Increased corpus callosum size in musicians

The relationship of music to the melody of speech and to syntactic processing disorders in aphasia

Two new empirical studies address the relationship between music and language. The first focuses on melody and uses research in phonetics to investigate the long-held notion that instrumental music reflects speech patterns in a composer's native language. The second focuses on syntax and addresses the relationship between musical and linguistic syntactic processing via the study of aphasia, an approach that has been explored very little. The results of these two studies add to a growing body of evidence linking music and language with regard to structural patterns and brain processing.

Sound processing in amateur musicians and nonmusicians: event-related potential and behavioral indices

To increase our understanding of auditory neurocognition in musicians, we compared nonmusicians with amateur band musicians in their neural and behavioral sound encoding accuracy. Mismatch negativity and P3a components of the auditory event-related potentials were recorded to changes in basic acoustic features (frequency, duration, location, intensity, gap) and abstract features (melodic contour and interval size). Mismatch negativity was larger in musicians than in nonmusicians for location changes whereas no statistically significant group difference was observed in response to other feature changes or in abstract-feature mismatch negativity. P3a was observed only in musicians in response to location changes. This suggests that when compared with nonmusicians, even amateur musicians have neural sound processing advantages with acoustic information most essential to their musical genre.

Classical conditioned responses to absent tones

Background

Recent evidence for a tight coupling of sensorimotor processes in trained musicians led to the question of whether this coupling extends to preattentively mediated reflexes; particularly, whether a classically conditioned response in one of the domains (auditory) is generalized to another (tactile/motor) on the basis of a prior association in a second-order Pavlovian paradigm. An eyeblink conditioning procedure was performed in 17 pianists, serving as a model for overlearned audiomotor integration, and 14 non-musicians. Results: During the training session, subjects were conditioned to respond to auditory stimuli (piano tones). During a subsequent testing session, when subjects performed keystrokes on a silent piano, pianists showed significantly higher blink rates than non-musicians.

Conclusion

These findings suggest a tight coupling of the auditory and motor domains in musicians, pointing towards training-dependent mechanisms of strong cross-modal sensorimotor associations even on sub-cognitive processing levels.

Reduced P50 auditory sensory gating response in professional musicians

Evoked potential studies have demonstrated that musicians have the ability to distinguish musical sounds preattentively and automatically at the temporal, spectral, and spatial levels in more detail. It is however not known whether there is a difference in the early processes of auditory data processing of musicians. The most emphasized and studied early process, especially for neuropsychiatric purposes, is sensory gating. The suppression percentage of the midlatency auditory evoked potential P50, and rarely the N100, wave is used for sensory gating studies. Our aim in this study was to investigate whether there was a difference in the auditory P50 and N100 suppression of control subjects who were professional musicians with no psychiatric problems. 34 professional musicians and 19 non-musicians (the control group) were included in this study. P50 and N100 measurements were taken, the suppression percentage of P50 and N100 was calculated and the results compared. Musicians showed significantly less P50 suppression when compared to non-musicians. There was no significant difference for N100 suppression. What the decreased P50 suppression in musicians when compared to non-musician subjects means, when we also take into account that N100 suppression is not decreased, and how it may contribute to the music perception and production processes of these persons is discussed.

Music and the brain: disorders of musical listening

The study of the brain bases for normal musical listening has advanced greatly in the last 30 years. The evidence from basic and clinical neuroscience suggests that listening to music involves many cognitive components with distinct brain substrates. Using patient cases reported in the literature, we develop an approach for understanding disordered musical listening that is based on the systematic assessment of the perceptual and cognitive analysis of music and its emotional effect. This approach can be applied both to acquired and congenital deficits of musical listening, and to aberrant listening in patients with musical hallucinations. Both the bases for normal musical listening and the clinical assessment of disorders now have a solid grounding in systems neuroscience.

