of Language Areas J1.Neurosci,.January1.1997.17353-362359 although important for auditory processing,is not the primary sinclude.but may not be limited to,the angular gyrus,MTG prefrontal cortex Frontal lobe lang areas Language compreher ion and We nicke's area e (Mohr.1976:1978 che transient anctering Brocaphasia coust et al.,1987).The aerleoalhesioasentrehyoideBoeareaintdg 97 te 1 Lin by the material. are typi large lesio is of language cortex in several prefro ontal regions outside Selnes etal 1984:Damasio,1989 Metter et al left fre sing isa 90).1 mate (t 994:Fie Henschen -192:Nielsen, e of th s is the nature of the lingustic distur in the medial fro ntal lobe (Wise et al 1991:Ra chle et al1994 may affe ony a particula cat as tha wledge or selective anis m related to these e cat- ontal gyru s a res 1984Ha (Warrington 是 from 1991;Damas Tranel,1993:I nasio ctal,19961. the left al lob orm gyrus 59 thers left frontal activation during receptiv a et)Finally.man ron onstrate th ing in left te and ITG(Frithe 1991:Demonet a g a1996 Price et al.. 1996:Warburton et al 1996). The location of lef be c outcome given the diversity of language tasks used by the differen In summary.converging evidence from and functiona egies.After left frontal injury,it is p ha eft STC Cdinting functions are taken over by other igg tontoparietalcate the need for at least some revision to this classical model. These converging sources all suggest that (1) Wernicke’s area, although important for auditory processing, is not the primary location where language comprehension occurs; (2) language comprehension involves several left temporoparietal regions out￾side Wernicke’s area, as well as the left frontal lobe; and (3) the frontal areas involved in language extend well beyond the tradi￾tional Broca’s area to include much of the lateral and medial prefrontal cortex. Language comprehension and Wernicke’s area Isolated damage to the left STG (Wernicke’s area) probably does not produce multimodal language comprehension deficits (Hen￾schen, 1920 –1922). STG lesions, even when fairly extensive and involving adjacent MTG, result instead in the syndrome of pure word deafness, in which there is a defect in decoding the complex acoustic signals in speech but preserved comprehension of lan￾guage at a semantic level (Barrett, 1910; Henschen, 1918 –1919; Kanshepolsky et al., 1973; Tanaka et al., 1987). These observa￾tions are consonant with functional imaging data, which demon￾strate that the STG is activated bilaterally by both speech and complex nonspeech sounds, and that this activation is modulated neither by the semantic content (“meaningfulness”) of stimuli nor by the type of cognitive task performed by the subject (Wise et al., 1991; Binder et al., 1994a,b, 1996a; Millen et al., 1995). In contrast, multimodal comprehension disturbances, involving both auditory and visual material, are typically associated with large lesions extending beyond the STG and including the MTG, angular, and supramarginal gyri (Kertesz et al., 1979, 1993; Nae￾ser et al., 1981; Selnes et al., 1984; Damasio, 1989; Metter et al., 1990). Isolated angular gyrus lesions are well known to produce language deficits, particularly for written material (Dejerine, 1892; Marie, 1917; Henschen, 1920 –1922; Nielsen, 1946; Penfield and Roberts, 1959; Geschwind, 1965). An increasing number of imaging studies confirm that isolated lesions of the left MTG and ITG produce multimodal comprehension deficits (Damasio, 1981; Kertesz et al., 1982; Alexander et al., 1989). A striking feature of some of these cases is the selective nature of the linguistic distur￾bance, which may affect only a particular lexical–semantic cate￾gory or word class, leading to the hypothesis that it is the stored knowledge or selective retrieval mechanism related to these cat￾egories or classes that is lost as a result of the lesion (Warrington and Shallice, 1984; Hart and Gordon, 1990; Hillis and Caramazza, 1991; Damasio and Tranel, 1993; Damasio et al., 1996). Data obtained from invasive electrophysiology also confirm the existence of language areas in the lateral and ventral left temporal lobe, including the fusiform gyrus (Penfield and Roberts, 1959; Ojemann et al., 1989; Lu¨ders et al., 1991; Hart et al., 1992; Nobre et al., 1994). Finally, many positron emission tomographic (PET) studies demonstrate activation associated with language process￾ing in left temporoparietal regions outside the STG, including the angular gyrus, MTG, and ITG (Frith et al., 