Megan Zirnstein (Pennsylvania State University), Janet G. Van Hell (Pennsylvania State University, Radboud University Nijmegen), & Judith F. Kroll (Pennsylvania State University)

mkz2@psu.edu

Inhibitory control; L2 comprehension; Letter fluency; ERPs

Bilingual experience has been shown to have an impact on executive function skill across the lifespan. A majority of the research on this topic, however, focuses on the relationship between language production and performance on non-linguistic control tasks. As such, very little is known about how these reported changes in cognitive control ability might influence other aspects of language use, such as reading comprehension. By utilizing an aspect of reading comprehension that has been shown to rely on executive function skill (i.e., recovery from disconfirmed predictions), our aim was to investigate how those control processes that have been implicated as critical for bilingual language processing might support online language use.

In a series of studies, we asked participants to read sentences in the L2 while their EEG was recorded. ERPs were time-locked to target words that were highly expected or unexpected, based on prior context. Performance on a domain-general inhibitory control task significantly predicted modulation of processing costs related to having a lexical prediction disconfirmed (i.e., a reduction in the late frontal positivity for unexpected target words). This effect was found for both monolinguals and bilinguals, in the L1 and L2, and for bilinguals in different immersion contexts, suggesting that the recruitment of domain-general inhibitory control mechanisms during reading is not restricted only to native readers.

Based on this finding, a remaining question was whether this recruitment of domain-general inhibition is in any way related to the types of language-related inhibition effects typically reported for bilingual language production. Therefore, in a follow-up study, we used a blocked letter fluency task to test the degree to which a group of previously tested bilingual participants were capable of disinhibiting their more dominant, native language. In this task, participants were asked to produce words that began with particular letters (e.g., F, A, S). Previous work has shown that producing first in the L2 and then in the L1, and having to produce words beginning with the same letters across languages, is most likely to induce costs related to difficulty with dis-inhibiting the L1.

Our results indicated a strong relationship between domain-general and language-related inhibition. Bilinguals with better domain-general control tended to produce more words overall in the L1 block, suggesting better skill in dis-inhibiting the L1. In addition, cognate status of the words produced in the L1, as well as the degree of orthographic overlap between that word and its L2 translation equivalent, was also important. Overall, then, we show that bilinguals, who utilize domain-general control during L2 comprehension to greater success, are also more capable of flexibly switching languages, providing much stronger evidence for the claim that bilingual language experience has a widespread effect on executive function skill.

Alexandre Chauvin (Concordia University) & Natalie Phillips (Concordia University)

alexandre.bchauvin@gmail.com

Bilingualism; Bilingual advantage; Cognitive control; Executive control; Code-switching; Event-related brain potentials (ERP); Individual differences

Evidence suggests that bilinguals exhibit superior cognitive control compared to monolinguals by using a flexible combination of proactive processes (monitoring for relevant cues) and reactive processes (inhibiting irrelevant information) to cope with interference from the non-target language¹This flexibility may be related to individual differences in language-switching behaviours, bilingual proficiency, age of acquisition of the second language (L2), or general executive functioning.

We used event-related brain potentials (ERPs) to examine proactive and reactive control processes in 15 young adult bilinguals (English-French or French-English; mean age = 24; mean self-rated proficiency: L1 = 4.84/5; L2 = 3.8/5) during the AX-CPT task. Participants were presented with the following cue-target letter pairs: A-X, A-Y, B-X, or B-Y (where B and Y are any letter other than A or X). The task was to press the “yes” key to an X target only if preceded by an A cue; all other targets should elicit a “no” response. There was a 750 millisecond interval between cue offset and target onset. We varied the global context of each block (70% A-X, 70% A-Y, 70% B-X), thus altering the degree to which proactive processes could be used to guide performance.

