Hearing in the Mind's Ear: A PET Investigation of Musical Imagery and Perception

Neural signatures of imaginary motivational states: desire for music, movement and social play

The literature has demonstrated the potential for detecting accurate electrical signals that correspond to the will or intention to move, as well as decoding the thoughts of individuals who imagine houses, faces or objects. This investigation examines the presence of precise neural markers of imagined motivational states through the combining of electrophysiological and neuroimaging methods. 20 participants were instructed to vividly imagine the desire to move, listen to music or engage in social activities. Their EEG was recorded from 128 scalp sites and analysed using individual standardized Low-Resolution Brain Electromagnetic Tomographies (LORETAs) in the N400 time window (400-600 ms). The activation of 1056 voxels was examined in relation to the 3 motivational states. The most active dipoles were grouped in eight regions of interest (ROI), including Occipital, Temporal, Fusiform, Premotor, Frontal, OBF/IF, Parietal, and Limbic areas. The statistical analysis revealed that all motivational imaginary states engaged the right hemisphere more than the left hemisphere. Distinct markers were identified for the three motivational states. Specifically, the right temporal area was more relevant for "Social Play", the orbitofrontal/inferior frontal cortex for listening to music, and the left premotor cortex for the "Movement" desire. This outcome is encouraging in terms of the potential use of neural indicators in the realm of brain-computer interface, for interpreting the thoughts and desires of individuals with locked-in syndrome.

Neurophysiological evidence of motor preparation in inner speech and the effect of content predictability

Self-generated overt actions are preceded by a slow negativity as measured by electroencephalogram, which has been associated with motor preparation. Recent studies have shown that this neural activity is modulated by the predictability of action outcomes. It is unclear whether inner speech is also preceded by a motor-related negativity and influenced by the same factor. In three experiments, we compared the contingent negative variation elicited in a cue paradigm in an active vs. passive condition. In Experiment 1, participants produced an inner phoneme, at which an audible phoneme whose identity was unpredictable was concurrently presented. We found that while passive listening elicited a late contingent negative variation, inner speech production generated a more negative late contingent negative variation. In Experiment 2, the same pattern of results was found when participants were instead asked to overtly vocalize the phoneme. In Experiment 3, the identity of the audible phoneme was made predictable by establishing probabilistic expectations. We observed a smaller late contingent negative variation in the inner speech condition when the identity of the audible phoneme was predictable, but not in the passive condition. These findings suggest that inner speech is associated with motor preparatory activity that may also represent the predicted action-effects of covert actions.

Cognitive Crescendo: How Music Shapes the Brain's Structure and Function

Music is a complex phenomenon with multiple brain areas and neural connections being implicated. Centuries ago, music was discovered as an efficient modality for psychological status enrichment and even for the treatment of multiple pathologies. Modern research investigations give a new avenue for music perception and the understanding of the underlying neurological mechanisms, using neuroimaging, especially magnetic resonance imaging. Multiple brain areas were depicted in the last decades as being of high value for music processing, and further analyses in the neuropsychology field uncover the implications in emotional and cognitive activities. Music listening improves cognitive functions such as memory, attention span, and behavioral augmentation. In rehabilitation, music-based therapies have a high rate of success for the treatment of depression and anxiety and even in neurological disorders such as regaining the body integrity after a stroke episode. Our review focused on the neurological and psychological implications of music, as well as presenting the significant clinical relevance of therapies using music.

Decoding reveals the neural representation of held and manipulated musical thoughts

Imagine a song you know by heart. With little effort you could sing it or play it vividly in your mind. However, we are only beginning to understand how the brain represents, holds, and manipulates these musical "thoughts". Here, we decoded listened and imagined melodies from MEG brain data (N = 71) to show that auditory regions represent the sensory properties of individual sounds, whereas cognitive control (prefrontal cortex, basal nuclei, thalamus) and episodic memory areas (inferior and medial temporal lobe, posterior cingulate, precuneus) hold and manipulate the melody as an abstract unit. Furthermore, the mental manipulation of a melody systematically changes its neural representation, reflecting the volitional control of auditory images. Our work sheds light on the nature and dynamics of auditory representations and paves the way for future work on neural decoding of auditory imagination.

Dual-stream cortical pathways mediate sensory prediction

Predictions are constantly generated from diverse sources to optimize cognitive functions in the ever-changing environment. However, the neural origin and generation process of top-down induced prediction remain elusive. We hypothesized that motor-based and memory-based predictions are mediated by distinct descending networks from motor and memory systems to the sensory cortices. Using functional magnetic resonance imaging (fMRI) and a dual imagery paradigm, we found that motor and memory upstream systems activated the auditory cortex in a content-specific manner. Moreover, the inferior and posterior parts of the parietal lobe differentially relayed predictive signals in motor-to-sensory and memory-to-sensory networks. Dynamic causal modeling of directed connectivity revealed selective enabling and modulation of connections that mediate top-down sensory prediction and ground the distinctive neurocognitive basis of predictive processing.

Why art? The role of arts in arts and health

This article is an answer to a report called "What is the evidence on the role of the arts in improving health and well-being?" The authors conclude that the arts have an impact on mental and physical health. Yet, the question of the role of the arts remains unanswered. What is and what is not an art effect? Recently, embodied theory has inspired articles on the perception of art. These articles have not yet received attention in the field of Arts and Health. Scholars in psychosomatic medicine have argued for an approach based on recent work in enactive embodied theory to investigate the connection between the body and the mind. The present article examines how key concepts in this theory relate to art. This leads to a discussion of art in terms of empathy-the relation between the internal state of the artist and the internal state of the beholder. I exemplify with a conceptual framework of musical empathy. Implications for health are addressed.