Structural and functional neural correlates of music perception

This review article highlights state-of-the-art functional neuroimaging studies and demonstrates the novel use of music as a tool for the study of human auditory brain structure and function. Music is a unique auditory stimulus with properties that make it a compelling tool with which to study both human behavior and, more specifically, the neural elements involved in the processing of sound. Functional neuroimaging techniques represent a modern and powerful method of investigation into neural structure and functional correlates in the living organism. These methods have demonstrated a close relationship between the neural processing of music and language, both syntactically and semantically. Greater neural activity and increased volume of gray matter in Heschl's gyrus has been associated with musical aptitude. Activation of Broca's area, a region traditionally considered to subserve language, is important in interpreting whether a note is on or off key. The planum temporale shows asymmetries that are associated with the phenomenon of perfect pitch. Functional imaging studies have also demonstrated activation of primitive emotional centers such as ventral striatum, midbrain, amygdala, orbitofrontal cortex, and ventral medial prefrontal cortex in listeners of moving musical passages. In addition, studies of melody and rhythm perception have elucidated mechanisms of hemispheric specialization. These studies show the power of music and functional neuroimaging to provide singularly useful tools for the study of brain structure and function.

It don't mean a thing…

Music is experienced and understood on the basis of foreground/background relationships created between actual music and the underlying meter. In contemporary styles of music so-called polyrhythmic, structures hence create tension between a counter pulse and the main pulse. This exerts a marked influence on the listener, particularly when the experience of the original meter is maintained during the counter pulse. We here demonstrate that Brodmann area 47, an area associated with higher processing of language, is activated bilaterally when musicians tap the main pulse in a polymetric context where the music emphasizes a counter meter. This suggests that the processing of metric elements of music relies on brain areas also involved in language comprehension. We propose that BA47 is involved in general neuronal processing of temporal coherence subserving both language and music.

Music in dreams

Music in dreams is rarely reported in scientific literature, while the presence of musical themes in dreams of famous musicians is anecdotally reported. We did a systematic investigation to evaluate whether the occurrence of musical dreams could be related to musical competence and practice, and to explore specific features of dreamt pieces. Thirty-five professional musicians and thirty non-musicians filled out a questionnaire about the characteristics of their musical activity and a structured dream log on the awakening for 30 consecutive days. Musicians dream of music more than twice with respect to non-musicians; musical dreams frequency is related to the age of commencement of musical instruction, but not to the daily load of musical activity. Nearly half of the recalled music was non-standard, suggesting that original music can be created in dreams.

Exposure to music in the perinatal period enhances learning performance and alters BDNF/TrkB signaling in mice as adults

Music has been suggested to have a beneficial effect on various types of performance in humans. However, the physiological and molecular mechanism of this effect remains unclear. We examined the effect of music exposure during the perinatal period on learning behavior in adult mice, and measured the levels of brain-derived neurotrophic factor (BDNF) and its receptor, tyrosine kinase receptor B (TrkB), which play critical roles in synaptic plasticity. In addition, we measured the levels of 3-phosphoinositide-dependent protein kinase-1 (PDK1) and mitogen-activated protein kinase (MAPK), downstream targets of two main pathways in BDNF/TrkB signaling. Music-exposed mice completed a maze learning task with fewer errors than the white noise-exposed mice and had lower levels of BDNF and higher levels of TrkB and PDK1 in the cortex. MAPK levels were unchanged. Furthermore, TrkB and PDK1 protein levels in the cortex showed a significant negative correlation with the number of errors on the maze. These results suggest that perinatal exposure of mice to music has an influence on BDNF/TrkB signaling and its intracellular signaling pathway targets, including PDK1, and thus may induce improved learning and memory functions.

Shared networks for auditory and motor processing in professional pianists: Evidence from fMRI conjunction

To investigate cortical auditory and motor coupling in professional musicians, we compared the functional magnetic resonance imaging (fMRI) activity of seven pianists to seven non-musicians utilizing a passive task paradigm established in a previous learning study. The tasks involved either passively listening to short piano melodies or pressing keys on a mute MRI-compliant piano keyboard. Both groups were matched with respect to age and gender, and did not exhibit any overt performance differences in the keypressing task. The professional pianists showed increased activity compared to the non-musicians in a distributed cortical network during both the acoustic and the mute motion-related task. A conjunction analysis revealed a distinct musicianship-specific network being co-activated during either task type, indicating areas involved in auditory-sensorimotor integration. This network is comprised of dorsolateral and inferior frontal cortex (including Broca's area), the superior temporal gyrus (Wernicke's area), the supramarginal gyrus, and supplementary motor and premotor areas.

