Neural Basis of Language
and Set Shifting in
Bilinguals
Cesar Avila, Gabriele Garbin, Ana Sanjuan, Cristina
Forn, Juan-Carlos Bustamante, Aina RodríguezPujadas, Mireia Hernández & Albert Costa
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
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GENERAL PURPOSE
At least for some kind of early and
high proficient bilinguals, language
and cognitive switching would share
similar neural mechanisms.
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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
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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.
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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)

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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.

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Language control in early
bilinguals
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NEURAL BASIS OF LANGUAGE
CONTROL
Proposed by Abulatebi and Green,
2007
LIFG (Broca’s
area) and RIFG:
task switching
and language
control
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Abutalebi (2008)
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Behavioral Studies in language control
Picture 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
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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
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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)
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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)
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Wang et al. (2007)
“English”
(200ms)
(2800 ms)
(200ms)
(2800 ms)
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Wang et al. (2007)
Forward switching
L1 to L2
Backward switching
L2 to L1
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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
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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
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Results I (Abutalebi et al., 2008)
Abutalebi et al., 2008
Naming L1 in dual vs single task: LIFG,
SMA
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Results II (Abutalebi et al., 2008)
Abutalebi et al., 2008
Naming L1 in bilingual vs monolingual task:
LIFG, RIFG, ACC, bilateral striatum
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Results III (Abutalebi et al., 2008)
Abutalebi et al., 2008
Naming L1 in bilingual vs dual task: LIFG,
RIFG, ACC and left striatum
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Results IV (Abutalebi et al., 2008)
Naming L2 vs L1 in bilingual context: LIFG,
RIFG, ACC and bilateral striatum
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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.

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Language control and lexical competition in bilinguals: an
event-related fMRI study (Abutalebi et al., 2008)
Participants
12 early bilinguals (6 females). L1: Italian; L2: French; AOA=
less than 3. More exposed to L2 than to L1
fMRI task
Passively listening four types of sentences:
1. Control: L1
2. Control: L2
3. Language switch from L1 to L2.
4. Language switch from L2 to L1.
Results I (Abutalebi et al., 2007)

Switch vs non-switching activated the
LIFG, RIFG and bilateral superior temporal
gyrus.
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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

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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

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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-
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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.
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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.
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Naming sequence
COMETA / MILOTXA, ESTEL
LAVADORA / RENTADORA
CERDO / PORC
MANZANA / POMA
OJO / ULL
PATO / ÀNEC
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Task
There were 240 trials:
-120 switch trials:
60 Spanish Catalan
60 Catalan  Spanish
-120 non-switch trials: 60 Spanish Spanish
60 Catalan Catalan
An examiner inside the scanner room registered
responses
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Behavioral results.
Omissions and commission errors
There were no significant
differences between
languages in omission
errors, but differences in
commission errors
reached significance (p <
.05)
Catalan
Spanish
%
Percentage of errors was
low.
5
4
3
2
1
0
Omissions
Commissions
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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).
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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 nonswitching (red cluster) and of
backward switching (from L2 to
L1) relative to L1 non-switching
(blue cluster).
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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

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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.
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Cognitive control in early
bilinguals
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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
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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
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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)
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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).
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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
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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.
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Task switching
COLOR
COLOR
SHAPE
Thumb
button
SHAPE
SHAPE
SHAPE
COLOR
COLOR
Index
Button
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Task switching
Conditions:
-60 Non switch trials: Color-Color
or Shape-Shape
-60 Switch trials: Color-Shape or
Shape-Color
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Behavioral results
Switch costs: 32 ms for monolinguals and 4ms for bilinguals (p=0.051)
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Behavioral results
Switch costs: 4% for monolinguals and 0% for bilinguals (p < .05)
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fMRI: Monolinguals
Increased activity in the left AAC and right IFG
fMRI: Bilinguals
Increased activity in the LIFG
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fMRI: Bilinguals vs. Monolinguals
•Bilinguals> Monolinguals: Increased activation in the left
inferior frontal gyrus (IFG) (blue cluster).
•Monolinguals> Bilinguals: Increased activation in the right IFG
(red cluster).
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Performance correlates in bilinguals
Lower switching costs Stronger activity in language control
areas (striatum and LIFG)
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Performance correlates in bilinguals
Higher switching costs Stronger activity in task switching areas
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Conclusions
- Monolinguals have shown significant switching costs and neural
activity in brain areas typically related to task switching: RIFG
and ACC.
-Bilinguals have shown no switching costs and a neural activity in
brain areas typically related to language control: LIFG
-Bilinguals seem to be an heterogeneous group: those with lower
switching costs activate the language control network (LIFG and
striatum), whereas those with higher switching costs activate as
monolinguals the rIFG.
The present results are consistent with the hypothesis that
bilinguals' early training in mixing languages leads to the
involvement of language control brain areas when performing
non-linguistic cognitive tasks.
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General Conclusions

Language swtiching in bilinguals activates
brain areas involved in language control:
LIFG, RIFG, striatum and ACC.


Language
related to
Language
related to
control in early bilinguals is more
the striatum
control in late bilinguals is more
ACC.
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General Conclusions
Set-switching in monolinguals is related to
rIFG.
 Set-switching in early, high proficient
bilinguals is related to the language
control network: LIFG and the striatum.
 Early and high proficient bilinguals may
overlap brain areas involved the language
and cognitive switching
 Future studies should serve to delimitate
which factor or factors are responsible for
these effects

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Thank You very much....
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Neural Basis of lan