Meta-analytic evidence for a novel hierarchical model of conceptual processing

Conceptual knowledge plays a pivotal role in human cognition. Grounded cognition theories propose that concepts consist of perceptual-motor features represented in modality-specific perceptual-motor cortices. However, it is unclear whether conceptual processing consistently engages modality-specific areas. Here, we performed an activation likelihood estimation (ALE) meta-analysis across 212 neuroimaging experiments on conceptual processing related to 7 perceptual-motor modalities (action, sound, visual shape, motion, color, olfaction-gustation, and emotion). We found that conceptual processing consistently engages brain regions also activated during real perceptual-motor experience of the same modalities. In addition, we identified multimodal convergence zones that are recruited for multiple modalities. In particular, the left inferior parietal lobe (IPL) and posterior middle temporal gyrus (pMTG) are engaged for three modalities: action, motion, and sound. These "trimodal" regions are surrounded by "bimodal" regions engaged for two modalities. Our findings support a novel model of the conceptual system, according to which conceptual processing relies on a hierarchical neural architecture from modality-specific to multimodal areas up to an amodal hub.

Evidence for predictions established by phantom sound

Predictions, the bridge between the internal and external worlds, are established by prior experience and updated by sensory stimuli. Responses to omitted but unexpected stimuli, known as omission responses, can break the one-to-one mapping of stimulus-response and can expose predictions established by the preceding stimulus built up. While research into exogenous predictions (driven by external stimuli) is often reported, that into endogenous predictions (driven by internal percepts) is rarely available in the literature. Here, we report evidence for endogenous predictions established by the Zwicker tone illusion, a phantom pure-tone-like auditory percept following notch noises. We found that MMN, P300, and theta oscillations could be recorded using an omission paradigm in subjects who can perceive Zwicker tone illusions, but could not in those who cannot. The MMN and P300 responses relied on attention, but theta oscillations did not. In-depth analysis shows that an increase in single-trial theta power, including total and induced theta, with the endogenous prediction, is lateralized to the left frontal brain areas. Our study depicts that the brain automatically analyzes internal perception, progressively establishes predictions and yields prediction errors in the left frontal region when a violation occurs.

Neural functional correlates of hypnosis and hypnoanalgesia: Role of the cingulate cortex

Hypnosis is a hetero-induced or self-induced altered state of consciousness that involves focused attention and reduced peripheral awareness. It is determined by response to suggestions and can be used in the management of various clinical conditions. Nowadays there is growing attention to the neurobiological correlates of hypnosis because of its future clinical applications. The greater attention is due to the wide range of applications that might stem from its knowledge. Functional neuroimaging studies show that hypnosis affects attention by modulating the activation of the anterior cingulate cortex and other brain areas, modifying the conflict monitoring and cognitive control. During hypnoanalgesia, several changes in brain functions occur in all the areas of the pain network, and other brain areas. Among these, the anterior cingulate cortex is significantly involved in modulating the activity of pain circuits under hypnosis, both in the affective, sensory-cognitive, and behavioral aspects. The study of the functionality of the cingulate cortices, mainly the anterior and medial portions, appears to be crucial for better understanding the hypnotic phenomena, related to both the neurocognitive and somatosensory aspects.

Music in the brain

Music is ubiquitous across human cultures - as a source of affective and pleasurable experience, moving us both physically and emotionally - and learning to play music shapes both brain structure and brain function. Music processing in the brain - namely, the perception of melody, harmony and rhythm - has traditionally been studied as an auditory phenomenon using passive listening paradigms. However, when listening to music, we actively generate predictions about what is likely to happen next. This enactive aspect has led to a more comprehensive understanding of music processing involving brain structures implicated in action, emotion and learning. Here we review the cognitive neuroscience literature of music perception. We show that music perception, action, emotion and learning all rest on the human brain's fundamental capacity for prediction - as formulated by the predictive coding of music model. This Review elucidates how this formulation of music perception and expertise in individuals can be extended to account for the dynamics and underlying brain mechanisms of collective music making. This in turn has important implications for human creativity as evinced by music improvisation. These recent advances shed new light on what makes music meaningful from a neuroscientific perspective.

Vocal melody and musical background are simultaneously processed by the brain for musical predictions

Musical pleasure is related to the capacity to predict and anticipate the music. By recording early cerebral responses of 16 participants with electroencephalography during periods of silence inserted in known and unknown songs, we aimed to measure the contribution of different musical attributes to musical predictions. We investigated the mismatch between past encoded musical features and the current sensory inputs when listening to lyrics associated with vocal melody, only background instrumental material, or both attributes grouped together. When participants were listening to chords and lyrics for known songs, the brain responses related to musical violation produced event-related potential responses around 150-200 ms that were of a larger amplitude than for chords or lyrics only. Microstate analysis also revealed that for chords and lyrics, the global field power had an increased stability and a longer duration. The source localization identified that the right superior temporal and frontal gyri and the inferior and medial frontal gyri were activated for a longer time for chords and lyrics, likely caused by the increased complexity of the stimuli. We conclude that grouped together, a broader integration and retrieval of several musical attributes at the same time recruit larger neuronal networks that lead to more accurate predictions.

The Music of Silence: Part I: Responses to Musical Imagery Encode Melodic Expectations and Acoustics

Musical imagery is the voluntary internal hearing of music in the mind without the need for physical action or external stimulation. Numerous studies have already revealed brain areas activated during imagery. However, it remains unclear to what extent imagined music responses preserve the detailed temporal dynamics of the acoustic stimulus envelope and, crucially, whether melodic expectations play any role in modulating responses to imagined music, as they prominently do during listening. These modulations are important as they reflect aspects of the human musical experience, such as its acquisition, engagement, and enjoyment. This study explored the nature of these modulations in imagined music based on EEG recordings from 21 professional musicians (6 females and 15 males). Regression analyses were conducted to demonstrate that imagined neural signals can be predicted accurately, similarly to the listening task, and were sufficiently robust to allow for accurate identification of the imagined musical piece from the EEG. In doing so, our results indicate that imagery and listening tasks elicited an overlapping but distinctive topography of neural responses to sound acoustics, which is in line with previous fMRI literature. Melodic expectation, however, evoked very similar frontal spatial activation in both conditions, suggesting that they are supported by the same underlying mechanisms. Finally, neural responses induced by imagery exhibited a specific transformation from the listening condition, which primarily included a relative delay and a polarity inversion of the response. This transformation demonstrates the top-down predictive nature of the expectation mechanisms arising during both listening and imagery.SIGNIFICANCE STATEMENT It is well known that the human brain is activated during musical imagery: the act of voluntarily hearing music in our mind without external stimulation. It is unclear, however, what the temporal dynamics of this activation are, as well as what musical features are precisely encoded in the neural signals. This study uses an experimental paradigm with high temporal precision to record and analyze the cortical activity during musical imagery. This study reveals that neural signals encode music acoustics and melodic expectations during both listening and imagery. Crucially, it is also found that a simple mapping based on a time-shift and a polarity inversion could robustly describe the relationship between listening and imagery signals.

