Aby wyświetlić tę treść, wymagana jest subskrypcja JoVE. Zaloguj się lub rozpocznij bezpłatny okres próbny.
Method Article
The neural correlates of listening to consonant and dissonant intervals have been widely studied, but the neural mechanisms associated with production of consonant and dissonant intervals are less well known. In this article, behavioral tests and fMRI are combined with interval identification and singing tasks to describe these mechanisms.
The neural correlates of consonance and dissonance perception have been widely studied, but not the neural correlates of consonance and dissonance production. The most straightforward manner of musical production is singing, but, from an imaging perspective, it still presents more challenges than listening because it involves motor activity. The accurate singing of musical intervals requires integration between auditory feedback processing and vocal motor control in order to correctly produce each note. This protocol presents a method that permits the monitoring of neural activations associated with the vocal production of consonant and dissonant intervals. Four musical intervals, two consonant and two dissonant, are used as stimuli, both for an auditory discrimination test and a task that involves first listening to and then reproducing given intervals. Participants, all female vocal students at the conservatory level, were studied using functional Magnetic Resonance Imaging (fMRI) during the performance of the singing task, with the listening task serving as a control condition. In this manner, the activity of both the motor and auditory systems was observed, and a measure of vocal accuracy during the singing task was also obtained. Thus, the protocol can also be used to track activations associated with singing different types of intervals or with singing the required notes more accurately. The results indicate that singing dissonant intervals requires greater participation of the neural mechanisms responsible for the integration of external feedback from the auditory and sensorimotor systems than does singing consonant intervals.
Certain combinations of musical pitches are generally acknowledged to be consonant, and they are typically associated with a pleasant sensation. Other combinations are generally referred to as dissonant and are associated with an unpleasant or unresolved feeling1. Although it seems sensible to assume that enculturation and training play some part in the perception of consonance2, it has been recently shown that the differences in perception of consonant and dissonant intervals and chords probably depend less on musical culture than was previously thought3 and may even derive from simple biological bases4,5,6. In order to prevent an ambiguous understanding of the term consonance, Terhardt7 introduced the notion of sensory consonance, as opposed to consonance in a musical context, where harmony, for example, may well influence the response to a given chord or interval. In the present protocol, only isolated, two-note intervals were used precisely to single out activations solely related to sensory consonance, without interference from context-dependent processing8.
Attempts to characterize consonance through purely physical means began with Helmholtz9, who attributed the perceived roughness associated with dissonant chords to the beating between adjacent frequency components. More recently, however, it has been shown that sensory consonance is not only associated with the absence of roughness, but also with harmonicity, which is to say the alignment of the partials of a given tone or chord with those of an unheard tone of a lower frequency10,11. Behavioral studies confirm that subjective consonance is indeed affected by purely physical parameters, such as frequency distance12,13, but a wider range of studies have conclusively demonstrated that physical phenomena cannot solely account for the differences between perceived consonance and dissonance14,15,16,17. All of these studies, however, report these differences when listening to a variety of intervals or chords. A variety of studies using Positron Emission Tomography (PET) and functional Magnetic Resonance Imaging (fMRI) have revealed significant differences in the cortical regions that become active when listening to either consonant or dissonant intervals and chords8,18,19,20. The purpose of the present study is to explore the differences in brain activity when producing, rather than listening to, consonant and dissonant intervals.
The study of sensory-motor control during musical production typically involves the use of musical instruments, and very often it then requires the fabrication of instruments modified specifically for their use during neuroimaging21. Singing, however, would seem to provide from the start an appropriate mechanism for the analysis of sensory-motor processes during music production, as the instrument is the human voice itself, and the vocal apparatus does not require any modification in order to be suitable during imaging22. Although the neural mechanisms associated with aspects of singing, such as pitch control23, vocal imitation24, training-induced adaptive changes25, and the integration of external feedback25,26,27,28,29, have been the subject of a number of studies over the past two decades, the neural correlates of singing consonant and dissonant intervals were only recently described30. For this purpose, the current paper describes a behavioral test designed to establish the adequate recognition of consonant and dissonant intervals by participants. This is followed by an fMRI study of participants singing a variety of consonant and dissonant intervals. The fMRI protocol is relatively straightforward, but, as with all MRI research, great care must be taken to correctly set up the experiments. In this case, it is particularly important to minimize head, mouth, and lip movement during singing tasks, making the identification of effects not directly related to the physical act of singing more straightforward. This methodology may be used to investigate the neural mechanisms associated with a variety of activities involving musical production by singing.
Access restricted. Please log in or start a trial to view this content.
This protocol has been approved by the Research, Ethics, and Safety Committee of the Hospital Infantil de México "Federico Gómez".
1. Behavioral Pretest
2. fMRI Experiment
Figure 1: Sparse-sampling Design. (A) Timeline of events within a trial involving only listening to a two-tone interval (2 s), without subsequent overt reproduction. (B) Timeline of events within a trial involving listening and singing tasks. Please click here to view a larger version of this figure.
3. Data Analysis
Access restricted. Please log in or start a trial to view this content.
All 11 participants in our experiment were female vocal students at the conservatory level, and they performed well enough in the interval recognition tasks to be selected for scanning. The success rate for the interval identification task was 65.72 ±21.67%, which is, as expected, lower than the success rate when identifying dissonant and consonant intervals, which was 74.82 ±14.15%.
In order to validate the basic desi...
Access restricted. Please log in or start a trial to view this content.
This work describes a protocol in which singing is used as a means of studying brain activity during the production of consonant and dissonant intervals. Even though singing provides what is possibly the simplest method for the production of musical intervals22, it does not allow for the production of chords. However, although most physical characterizations of the notion of consonance rely, to some degree, on the superposition of simultaneous notes, a number of studies have shown that intervals c...
Access restricted. Please log in or start a trial to view this content.
The authors declare no conflicts of interest.
The authors acknowledge financial support for this research from Secretaría de Salud de México (HIM/2011/058 SSA. 1009), CONACYT (SALUD-2012-01-182160), and DGAPA UNAM (PAPIIT IN109214).
Access restricted. Please log in or start a trial to view this content.
Name | Company | Catalog Number | Comments |
Achieva 1.5-T magnetic resonance scanner | Philips | Release 6.4 | |
Audacity | Open source | 2.0.5 | |
Audio interface | Tascam | US-144MKII | |
Audiometer | Brüel & Kjaer | Type 1800 | |
E-Prime Professional | Psychology Software Tools, Inc. | 2.0.0.74 | |
Matlab | Mathworks | R2014A | |
MRI-Compatible Insert Earphones | Sensimetrics | S14 | |
Praat | Open source | 5.4.12 | |
Pro-audio condenser microphone | Shure | SM93 | |
SPSS Statistics | IBM | 20 | |
Statistical Parametric Mapping | Wellcome Trust Centre for Neuroimaging | 8 |
Access restricted. Please log in or start a trial to view this content.
Zapytaj o uprawnienia na użycie tekstu lub obrazów z tego artykułu JoVE
Zapytaj o uprawnieniaThis article has been published
Video Coming Soon
Copyright © 2025 MyJoVE Corporation. Wszelkie prawa zastrzeżone