Elvira Brattico

Distinct neural responses to chord violations: A multiple source analysis study

The human brain is constantly predicting the auditory environment by representing sequential similarities and extracting temporal regularities. It has been proposed that simple auditory regularities are extracted at lower stations of the auditory cortex and more complex ones at other brain regions, such as the prefrontal cortex. Deviations from auditory regularities elicit a family of early negative electric potentials distributed over the frontal regions of the scalp. In this study, we wished to disentangle the brain processes associated with sequential vs. hierarchical auditory regularities in a musical context by studying the event-related potentials (ERPs), the behavioral responses to violations of these regularities, and the localization of the underlying ERP generators using two different source analysis algorithms. To this aim, participants listened to musical cadences constituted by seven chords, each containing either harmonically congruous chords, harmonically incongruous chords, or harmonically congruous but mistuned chords. EEG was recorded and multiple source analysis was performed. Incongruous chords violating the rules of harmony elicited a bilateral ERAN, whereas mistuned chords within chord sequences elicited a right-lateralized MMN. We found that the dominant cortical sources for the ERAN were localized around Brocas area and its right homolog, whereas the MMN generators were localized around the primary auditory cortex. These findings suggest a predominant role of the auditory cortices in detecting sequential scale regularities and the posterior prefrontal cortex in parsing hierarchical regularities in music.

Subjective Appraisal of Music Neuroimaging Evidence

In the neurosciences of music, a consensus on the nature of affective states during music listening has not been reached. What is undeniable is that subjective affective states can be triggered by various and even opposite musical events. Here we review the few recent studies on the neural determinants of subjective affective processes of music, contrasted with early automatic neural processes linked to the objective universal properties of music. In particular, we focus on the evaluative judgments of music by subjects according to its aesthetic and structural values, on music‐specific emotions felt by listeners, and on conscious liking. We then discuss and seek to stimulate further research on the interplay between the emotional attributes of music and the subjective cognitive, psychological, and biographic factors, such as personality traits and cognitive strategies of listening. We finally draw the neuroscientists attention to the sociocultural context as a relevant variable to study when considering music as an aesthetic domain.

Dynamics of brain activity underlying working memory for music in a naturalistic condition

We aimed at determining the functional neuroanatomy of working memory (WM) recognition of musical motifs that occurs while listening to music by adopting a non-standard procedure. Western tonal music provides naturally occurring repetition and variation of motifs. These serve as WM triggers, thus allowing us to study the phenomenon of motif tracking within real music. Adopting a modern tango as stimulus, a behavioural test helped to identify the stimulus motifs and build a time-course regressor of WM neural responses. This regressor was then correlated with the participants (musicians) functional magnetic resonance imaging (fMRI) signal obtained during a continuous listening condition. In order to fine-tune the identification of WM processes in the brain, the variance accounted for by the sensory processing of a set of the stimulus acoustic features was pruned from participants neurovascular responses to music. Motivic repetitions activated prefrontal and motor cortical areas, basal ganglia, medial temporal lobe (MTL) structures, and cerebellum. The findings suggest that WM processing of motifs while listening to music emerges from the integration of neural activity distributed over cognitive, motor and limbic subsystems. The recruitment of the hippocampus stands as a novel finding in auditory WM. Effective connectivity and agglomerative hierarchical clustering analyses indicate that the hippocampal connectivity is modulated by motif repetitions, showing strong connections with WM-relevant areas (dorsolateral prefrontal cortex - dlPFC, supplementary motor area - SMA, and cerebellum), which supports the role of the hippocampus in the encoding of the musical motifs in WM, and may evidence long-term memory (LTM) formation, enabled by the use of a realistic listening condition.

Superior Analgesic Effect of an Active Distraction versus Pleasant Unfamiliar Sounds and Music: The Influence of Emotion and Cognitive Style

Listening to music has been found to reduce acute and chronic pain. The underlying mechanisms are poorly understood; however, emotion and cognitive mechanisms have been suggested to influence the analgesic effect of music. In this study we investigated the influence of familiarity, emotional and cognitive features, and cognitive style on music-induced analgesia. Forty-eight healthy participants were divided into three groups (empathizers, systemizers and balanced) and received acute pain induced by heat while listening to different sounds. Participants listened to unfamiliar Mozart music rated with high valence and low arousal, unfamiliar environmental sounds with similar valence and arousal as the music, an active distraction task (mental arithmetic) and a control, and rated the pain. Data showed that the active distraction led to significantly less pain than did the music or sounds. Both unfamiliar music and sounds reduced pain significantly when compared to the control condition; however, music was no more effective than sound to reduce pain. Furthermore, we found correlations between pain and emotion ratings. Finally, systemizers reported less pain during the mental arithmetic compared with the other two groups. These findings suggest that familiarity may be key in the influence of the cognitive and emotional mechanisms of music-induced analgesia, and that cognitive styles may influence pain perception.

Affective reactions to musical stimuli reflect emotional use of music in everyday life

Music is a common means for regulating affective states in everyday life, but little is known about the individual differences in this behaviour. We investigated affective reactions to musical stimuli as an explanatory factor. Forty-four young adults rated self-selected music regarding perceived and felt emotions, preference, pleasantness and beauty. The ratings were reduced into five factors representing affective response tendencies. The participants also filled in the Music in Mood Regulation (MMR) questionnaire assessing seven music-related mood regulation strategies in everyday life. High beauty and pleasantness ratings for liked music correlated with the use of music for inducing strong emotional experiences, while ratings reflecting high agreement with the emotional content of preferred musical stimuli correlated with using music as a means for dealing with personal negative emotions. Regarding musical background, informal engagement through listening, but not formal musical training, correlated with increased use of music for mood regulation. The results clarify the link between the affective reactivity to music and the individual ways of using music as a tool for emotional self-regulation in everyday life.

Electrophysiological correlates of aesthetic music processing: comparing experts with laypersons.

We analyzed the processes of making aesthetic judgments of music, focusing on the differences between music experts and laypersons. Sixteen students of musicology and 16 control subjects (also students) judged the aesthetic value as well as the harmonic correctness of chord sequences. Event‐related potential (ERP) data indicate differences between experts and laypersons in making aesthetic judgments at three different processing stages. Additionally, effects of expertise on ERP components that have previously been proven to be sensitive to musical training were replicated. The study thus provides insights into the effects of musical expertise on neural correlates of aesthetic music processing.

Diffusion map for clustering fMRI spatial maps extracted by independent component analysis

Functional magnetic resonance imaging (fMRI) produces data about activity inside the brain, from which spatial maps can be extracted by independent component analysis (ICA). In datasets, there are n spatial maps that contain p voxels. The number of voxels is very high compared to the number of analyzed spatial maps. Clustering of the spatial maps is usually based on correlation matrices. This usually works well, although such a similarity matrix inherently can explain only a certain amount of the total variance contained in the high-dimensional data where n is relatively small but p is large. For high-dimensional space, it is reasonable to perform dimensionality reduction before clustering. In this research, we used the recently developed diffusion map for dimensionality reduction in conjunction with spectral clustering. This research revealed that the diffusion map based clustering worked as well as the more traditional methods, and produced more compact clusters when needed.