Lemniscal Corticothalamic Feedback in Auditory Scene Analysis

Sound information is transmitted from the ear to central auditory stations of the brain via several nuclei. In addition to these ascending pathways there exist descending projections that can influence the information processing at each of these nuclei. A major descending pathway in the auditory system is the feedback projection from layer VI of the primary auditory cortex (A1) to the ventral division of medial geniculate body (MGBv) in the thalamus. The corticothalamic axons have small glutamatergic terminals that can modulate thalamic processing and thalamocortical information transmission. Corticothalamic neurons also provide input to GABAergic neurons of the thalamic reticular nucleus (TRN) that receives collaterals from the ascending thalamic axons. The balance of corticothalamic and TRN inputs has been shown to refine frequency tuning, firing patterns, and gating of MGBv neurons. Therefore, the thalamus is not merely a relay stage in the chain of auditory nuclei but does participate in complex aspects of sound processing that include top-down modulations. In this review, we aim (i) to examine how lemniscal corticothalamic feedback modulates responses in MGBv neurons, and (ii) to explore how the feedback contributes to auditory scene analysis, particularly on frequency and harmonic perception. Finally, we will discuss potential implications of the role of corticothalamic feedback in music and speech perception, where precise spectral and temporal processing is essential.

Auditory perceptual processing during musical imagery: An event-related potential study

The perceptual processing of a sound is facilitated when the sound matches auditory imagery. Previous studies have shown that auditory imagery and actual sound activate the auditory cortex in a similar fashion. To investigate whether auditory imagery is a modality-specific representation or an amodal representation, the current study examined how watching silent music videos affected the auditory processing of sound excerpts. Twenty university students were asked to form musical imagery of Japanese popular songs while watching the official music videos. Event-related brain potentials were recorded in response to short sound excerpts from the on-screen video or from a different video. The results showed that the amplitude of the exogenous N1 component (90-110 ms) was smaller for imagery-matched than for unmatched sound excerpts. The electrical source of the difference was estimated in the auditory cortex. After the N1, the matched excerpts elicited a larger late positive potential (400-800 ms) than the unmatched excerpts. These findings suggest that auditory imagery involves modality-specific neural processing and that imagery-matched sounds are processed efficiently at an early stage, inducing additional cognitive processing at a later stage.

Mapping Specific Mental Content during Musical Imagery

Humans can mentally represent auditory information without an external stimulus, but the specificity of these internal representations remains unclear. Here, we asked how similar the temporally unfolding neural representations of imagined music are compared to those during the original perceived experience. We also tested whether rhythmic motion can influence the neural representation of music during imagery as during perception. Participants first memorized six 1-min-long instrumental musical pieces with high accuracy. Functional MRI data were collected during: 1) silent imagery of melodies to the beat of a visual metronome; 2) same but while tapping to the beat; and 3) passive listening. During imagery, inter-subject correlation analysis showed that melody-specific temporal response patterns were reinstated in right associative auditory cortices. When tapping accompanied imagery, the melody-specific neural patterns were reinstated in more extensive temporal-lobe regions bilaterally. These results indicate that the specific contents of conscious experience are encoded similarly during imagery and perception in the dynamic activity of auditory cortices. Furthermore, rhythmic motion can enhance the reinstatement of neural patterns associated with the experience of complex sounds, in keeping with models of motor to sensory influences in auditory processing.

Hallucination, imagery, dreaming: reassembling stimulus-independent perceptions based on Edmund Parish's classic misperception framework

Within the broad field of human perception lies the category of stimulus-independent perceptions, which draws together experiences such as hallucinations, mental imagery and dreams. Traditional divisions between medical and psychological sciences have contributed to these experiences being investigated separately. This review aims to examine their similarities and differences at the levels of phenomenology and underlying brain function and thus reassemble them within a common framework. Using Edmund Parish's historical work as a guiding tool and the latest research findings in the cognitive, clinical and computational sciences, we consider how different perspectives may be reconciled and help generate novel hypotheses for future research. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.

Involuntary musical imagery as a component of ordinary music cognition: A review of empirical evidence

Involuntary musical imagery (INMI) refers to a conscious mental experience of music that occurs without deliberate efforts to initiate or sustain it. This experience often consists of the repetition of a short fragment of a melody, colloquially called an "earworm." Here, we present the first comprehensive, qualitative review of published empirical research on INMI to date. We performed an extensive literature search and discovered, in total, 47 studies from 33 peer-reviewed articles that met the inclusion criteria for the review. In analyzing the content of these studies, we identified four major research themes, which concern the phenomenology, dynamics, individual differences, and musical features of INMI. The findings answer many questions of scientific interest-for instance, what is typical in terms of INMI frequency, duration, and content; which factors influence INMI onset; and whether demographic and personality factors can explain individual differences in susceptibility and responses to INMI. This review showcases INMI as a well-established phenomenon in light of a substantial body of empirical studies that have accumulated consistent results. Although the populations under study show an unfavorable bias towards Western, educated participants, the evidence depicts INMI as a universal psychological phenomenon, the possible function of which we do not yet fully understand. The concluding section introduces several suggestions for future research to expand on the topic.

