Bach Speaks: A Cortical ���Language-Network��� Serves the Processing of Music Stefan Koelsch,*,���,1 Thomas C. Gunter,* D. Yves v. Cramon,* Stefan Zysset,* Gabriele Lohmann,* and Angela D. Friederici* *Max Planck Institute of Cognitive Neuroscience, Leipzig, Germany and ���Department of Neurology, Harvard Medical School, 330 Brookline Avenue, Boston, Massachusetts 02215 Received October 30, 2000 The aim of the present study was the investigation of neural correlates of music processing with fMRI. Chord sequences were presented to the participants, infrequently containing unexpected musical events. These events activated the areas of Broca and Wer- nicke, the superior temporal sulcus, Heschl���s gyrus, both planum polare and planum temporale, as well as the anterior superior insular cortices. Some of these brain structures have previously been shown to be involved in music processing, but the cortical network comprising all these structures has up to now been thought to be domain-specific for language processing. To what extent this network might also be activated by the processing of non-linguistic information has remained unknown. The present fMRI-data reveal that the human brain employs this neuronal network also for the processing of musical information, sug- gesting that the cortical network known to support language processing is less domain-specific than pre- viously believed. �� 2002 Elsevier Science (USA) Key Words: brain music language fMRI Broca Wer- nicke superior temporal sulcus superior temporal gy- rus insular cortex modulation. INTRODUCTION In recent ERP-studies, brain responses reflecting the processing of musical chord-sequences were similar, although not identical, to brain activity elicited during the perception of language, in both musicians (Patel et al., 1998 Koelsch et al., in press) and nonmusicians (Koelsch et al., 2000a, 2001, 2002). While relatively early (around 180���350 ms) electrical brain responses to unexpected items in a structured sequence were often lateralized to the left when processing language (Friederici et al., 1993 Hahne and Friederici, 1999), they were often lateralized to the right when process- ing music (Patel et al., 1998 Koelsch et al., 2000a). The early brain responses (maximal around 200���350 ms) elicited by violations of musical regualrities were taken to reflect the processing of music-syntactic information (Patel et al., 1998 Koelsch et al., 2000a). Later brain responses (maximal around 500���550 ms) were hypoth- esized to reflect the processing of meaning information in music (Koelsch et al., 2000a). In a recent MEG study, early brain responses hy- pothesized to reflect music-syntactic processing were localized in Broca���s area and its right homologue (Koelsch et al., 2000b Maess et al., 2001), areas known to be involved in syntactic language processing (Just et al., 1996 Dapretto and Bookheimer, 1999 Friederici et al., 2000b Meyer et al., 2000b). In that MEG study, however, the neural generators of later brain responses found with EEG could not be localized, raising the question which other areas in the brain might be in- volved in the processing of music, and whether there is further overlap of brain structures involved in the pro- cessing of music with brain structures known to be involved in the processing of language. Recent brain imaging studies on language process- ing (with auditory stimulation) have shown that tem- poral and frontal areas of both hemisperes are involved in the processing of connected speech, with a prepon- derance of the left hemisphere for the on-line process- ing of syntactic features (Friederici et al., 2000a) and a preponderance of the right hemisphere for the on-line processing of prosody (for example, melody and metre of speech Meyer et al., 2000a). The involvement of areas known to be involved in the processing of language has been shown for music pro- cessing, although only for melodies, i.e., one-part stim- uli (e.g., Peretz et al., 1994), and only for single areas located either in temporal areas (e.g., Liegeois-Chauvel et al., 1998), or located in frontal areas (e.g., Zatorre et al., 1992). Interactions between frontal and temporal cortices (but excluding Wernicke���s area) and frontal cortices have been reported for working memory of tonal pitch (Zatorre et al., 1994). Especially the supe- 1 To whom correspondence and reprint requests should be ad- dressed. Fax: 617-667-8695. E-mail: mail@stefan-koelsch.de. NeuroImage 17, 956���966 (2002) doi:10.1006/nimg.2002.1154 956 1053-8119/02 $35.00 �� 2002 Elsevier Science (USA) All rights reserved.