Musician Children Detect Pitch Violations in Both Music and Language Better than Nonmusician Children: Behavioral and Electrophysiological Approaches

The idea that extensive musical training can influence processing in cognitive domains other than music has received considerable attention from the educational system and the media. Here we analyzed behavioral data and recorded event-related brain potentials (ERPs) from 8-year-old children to test the hypothesis that musical training facilitates pitch processing not only in music but also in language. We used a parametric manipulation of pitch so that the final notes or words of musical phrases or sentences were congruous, weakly incongruous, or strongly incongruous. Musician children outperformed nonmusician children in the detection of the weak incongruity in both music and language. Moreover, the greatest differences in the ERPs of musician and nonmusician children were also found for the weak incongruity: whereas for musician children, early negative components developed in music and late positive components in language, no such components were found for nonmusician children. Finally, comparison of these results with previous ones from adults suggests that some aspects of pitch processing are in effect earlier in music than in language. Thus, the present results reveal positive transfer effects between cognitive domains and shed light on the time course and neural basis of the development of prosodic and melodic processing.

Are we "experienced listeners"? A review of the musical capacities that do not depend on formal musical training

The present paper reviews a set of studies designed to investigate different aspects of the capacity for processing Western music. This includes perceiving the relationships between a theme and its variations, perceiving musical tensions and relaxations, generating musical expectancies, integrating local structures in large-scale structures, learning new compositional systems and responding to music in an emotional (affective) way. The main focus of these studies was to evaluate the influence of intensive musical training on these capacities. The overall set of data highlights that some musical capacities are acquired through exposure to music without the help of explicit training. These capacities reach such a degree of sophistication that they enable untrained listeners to respond to music as "musically experienced listeners" do.

The advantage of a decreasing right-hand superiority: The influence of laterality on a selected musical skill (sight reading achievement)

In this study, the unrehearsed performance of music, known as 'sight reading', is used as a model to examine the influence of motoric laterality on highly challenging musical performance skills. As expertise research has shown, differences in this skill can be partially explained by factors such as accumulated practise and an early start to training. However, up until now, neurobiological factors that may influence highly demanding instrumental performance have been widely neglected. In an experiment with 52 piano students at a German university music department, we could show that the most challenging musical skill, sight reading (which is characterized by extreme demands on the performer's real time information processing), is positively correlated with decreasing right-hand superiority of performers. Laterality was measured by the differences between left and right-hand performance in a speed tapping task. SR achievement was measured using an accompanying task paradigm. An overall superiority of 22% for non-right-handed pianists was found. This effect is gender-related and stronger in non-right-handed males (r(24) = -0.49, p<0.05) than in non-right-handed females (r(28) = -0.16, p>0.05). We conclude that non-right-handed motoric laterality is associated with neurobiological advantages required for sight reading, an extremely demanding musical subskill.

Brain activation during music listening in individuals with or without prior music training

The present study investigated activation during listening to music with and without a task in female musicians and non-musicians. Five subjects with long musical training for a mean period of 19+/-1 years (musician group) and five subjects with no training in musical instruments (non-musician group) were imaged in a 1.5T scanner, while they simply listened to short segments of piano pieces (LIS), and while they performed a distorted tune test, designed using the same pieces (DTT). A significant group effect with higher signals in the musician group was observed in the right superior and middle temporal gyri, the right inferior frontal gyrus, and the left supramarginal gyrus. A task effect with higher signals during DTT was observed in the left sensorimotor cortex, where the interaction between the task and group effects was also significant. Thus, the pattern of brain activation differed depending on tasks when identical music stimuli were used, and more importantly, comparable music tasks activated the brain differently depending on prior musical training of subjects.

Are there pre-existing neural, cognitive, or motoric markers for musical ability?

Adult musician's brains show structural enlargements, but it is not known whether these are inborn or a consequence of long-term training. In addition, music training in childhood has been shown to have positive effects on visual-spatial and verbal outcomes. However, it is not known whether pre-existing advantages in these skills are found in children who choose to study a musical instrument nor is it known whether there are pre-existing associations between music and any of these outcome measures that could help explain the training effects. To answer these questions, we compared 5- to 7-year-olds beginning piano or string lessons (n=39) with 5- to 7-year-olds not beginning instrumental training (n=31). All children received a series of tests (visual-spatial, non-verbal reasoning, verbal, motor, and musical) and underwent magnetic resonance imaging. We found no pre-existing neural, cognitive, motor, or musical differences between groups and no correlations (after correction for multiple analyses) between music perceptual skills and any brain or visual-spatial measures. However, correlations were found between music perceptual skills and both non-verbal reasoning and phonemic awareness. Such pre-existing correlations suggest similarities in auditory and visual pattern recognition as well a sharing of the neural substrates for language and music processing, most likely due to innate abilities or implicit learning during early development. This baseline study lays the groundwork for an ongoing longitudinal study addressing the effects of intensive musical training on brain and cognitive development, and making it possible to look retroactively at the brain and cognitive development of those children who emerge showing exceptional musical talent.

