1 / 57

Neural Basis of Language and Set Shifting in Bilinguals

Neural Basis of Language and Set Shifting in Bilinguals. Cesar Avila, Gabriele Garbin, Ana Sanjuan, Cristina Forn, Juan-Carlos Bustamante, Aina Rodríguez-Pujadas, Mireia Hernández & Albert Costa. SUMMARY. Some reflections about Spanish-Catalan bilingualism Language control in bilingualism

orenda
Download Presentation

Neural Basis of Language and Set Shifting in Bilinguals

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Neural Basis of Language and Set Shifting in Bilinguals Cesar Avila, Gabriele Garbin, Ana Sanjuan, Cristina Forn, Juan-Carlos Bustamante, Aina Rodríguez-Pujadas, Mireia Hernández & Albert Costa

  2. SUMMARY • Some reflections about Spanish-Catalan bilingualism • Language control in bilingualism • Study 1: Language control in Spanish-Catalan bilinguals • Task switching in bilinguals • Study 2: Task switching in Spanish-Catalan bilinguals and monolinguals • Conclusions BrainGlot 2009 - Barcelona

  3. GENERAL PURPOSE At least for some kind of early and high proficient bilinguals, language and cognitive switching would share similar neural mechanisms. BrainGlot 2009 - Barcelona

  4. Spanish-Catalan Bilingualism: Some reflections • Both languages are similar and easy to learn simultaneously. • There are a lot of bilinguals, with a diverse level of proficiency in Catalan. • Bilingualism developed because a person lives in a regional context in which two languages are co-official • There is often a concurrent L1 and L2 development since early infancy Intense training in both languages BrainGlot 2009 - Barcelona

  5. Spanish-Catalan Bilingualism: A good scenario for training executive functions since infancy.For example, one child can speak or hear L1 or L2 as a function of a cue: • Catalan: father, grandparents (father), school, some friends, some relatives.... • Spanish: mother, grandparents (mother), at kindergarten, some other friends, some other relatives... • Plus zapping TV, reading, etc. • Involved in continous task switching....Mixing languages becomes effortless. BrainGlot 2009 - Barcelona

  6. Spanish-Catalan Bilingualism: Some reflections • Special case of bilingualism where switching may be trained since early infancy This implies that the development of some executive functions (response selection, response inhibition, etc.) is intensively trained in parallel to the development of language learning. • Special case for the development of a “passive” bilingualism A good comprehension but low expression in L2 (See poster) BrainGlot 2009 - Barcelona

  7. Objectives • To study the neural basis of language control in Spanish-Catalan early bilinguals • To study the neural basis of task switching in Spanish-Catalan early bilinguals when compared with monolinguals • To test if both processes share the same neural basis. BrainGlot 2009 - Barcelona

  8. Language control in early bilinguals BrainGlot 2009 - Barcelona

  9. NEURAL BASIS OF LANGUAGE CONTROL Proposed by Abulatebi and Green, 2007 LIFG (Broca’s area) and RIFG: task switching and language control BrainGlot 2009 - Barcelona

  10. Abutalebi (2008) BrainGlot 2009 - Barcelona

  11. Behavioral Studies in language controlPicture Naming Task (Costa & Santesteban, 2004) Switching bewteen L1 and L2 L1=Spanish Red pictures L2=Catalan  Blue pictures Non-Switch Backward Switch Non-Switch Forward-Switch Backward Switch BrainGlot 2009 - Barcelona

  12. PREVIOUS BEHAVIORAL STUDIES • Asymmetrical switching costs in low proficient bilinguals: • Switching is slower than non-switching • Naming in L1 from L2 is slower than naming in L2 from L1. • Specific for late bilinguals BrainGlot 2009 - Barcelona

  13. PREVIOUS BEHAVIORAL STUDIES • Symmetrical switching costs in early, high proficient bilinguals: • Switching is slower than non-switching • Naming in L1 is slower than naming in L2. • Specific for early bilinguals independently of proficiency (for L3) BrainGlot 2009 - Barcelona

  14. Language control and lexical competition in bilinguals: an event-related fMRI study. Neuroimage Wang et al. (2007) Participants Twelve late bilingual students (6 females) mean age 19.5 (from 18 to 21) L1: Chinese L2: English learnt at 12.67(SD + 1.2) years old (poor proficiency score=3 over 5) BrainGlot 2009 - Barcelona