rior temporal gyrus (STG, Zatorre, 1984 Peretz, 1990 Platel et al., 1997 Liegeois-Chauvel et al., 1998 Zatorre et al., 1992) and the anterior portion of the right hemisphere, presumably including the right fron- tal lobe (Shapiro et al., 1981 Grossman et al., 1981) have been shown to be involved in music processing. However, up to now the network comprising the areas of both Broca and Wernicke has not been shown to be involved in music processing. This may partly be due to the fact that previous studies merely employed one- part stimuli (in contrast to Western tonal music, which is mostly multipart for an imaging study investigating emotional responses to music with multi-part music see Blood et al., 1999). In the present study, the experimental protocol was similar to previous EEG- and MEG-studies (Koelsch et al., 2000a, 2001, 2002 Maess et al., 2001): Chord- sequences (i.e., multipart stimuli) were presented to nonmusicians, each sequence consisting of five chords (Fig. 1). One sequence directly followed the other, sounding like a musical piece. Most of the sequences were played by a piano and consisted of expected in-key chords only (left of Fig. 1). These sequences were com- posed in a way that a musical context was built up toward the end of each sequence, similar to the buildup of semantic context in a sentence (Krumhansl and Kessler, 1982 Koelsch et al., 2000a). During such a sequence, a strong expectancy for harmonically related chords is generated in the brains of listeners (Patel et al., 1998 Krumhansl and Kessler, 1982 Bharucha and Krumhansl, 1983 Bigand and Pineau, 1997 Tillmann et al., 2000 Koelsch et al., 2000a). Infrequently, in some of the chord-sequences the tonal key was moved to another key (right of Fig. 1). Such a move is, in musical terms, denoted modulation and a very prominent stylistic feature of Western tonal music. Modulating chords were all perfectly consonant and harmonic, but they contained out-of-key notes (with respect to the preceding harmonic context) and were harmonically less related to the preceding har- monic context (e.g., in the sense of the circle of fifths see Schonberg, �� 1969 Krumhansl and Kessler, 1982 Bharucha and Krumhansl, 1983 Patel et al., 1998). Since harmonically less related chords are perceived as more unexpected, modulating chords were perceived as more unexpected compared to the in-key chords (cf. Krumhansl and Kessler, 1982). Within a modulating chord sequence, a detection of a modulation could only be performed by the application of (implicit) knowledge about music-theoretical principles of harmonic dis- tance and relatedness. These principles constitute the major-minor tonal system, i.e. the system of Western tonal music. Moreover, some chord-sequences were not termi- nated by an expected in-key chord, but by a dissonant tone-cluster (middle of Fig. 1). In contrast to chords, these clusters had a highly dissonant, i.e. non-har- monic interval-structure. In addition, clusters con- tained out-of-key notes (like modulations), and were hence harmonically unrelated to the preceding har- monic context. That is, clusters violated musical ex- pectancies of listeners to a higher degree than modu- lations and were, thus, more salient than modulations. Finally, in some sequences one or two in-key chords were played by an instrument other than piano (e.g., electric guitar, trumpet, organ). Participants were asked to detect sequences with clusters or deviant in- struments, but instructed to respond behaviorally only to the deviant instruments (see Methods). METHODS Subjects. Ten nonmusicians participated in the ex- periment (20 ���29 years of age, 5 females). None of them had any special musical expertise or education, no subject had learned an instrument or had singing les- sons. All subjects were right-handed and had normal- hearing. Stimuli. A pool of stimuli consisted of 34 different chord-sequences (each sequence consisted of five chords). The first chord was always the tonic of the following chord-sequence. Chords at the second posi- tion were tonic, dominant, mediant, submediant, sub- dominant. Chords at the third position were subdomi- nant, subdominant with sixte ajoutee, �� dominant, dominant six-four chord, dominant seventh chord, and at the fourth position dominant seventh. Chords at the fifth position were tonic or cluster. Clusters consisted (with respect to the tonic) either of minor sixth, major sixth, and minor seventh, or of minor second, major second, and minor third. In modulating sequences, dominant chords at the second position were subdomi- FIG. 1. Experimental paradigm. Top: examples of chord-se- quences consisting of in-key chords only (left), terminated by a tone- cluster (middle), and modulating (in the example from C major to D major, right). All sequence-types consisted of five chords and were presented in blocks comprising two to seven sequences of each type (middle row, in the example six in-key sequences are followed by four cluster sequences, etc.). All chords of these sequence-types were played on a piano. Each sequence had a duration of ca. 3.5 s, se- quences were presented one directly succeeding the other. Three functional images of nine slices each were continuously acquired per sequence (i.e., one image per bar, bottom row, each vertical line indicates one image). Subjects had to differentiate between in-key chords, clusters, and chords played by instruments deviating from piano (not depictured in this figure). 957 CORTICAL PROCESSING OF MUSIC