doctoralThesis
Aspectos comportamentais e eletrofisiológicos da percepção de alturas sonoras: um estudo sobre o ouvido absoluto
Fecha
2017-02-23Registro en:
LEITE, Raphael Bender Chagas. Aspectos comportamentais e eletrofisiológicos da percepção de alturas sonoras: um estudo sobre o ouvido absoluto. 2017. 148f. Tese (Doutorado em Neurociências) - Universidade Federal do Rio Grande do Norte, Universidade Federal do Rio Grande do Norte, Natal, 2017.
Autor
Leite, Raphael Bender Chagas
Resumen
In humans, the processing of sound information allowed the appearance of speech and music.
The pitch - which allows the melody of a song and prosody in spoken discourse - is one of
these attributes. Pitch perception is a universal skill, however, just a few individuals are able
to identify or produce a tone at a particular pitch without an external tonal reference, an ability
known as the Absolute Pitch (AP). However, the neural mechanisms responsible for such
ability are not yet fully understood. The present work has the objective to contribute to the
understanding of the neural processes involved in the perception of pitch in AP possessors. In
the first study, we evaluated AP prevalence in a local population of musicians (School of
Music, UFRN). For this, we used psychophysical tools and a questionnaire. This first work
showed that AP is not an "all-or-nothing" process, but rather that it has different levels of
performance: from people that perform below chance, until it increases gradually to 100% of
correct answers. While traditional thresholds (~85%) showed a prevalence of AP similar to
that observed in musicians in Europe and the United States, the application of a statistical
threshold resulted in the detection of a greater number of individuals with some degree of AP.
In addition, we showed that AP possessors hit more the natural notes (those with the whitekeys
of the piano) than those that are accidental (flat or sharp, i.e. the black keys of the piano).
We also observed that AP possessors present an earlier onset of musical training. Finally, we
showed that AP was more prevalent in a high proficiency group in comparison to the average
proficiency group. In a second study, we used the auditory brainstem evoked potentials
(ABR) to quantify the activation of brainstem nuclei in the processing of heights of
individuals with OA. In this work, we showed that sustained responses (but not the transient
ones) present a higher energy in individuals with AP than in control musicians. We also found that the amplitude of this sustained response correlates with the reaction time in a pitch
naming test. These results suggest that individuals with AP have an increased refinement in
the processing of acoustic information in the early stages of auditory processing, which would
thus contribute to a greater automation of pitch identification. We believe that this thesis will
contribute to the understanding of the relationship between nervous system development and
musical learning, thus contributing to the development of new music teaching techniques and
training programs.