  15. Wang et al. (2007) “English” (200ms) (2800 ms) (2800 ms) (200ms) BrainGlot 2009 - Barcelona

  16. Wang et al. (2007) Backward switching L2 to L1 Forward switching L1 to L2 BrainGlot 2009 - Barcelona

  17. Neural bases of asymmetric language switching in second-language learners: An ER-fMRI study(Wang et al., 2007) Wang’s conclusion: the neural correlates of language switching differ depending on the direction of the switch and there does not seem to be a specific brain area acting as a “language switch”. But: 3 seconds of ITI is too long to investigate language switching Different types of bilingualism should be considered BrainGlot 2009 - Barcelona

  18. Language control and lexical competition in bilinguals: an event-related fMRI study (Abutalebi et al., 2008) Participants 12 late bilinguals (10 females). L1: German; L2: French; AOA= 11.6. fMRI tasks Simple Naming (SNc):naming pictures in L1 Task Selection (TSc): naming pictures or generating verbs from pictures as a function of a cue (all in L1) Language Selection (LSc): naming pictures in L1 or L2 as a function of a cue BrainGlot 2009 - Barcelona

  19. Results I (Abutalebi et al., 2008) Abutalebi et al., 2008 Naming L1 in dual vs single task: LIFG, SMA BrainGlot 2009 - Barcelona

  20. Results II (Abutalebi et al., 2008) Abutalebi et al., 2008 Naming L1 in bilingual vs monolingual task: LIFG, RIFG, ACC, bilateral striatum BrainGlot 2009 - Barcelona

  21. Results III (Abutalebi et al., 2008) Abutalebi et al., 2008 Naming L1 in bilingual vs dual task: LIFG, RIFG, ACC and left striatum BrainGlot 2009 - Barcelona

  22. Results IV (Abutalebi et al., 2008) Naming L2 vs L1 in bilingual context: LIFG, RIFG, ACC and bilateral striatum BrainGlot 2009 - Barcelona

  23. Discussion • Results have confirmed Abutalebi and Green’s model involving LIFG, RIFG, ACC and the striatum in language control. • Directional changes from L1 to L2 and vice-versa, were not considered. • Strange results: naming in L1 in bilingual context overactivated the network more than in a monolingual context, but less than naming L2. BrainGlot 2009 - Barcelona

  24. Language control and lexical competition in bilinguals: an event-related fMRI study (Abutalebi et al., 2008) Participants 12 earlybilinguals (6 females). L1: Italian; L2: French; AOA= lessthan 3. More exposedto L2 thanto L1 fMRI task Passivelylisteningfourtypes of sentences: • Control: L1 • Control: L2 • Languageswitchfrom L1 to L2. • Languageswitchfrom L2 to L1.

  25. Results I (Abutalebi et al., 2007) • Switch vs non-switching activated the LIFG, RIFG and bilateral superior temporal gyrus. BrainGlot 2009 - Barcelona

  26. Results II (Abutalebi et al., 2008) • Forward switching into a less dominant language (L1) activated the left striatum and ventral ACC • Backward switching into a dominant language (L2) did not activate the language control network BrainGlot 2009 - Barcelona

  27. Discussion • Switching into a less dominant language activated the language control network, but not switching into a dominant language. • This replicates Wang et al. study BrainGlot 2009 - Barcelona

  28. Study 1: Objective • To replicate Wang et al’s study in early and high proficient bilinguals. Some modifications were made: • ITI was 2 sec. • Performance was controlled: responses were aloud • Cues and pictures were simultaneous- BrainGlot 2009 - Barcelona

  29. Picture Naming Task • Participants:19 Spanish/Catalan early bilinguals. • - 7 males and 12 females • - 11 bilinguals learnt one language at home and the other at the kindergarten, and each father speaks a different language in 8 participants • High proficiency in both Spanish and Catalan. • All subjects were right-handed. • L1 and L2 were determined from infancy data: L1 was Catalan for 11 and Spanish for 8. BrainGlot 2009 - Barcelona

  30. Task • Subjects were instructed to name simple pictures in the correct language according to picture colour (red, blue): • Forty-four pictures of common objects with non-cognate names • Interstimuli interval: 2 seconds • Switch and non-switch trials • Responses were aloud. BrainGlot 2009 - Barcelona

  31. Naming sequence COMETA / MILOTXA, ESTEL LAVADORA / RENTADORA CERDO / PORC MANZANA / POMA OJO / ULL PATO / ÀNEC BrainGlot 2009 - Barcelona

