Summary
This article ties into the
debate regarding the similarity between linguistic and musical syntactic
processing. Neuroimaging studies of
language and music have revealed overlap in the brain’s response to difficult
syntactic integrations. This intuitively
makes sense considering both language and music combine discrete elements to
form hierarchically structured sequences such as sentences and chord
progressions. However, cases following
brain injury, of amusia without aphasia and aphasia without amusia, seem to indicate
dissociations between the two processes.
Patel proposes that language and music have distinct syntactic
representations where information is permanently stored, but they both draw on
a common pool of limited neural resources.
Therefore, injury to an area where language information is permanently
stored can lead to loss of speaking ability with music information retained;
however, Patel predicts that these individuals will exhibit parallel deficits
in both linguistic and musical syntactic processing.
Two
studies were completed. The first
examines linguistic and musical syntactic processing with linguistic semantic
processing also tested in order to check for a relationship between linguistic
semantic processing and musical syntactic processing. The aphasic individuals studied were all
native Dutch speakers who had suffered an ischaemic stroke in the left hemisphere
of the brain. They were given both a
linguistic and musical task. The
linguistic task consisted of 120 pre-recorded sentences, and the individuals
were asked if the sentences were correct.
Incorrect sentences either contained a violation between subject-verb
agreement between the first noun and the second verb or a semantic violation, for
example, “Anne scratched her name with her tomato
on the wooden door”. The musical task
consisted of 60 pop-style chord progressions.
Half contained an out-of-key chord, and the individuals were asked if
all tones belonged together. The aphasic
participants’ results were compared to that of a control group and showed a
musical syntactic deficit, not as large as the linguistic syntactic deficit but
still significant. Aphasics also
performed slightly worse on semantic
tasks.
The
second experiment further studied musical syntactic processing in aphasics
using harmonic priming. Harmonic priming
tests the influence of preceding harmonic context on the processing of chords. It occurs when there is a faster reaction
time to close verses distant chords in the circle of fifths. The test contained two distinct variables. Chords were presented either close or distant
in harmonic context, but some chords were in tune and others mistuned, with the
upper note of the triad being flat. The
results indicated aphasic participants failed to show a priming effect, meaning
that, while the control group responded faster when the chord was close in
harmonic context, aphasics did not. This
suggests that their responses were not driven by harmonic knowledge.
The
author recognizes that further research in this field is necessary and offers
suggestions for future research. He
recommends testing patrons with specific anterior lesion profiles,
experimenting with different linguistic syntactic operations, discovering which
kinds of linguistic tasks correlate with performance on musical syntactic tasks,
and discovering whether performance on musical tasks correlates with other
aspects of language comprehension besides syntax.
Response
Something I found really
interesting about this article is that, apparently, all reported cases of
aphasia without amusia involve professional musicians. Also, their ability to retain music
processing abilities after brain injury could be due to the fact that
professional musician’s brains differ from those of non-musicians. They have increased grey matter density in
the frontal regions. Therefore, in a
study like Patel’s, it is important that all participants be non musicians
which he indicated in his article. He
also makes note of how helpful it would be for localisationist techniques such
as fMRI to be applied to comparisons of syntactic processing in language and
music. Patel speculates that neural
resources for processing language and music reside in frontal brain regions and
representations where information is stored for more challenging processing
tasks are in the posterior regions, but this has not yet been proven. If we knew for certain where specific language
and music processing tasks take place in the brain, the relationship between
language and music would be much clearer.
This is also why it would be helpful to test individuals who have all
been injured in a very specific area of the brain. Patel predicted that aphasic individuals with
“compromised resource networks” from brain injuries would exhibit “parallel
deficits in linguistic and musical syntactic processing”; however, it appears
that the deficits in people with aphasia are greater in linguistic processing than
musical processing since they have more difficulty in processing sentence
structure than musical sequences. While
the abilities to process language and music likely do not suffer equally from
brain damage in aphasia, there is enough evidence to show a significant
decrease in musical processing ability compared to the control group. Therefore, I think that this is an
interesting field that deserves more attention.
Patel concedes that there are many cases of amusia without aphasia
reported, but how in depth have these studies been examined? It is surely possible that these individuals
with amusia have some sort of limitation in language processing that they may
not be fully aware of. This may or may
not have to do specifically with syntax in language which Patel recognizes in his
article. Information from further
investigation into these studies could reveal interesting insights into the
connection between language and music processing.
1 comment:
I found a few things in this article very interesting. For one thing, it is interesting for me that loss of musical syntactic processing can happen along with linguistic syntactic processing in certain lesions, since often music is used therapeutically to retrieve language after brain injury. Thus I assumed that amusia and aphasia would not occur together. However, I just read an article by Hartley, Turry and Raghavan that musical syntactic processing was shown by MEG to occur in Broca’s area. So this would make sense- that a left sided lesion would affect both. But then it is interesting, as you say, that no musicians have had amusia with aphasia. I suppose it is true that professional musicians process music differently than non-professionals.
Finally, I found the idea of testing linguistic semantic as well as syntactic processing in Brocas area neat. It seems that decoding where in the brain different speech capabilities occur is very relevant in knowing how certain lesions will affect an individual. It again emphasizes the complexity of the brain- how in just speech, there are so many areas involved in production and comprehension.
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