EDITORIAL

Introduction to the Special Issue on FunctionalBrain Imaging of Language

Li Hai Tan,1* Jia-Hong Gao,2 and Peter T. Fox2

1Joint Laboratories for Language and Cognitive Neuroscience, University of Hong Kong, Hong Kong2Research Imaging Center, University of Texas Health Science Center, San Antonio, Texas

Language is one of the most significant and immenseaspects of human evolution. Not surprisingly, it has beena research topic of scientists working in many disci-plines. Numerous questions have been raised from thisimportant research: Why is language so quickly acquiredby children living in very different cultures with verydifferent languages? How does the human brain pro-duce and comprehend language? How is second-lan-guage learning influenced by the native language? Is theneural network that mediates language processing uni-versal across languages? For years, scientists have at-tempted to answer these questions.

With the advent of new technology, such aspositron emission tomography (PET) and functionalmagnetic resonance imaging (fMRI), the past decadehas seen an extremely rapid expansion of researchon the aforementioned issues. Such technical ad-vances have given researchers great power to visu-alize the activity of the intact human brain that isassociated with language processing and languagelearning, and have consequently made significantcontributions to the vast amount of discoveries inbrain research.

Whilst imaging technologies are improving everyyear, because language processing demands higher-order cognition, its neuro-cognitive mechanisms arevery complex and much research remains to bedone. Cross-linguistic studies provide a powerfulcontrast to elucidate the universality and specificityof the neural basis of language. Although the directsubtraction of the processing of the native languagein one population (Language A) from the processingin another population (Language B) might seem likean interesting comparison, cognitive and psycholin-guistic research has established that even at thelexical level, cognitive processing involves dozensof variables, such as visual and auditory complex-ity, spelling–sound regularity, word frequency,word familiarity, and age of acquisition. Thus, inbrain mapping research, direct subtraction of twodifferent populations may include a confounding oflinguistic variables in two different languages, andthese variables are often un-confoundable. For ex-ample, it might be possible to find seemingly iden-tical words in two different languages (“banana” isbanana in English and banana in Italian). However,the processing might be quite different due to manyfactors such as syllable structure (banana has amuch more typical structure in Italian than in En-glish), how common the spelling–sound relation-ships are (because far fewer spelling–sound rela-tionships exist in Italian than in English, they aremuch more frequent), how consistent the spelling–sound relationships are (graphemes in English often

*Correspondence to: Li Hai Tan, PhD, Joint Laboratories for Lan-guage and Cognitive Neuroscience, 3A, 2 University Drive, Univer-sity of Hong Kong, Hong Kong. E-mail: tanlh@hkucc.hku.hkDOI 10.1002/hbm.10087

� Human Brain Mapping 18:147–148(2003) �

© 2003 Wiley-Liss, Inc.

map onto many different sounds but in Italian theytypically do not), and so on. A better understanding ofthe generality and specificity of neural mechanisms as-sociated with language should build on knowledge andconclusions from research on individual languages,rather than from a direct subtraction approach. A num-ber of studies in this special issue show how cross-language research can lead to important insights.

This special issue emerged from a research sympo-sium in April 2002 at the University of Hong Kong, in

which we as co-organizers invited researchers who werevery active in the fields of cognitive neuroscience, cog-nitive psychology, and linguistics to present their func-tional brain imaging findings. These pages feature con-trastive studies of Chinese and English, two languagesthat differ markedly in almost every aspect: phonology,orthography, semantics, and syntax. We hope that ourreaders will learn from these new findings, and will beinspired to further such research with their own partic-ular knowledge and skills.

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