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ECoG high gamma activity reveals distinct cortical representations of lyrics passages, harmonic and timbre-related changes in a rock song.

Sturm I, Blankertz B, Potes C, Schalk G, Curio G - Front Hum Neurosci (2014)

Bottom Line: The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song integrated in instrumental music represents a distinct dimension in complex music.In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics.This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli.

View Article: PubMed Central - PubMed

Affiliation: Berlin School of Mind and Brain, Humboldt Universität zu Berlin Berlin, Germany ; Neurotechnology Group, Department of Electrical Engineering and Computer Science, Berlin Institute of Technology Berlin, Germany ; Neurophysics Group, Department of Neurology and Clinical Neurophysiology, Charité - University Medicine Berlin Berlin, Germany.

ABSTRACT
Listening to music moves our minds and moods, stirring interest in its neural underpinnings. A multitude of compositional features drives the appeal of natural music. How such original music, where a composer's opus is not manipulated for experimental purposes, engages a listener's brain has not been studied until recently. Here, we report an in-depth analysis of two electrocorticographic (ECoG) data sets obtained over the left hemisphere in ten patients during presentation of either a rock song or a read-out narrative. First, the time courses of five acoustic features (intensity, presence/absence of vocals with lyrics, spectral centroid, harmonic change, and pulse clarity) were extracted from the audio tracks and found to be correlated with each other to varying degrees. In a second step, we uncovered the specific impact of each musical feature on ECoG high-gamma power (70-170 Hz) by calculating partial correlations to remove the influence of the other four features. In the music condition, the onset and offset of vocal lyrics in ongoing instrumental music was consistently identified within the group as the dominant driver for ECoG high-gamma power changes over temporal auditory areas, while concurrently subject-individual activation spots were identified for sound intensity, timbral, and harmonic features. The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song integrated in instrumental music represents a distinct dimension in complex music. In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics. This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli.

No MeSH data available.


Related in: MedlinePlus

Single subjects (individual brain models), music condition: Cortical distribution of significant correlation with each of the five acoustic features after removing the influence of the remaining four features by calculating partial correlation coefficients. A value of 2 corresponds to a p-value of 0.01. Correlation coefficients determined as significant by permutation tests ranged between r = 0.07 and r = 0.26.
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Figure 4: Single subjects (individual brain models), music condition: Cortical distribution of significant correlation with each of the five acoustic features after removing the influence of the remaining four features by calculating partial correlation coefficients. A value of 2 corresponds to a p-value of 0.01. Correlation coefficients determined as significant by permutation tests ranged between r = 0.07 and r = 0.26.

Mentions: Figure 4 shows the significance values of partial correlation of ECoG high-gamma features with each of the five music features for each individual patient. Significant high-gamma correlations with vocals on/off are present in 9/10 of the subjects, and exceed in spatial extent those of all other acoustic features. In all of these nine patients, significant positive correlations are present in auditory areas around the Sylvian fissure, either confined to a region on the posterior superior temporal gyrus (pSTG) (S1, S2, S4, S6, and S8), or extending also to the anterior part of the STG and dorsally from the Sylvian fissure (S3, S5, S9, and S10). In addition, significant correlation in an isolated area at the dorsal precentral cortex is present in three subjects (S3, S5, and S9). Compared to the effect related to vocals on/off, correlation with sound intensity (after calculating the partial correlation and thereby rendering it now independent from fluctuations in the other four acoustic parameters, including vocals on/off) is low, reaching significance only in subject S4, S5, S7, and S10) and is detected only in a smaller region on the posterior STG. Correlation with spectral centroid is significant only in subject S5 and S10 and distributed similarly to the feature vocals on/off, but spatially less extended. For harmonic change, significant correlation is present in four subjects (subject S3, S5, S9, and S10) on the posterior STG and in subject S3 in frontal areas. The correlation with pulse clarity reaches significance in only one subjects (S6) in a small region on the precentral cortex.


ECoG high gamma activity reveals distinct cortical representations of lyrics passages, harmonic and timbre-related changes in a rock song.