  32. Task • Therewere 240 trials: • 120 switch trials: 60 Spanish Catalan • 60 Catalan  Spanish • -120 non-switch trials: 60 SpanishSpanish • 60 Catalan Catalan • Anexaminerinsidethescannerroomregisteredresponses BrainGlot 2009 - Barcelona

  33. Behavioral results. Omissions and commission errors Percentage of errors was low. There were no significant differences between languages in omission errors, but differences in commission errors reached significance (p < .05) BrainGlot 2009 - Barcelona

  34. General Switching Brain regions involved in language switching. The comparison switching (L1L2, L2L1) vs. non switching (L1L1, L2L2) events result in increased activation in the left striatum (p FWE-cor < .05). BrainGlot 2009 - Barcelona

  35. Forward and Backward Switching Brain regions involved in forward and backward language switching. Activation maps of forward switching (from L1 to L2) relative to L2 non-switching (red cluster) and of backward switching (from L2 to L1) relative to L1 non-switching (blue cluster). BrainGlot 2009 - Barcelona

  36. Discussion • Language swtiching in early and high proficient bilinguals activated the left striatum This structure have been involved in language selection and switching. • Recent research has specifically involved the left striatum in detecting language changes (Crinion et al., 2006; see Poster Sanjuan et al). • No involvement of ACC and LIFG in language swithing BrainGlot 2009 - Barcelona

  37. Discussion • When directional changes were studied: • Forward switching was associated with the left striatum (as Abutalebi et al., 2007). • Backward switching was associated with the right striatum (see also Wang et al., 2007; Abutalebi et al., 2008). Less is known about the role of this area in language selection. BrainGlot 2009 - Barcelona

  38. Cognitive control in early bilinguals BrainGlot 2009 - Barcelona

  39. PREVIOUS BEHAVIORAL STUDIES • Several studies have evidenced that bilinguals outperform monolinguals in non-linguistic contexts requiring cognitive control, such as Stroop-like tasks (e.g. Bialystok & Martin, 2004; Carlson & Meltzoff, 2008; Costa et al., 2008, 2009; Hernández et al., 2009; Martin-Rhee & Bialystok, 2008). • No previous neuroimaging studies BrainGlot 2009 - Barcelona

  40. PREVIOUS BEHAVIORAL STUDIES. (Costa et al., 2008) Used the ANT task to measure activity in three different attentional networks: alerting, orienting and executive control. Bilingual participants were faster in performing the task Bilinguals were more efficient in the alerting and executive control networks BrainGlot 2009 - Barcelona

  41. PREVIOUS BEHAVIORAL STUDIES. (Costa et al., 2008) They also studied switching costs analyzing the sequence of trials: Switching cost= C-I, I-C > C-C, I-I Monolinguals suffered a greater switching cost than bilinguals This result has been also obtained in children (Bialystok & Viswanathan, 2009) BrainGlot 2009 - Barcelona

  42. Study 2: Objective • To investigate neural basis of task switching in early and high proficient bilinguals and monolinguals. • No previous studies on this topic, but task swithcing has been associated with the RIFG, the striatum and the ACC (Robbins, 2007). BrainGlot 2009 - Barcelona

  43. Task switching • Participants • 19 Spanish/Catalan early bilinguals • - 11 bilinguals learnt one language at home and the other in kindergarten, and in 8 each father speaks a different language • High proficiency in both Spanish and Catalan. • All subjects were right-handed. • 21 Spanish monolinguals: students from monolingual regions just arrived to Castellon BrainGlot 2009 - Barcelona

  44. Task switching • Scanner: 1.5 T Siemens • Task: Subjects were asked to press one of two buttons according to a combination of geometrical pictures • CUES: SHAPE OR COLOR. Cues simultaneously presented to pictures. BrainGlot 2009 - Barcelona

  45. Task switching COLOR COLOR SHAPE SHAPE COLOR COLOR SHAPE SHAPE Index Button Thumb button BrainGlot 2009 - Barcelona

  46. Task switching • Conditions: • 60 Non switch trials: Color-Color or Shape-Shape • 60 Switch trials: Color-Shape or Shape-Color BrainGlot 2009 - Barcelona

  47. Behavioral results Switch costs: 32 ms for monolinguals and 4ms for bilinguals (p=0.051) BrainGlot 2009 - Barcelona

  48. Behavioral results Switch costs: 4% for monolinguals and 0% for bilinguals (p < .05) BrainGlot 2009 - Barcelona

  49. fMRI: Monolinguals Increased activity in the left AAC and right IFG

  50. fMRI: Bilinguals Increased activity in the LIFG BrainGlot 2009 - Barcelona

More Related