1. Crinion et al. (2006) Amanda Lee PSYC 260

2.  Introduction  Method  Results  Discussion  Thoughts: Strengths and Limitations  Summary

3.  Multilingualism is a valuable asset and becoming more widespread  How does the bilingual brain use and process different languages?  Previous studies: both languages that a bilingual individual speaks activate the same brain areas:  Frontal, temporal and parietal regions

4.  No specific areas determined for multilingualism  Left anterior temporal region highlighted in past research  Not confirmed to be responsible  Objective: identify language-dependent neuronal mechanisms to be tested on a semantic level

5.  Hypothesis: reduced activation in the left anterior temporal region when two semantically similar words are presented compared to a dissimilar pair.  Eg: trout-SALMON = less activation than trout-HORSE  Semantic priming effect  Both words in the pair also tested in different languages  Language-independent  neuronal responses the same throughout brain ▪ i.e. trout-SALMON = less activation regardless of language ▪ Only semantics affect brain activation  Language-dependent  different neuronal responses based on both semantics and language of target word

6.  Group 1: 11 German-English bilinguals  PET  Group 2: 14 German-English bilinguals fMRI  Group 3: 10 Japanese-English bilinguals

7.  1750 ms long period  250 ms to view prime word  Semantic decision based on physical characteristic  Baseline brain activation = deciding whether or not non- literary symbols were the same  Independent variables: congruency of the prime and target words in semantic relation and language  Dependent variables: Response time (s), accuracy (%), brain activation

8.  All 3 groups: brain activation in frontal, temporal, parietal regions and visual cortices  Semantic priming evident in all cases  Response time for semantically related words (S) was 41 ms faster than unrelated words (U)

9.  Reduced activation in left ventral anterior temporal lobe for semantically related word pairs  Same effect for both languages  Neural response only changed with semantic content (A) German-English fMRI. (B) Japanese-English fMRI. (C) German-English PET

10.  Reduced activation in left caudate nucleus for semantically related words  Only if the prime and target words were the same language  Change accompanies language and semantics

11.  Anterior temporal lobe  language-independent  Left caudate nucleus  language-dependent  Works to extract the same semantic meaning from two different terms and make them equivalent

12.  Possible neural mechanism of left caudate:  Same neurons respond to both languages  Increased neuronal firing when language input changes  Helps us modify output and use appropriate language

13.  Damaged left caudate nucleus:  Impairs ability to respond to input change  Language production affected  switch languages inappropriately  Support for hypothesis and idea of general language- dependent structure  Not left anterior temporal lobe as thought  Left caudate projects to frontal, temporal, parietal lobes  thalamus  motor sequences for articulation

14.  Test wider variety of languages that are also more different from English  Tonal languages, different phonetics  Arrive at universal conclusion for language  Other aspects of language  Syntax, pragmatics, etc.  Study the left caudate  How does it connect to other brain structures to create a mechanism responsible for multilingualism?

15.  Strengths:  Thorough discussion on possible neuronal mechanisms for left caudate nucleus  Pinpointed specific structure and examined entire brain  Limitations  Not well laid out: data all in figure captions  Lack of detail  difficult to replicate experiment  Confusing 2 x 2 x 2 design: hard to track dependent variable  Ability to generalize results is questionable

16.  Left anterior temporal lobe is language-independent  only responds to semantic meaning  Left caudate nucleus plays a critical role in language control  activates upon change in semantic/language input  is the language-dependent mechanism for monitoring language  Future studies could test the proposed mechanism: left caudate and surrounding areas  broaden scope of languages tested to come to universal conclusion

17.  Crinion, J., Turner, R., Grogan, A., Hanakawa, T., Noppeney, U., Devlin, J.T., Aso, T., Urayama, S., Stockton, K., Usui, K., Green, D.W., Price, C.J. (2006). Language control in the bilingual brain. Science, 312 (5779), 1537-1540.

18. Questions?