Bringing meaning to mind in two languages: A brain imaging study of translation priming and episodic encoding in fluent Spanish-English bilinguals

This study examines how proficient adult Spanish/English bilinguals obtain access to the meaning of words. To identify the brain systems that support semantic retrieval, participants were scanned using FMRI while they decided whether presented words in both of their languages represented abstract or concrete entities. Previous research has shown that this semantic decision task elicits brain activity in left inferior prefrontal cortex (LIPC), a region that has been associated with semantic and phonological processing.; It has been posited that the anterior subregion of LIPC (anterior LIPC) controls access to meaning whenever retrieval of knowledge is not possible automatically. In this view, repetition priming in anterior LIPC---reduced brain activity during repeated item processing relative to initial item processing---may reflect a reduced need for control processes. This priming-related reduction in controlled processing may occur because initial processing of an item makes the relevant meaning of the item more accessible during later meaning retrieval.; The central aim of the study is to examine the implications of the above hypothesis for bilingual lexical processing and learning. If anterior LIPC contributes to meaning retrieval in each of bilinguals' languages, and initial processing of an item makes its meaning more accessible within and across languages, repeated processing of an item should result in anterior LIPC priming, regardless of whether initial and repeated items are identical (e.g., chair-chair) or translation equivalents (e.g., chair-silla).; Behavioral measures of priming, as indexed by response time, revealed within-language repetition priming in English and Spanish, and translation priming from Spanish-to-English but not in the reverse direction. This pattern of behavioral priming was maintained for abstract and concrete words. Within-language priming and translation priming were associated with decreased activity in several brain regions including anterior LIPC, providing brain evidence that translations share meaning representations. However, word type results revealed that anterior LIPC priming depended on whether words were abstract or concrete providing support for a mixed-representational organization in bilingual memory. Subsequent item recognition was similar for words whether they were encoded twice in English or Spanish, or once in one language and then in the other, replicating the bilingual equivalence effect.