Neuropsychologia 41 (2003) 1199–1207 Linguistic theory and neuroimaging evidence: an fMRI study of Broca’s area in lexical semantics Ralph-Axel Müller a,b,∗ , Natalia Kleinhans e , Eric Courchesne c,d a Department of Psychology, San Diego State University, MC 1863, San Diego, CA 92120, USA b Department of Cognitive Science, University of California, San Diego, CA 92093, USA c Department of Neurosciences, University of California, San Diego, CA 92093, USA d Laboratory for the Neuroscience of Autism, Children’s Hospital Research Center, La Jolla, CA 92037, USA e Joint Doctoral Program in Clinical Psychology, San Diego State University & University of California, San Diego, CA 92120, USA Received 18 July 2001; received in revised form 7 January 2003; accepted 7 January 2003 Abstract There has been a long debate on the functional characterization of left inferior frontal cortex, including proposals regarding syntactic and lexico-semantic involvement. We studied nine right-handed adults, using functional magnetic resonance imaging (fMRI) during performance on a semantic decision task in which subjects had to determine whether noun–verb pairs were semantically associated. In comparison with a visuoperceptual control task, activation clusters were seen in left inferior frontal and middle temporal regions, as well as the bilateral superior frontal gyrus. In agreement with previous studies, our findings suggest that Broca’s area is involved in semantic processing. Findings of lexico-semantic as well as syntactic processing in the inferior frontal lobe may be accounted for in terms of working memory demands. © 2003 Elsevier Science Ltd. All rights reserved. Keywords: Broca’s area; Inferior frontal lobe; Lexicon; Semantics; Working memory; Functional MRI 1. Introduction Following Chomsky’s seminal work in the late 1950s [1], linguistic theory underwent dramatic changes in the con- text of the emerging “cognitive sciences” [2,3]. Refuting behaviorist [4] as well as Piagetian [5] accounts, according to which language acquisition was based on general cog- nitive processes [6,7], Chomsky [8] claimed that syntactic rule systems were autonomous from those of other cogni- tive domains. Fodor [9,10] expanded on the Chomskian ap- proach by suggesting that this innately specified autonomy implied modularity also on the level of neural organization. Fodor’s hypothesis of neurally based modularity became one of the fundamental concepts characterizing the study of mind/brain in cognitive science [2]. Even though it is con- tentious to what extent the syntactic autonomy concept is compatible with neurobiological evidence [11,12], the idea of genetically prespecified and modular brain systems being specifically involved in syntactic processing continues to be considered [13–19]. ∗ Corresponding author. Tel.: +1-619-594-5276. E-mail address: amueller@sciences.sdsu.edu (R.-A. Müller). Traditionally, the “language areas” of Broca and Wer- nicke have been viewed in terms of primary involvement in expressive versus receptive language functions [20]. Even though this view seems grossly supported by lesion stud- ies demonstrating severe impairment of expressive speech in patients with left anterior perisylvian lesion and fluent but anomalous expressive language following posterior perisyl- vian injury [21,22], more recent studies suggest that links between lesion sites and symptom complexes are less sim- ple [23–25]. In particular, receptive deficits in decoding syn- tactically complex sentences have been observed in patients with damage in the left inferior frontal lobe [13,25–27]. This has led some investigators to relate Broca’s area to the modular concept of syntactic autonomy (e.g. [13,26,28,29]). For instance, Grodzinsky [30] has recently put forth radical claims pertaining to a modular specialization of Broca’s area in syntactic transformations and intrasentential dependency relations. Following the long tradition of Chomskian linguis- tics that views grammar as a ‘mental organ’, ultimately to be explained in neurobiological terms (e.g. [31]), Grodzinsky answers the question of “where ... human syntactic abili- ties reside” (p. 18; our italics) as follows: “There is a distinct and dedicated ‘language organ’ in the human left cerebral hemisphere (p. 20).” This language organ is Broca’s area, 0028-3932/03/$ – see front matter © 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0028-3932(03)00045-9