Mental Effort When Playing, Listening, and Imagining Music in One Pianist's Eyes and Brain

We investigated "musical effort" with an internationally renowned, classical, pianist while playing, listening, and imagining music. We used pupillometry as an objective measure of mental effort and fMRI as an exploratory method of effort with the same musical pieces. We also compared a group of non-professional pianists and non-musicians by the use of pupillometry and a small group of non-musicians with fMRI. This combined approach of psychophysiology and neuroimaging revealed the cognitive work during different musical activities. We found that pupil diameters were largest when "playing" (regardless of whether there was sound produced or not) compared to conditions with no movement (i.e., "listening" and "imagery"). We found positive correlations between pupil diameters of the professional pianist during different conditions with the same piano piece (i.e., normal playing, silenced playing, listen, imagining), which might indicate similar degrees of load on cognitive resources as well as an intimate link between the motor imagery of sound-producing body motions and gestures. We also confirmed that musical imagery had a strong commonality with music listening in both pianists and musically naïve individuals. Neuroimaging provided evidence for a relationship between noradrenergic (NE) activity and mental workload or attentional intensity within the domain of music cognition. We found effort related activity in the superior part of the locus coeruleus (LC) and, similarly to the pupil, the listening and imagery engaged less the LC-NE network than the motor condition. The pianists attended more intensively to the most difficult piece than the non-musicians since they showed larger pupils for the most difficult piece. Non-musicians were the most engaged by the music listening task, suggesting that the amount of attention allocated for the same task may follow a hierarchy of expertise demanding less attentional effort in expert or performers than in novices. In the professional pianist, we found only weak evidence for a commonality between subjective effort (as rated measure-by-measure) and the objective effort gauged with pupil diameter during listening. We suggest that psychophysiological methods like pupillometry can index mental effort in a manner that is not available to subjective awareness or introspection.

Mental operations in rhythm: Motor-to-sensory transformation mediates imagined singing

What enables the mental activities of thinking verbally or humming in our mind? We hypothesized that the interaction between motor and sensory systems induces speech and melodic mental representations, and this motor-to-sensory transformation forms the neural basis that enables our verbal thinking and covert singing. Analogous with the neural entrainment to auditory stimuli, participants imagined singing lyrics of well-known songs rhythmically while their neural electromagnetic signals were recorded using magnetoencephalography (MEG). We found that when participants imagined singing the same song in similar durations across trials, the delta frequency band (1–3 Hz, similar to the rhythm of the songs) showed more consistent phase coherence across trials. This neural phase tracking of imagined singing was observed in a frontal-parietal-temporal network: the proposed motor-to-sensory transformation pathway, including the inferior frontal gyrus (IFG), insula (INS), premotor area, intra-parietal sulcus (IPS), temporal-parietal junction (TPJ), primary auditory cortex (Heschl’s gyrus [HG]), and superior temporal gyrus (STG) and sulcus (STS). These results suggest that neural responses can entrain the rhythm of mental activity. Moreover, the theta-band (4–8 Hz) phase coherence was localized in the auditory cortices. The mu (9–12 Hz) and beta (17–20 Hz) bands were observed in the right-lateralized sensorimotor systems that were consistent with the singing context. The gamma band was broadly manifested in the observed network. The coherent and frequency-specific activations in the motor-to-sensory transformation network mediate the internal construction of perceptual representations and form the foundation of neural computations for mental operations.

What enables our mental activities for thinking verbally or humming in our mind? Using an imagined singing paradigm with magnetoencephalography recordings, this study shows that neural oscillations in the motor-to-sensory transformation network tracked inner speech and covert singing.

Walking in My Shoes: Imagined Synchrony Improves Attitudes Towards Out-groups

People are prone to dividing others into the categories of ‘us’ and ‘them’. This can be particularly detrimental to minorities who may experience social exclusion, prejudice, and reduced access to equal opportunities. One method of improving intergroup relations is to create opportunities for contact. Common contact interventions have members of different groups meet and engage in conversation. There are also non-verbal embodied intergroup activities that produce the same effects. Previous work has shown that the pro-social effects of coordination may be linked to whether co-actors are classed as in or out-group members. The current study explored whether imagining walking in synchrony with in- or out-group members changed majority members’ attitudes towards those individuals. Imagining walking in synchrony fostered greater increases in empathy and decreases in negative attitudes only towards minority group members following imagined coordination (not in-groups). Implications and future directions are discussed.

Mental imagery in animals: Learning, memory, and decision-making in the face of missing information

When we open our eyes, we see a world filled with objects and events. Yet, due to occlusion of some objects by others, we only have partial perceptual access to the events that transpire around us. I discuss the body of research on mental imagery in animals. I first cover prior studies of mental rotation in pigeons and imagery using working memory procedures first developed for human studies. Next, I discuss the seminal work on a type of learning called mediated conditioning in rats. I then provide more in-depth coverage of work from my lab suggesting that rats can use imagery to fill in missing details of the world that are expected but hidden from perception. We have found that rats make use of an active expectation (i.e., an image) of a hidden visual event. I describe the behavioral and neurobiological studies investigating the use of a mental image, its theoretical basis, and its connections to current human cognitive neuroscience research on episodic memory, imagination, and mental simulations. Collectively, the reviewed literature provides insight into the mechanisms that mediate the flexible use of an image during ambiguous situations. I position this work in the broader scientific and philosophical context surrounding the concept of mental imagery in human and nonhuman animals.

Mental Singing Reduces Gait Variability More Than Music Listening for Healthy Older Adults and People With Parkinson Disease

BACKGROUND AND PURPOSE

Previously, we showed that internal cues (such as singing) produce similar motor benefits as external cues (such as listening to music) for people with Parkinson disease (PD). This study takes that research further by exploring how singing-either aloud or mentally-at different tempos can ameliorate gait, and it offers insight into how internal cueing techniques may enhance motor performance for older adults and people with PD.

METHODS

Sixty participants aged 50 years and older (30 female) were recruited; 30 had PD and 30 were healthy age-matched controls. Participants completed walking trials involving internal and external cueing techniques at 90%, 100%, and 110% of preferred cadence. The effects of different cue types and rates were assessed in a repeated-measures cross-sectional study by comparing gait characteristics (velocity, cadence, stride length) and variabilities (coefficients of variation of stride length, stride time, single support time).

RESULTS

All participants modified their cadence and stride length during cued conditions, resulting in changes in gait velocity closely reflecting expected changes based upon cue rate. External cues resulted in increased gait variability, whereas internal cues decreased gait variability relative to uncued walking. Variability decreases were more substantial during mental singing at tempos at or above preferred cadence.

