimal combinatory phrase, such as red boat, can be primed, as evidenced by the spatiotemporal profiles
more » ... of magnetoencephalography (MEG) signals. Specifically, we built upon recent progress on the neural signatures of phrasal composition and tested whether the brain activities implicated for the basic combination of two words could be primed. In two experiments, MEG was recorded during a picture naming task where the prime trials were designed to replicate previously reported combinatory effects and the target trials to test whether those combinatory effects could be primed. The manipulation of the primes was successful in eliciting larger activity for adjective-noun combinations than single nouns in left anterior temporal and ventromedial prefrontal cortices, replicating prior MEG studies on parallel contrasts. Priming of similarly timed activity was observed during target trials in anterior temporal cortex, but only when the prime and target shared an adjective. No priming in temporal cortex was observed for single word repetition and two control tasks showed that the priming effect was not elicited if the prime pictures were simply viewed but not named. In sum, this work provides evidence that very basic combinatory operations can be primed, with the necessity for some lexical overlap between prime and target suggesting combinatory conceptual, as opposed to syntactic processing. Both our combinatory and priming effects were early, onsetting between 100 and 150 ms after picture onset and thus are likely to reflect the very earliest planning stages of a combinatory message. Thus our findings suggest that at the earliest stages of combinatory planning in production, a combinatory memory representation is formed that affects the planning of a relevantly similar combination on a subsequent trial. that ambiguity easily brings out priming in comprehension, given that ambiguity resolution also involves a decision process between competing representations. In all, although the structural priming literature clearly shows that priming can be observed above the word level in sentence processing, it does not yet tell us exactly which processing levels can be primed and which cannot. To approach this question systematically, one would ideally start with the simplest processes that lie closest to lexical access, given that lexical access can be primed. The next step up in the computational hierarchy of language is the basic combinatory operations that build phrases out of words. Could the act of combining black with cat be primed? If yes, the composition of black cat should facilitate the subsequent composition of, say, brown table, which is built exactly by the same combinatory rule although none of the same words are involved. In other words, does the application of the abstract adjective + noun rule form a primeable memory representation? We addressed this basic question by measuring the earliest stages of combinatory processing with magnetoencephalography (
doi:10.1016/j.cognition.2017.09.010 pmid:28942354 pmcid:PMC5705448 fatcat:zvexotlsizgyrpsqgnovrzu7qm