Mapping brain maturation and cognitive development during adolescence

Non-invasive mapping of brain structure and function with magnetic resonance imaging (MRI) has opened up unprecedented opportunities for studying the neural substrates underlying cognitive development. There is an emerging consensus of a continuous increase throughout adolescence in the volume of white matter, both global and local. There is less agreement on the meaning of asynchronous age-related decreases in the volume of grey matter in different cortical regions; these might equally represent loss ("pruning") or gain (intra-cortical myelination) of tissue. Functional MRI studies have so far focused mostly on executive functions, such as working memory and behavioural inhibition, with very few addressing questions regarding the maturation of social cognition. Future directions for research in this area are discussed in the context of processing biological motion and matching perceptions and actions.

Transmodal Sensorimotor Networks during Action Observation in Professional Pianists

Audiovisual perception and imitation are essential for musical learning and skill acquisition. We compared professional pianists to musically naive controls with fMRI while observing piano playing finger–hand movements and serial finger–thumb opposition movements both with and without synchronous piano sound. Pianists showed stronger activations within a fronto-parieto-temporal network while observing piano playing compared to controls and contrasted to perception of serial finger–thumb opposition movements. Observation of silent piano playing additionally recruited auditory areas in pianists. Perception of piano sounds coupled with serial finger–thumb opposition movements evoked increased activation within the sensorimotor network. This indicates specialization of multimodal auditory– sensorimotor systems within a fronto-parieto-temporal network by professional musical training. Musical “language,” which is acquired by observation and imitation, seems to be tightly coupled to this network in accord with an observation– execution system linking visual and auditory perception to motor performance.

Musical experience and dementia. Hypothesis

BACKGROUND AND AIMS

Cognitively stimulating activities appear to protect against the development of dementing illness--playing a musical instrument may be one of these activities. Consistent with this notion, the aim of this study was to explore the hypothesis that dementia might be less common among orchestral musicians.

METHODS

A cross-sectional survey of 23 older orchestral musicians who were former members of a single orchestra was carried out. Prior musical background, family history, and health history were obtained. A cognitive screen was administered in person or by telephone. Musicians were also queried regarding their awareness of living former orchestral colleagues with dementia.

RESULTS

The mean age of participants was 76.9 +/- 6.8 (SD). No participant was aware of a living former or current orchestral member with either reported or suspected dementia.

CONCLUSIONS

The results are consistent with the hypothesis that dementing illness may be less among orchestral musicians--possibly from a lifetime engaged in a cognitively stimulating endeavor.

Ipsilateral and contralateral motor inhibitory control in musical and vocalization tasks

The inhibitory motor control mechanisms in human singing and vocalization are not well understood. Using transcranial magnetic stimulation (TMS), we show that singing resulted in right-sided prolongation of ipsilateral silent period and bilateral reduction in contralateral silent period. Reading led to reduced contralateral silent period duration with right-sided TMS only, but no significant inhibitory changes, both ipsilateral and contralateral, were evident with humming. The findings support the presence of enhanced interhemispheric inhibitory motor interaction during singing, as opposed to reading tasks, in dynamic word generation coupled with production of melody.

Reduced recruitment of motor association areas during bimanual coordination in concert pianists

Bimanual motor coordination is essential for piano playing. The functional neuronal substrate for high-level bimanual performance achieved by professional pianists is unclear. We compared professional pianists to musically naïve controls while carrying out in-phase (mirror) and anti-phase (parallel) bimanual sequential finger movements during functional magnetic resonance imaging (fMRI). This task corresponds to bimanually playing scales practiced daily by pianists from the beginning of piano playing. Musicians and controls showed significantly different functional activation patterns. When comparing performance of parallel movements to rest, musically naïve controls showed stronger activations than did pianists within a network including anterior cingulate cortex, right dorsal premotor cortex, both cerebellar hemispheres, and right basal ganglia. The direct comparison of bimanual parallel to mirror movements between both groups revealed stronger signal increases in controls within mesial premotor cortex (SMA), bilateral cerebellar hemispheres and vermis, bilateral prefrontal cortex, left ventral premotor cortex, right anterior insula, and right basal ganglia. These findings suggest increased efficiency of cortical and subcortical systems for bimanual movement control in musicians. This may be fundamental to achieve high-level motor skills allowing the musician to focus on artistic aspects of musical performance.

