Does the representation of musical rules involve the same brain areas as that of linguistic rules ? Ani Patel, followed by Katz and Pesetsky, proposes two simple hypotheses. Firstly, the basic elements and organizational rules of music and language are distinct. We would therefore expect to observe the activation of specialized auditory regions for one and the other, as well as dissociations between language and music in neuropsychology. On the other hand, the execution of these syntactic rules calls on shared resources. This second hypothesis predicts that brain activation should partially overlap, especially in comparisons that isolate the syntactic level from musical or linguistic processing. It also suggests that there should be interference between language and music when the task requires a subject to process the syntax of both domains at the same time.
In the lecture, we saw that these predictions are fairly well verified. Very recent experiments, carried out on an individual scale, indeed show that within the auditory areas, distinct sectors are concerned with music and speech. Cases of aphasia without amusia, such as that of Moscow composer Vissarion Shebalin, confirm that the circuits are partly separable. However, when we look at the syntactic level, the similarity between music and language becomes more pronounced. In particular, the introduction of an inappropriate note or chord, which violates musical syntax, generates brain responses very similar to those evoked by a syntactic violation within a written or spoken sentence (ELAN wave, inferior frontal activation on functional MRI). There is thus a beginning of proof for the existence of syntactic structures in music, with more or less convincing parallels at two levels: the rhythmic structure of music would correspond to the prosody of language, while its harmonic structure would correspond to syntax. At higher spatial resolution, however, Ev Fedorenko's functional MRI work casts doubt on whether these are exactly the same regions.
