Rick and other Wonderful TIPSters who may be interested,
"My question:
Is there any evidence that a second language (in this case, learned
during adulthood) may be associated with activity in the right
hemisphere when the native language is associated with activity in the
left hemisphere?"
Yes ! Based on the data, however, one would look for more right frontal
damage than right parietal. . .
About to start writing a section on Neuropsychology of Language next week, so
I thought I'd address your question. I have not completed an updated
literature search, however, the following recent abstracts are consistent
with my understanding from previous reading: Note that time of acquisition is
likely an important factor affecting the cerebral distribution of 2nd
language function. . . I recall that this relationship holds true as well for
the evoked/event-related potential data. In addition, the neurophysiology
data suggest a gender difference in the distribution of second language
function which may account for the variability in the first study below. I
have to get the original paper to look into this.
Neuroreport 1997 Dec 1;8(17):3809-15
Anatomical variability in the cortical representation of first and second
language.
Dehaene S, Dupoux E, Mehler J, Cohen L, Paulesu E, Perani D, van de Moortele
PF, Lehericy S, Le Bihan D
Laboratoire de Sciences Cognitives et Psycholinguistique, EHESS/CNRS URA
1198, Paris, France.
Functional magnetic resonance imaging was used to assess inter-subject
variability in the cortical representation of language comprehension
processes. Moderately fluent French-English bilinguals were scanned while
they listened to stories in their first language (L1 = French) or in a second
language (L2 = English) acquired at school after the age of seven. In all
subjects, listening to L1 always activated a similar set of areas in the left
temporal lobe, clustered along the left superior temporal sulcus. Listening
to L2, however, activated a highly variable network of left and right
temporal and frontal areas, sometimes restricted only to right-hemispheric
regions. These results support the hypothesis that first language acquisition
relies on a dedicated left-hemispheric cerebral network, while late second
language acquisition is not necessarily associated with a reproducible
biological substrate. The postulated contribution of the right hemisphere to
L2 comprehension is found to hold only on average, individual subjects
varying from complete right lateralization to standard left lateralization
for L2.
Nature 1997 Jul 10;388(6638):171-4
Distinct cortical areas associated with native and second languages.
Kim KH, Relkin NR, Lee KM, Hirsch J
Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York,
New York 10021, USA.
The ability to acquire and use several languages selectively is a unique and
essential human capacity. Here we investigate the fundamental question of how
multiple languages are represented in a human brain. We applied functional
magnetic resonance imaging (fMRI) to determine the spatial relationship
between native and second languages in the human cortex, and show that within
the frontal-lobe language-sensitive regions (Broca's area), second languages
acquired in adulthood ('late' bilingual subjects) are spatially separated
from native languages. However, when acquired during the early language
acquisition stage of development ('early' bilingual subjects), native and
second languages tend to be represented in common frontal cortical areas. In
both late and early bilingual subjects, the temporal-lobe language-sensitive
regions (Wernicke's area) also show effectively little or no separation of
activity based on the age of language acquisition. This discovery of
language-specific regions in Broca's area advances our understanding of the
cortical representation that underlies multiple language functions.
Hope this helps,
Sandra Nagel Randall
in Michigan
<A HREF="http://members.aol.com/snrandall">Sandra Nagel Randall - Curriculum
Vitae</A>
p.s. glad to learn that your text is soon to be published. Is this the one
with an applied slant ??