1991; De´monet et al., 1992; Howard et al., 1992; Bottini et al., 1994; Raichle et al., 1994; Bookheimer et al., 1995; Damasio et al., 1996; Fiez et al., 1996; Price et al., 1996; Warburton et al., 1996). The location of left temporoparietal activations in these various reports agrees quite closely with the results of the present study, a somewhat surprising outcome given the diversity of language tasks used by the different investigators. In summary, converging evidence from lesion and functional imaging research suggests that the left STG plays an important role in analyzing speech sounds. However, this region has been somewhat overemphasized in traditional neuroanatomical models of language processing to the exclusion of large temporoparietal regions in the left hemisphere that probably play a more impor￾tant role in comprehension at a linguistic–semantic level. These areas include, but may not be limited to, the angular gyrus, MTG, ITG, and fusiform gyrus (approximately Brodmann areas 39, 21, 20, 37, and 36). Frontal lobe language areas Lesions confined to Broca’s area (i.e., the posterior left IFG, variously including the pars opercularis, pars triangularis, or both) typically cause apraxic deficits of articulation, with, at most, a transient disturbance of language (Mohr, 1976; Mohr et al., 1978). In contrast, the linguistic deficits characterizing Broca’s aphasia are associated with much larger lesions, usually involving the anterior IFG, middle frontal gyrus, insula, ventral pre- and post￾central gyri, or anterior parietal areas in addition to Broca’s area (Mohr, 1976; Mohr et al., 1978). Aphasic disorders also occur after left frontal lesions entirely outside Broca’s area, in dorsolat￾eral prefrontal cortex and in the superior frontal gyrus (Rubens, 1976; Freedman et al., 1984; Rapcsak and Rubens, 1994). Lin￾guistic deficits reported in such patients include impaired com￾prehension for syntactically complex material, agrammatism, ver￾bal paraphasia, inability to formulate narrative discourse, and a striking inability to generate word lists (Rubens, 1976; Alexander and Schmitt, 1980; Freedman et al., 1984; Stuss and Benson, 1986; Costello and Warrington, 1989). Together, these data indicate the existence of language cortex in several prefrontal regions outside Broca’s area. Extensive left frontal activation during language processing is a frequent finding in PET research (Frith et al., 1991; Wise et al., 1991; De´monet et al., 1992; Raichle et al., 1994; Fiez et al., 1996; Price et al., 1996). Activation involving all three frontal gyri and anterior cingulate, similar to our results, was noted in a few instances (Bottini et al., 1994; Bookheimer et al., 1995; Warburton et al., 1996), whereas other studies showed IFG activation extend￾ing into the posterior middle frontal gyrus, with a separate focus in the medial frontal lobe (Wise et al., 1991; Raichle et al., 1994; Price et al., 1996). A striking finding in the present study was that although language activation involved much of the left prefrontal cortex, a large region in the center of the middle frontal gyrus (approximately Brodmann area 9) was not activated, suggesting that this area has functions clearly distinct from those of other prefrontal areas. Although the left frontal lobe is traditionally understood as having “expressive” or “output” functions, our study and several others demonstrated left frontal activation during receptive lan￾guage tasks with little or no requirement for speech production (De´monet et al., 1992; Bottini et al., 1994; Price et al., 1996). The classical view of frontal lobe language function arose from lesion studies, most of which were conducted well after the acute illness and were intended to reveal the areas “critical” for a given function. Functional imaging techniques, in contrast, do not dis￾tinguish critical areas from those that participate in a function but can be compensated by other areas. Left frontal regions may participate in receptive language processing in the normal, unin￾jured state, playing a “language executive” role in coordinating the sensory and semantic processes occurring in posterior areas and accommodating moment-by-moment shifts in goals and strat￾egies. After left frontal injury, it is possible that many of these coordinating functions are taken over by other areas. This would explain the observation that patients with large left frontoparietal Binder et al. • FMRI of Language Areas J. Neurosci., January 1, 1997, 17(1):353–362 359