FUNCTIONAL magnetic resonance imaging (fMRI) was used to compare the c
erebral organization during sentence processing in English and in Amer
ican sign language (ASL). Classical language areas within the left hem
isphere were recruited by both English in native speakers and ASL in n
ative signers. This suggests a bias of the left hemisphere to process
natural languages independently of the modality through which language
is perceived. Furthermore, in contrast to English, ASL strongly recru
ited right hemisphere structures. This was true irrespective of whethe
r the native signers were deaf or hearing. Thus, the specific processi
ng requirements of the language also in part determine the organizatio
n of the language systems of the brain. (C) 1998 Rapid Science Ltd.