We hypothesized that participants would respond faster and more accurately to A-X pairs compared to A-Y pairs in the A-X-70% block due to the facilitating effect of the global block context (i.e., respond “yes” 70% of the time). In contrast, participants should respond slower and less accurately on A-X pairs compared to A-Y pairs in the A-Y-70% block. In terms of the electrophysiological data, cue-locked ERPs should reflect proactive processes whereas target-locked ERPs should primarily reflect reactive processes. Of particular interest is the N2 ERP component, a negative-going component that peaks 200-350 msec after the onset of a stimulus and is thought to be a marker of conflict detection². We observed a larger target-locked N2 on A-Y trials compared to A-X trials in the AX-70% block. We hypothesize that this is due to the conflict between 1) the task set preparation as a function of both the cue and global context of the block (i.e., prepare “yes” response), and 2) the nature of the target (i.e., withhold “yes” response) . In contrast, we did not observe a significant target-locked N2 on A-Y trials in the A-Y-70% block because the prepared “no” response initiated by the cue is congruent with the information subsequently given by the target.

We will report the extent to which these behavioural and ERP effects are modulated by individual differences in language-switching behaviours, proficiency, age of acquisition of L2, and general executive functioning.

References

[1] Morales, J., Yudes, C., Gómez-Ariza, C. J., & Bajo, M. T. Bilingualism modulates dual mechanisms of cognitive control: Evidence from ERPs. Neuropsychologia, 66:157-169, 2014.

[2] Folstein, J., & Van Petten, C. Influence of cognitive control and mismatch on the N2 component of the ERP: a review. Psychophysiology, 45(1):152-170, 2008.

Kelly A. Vaughn (University of Houston), Aurora I. Ramos-Nuñez (University of Houston), Maya R. Greene (University of Houston), David Vasquez (University of California-Riverside), Adam Felton (University of California-Riverside), Christine Chiarello (University of California-Riverside), & Arturo E. Hernandez (University of Houston)

kavaughn3@uh.edu

Cortical thickness; task switching; bilingual; inferior parietal lobule

Previous research involving patients with brain damage, children with ADHD, aging adults, Alzheimer’s patients, and normal monolingual children and adults suggests that cortical thickness in certain regions of the brain, specifically the dorsolateral prefrontal cortex, anterior cingulate cortex, inferior parietal lobule, and inferior frontal gyrus, is related to cognitive control abilities. In general, greater cortical thickness in these regions is associated with better cognitive control, and lesser cortical thickness is associated with poorer cognitive control. Surprisingly, researchers have not yet examined this relationship within the bilingual population, although bilinguals may have enhanced cognitive control abilities. Additionally, previous research suggests that greater grey matter density in one of these regions, the inferior parietal lobule, is greater for bilinguals than monolinguals, and is related to earlier age of second language acquisition, higher second language proficiency, more language exposure, and better overall language skills (Abutalebi, Canini, Della Rosa, Green, & Weekes, 2015; Della Rosa et al., 2013; Mechelli et al., 2004). Therefore, in order to fully understand the relationship between cortical thickness and cognitive control, it is important to examine the relationship between cortical thickness in the aforementioned regions and performance by bilinguals on a cognitive control task.

This study measured cognitive control using a non-verbal switching task in which participants switched between sorting images by color and sorting images by shape as indicated by a symbolic cue presented randomly throughout the task. Switch costs were calculated for the difference in response time and accuracy for the trial immediately following the switch cue or non-switch cue. Cue costs were calculated for the difference in response time and accuracy for the trial immediately following the cue and a later trial. Results indicate that, in this bilingual sample, cortical thickness is unrelated to reaction time costs for both switch and cue, but cortical thickness of the left inferior parietal lobule correlates with accuracy costs for both switch and cue. These findings shed light on the relationship between cognitive control and language in the brain.

References

[1] Abutalebi, J., Canini, M., Della Rosa, P. A., Green, D. W., & Weekes, B. S. The neuroprotective effects of bilingualism upon the inferior parietal lobule: A Structural Neuroimaging Study in Aging Chinese Bilinguals. Journal of Neurolinguistics, 33:3-13, 2015.

[2] Della Rosa, P. A., Videsott, G., Borsa, V. M., Canini, M., Weekes, B. S., Franceschini, R., & Abutalebi, J. A neural interactive location for multilingual talent. Cortex, 49(2):605-608, 2013.

[3] Mechelli, A., Crinion, J. T., Noppeney, U., O’Doherty, J., Ashburner, J., Frackowiak, R. S., & Price, C. J. Structural plasticity in the bilingual brain: Proficiency in a second language and age at acquisition affect grey-matter density. Nature, 431(7010), 2004.