Sturm I, Blankertz B, Potes C, Schalk G, Curio G - Front Hum Neurosci (2014)

Single subjects (individual brain models), music condition: Cortical distribution of significant correlation with each of the five acoustic features after removing the influence of the remaining four features by calculating partial correlation coefficients. A value of 2 corresponds to a p-value of 0.01. Correlation coefficients determined as significant by permutation tests ranged between r = 0.07 and r = 0.26.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4195312&req=5

Figure 4: Single subjects (individual brain models), music condition: Cortical distribution of significant correlation with each of the five acoustic features after removing the influence of the remaining four features by calculating partial correlation coefficients. A value of 2 corresponds to a p-value of 0.01. Correlation coefficients determined as significant by permutation tests ranged between r = 0.07 and r = 0.26.
Mentions: Figure 4 shows the significance values of partial correlation of ECoG high-gamma features with each of the five music features for each individual patient. Significant high-gamma correlations with vocals on/off are present in 9/10 of the subjects, and exceed in spatial extent those of all other acoustic features. In all of these nine patients, significant positive correlations are present in auditory areas around the Sylvian fissure, either confined to a region on the posterior superior temporal gyrus (pSTG) (S1, S2, S4, S6, and S8), or extending also to the anterior part of the STG and dorsally from the Sylvian fissure (S3, S5, S9, and S10). In addition, significant correlation in an isolated area at the dorsal precentral cortex is present in three subjects (S3, S5, and S9). Compared to the effect related to vocals on/off, correlation with sound intensity (after calculating the partial correlation and thereby rendering it now independent from fluctuations in the other four acoustic parameters, including vocals on/off) is low, reaching significance only in subject S4, S5, S7, and S10) and is detected only in a smaller region on the posterior STG. Correlation with spectral centroid is significant only in subject S5 and S10 and distributed similarly to the feature vocals on/off, but spatially less extended. For harmonic change, significant correlation is present in four subjects (subject S3, S5, S9, and S10) on the posterior STG and in subject S3 in frontal areas. The correlation with pulse clarity reaches significance in only one subjects (S6) in a small region on the precentral cortex.

Bottom Line: The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song integrated in instrumental music represents a distinct dimension in complex music.In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics.This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli.

View Article: PubMed Central - PubMed

Affiliation: Berlin School of Mind and Brain, Humboldt Universität zu Berlin Berlin, Germany ; Neurotechnology Group, Department of Electrical Engineering and Computer Science, Berlin Institute of Technology Berlin, Germany ; Neurophysics Group, Department of Neurology and Clinical Neurophysiology, Charité - University Medicine Berlin Berlin, Germany.

ABSTRACT
Listening to music moves our minds and moods, stirring interest in its neural underpinnings. A multitude of compositional features drives the appeal of natural music. How such original music, where a composer's opus is not manipulated for experimental purposes, engages a listener's brain has not been studied until recently. Here, we report an in-depth analysis of two electrocorticographic (ECoG) data sets obtained over the left hemisphere in ten patients during presentation of either a rock song or a read-out narrative. First, the time courses of five acoustic features (intensity, presence/absence of vocals with lyrics, spectral centroid, harmonic change, and pulse clarity) were extracted from the audio tracks and found to be correlated with each other to varying degrees. In a second step, we uncovered the specific impact of each musical feature on ECoG high-gamma power (70-170 Hz) by calculating partial correlations to remove the influence of the other four features. In the music condition, the onset and offset of vocal lyrics in ongoing instrumental music was consistently identified within the group as the dominant driver for ECoG high-gamma power changes over temporal auditory areas, while concurrently subject-individual activation spots were identified for sound intensity, timbral, and harmonic features. The distinct cortical activations to vocal speech-related content embedded in instrumental music directly demonstrate that song integrated in instrumental music represents a distinct dimension in complex music. In contrast, in the speech condition, the full sound envelope was reflected in the high gamma response rather than the onset or offset of the vocal lyrics. This demonstrates how the contributions of stimulus features that modulate the brain response differ across the two examples of a full-length natural stimulus, which suggests a context-dependent feature selection in the processing of complex auditory stimuli.

No MeSH data available.


Related in: MedlinePlus