The Neural Correlates of Semantic and Grammatical Encoding During Sentence Production in a Second Language: Evidence From an fMRI Study Using Structural Priming.

Eri Nakagawa,Norihiro Sadato,Hirokazu Yokokawa,Kai Makita,Motofumi Sumiya,Haruyo Yoshida,Koji Shimada,Takahiko Koike

doi:10.3389/fnhum.2021.753245

Abstract

Japanese English learners have difficulty speaking Double Object (DO; give B A) than Prepositional Object (PO; give A to B) structures which neural underpinning is unknown. In speaking, syntactic and phonological processing follow semantic encoding, conversion of non-verbal mental representation into a structure suitable for expression. To test whether DO difficulty lies in linguistic or prelinguistic process, we conducted functional magnetic resonance imaging. Thirty participants described cartoons using DO or PO, or simply named them. Greater reaction times and error rates indicated DO difficulty. DO compared with PO showed parieto-frontal activation including left inferior frontal gyrus, reflecting linguistic process. Psychological priming in PO produced immediately after DO and vice versa compared to after control, indicated shared process between PO and DO. Cross-structural neural repetition suppression was observed in occipito-parietal regions, overlapping the linguistic system in pre-SMA. Thus DO and PO share prelinguistic process, whereas linguistic process imposes overload in DO.

Highlights

Speaking is an automatic yet highly complex process
We evaluated the following two contrasts: First, to reveal the neural substrates related to the prelinguistic process, the contrast of repetition suppression of crossstructural priming with the effect of N priming removed for Prepositional Object (PO) ([dP < nP] + [nN < dN]) and Double Object (DO) ([pD < nD] + [nN < pN]) was evaluated using a conjunction null analysis (Friston et al, 2005)
Correcting for Inter-Subject Variability There were four covariates, as follows: The Versant English test score, age, age of acquisition, and the amount of time spent in an English-speaking environment, that were considered to account for the differences in inter-subject variability

Summary

Introduction

Speaking is an automatic yet highly complex process. According to one widely cited model of speech production (Figure 1), it involves the generation of a preverbal message (conceptualization), translating it into a grammatical linguistic form (formulation), and articulating the phonetic plan (articulation) (Levelt, 1989). Semantic encoding occurs, which converts a non-verbal mental representation of the entity to be expressed (reference) into a semantic structure suitable for expression (sense) (Menenti et al, 2012a). Sense is the interface between conceptualization and formulation. The formulation process involves grammatical encoding (Bock and Levelt, 1994), whereby syntax, the rules used to construct sentences (in specific languages) (Chomsky, 1957), is computed. Grammatical encoding is “no more accessible to conscious experience than the corresponding comprehension”

Objectives

Methods

Results

Discussion

Conclusion