Brandin Munson, Pilar Archila-Suerte and Arturo Hernandez (The University of Houston)

bamunson@uh.edu

Executive function; fMRI; L1-L2 processing; Speech Perception; Spanish English

This fMRI study investigated neural activity evoked by L2 speech syllables in brain regions of executive function typically recruited by bilinguals in cognitive control tasks. The main areas examined were the bilateral anterior cingulate, bilateral supplementary motor area, bilateral inferior frontal gyrus, and bilateral middle frontal gyrus. Based on the degree of discrepancy between L1 and L2 proficiency scores, twenty-nine children classified as balanced (smaller discrepancy) or unbalanced (larger discrepancy) dual language learners were matched for age, socioeducational background, years of education in L2, and L2 age of acquisition. Children passively listened to L2 syllables while a muted film was presented. The results showed that unbalanced learners had increased activity in multiple frontal regions bilaterally relative to balanced learners. Balanced learners showed activity in a region of the right temporal lobe. The results suggest that unbalanced learners engage regions of executive function to support the processing of L2 speech perception.

References

[1] Archila-Suerte, P., Zevin, J., & Hernandez, A. E. (2015). The effect of age of acquisition, socioeducational status, and proficiency on the neural processing of second language speech sounds. Brain Lang, 141, 35-49.

[2] Archila-Suerte, P., Zevin, J., Ramos, A., & Hernandez, A. (2013). The Neural Basis of Non-Native Speech Perception in Bilingual Children. NeuroImage, 67, 51-63.

[3] Kuhl, P., Conboy, B., Padden, D., Nelson, T., & Pruitt, J. (2005). Early speech perception and later language development: Implications for the “Critical Period”. Language Learning and Development, 1(3), 237-264.

Hilary D. Duncan (Concordia University), Jim Nikelski (Lady Davis Institute for Medical Research), Randi Pilon (Lady Davis Institute for Medical Research), Victor Whitehead (Lady Davis Institute for Medical Research), Howard Chertkow (McGill University, Lady Davis Institute for Medical Research), & Natalie Phillips (Concordia University, Centre for Research in Human Development, Lady Davis Institute for Medical Research)

Natalie.Phillips@Concordia.ca

Cognitive reserve; Alzheimer disease; mild cognitive impairment; MRI; cortical thickness; tissue density

According to the cognitive reserve (CR) hypothesis [1] certain lifestyle factors (e.g., physical activity, level of education) may mediate the relationship between degree of brain pathology and clinical manifestation of damage. Recent studies hypothesize that bilingualism may contribute to CR and protect against the onset of dementia [e.g., 2]. The current study intends to contribute to the small body of CR literature examining differences between the brains of monolingual and bilingual older adults and Alzheimer disease patients (e.g., [3,4]).

MRI scans were obtained from ninety-four patients of the Memory Clinic of McGill University at the Jewish General Hospital. Of this group, 68 patients were diagnosed with MCI (34 monolingual, 34 multilingual), and 26 as AD (13 monolingual, 13 multilingual) at the time of their scan. Monolingual participants spoke only one language. Multilingualism was defined according to the criterion set out by Bialystok and colleagues [5] for bilingualism (majority of life regularly using at least two languages). We did not control specifically for the age at which the second language was learned. Within each diagnosis group, patients were matched across language groups on age at time of scan, education, and symptom severity (Mini Mental Status Examination).

For both cortical thickness (Ct) and voxel-based morphometry (VBM) analyses, the dependent variable (vertex-level cortical thickness, voxel-level tissue density) was regressed onto age, Language group (monolingual or multilingual) and Diagnosis group (MCI or AD). Regions of interest were defined based on relevant literature, namely 1) those associated with differences between monolinguals and multilinguals, and 2) those typically associated with AD pathology in its early stages.

Uncorrected regression analyses demonstrate that multilinguals have thicker cortex in areas related to bilingualism (the right inferior frontal gyrus, right rostral middle temporal gyrus, left medial superior frontal gyrus, left rostral inferior temporal gyrus, left inferior parietal cortex, and the right ventromedial prefrontal cortex); none of these areas showed an effect of Diagnosis group. Areas associated with language processing and comprehension (right and left supramarginal gyri, left ventral inferior temporal gyrus) and with AD-pathology (left and right rhinal sulci, left and right caudal parahippocampal gyri) showed an interaction effect, with multilingual MCI showing thicker cortex than monolingual MCI patients; however, this language group advantage was lost when comparing the AD patients. These results suggest that multilingual AD and MCI patients show evidence of cognitive reserve in brain areas related to bilingualism, but that only those earlier in the disease process (MCI patients) continue to show an advantage in areas related to the disease pathology.

