functional brain imaging and native language

[gusl]

Around here, fMRI studies usually require subjects to be native English speakers, meaning they were immersed in it when no older than ~5 years old, regardless of their current level of fluency.

Clearly, the purpose is to eliminate an irrelevant source of variation (assuming the study is not about the effects of native-language). But why filter by native-language, rather than other cognitively relevant dimensions?

How can native-language affect the results of functional brain imaging studies? Is it because:

(1) non-native speakers, regardless of how well they perform on language tests, are never quite as fluent as native speakers, and wouldn't understand the instructions as well (or as quickly)

(2a) non-native speakers use a different part of the brain when interpreting spoken English (i.e. they use a "foreign-language region", rather than the "native-language region")

(2b) each language uses different physical regions in the brain (e.g. "Portuguese is a rather dorsolateral language")

(3) people raised in different languages will tend to perform the same tasks differently, i.e., even if you translated all instructions into the subject's native language, they would have a different way of performing them.

?

Comments

[afanesvoltaje.livejournal.com]

I've always assumed it was some 2a-ish type concern.

It fits with the observations that strokes can, for example, pretty much wipe out a person's native language while leaving a well-used second language totally intact.

[gustavolacerda.livejournal.com]

that sounds fascinating.

[gustavolacerda.livejournal.com]

e.g. L1 = Galician (Galego), L2 = Spanish: here

[bhudson.livejournal.com]

I'm pretty sure I've heard of fMRI studies that directly looked at this, from a few years back.

[qatar.livejournal.com]

I once knew someone who used to have seizures, during which he could only speak in his native language. He could understand his acquired language, and thought he was replying in it, but what came out was his native language. A quick Google search on seizures in bilingual people suggests this is not uncommon.

But I'm still not sure why they'd choose to control that variable and not others.

[(Anonymous)]

Isn't the answer that they usually do control for other variables, for instance handedness, age, education level, absence of neurological damage and psychiatric conditions, etc, etc.

Andy

[gustavolacerda.livejournal.com]

Andy Fugard?

Perhaps they do. I guess I didn't notice the other restrictions.

[(Anonymous)]

Yeah it is I :-) I should open another account so I can post here (I deleted my previous account).

http://garry.honey.googlepages.com/Corlett-Brain-2007.pdf

There's an example I found just now. Check out around the middle of the second paragraph of the Subjects bit in the Experimental procedure.

Andy

tangentially related to (2b)

[gustavolacerda.livejournal.com]

R. Salmelin et al - Native language, gender, and functional organization of the auditory cortex

<< Activations elicited by the tones
were mutually indistinguishable in German and Finnish
women. In contrast, German men showed significantly stronger
auditory responses to pure tones in the left, languagedominant
hemisphere than Finnish men. We discuss the
possibility that the prominent left-hemisphere activation in
German males reflects higher frequency resolution required
for, distinguishing between German than Finnish vowels and
that the clear effect of native language in male but not in
female auditory cortex derives from more pronounced functional
lateralization in men. The present data suggest that the
influence of native language can extend to auditory cortical
processing of pure-tone stimuli with no linguistic content and
that this effect is conspicuous in the male brain. >>

<< In conclusion, the present data illustrate that responses to
pure tones in the human left auditory cortex vary with native
language. This effect appears to be stronger in male than
female subjects, probably because of more pronounced functional
lateralization in the male brain. >>