Musical Training Enhances Automatic Encoding of Melodic Contour and Interval Structure

In music, melodic information is thought to be encoded in two forms, a contour code (up/down pattern of pitch changes) and an interval code (pitch distances between successive notes). A recent study recording the mismatch negativity (MMN) evoked by pitch contour and interval deviations in simple melodies demonstrated that people with no formal music education process both contour and interval information in the auditory cortex automatically. However, it is still unclear whether musical experience enhances both strategies of melodic encoding. We designed stimuli to examine contour and interval information separately. In the contour condition there were eight different standard melodies (presented on 80% of trials), each consisting of five notes all ascending in pitch, and the corresponding deviant melodies (20%) were altered to descending on their final note. The interval condition used one five-note standard melody transposed to eight keys from trial to trial, and on deviant trials the last note was raised by one whole tone without changing the pitch contour. There was also a control condition, in which a standard tone (990.7 Hz) and a deviant tone (1111.0 Hz) were presented. The magnetic counterpart of the MMN (MMNm) from musicians and nonmusicians was obtained as the difference between the dipole moment in response to the standard and deviant trials recorded by magnetoencephalography. Significantly larger MMNm was present in musicians in both contour and interval conditions than in nonmusicians, whereas MMNm in the control condition was similar for both groups. The interval MMNm was larger than the contour MMNm in musicians. No hemispheric difference was found in either group. The results suggest that musical training enhances the ability to automatically register abstract changes in the relative pitch structure of melodies.

Long-term training affects cerebellar processing in skilled keyboard players

We studied cerebellar hemodynamic responses in highly skilled keyboard players and control subjects during complex tasks requiring unimanual and bimanual finger movements. Both groups showed strong hemodynamic responses in the cerebellum during the task conditions. However, non-musicians showed generally stronger hemodynamic responses in the cerebellum than keyboard players. We conclude that, due to long-term motor practice a different cortical activation pattern can be visualized in keyboard players. For the same movements fewer neurons need to be recruited. The different volume of the activated cortical areas might therefore reflect the different effort necessary for motor performance in both groups.

A voxel-based approach to gray matter asymmetries

Voxel-based morphometry (VBM) was used to analyze gray matter (GM) asymmetries in a large sample (n = 60) of male and female professional musicians with and without absolute pitch (AP). We chose to examine these particular groups because previous studies using traditional region-of-interest (ROI) analyses have shown differences in hemispheric asymmetry related to AP and gender. Voxel-based methods may have advantages over traditional ROI-based methods since the analysis can be performed across the whole brain with minimal user bias. After determining that the VBM method was sufficiently sensitive for the detection of differences in GM asymmetries between groups, we found that male AP musicians were more leftward lateralized in the anterior region of the planum temporale (PT) than male non-AP musicians. This confirmed the results of previous studies using ROI-based methods that showed an association between PT asymmetry and the AP phenotype. We further observed that male non-AP musicians revealed an increased leftward GM asymmetry in the postcentral gyrus compared to female non-AP musicians, again corroborating results of a previously published study using ROI-based methods. By analyzing hemispheric GM differences across our entire sample, we were able to partially confirm findings of previous studies using traditional morphometric techniques, as well as more recent, voxel-based analyses. In addition, we found some unusually pronounced GM asymmetries in our musician sample not previously detected in subjects unselected for musical training. Since we were able to validate gender- and AP-related brain asymmetries previously described using traditional ROI-based morphometric techniques, the results of our analyses support the use of VBM for examinations of GM asymmetries.

Bilingual corpus callosum variability

Magnetic resonance imaging was used to produce midsagittal images of the corpus callosum of 19 right-handed adult male and female subjects. The preliminary findings of this study indicate that significant adaptation in the anterior midbody of the corpus callosum has occurred to accommodate multiple language capacity in bilingual individuals compared to monolingual individuals. The main interpretation of this finding is that the precentral gyrus is involved in bilingual faculty adaptation assuming a role consistent with the somatotopical input to areas dedicated to the mouth, and input to association tracts connecting the premotor and supplementary motor cortices. This paper discusses possible implications to neuroscientists, second language educators, and their students.