References

[1]. Stern, Y. Cognitive reserve. Neuropsychologia, 47 :2015-2028, 2009.

[2]. Craik, F.I.M., Bialystok, E., & Freedman, M. Delaying the onset of Alzheimer’s disease: Bilingualism as a form of cognitive reserve. Neurology, 75: 1726-1729, 2010.

[3]. Abutalebi, J., et al. Bilingualism protects anterior temporal lobe integrity in aging. Neurobiology of Aging, 35(9):2126-83, 2014.

[4]. Schweizer, T., Ware, J., Fischer, C., Craik, F., & Bialystok, E. Bilingualism as a contributor to cognitive reserve: Evidence from brain atrophy in Alzheimer’s disease. Cortex, 48: 991-996, 2012.

[5]. Bialystok, E. Craik, F., & Freedman, M. Bilingualism as a protection against the onset of symptoms in dementia. Neurospychologia, 45: 459-464, 2007.

Ashley Chung-Fat-Yim (York University), Matthias Berkes (York University), Laura Mesite (Harvard Graduate School of Education), Buddhika Bellana (Baycrest Rotman Research Institute), Gigi Luk (Harvard Graduate School of Education), and Ellen Bialystok (York University)

ashc88@yorku.ca

Bilingualism; Task switching; fMRI; White matter; TBSS

Previous research has reported behavioral differences between monolingual and bilingual participants in executive control but the brain structures underlying those differences remain largely unknown. Neuroimaging studies have found overlapping circuits for linguistic and nonlinguistic control in bilinguals, but no study to date has examined this in both monolingual and bilingual participants. Hence, we compared behavioral performance, functional connectivity, and brain structures of young adults who were unbalanced but proficient bilinguals and monolinguals who had minimal use of a second language on a verbal and nonverbal switching task in fMRI. Fourteen monolingual and 17 English-French bilingual young adults participated. Groups differed in French proficiency, (Bilingual = 90.2%, Monolingual = 19.8%, t = 18.72, p < .001) and French usage (Bilingual = 30.9%, Monolingual= 0.40%, t = 6.69, p < .001). Behavioral results showed equivalent group performance on the nonverbal task but slower performance by bilinguals in the verbal task. Analysis of DTI data showed that bilinguals had higher fractional anisotropy (FA) than monolinguals in association tracts in the left hemisphere, specifically in the superior longitudinal fasciculus, inferior longitudinal fasciculus and inferior fronto-occipital fasciculus (corrected p < .05). No area showed higher FA in monolinguals than bilinguals. The higher FA values for bilinguals in these regions are similar to regions found in studies with children[1,2], young adults[3], and older adults[4]. Functional seed partial least squares revealed that monolinguals and bilinguals had different functional connectivity with left temporal regions when engaging in verbal switching, but similar networks when the two groups were engaging in nonverbal switching. These results contribute to our understanding of the brain basis of performance differences shown between monolinguals and bilinguals.

References

[1] Mohades, S. G., Struys, E., Van Schuerbeek, P., Mondt, K., Van De Craen, P., & Luypaert, R. (2012). DTI reveals structural differences in white matter tracts between bilingual and monolingual children. Brain Research, 1435, 72–80.

[2] Mohades, S. G., Van Schuerbeek, P., Rosseel, Y., Van De Craen, P., Luypaert, R., & Baeken, C. (2015). White-matter development is different in bilingual and monolingual children: A longitudinal DTI study. PLOS one, 10(2), e0117968.

[3] Pliatsikas, C., Moschopoulou, E., & Saddy, J. D. (2015). The effects of bilingualism on the white matter structure of the brain. Proceedings of the National Academy of Sciences of the United States of America, 112(5), 1334–1337.

[4] Luk, G., Bialystok, E., Craik, F. I. M., & Grady, C. L. (2011). Lifelong bilingualism maintains white matter integrity in older adults. Journal of Neuroscience, 31, 16808–16813.