Singing in the brain: Neural representation of music and voice as revealed by fMRI

Abstract

The ubiquity of music across cultures as a means of emotional expression, and its proposed evolutionary relation to speech, motivated researchers to attempt a characterization of its neural representation. Several neuroimaging studies have reported that specific regions in the anterior temporal lobe respond more strongly to music than to other auditory stimuli, including spoken voice. Nonetheless, because most studies have employed instrumental music, which has important acoustic distinctions from human voice, questions still exist as to the specificity of the observed "music-preferred" areas. Here, we sought to address this issue by testing 24 healthy young adults with fast, high-resolution fMRI, to record neural responses to a large and varied set of musical stimuli, which, critically, included a capella singing, as well as purely instrumental excerpts. Our results confirmed that music; vocal or instrumental, preferentially engaged regions in the superior STG, particularly in the anterior planum polare, bilaterally. In contrast, human voice, either spoken or sung, activated more strongly a large area along the superior temporal sulcus. Findings were consistent between univariate and multivariate analyses, as well as with the use of a "silent" sparse acquisition sequence that minimizes any potential influence of scanner noise on the resulting activations. Activity in music-preferred regions could not be accounted for by any basic acoustic parameter tested, suggesting these areas integrate, likely in a nonlinear fashion, a combination of acoustic attributes that, together, result in the perceived musicality of the stimuli, consistent with proposed hierarchical processing of complex auditory information within the temporal lobes.

ERP Markers of Valence Coding in Emotional Speech Processing

“…Although from these studies it can be surely argued that similar mechanisms support the comprehension of emotional content of vocalizations and music, there is not a precise indication about the specific nature and timing of these neural processes, because of the different structure of stimuli usually compared. It is known that both types of complex stimuli are processed within the secondary auditory cortex (Whitehead and Armony, 2018). In a previous ERP study (Proverbio et al, 2019) positive and negative emotional vocalizations (e.g., laughing, crying) and digitally extracted musical tones (played on the violin) were used as stimuli.…”

Discerning the functional networks behind processing of music and speech through human vocalizations

“…An independent and very recent study compared cortical activity in response to instrumental music, speech and a capella singing, and also showed that the planum polare was preferentially activated when subjects listened to either kind of musical stimuli (sung or instrumental) 67 . As described above, the cortical areas that we found to be most active in response to listening to music include not only the temporal lobe, but also motor and pre-motor regions.…”

How the Brain Understands Spoken and Sung Sentences

“…The degree of linguistic or melodic features contained in the presented acoustic material seems relevant for a correct interpretation of found activations. In this vein of reasoning, a direct comparison between the listening to/production of spoken and sung material (e.g., familiar songs, words, phrases) showed an increased right-hemispheric dominance of the middle STG, the planum temporale (PT), and the OFC for sung compared to spoken songs [56][57][58]. The authors interpret the PT to be involved in the transformation of auditory input into motor representation relevant for speech production.…”

“…The OFC is assumed to process pleasant and unpleasant emotional aspects during music perception. Interestingly, when comparing sung (i.e., linguistic and melodic information) as well as instrumental music (i.e., only melodic information) to spoken songs (i.e., only linguistic information), an increased activation was found not only in the right planum temporale but also in bilateral anterior planum polare, suggesting that these regions encode music/timbre in both instrumental and sung music [57]. Furthermore, spoken and sung material activated the STS bilaterally, indicating that this area is sensitive to human nonlinguistic vocalizations.…”