DISCUSSION AND CONCLUSIONS

Matching movement to one's own voice improves gait characteristics while reducing gait variability for older adults and people with PD. Optimizing the use of internal cues to facilitate movement is an important step toward more effectively meeting the needs of people with gait disorders related to aging or neurological disease.Video Abstract available for more insights from authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A286).

An efficient and adaptive test of auditory mental imagery

The ability to silently hear music in the mind has been argued to be fundamental to musicality. Objective measurements of this subjective imagery experience are needed if this link between imagery ability and musicality is to be investigated. However, previous tests of musical imagery either rely on self-report, rely on melodic memory, or do not cater in range of abilities. The Pitch Imagery Arrow Task (PIAT) was designed to address these shortcomings; however, it is impractically long. In this paper, we shorten the PIAT using adaptive testing and automatic item generation. We interrogate the cognitive processes underlying the PIAT through item response modelling. The result is an efficient online test of auditory mental imagery ability (adaptive Pitch Imagery Arrow Task: aPIAT) that takes 8 min to complete, is adaptive to participant's individual ability, and so can be used to test participants with a range of musical backgrounds. Performance on the aPIAT showed positive moderate-to-strong correlations with measures of non-musical and musical working memory, self-reported musical training, and general musical sophistication. Ability on the task was best predicted by the ability to maintain and manipulate tones in mental imagery, as well as to resist perceptual biases that can lead to incorrect responses. As such, the aPIAT is the ideal tool in which to investigate the relationship between pitch imagery ability and musicality.

Fronto-temporal theta phase-synchronization underlies music-evoked pleasantness

Listening to pleasant music engages a complex distributed network including pivotal areas for auditory, reward, emotional and memory processing. On the other hand, frontal theta rhythms appear to be relevant in the process of giving value to music. However, it is not clear to which extent this oscillatory mechanism underlies the brain interactions that characterize music-evoked pleasantness and its related processes. The goal of the present experiment was to study brain synchronization in this oscillatory band as a function of music-evoked pleasantness. EEG was recorded from 25 healthy subjects while they were listening to music and rating the experienced degree of induced pleasantness. By using a multilevel Bayesian approach we found that phase synchronization in the theta band between right temporal and frontal signals increased with the degree of pleasure experienced by participants. These results show that slow fronto-temporal loops play a key role in music-evoked pleasantness.

How can we play together? Temporal inconsistencies in neural coding of music

If sensory organs encode environment, this code must be decoded to perception. The currently dominant theory of perception - predictive coding - assumes a "Bayesian decoder," a probability function, which will present (to whom?) an optimal guess, given previous encodings of the environment - old codes testing new codes. Such a process would delay perception noticeably. This is inconsistent with the perception of music, which for several reasons must be direct.

Neural Encoding of Auditory Features during Music Perception and Imagery

Despite many behavioral and neuroimaging investigations, it remains unclear how the human cortex represents spectrotemporal sound features during auditory imagery, and how this representation compares to auditory perception. To assess this, we recorded electrocorticographic signals from an epileptic patient with proficient music ability in 2 conditions. First, the participant played 2 piano pieces on an electronic piano with the sound volume of the digital keyboard on. Second, the participant replayed the same piano pieces, but without auditory feedback, and the participant was asked to imagine hearing the music in his mind. In both conditions, the sound output of the keyboard was recorded, thus allowing precise time-locking between the neural activity and the spectrotemporal content of the music imagery. This novel task design provided a unique opportunity to apply receptive field modeling techniques to quantitatively study neural encoding during auditory mental imagery. In both conditions, we built encoding models to predict high gamma neural activity (70-150 Hz) from the spectrogram representation of the recorded sound. We found robust spectrotemporal receptive fields during auditory imagery with substantial, but not complete overlap in frequency tuning and cortical location compared to receptive fields measured during auditory perception.

Music-related abilities among readers with dyslexia

Research suggests that a central difficulty in dyslexia may be impaired rapid temporal processing. Good temporal processing is also needed for musical perception, which relies on the ability to detect rapid changes. Our study is the first to measure the perception of adults with and without dyslexia on all three dimensions of music (rhythm, pitch, and spectrum), as well as their capacity for auditory imagery and detection of slow changes, while controlling for working memory. Participants were undergraduate students, aged 20-35 years: 26 readers with dyslexia and 30 typical readers. Participants completed a battery of tests measuring aptitude for recognizing the similarity/difference in tone pitch or rhythm, spectral resolution, vividness/control of auditory imagination, the ability to detect slow changes in auditory stimuli, and working memory. As expected, readers with dyslexia showed poorer performance in pitch and rhythm than controls, but outperformed them in spectral perception. The data for each test was analyzed separately while controlling for the letter-number sequencing score. No differences between groups were found in slow-change detection or auditory imagery. Our results demonstrated that rapid temporal processing appears to be the main difficulty of readers with dyslexia, who demonstrated poorer performance when stimuli were presented quickly rather than slowly and better performance on a task when no temporal component was involved. These findings underscore the need for further study of temporal processing in readers with dyslexia. Remediation of temporal processing deficits may unmask the preserved or even superior abilities of people with dyslexia, leading to enhanced ability in all areas that utilize the temporal component.

