106 Stefan Koelsch studies showing that words with semantic low-cloze probability elicit an N400 com-pared to words with semantic high-cloze probability (e. g., Gunter et al., 2000).Of particular interest in that study were, however, not the main effects, but the interactions between these effects, because such interactions indicate that the under-lying processes are driven at least partly by shared underlying neural resources. That is, it was investigated whether the processing of irregular chord functions has any effects on the simultaneous processing of language-syntactic and language-se-mantic incongruities. It was found that music-syntactic and language-syntactic pro-cessing interacted with each other: When elicited on irregular chords, the amplitude of the LAN was reduced (compared to the LAN elicited on regular chords). This suggests that the processing of irregular chords interfered with the syntactic pro-cessing of words (see also Slevc et al., 2009; Fedorenko et al., 2009, for behavioural studies reporting interactions between syntactic processing of music and language). Importantly, the N400 response (elicited by the semantically less expected words) did not interact with the ERAN, indicating that music-syntactic analysis does not af -fect language-semantic processing. No N5 was elicited by the irregular chords in that study (Koelsch et al., 2005), therefore no potential interactions between the N5 and the N4 (nor between the N5 and the LAN) could be investigated. The absence of an N5 after the presentation of an irregular chord function was new, and presum-ably due to the task, in which participants were instructed to read the sentences and judge whether the sentences were correct (the chord functions were task-irrelevant). That is, under this instruction, and when participants process chords and words simultaneously, no N5 is elicited.To investigate potential interactions between N5 and N400, we conducted an-other study (Steinbeis & Koelsch, 2008b) that used the same experimental paradigm as the previous study (Koelsch et al., 2005) except that 12% of the chord sequences contained a timbre deviant (harpsichord instead of the regular piano). Participants were instructed to read the sentences, judge their correctness, and to detect the in-frequently occurring timbre deviants. Thus, participants had a task that was related to both the sentences and the musical sequences. With this task, the irregular chords elicited the N5 (in addition to the ERAN), which enabled us to study both ERAN and N5, as well as their possible interactions with the LAN and the N400 elicited by the words.Results replicated the previous nding of the interaction between ERAN and LAN (that is, the LAN was reduced when elicited on irregular compared to regular chords). Moreover, it was also found that the ERAN was smaller when elicited on syntactically incorrect words (compared to the ERAN elicited on syntactically cor-rect words, see Figure 4A). The fact that such an ERAN modulation was not ob-served in our previous study (Koelsch et al., 2005) was presumably related to the task, which required participants to pay attention to the chord sequences (for effects of attention on the ERAN see Koelsch, 2009)However, the interesting and most relevant nding with regard to the processing of musical meaning was that the N5 interacted with the N400 (i.e., with the semantic