Neural Correlates of Processing Syntax in Music and ... - PubMan

Experiment II 120
et al., 2007; even though it was not evaluated there). Somewhat puzzling is that the
difference should be apparent in both groups if it is elicited by processing acoustical
information. A likely explanation is an interaction of the amplitude of this early difference
with that of the ERAN. Both ERP components have a comparable scalp distribution
but different polarity. Thus, it is possible that in children that show an ERAN (i.e.,
the children with TLD) this early difference is reduced because it overlaps with the
onset of the ERAN. In contrast, in children with SLI (that do not show an ERAN) this
effect can be more clearly observed since the onset of the ERAN does not overlap with
it and reduces its amplitude size.
To account for this finding one may assume two processes that contribute to the processing
of the two chords (tonic and supertonic): a merely acoustical and a merely cognitive
process. These processes are thought to interact and to complement each other. In
the model of Koelsch and Siebel (2005) the acoustic process may be related to “Gestalt
formation” whereas the cognitive process may be related to “Structure building” (see
chapter “Music Perception” for an introduction to this model). It might be further assumed
that the acquisition of the music-syntactic regularities may influence the processing
of acoustical information.
The acoustical process may be based on the overlap of the frequency spectrum of the
actual chord (used to extract the pitch) and an echoic memory representation that contains
the integral of the frequency spectrum of the preceding chords. In contrast, the
cognitive process is assumed to rely on (mainly implicit) knowledge about Western
tonal music (e.g., regular progressions of chords): The succession of chords activate a
given key representation and give rise to expectations for further events, notably for
events that are harmonically related to the context. Children with SLI, who lack this
knowledge, may merely rely on acoustical information and therefore show this difference
in the time range around 100 ms.
When the acoustical process, which is based on the function of echoic memory is modelled
(see Figure 9-1D), the supertonic (grey line) is the more expected compared to the
tonic (black line) at the onset of the fifth chord. With regard to the cognitive process, the
dominant-tonic progression is one of the most basic syntactic structures of Western
tonal music, and a prominent marker for the end of a harmonic sequence. Thus, the
expectations of the chord to follow will depend on which kind of processing is the predominant
one: when relying on the acoustic process, the supertonic is the most expected
chord at the end of the sequence; when relying on the cognitive process, the most expected
chord is the tonic. Children with TLD did acquire knowledge of harmonic relationships
and key membership. Thus, they may rely primarily on the cognitive process,
easily integrate an incoming acoustic stimulus into the tonal context, and rely less on