Neural Correlates of Music Listening and Recall in the Human Brain

Previous neuroimaging studies have identified various brain regions that are activated by music listening or recall. However, little is known about how these brain regions represent the time course and temporal features of music during listening and recall. Here we analyzed neural activity in different brain regions associated with music listening and recall using electrocorticography recordings obtained from 10 epilepsy patients of both genders implanted with subdural electrodes. Electrocorticography signals were recorded while subjects were listening to familiar instrumental music or recalling the same music pieces by imagery. During the onset phase (0-500 ms), music listening initiated cortical activity in high-gamma band in the temporal lobe and supramarginal gyrus, followed by the precentral gyrus and the inferior frontal gyrus. In contrast, during music recall, the high-gamma band activity first appeared in the inferior frontal gyrus and precentral gyrus, and then spread to the temporal lobe, showing a reversed temporal sequential order. During the sustained phase (after 500 ms), delta band and high-gamma band responses in the supramarginal gyrus, temporal and frontal lobes dynamically tracked the intensity envelope of the music during listening or recall with distinct temporal delays. During music listening, the neural tracking by the frontal lobe lagged behind that of the temporal lobe; whereas during music recall, the neural tracking by the frontal lobe preceded that of the temporal lobe. These findings demonstrate bottom-up and top-down processes in the cerebral cortex during music listening and recall and provide important insights into music processing by the human brain.SIGNIFICANCE STATEMENT Understanding how the brain analyzes, stores, and retrieves music remains one of the most challenging problems in neuroscience. By analyzing direct neural recordings obtained from the human brain, we observed dispersed and overlapping brain regions associated with music listening and recall. Music listening initiated cortical activity in high-gamma band starting from the temporal lobe and ending at the inferior frontal gyrus. A reversed temporal flow was observed in high-gamma response during music recall. Neural responses of frontal and temporal lobes dynamically tracked the intensity envelope of music that was presented or imagined during listening or recall. These findings demonstrate bottom-up and top-down processes in the cerebral cortex during music listening and recall.

Laryngeal and Pharyngeal Movements During Inner Singing: A Cross-Sectional Study

INTRODUCTION

Laryngeal and pharyngeal activity during inner singing is discussed in the context of vocal hygiene. Inner singing is defined as imagined singing, reading music silently, and listening to vocal music. When vocal rest is prescribed, doctors, speech therapists, and voice pedagogues recommend avoiding listening to music or reading music silently, since it is suggested that inner singing unconsciously influences the glottis, and thus moves the vocal folds involuntarily. The aim of this study was to compare the degree to which involuntary laryngeal and/or pharyngeal activity occur during inner singing, inner speech, and at rest, and to evaluate if current recommendations concerning vocal hygiene are still reasonable.

MATERIAL AND METHOD

Thirty vocally healthy participants were examined transnasally with a flexible videoendoscope. The sample consisted of 10 nonsingers, 10 lay singers, and 10 professional singers. Participants were examined during five tasks including rest, silent reading, imagining a melody, listening to music, and reading music. Two medical doctors specializing in phoniatrics analyzed the videos both qualitatively and quantitatively.

RESULTS

During the endoscopic examination, the raters identified movements at the base of the tongue, the posterior and lateral pharynx wall, the arytenoid cartilage, and the vocal folds. The inner singing tasks showed significantly more laryngeal movements as well as significantly more glottal closures than the control tasks (at rest, silent reading). Pharyngeal structures did not show an increase in activity during inner singing. These findings were independent of the level of proficiency in singing.

CONCLUSION

When total vocal rest is prescribed, patients should also be advised to avoid music imagination. Still, further research is needed to survey in detail the actual effects of these involuntary movements during inner singing on the regeneration process of vocal fold healing.

Towards reconstructing intelligible speech from the human auditory cortex

Auditory stimulus reconstruction is a technique that finds the best approximation of the acoustic stimulus from the population of evoked neural activity. Reconstructing speech from the human auditory cortex creates the possibility of a speech neuroprosthetic to establish a direct communication with the brain and has been shown to be possible in both overt and covert conditions. However, the low quality of the reconstructed speech has severely limited the utility of this method for brain-computer interface (BCI) applications. To advance the state-of-the-art in speech neuroprosthesis, we combined the recent advances in deep learning with the latest innovations in speech synthesis technologies to reconstruct closed-set intelligible speech from the human auditory cortex. We investigated the dependence of reconstruction accuracy on linear and nonlinear (deep neural network) regression methods and the acoustic representation that is used as the target of reconstruction, including auditory spectrogram and speech synthesis parameters. In addition, we compared the reconstruction accuracy from low and high neural frequency ranges. Our results show that a deep neural network model that directly estimates the parameters of a speech synthesizer from all neural frequencies achieves the highest subjective and objective scores on a digit recognition task, improving the intelligibility by 65% over the baseline method which used linear regression to reconstruct the auditory spectrogram. These results demonstrate the efficacy of deep learning and speech synthesis algorithms for designing the next generation of speech BCI systems, which not only can restore communications for paralyzed patients but also have the potential to transform human-computer interaction technologies.

The Stuck Song Syndrome: A Case of Musical Obsessions

Patient: Female, 32

Final Diagnosis: Obsessive compulsive disorder

Symptoms: Compulsive behavior • musical obsessions

Medication: —

Clinical Procedure: Treatment with serotonin selective reuptake inhibitors

Specialty: Psychiatry

Decoding Inner Speech Using Electrocorticography: Progress and Challenges Toward a Speech Prosthesis

Certain brain disorders resulting from brainstem infarcts, traumatic brain injury, cerebral palsy, stroke, and amyotrophic lateral sclerosis, limit verbal communication despite the patient being fully aware. People that cannot communicate due to neurological disorders would benefit from a system that can infer internal speech directly from brain signals. In this review article, we describe the state of the art in decoding inner speech, ranging from early acoustic sound features, to higher order speech units. We focused on intracranial recordings, as this technique allows monitoring brain activity with high spatial, temporal, and spectral resolution, and therefore is a good candidate to investigate inner speech. Despite intense efforts, investigating how the human cortex encodes inner speech remains an elusive challenge, due to the lack of behavioral and observable measures. We emphasize various challenges commonly encountered when investigating inner speech decoding, and propose potential solutions in order to get closer to a natural speech assistive device.

Evidence for a neural signature of musical preference during silence

One of the most basic and person-specific affective responses to music is liking. The present investigation sought to determine whether liking was preserved during spontaneous auditory imagery. To this purpose, we inserted two-second silent intervals into liked and disliked songs, a method known to automatically recreate a mental image of these songs. Neural correlates of musical preference were measured by high-density electroencephalography in twenty subjects who had to listen to a set of five pre-selected unknown songs the same number of times for two weeks. Time frequency analysis of the two most liked and the two most disliked songs confirmed the presence of neural responses related to liking. At the beginning of silent intervals (400-900 ms and 1000-1300 ms), significant differences in theta activity were originating from the inferior frontal and superior temporal gyrus. These two brain structures are known to work together to process various aspects of music and are also activated when measuring liking while listening to music. At the end of silent intervals (1400-1900 ms), significant alpha activity differences originating from the insula were observed, whose exact role remains to be explored. Although exposure was controlled for liked and disliked songs, liked songs were rated as more familiar, underlying the strong relationship that exists between liking, exposure, and familiarity.

More visual mind wandering occurrence during visual task performance: Modality of the concurrent task affects how the mind wanders

Mind wandering has been considered as a mental process that is either independent from the concurrent task or regulated like a secondary task. These accounts predict that the form of mind wandering (i.e., images or words) should be either unaffected by or different from the modality form (i.e., visual or auditory) of the concurrent task. Findings from this study challenge these accounts. We measured the rate and the form of mind wandering in three task conditions: fixation, visual 2-back, and auditory 2-back. Contrary to the general expectation, we found that mind wandering was more likely in the same form as the task. This result can be interpreted in light of recent findings on overlapping brain activations during internally- and externally-oriented processes. Our result highlights the importance to consider the unique interplay between the internal and external mental processes and to measure mind wandering as a multifaceted rather than a unitary construct.

The Multiple-Demand System in the Novelty of Musical Improvisation: Evidence from an MRI Study on Composers

The multiple-demand (MD) system has proven to be associated with creating structured mental programs in comprehensive behaviors, but the functional mechanisms of this system have not been clarified in the musical domain. In this study, we explored the hypothesis that the MD system is involved in a comprehensive music-related behavior known as musical improvisation. Under a functional magnetic resonance imaging (fMRI) paradigm, 29 composers were recruited to improvise melodies through visual imagery tasks according to familiar and unfamiliar cues. We found that the main regions of the MD system were significantly activated during both musical improvisation conditions. However, only a greater involvement of the intraparietal sulcus (IPS) within the MD system was shown when improvising with unfamiliar cues. Our results revealed that the MD system strongly participated in musical improvisation through processing the novelty of melodies, working memory, and attention. In particular, improvising with unfamiliar cues required more musical transposition manipulations. Moreover, both functional and structural analyses indicated evidence of neuroplasticity in MD regions that could be associated with musical improvisation training. These findings can help unveil the functional mechanisms of the MD system in musical cognition, as well as improve our understanding of musical improvisation.

Musical Imagery Involves Wernicke's Area in Bilateral and Anti-Correlated Network Interactions in Musicians

Musical imagery is the human experience of imagining music without actually hearing it. The neural basis of this mental ability is unclear, especially for musicians capable of engaging in accurate and vivid musical imagery. Here, we created a visualization of an 8-minute symphony as a silent movie and used it as real-time cue for musicians to continuously imagine the music for repeated and synchronized sessions during functional magnetic resonance imaging (fMRI). The activations and networks evoked by musical imagery were compared with those elicited by the subjects directly listening to the same music. Musical imagery and musical perception resulted in overlapping activations at the anterolateral belt and Wernicke’s area, where the responses were correlated with the auditory features of the music. Whereas Wernicke’s area interacted within the intrinsic auditory network during musical perception, it was involved in much more complex networks during musical imagery, showing positive correlations with the dorsal attention network and the motor-control network and negative correlations with the default-mode network. Our results highlight the important role of Wernicke’s area in forming vivid musical imagery through bilateral and anti-correlated network interactions, challenging the conventional view of segregated and lateralized processing of music versus language.

Neurophysiological evidence of efference copies to inner speech

Efference copies refer to internal duplicates of movement-producing neural signals. Their primary function is to predict, and often suppress, the sensory consequences of willed movements. Efference copies have been almost exclusively investigated in the context of overt movements. The current electrophysiological study employed a novel design to show that inner speech – the silent production of words in one’s mind – is also associated with an efference copy. Participants produced an inner phoneme at a precisely specified time, at which an audible phoneme was concurrently presented. The production of the inner phoneme resulted in electrophysiological suppression, but only if the content of the inner phoneme matched the content of the audible phoneme. These results demonstrate that inner speech – a purely mental action – is associated with an efference copy with detailed auditory properties. These findings suggest that inner speech may ultimately reflect a special type of overt speech.

As you read this text, the chances are you can hear your own inner voice narrating the words. You may hear your inner voice again when silently considering what to have for lunch, or imagining how a phone conversation this afternoon will play out. Estimates suggest that we spend at least a quarter of our lives listening to our own inner speech. But to what extent does the brain distinguish between inner speech and the sounds we produce when we speak out loud?

Listening to a recording of your own voice activates the brain more than hearing yourself speak out loud. This is because when the brain sends instructions to the lips, tongue, and vocal cords telling them to move, it also makes a copy of these instructions. This is known as an efference copy, and it enables regions of the brain that process sounds to predict what they are about to hear. When the actual sounds match those predicted – as when you hear yourself speak out loud – the brain’s sound-processing regions dampen down their responses.

But does the inner speech in our heads also generate an efference copy? To find out, Whitford et al. tracked the brain activity of healthy volunteers as they listened to speech sounds through headphones. While listening to the sounds, the volunteers had to produce either the same speech sound or a different speech sound inside their heads. A specific type of brain activity decreased whenever the inner speech sound matched the external speech sound. This decrease did not occur when the two sounds were different. This suggests that the brain produces an efference copy for inner speech similar to that for external speech.

These findings could ultimately benefit people who suffer from psychotic symptoms, for example as part of schizophrenia. Symptoms such as hearing voices are thought to reflect problems with producing and interpreting inner speech. The technique that Whitford et al. have developed will enable us to test this long-held but hitherto untestable idea. The results should increase our understanding of these symptoms and may eventually lead to new treatments.

Imagined Steps: Mental Simulation of Coordinated Rhythmic Movements Effects on Pro-sociality

Rhythmically coordinating with a partner can increase pro-sociality, but pro-sociality does not appear to change in proportion to coordination success, or particular classes of coordination. Pro-social benefits may have more to do with simply coordinating in a social context than the details of the actual coordination (Cross et al., 2016). This begs the question, how stripped down can a coordination task be and still affect pro-sociality? Would it be sufficient simply to imagine coordinating with others? Imagining a social interaction can lead to many of the same effects as actual interaction (Crisp and Turner, 2009). We report the first experiments to explore whether imagined coordination affects pro-sociality similarly to actual coordination. Across two experiments and over 450 participants, mentally simulated coordination is shown to promote some, but not all, of the pro-social consequences of actual coordination. Imagined coordination significantly increased group cohesion and de-individuation, but did not consistently affect cooperation.

Not all about sex: neural and biobehavioral functions of human dance

This paper provides an integrative review of neuroscientific and biobehavioral evidence about the effects of dance on the individual across cultural differences. Dance moves us, and many derive aesthetic pleasure from it. However, in addition-and beyond aesthetics-we propose that dance has noteworthy, deeper neurobiological effects. We first summarize evidence that illustrates the centrality of dance to human life indirectly from archaeology, comparative psychology, developmental psychology, and cross-cultural psychology. Second, we review empirical evidence for six neural and biobehavioral functions of dance: (1) attentional focus/flow, (2) basic emotional experiences, (3) imagery, (4) communication, (5) self-intimation, and (6) social cohesion. We discuss the reviewed evidence in relation to current debates in the field of empirical enquiry into the functions of human dance, questioning the positions that dance is (1) just for pleasure, (2) all about sex, (3) just for mood management and well-being, and (4) for experts only. Being a young field, evidence is still piecemeal and inconclusive. This review aims to take a step toward a systematization of an emerging avenue of research: a neuro- and biobehavioral science of dance.

Expertise shapes domain-specific functional cerebral asymmetry during mental imagery: the case of culinary arts and music

Mental imagery in experts has been documented in visual arts, music and dance. Here, we examined this issue in an understudied art domain, namely, culinary arts. Previous research investigating mental imagery in experts has reported either a stronger involvement of the right hemisphere or bilateral brain activation. The first aim of our study was to examine whether culinary arts also recruit such a hemispheric pattern specifically during odor mental imagery. In a second aim, we investigated whether expertise effects observed in a given sensory domain transfer to another modality. We combined psychophysics and neurophysiology to study mental imagery in cooks, musicians and controls. We collected response times and event-related potentials (ERP) while participants mentally compared the odor of fruits, the timbre of musical instruments and the size of fruits, musical instruments and manufactured objects. Cooks were faster in imagining fruit odors, and musicians were faster in imagining the timbre of musical instruments. These differences were not observed in control participants. This expertise effect was reflected in the ERP late positive complex (LPC): only experts showed symmetric bilateral activation, specifically when cooks imagined odors and when musicians imagined timbres. In contrast, the LPC was significantly greater in the left hemisphere than in the right hemisphere for non-expert participants in all conditions. These findings suggest that sensory expertise does not involve transfer of mental imagery ability across modalities and highlight for the first time that olfactory expertise in cooks induces a balance of activations between hemispheres as does musical expertise in musicians.

Measuring the representational space of music with fMRI: a case study with Sting

Functional brain imaging has revealed much about the neuroanatomical substrates of higher cognition, including music, language, learning, and memory. The technique lends itself to studying of groups of individuals. In contrast, the nature of expert performance is typically studied through the examination of exceptional individuals using behavioral case studies and retrospective biography. Here, we combined fMRI and the study of an individual who is a world-class expert musician and composer in order to better understand the neural underpinnings of his music perception and cognition, in particular, his mental representations for music. We used state of the art multivoxel pattern analysis (MVPA) and representational dissimilarity analysis (RDA) in a fixed set of brain regions to test three exploratory hypotheses with the musician Sting: (1) Composing would recruit neutral structures that are both unique and distinguishable from other creative acts, such as composing prose or visual art; (2) listening and imagining music would recruit similar neural regions, indicating that musical memory shares anatomical substrates with music listening; (3) the MVPA and RDA results would help us to map the representational space for music, revealing which musical pieces and genres are perceived to be similar in the musician's mental models for music. Our hypotheses were confirmed. The act of composing, and even of imagining elements of the composed piece separately, such as melody and rhythm, activated a similar cluster of brain regions, and were distinct from prose and visual art. Listened and imagined music showed high similarity, and in addition, notable similarity/dissimilarity patterns emerged among the various pieces used as stimuli: Muzak and Top 100/Pop songs were far from all other musical styles in Mahalanobis distance (Euclidean representational space), whereas jazz, R&B, tango and rock were comparatively close. Closer inspection revealed principaled explanations for the similarity clusters found, based on key, tempo, motif, and orchestration.

Can repetitive mental simulation of smoking engender habituation?

Smoking cue exposure sensitizes smokers to cigarettes (i.e., increases cravings). Research examining the overlap between perception and mental imagery suggests that mentally simulating smoking a cigarette in a manner analogous to actually smoking should lead to habituation or a decrease in a smoker's motivation to smoke. The authors sought to determine whether repetitive mental simulation of smoking can engender habituation thereby reducing smoking cue-induced craving and shifts in mood, latency to smoke, and the hedonic response to smoking. These hypotheses were tested in nontreatment seeking smokers (n = 61; 24 women/37 men) ages 18-55 years old, who were not incentivized to quit. The authors used a 2 (in vivo cue: smoking, neutral) × 2 (imagery: repetitive, limited) within-subjects design. Results revealed that repetitive imagery altered the effect of cue type for negative mood and subjective cigarette reward as evidenced by significant Imagery × Cue interactions. Repetitive imagery after a smoking cue reduced negative mood more than limited imagery (β = -1.19, p = .004). Repetitive imagery also reduced the reward derived from smoking a cigarette more than limited imagery (β = -.41, p < .0001). Only main effects of cue type on craving (β = 3.39, p = .01) and positive mood (β = -1.18, p = .03) were found. Greater imagery strength predicted a longer latency to smoke (β = .76, p = .001). Cognitive strategies that directly engage cue-induced craving through repetitive smoking imagery may reduce smoking cue-induced increases in negative mood and reward from a cigarette lapse potentially preventing smoking relapse. (PsycINFO Database Record