The music of speech: Music training facilitates pitch processing in both music and language

The main aim of the present experiment was to determine whether extensive musical training facilitates pitch contour processing not only in music but also in language. We used a parametric manipulation of final notes' or words' fundamental frequency (F0), and we recorded behavioral and electrophysiological data to examine the precise time course of pitch processing. We compared professional musicians and nonmusicians. Results revealed that within both domains, musicians detected weak F0 manipulations better than nonmusicians. Moreover, F0 manipulations within both music and language elicited similar variations in brain electrical potentials, with overall shorter onset latency for musicians than for nonmusicians. Finally, the scalp distribution of an early negativity in the linguistic task varied with musical expertise, being largest over temporal sites bilaterally for musicians and largest centrally and over left temporal sites for nonmusicians. These results are taken as evidence that extensive musical training influences the perception of pitch contour in spoken language.

The effect of musical training on the neural correlates of math processing: a functional magnetic resonance imaging study in humans

The neural correlates of the previously hypothesized link between formal musical training and mathematics performance are investigated using functional magnetic resonance imaging (fMRI). FMRI was performed on fifteen normal adults, seven with musical training since early childhood, and eight without, while they mentally added and subtracted fractions. Musical training was associated with increased activation in the left fusiform gyrus and prefrontal cortex, and decreased activation in visual association areas and the left inferior parietal lobule during the mathematical task. We hypothesize that the correlation between musical training and math proficiency may be associated with improved working memory performance and an increased abstract representation of numerical quantities.

Effect of musical expertise on visuospatial abilities: Evidence from reaction times and mental imagery

Recently, the relationship between music and nonmusical cognitive abilities has been highly debated. It has been documented that formal music training would improve verbal, mathematical or visuospatial performance in children. In the experiments described here, we tested if visual perception and imagery abilities were enhanced in adult musicians compared with nonmusicians. In our main experiment, we measured reaction times of subjects who had to detect on which side of a horizontal or a vertical line a target dot was flashed. In the "imagery" condition the reference line disappeared before the target dot was presented. In order to accomplish the task, subjects had to keep a mental image of the position of the line until the dot appeared. In the "perception" condition, the procedure and stimuli were the same except that the line remained on the screen until the dot was displayed. In both groups, reaction times were shorter for horizontal compared to vertical discrimination, but reaction times were significantly shorter in musicians in all conditions. Moreover, discrimination on the vertical dimension, especially in imaging condition, seemed to be greatly improved on the long term by musical expertise. Simple and choice visual reaction times indicate that this advantage could only be partly explained by better sensorimotor integration in adult musicians.

Prosodic and melodic processing in adults and children. Behavioral and electrophysiologic approaches

The results of a series of experiments aimed at directly comparing the prosodic level of processing in language with the melodic level of processing in music are reported. The first series of experiments was conducted on adults, musicians and nonmusicians, and the second one on 7- to 9-year-old musician and nonmusician children. However, as this last study is still in progress, only preliminary results will be presented. The theoretic framework within which these experiments are taking place is described. The first problem concerns the specificity of the perceptive and cognitive computations necessary to perceive and understand language. We argue that comparing language with music can provide interesting insights into this complex issue. The second problem is linked to the relationship between different types of learning. Does early musical training influence the way in which musicians process some aspects of language as prosody? These two problems are considered and the results of the experiments are described.

Brain plasticity in health and disease

Research during the last decades has greatly increased our understanding of brain plasticity, i.e. how neuronal circuits can be modified by experience, learning and in response to brain lesions. Currently available neuroimaging techniques that make it possible to study the function of the human brain in vivo have had an important impact. Cross-modal plasticity during development is demonstrated by cortical reorganization in blind or deaf children. Early musical training has lasting effects in shaping the brain. Albeit the plasticity is largest during childhood, the adult brain retains a capacity for functional and structural reorganization that earlier has been underestimated. Recent research on Huntington's disease has revealed the possibility of environmental interaction even with dominant genes. Scientifically based training methods are now being applied in rehabilitation of patients after stroke and trauma, and in the sensory retraining techniques currently applied in the treatment of focal hand dystonia as well as in sensory re-education after nerve repair in hand surgery. There is evidence that frequent participation in challenging and stimulating activities is associated with reduced cognitive decline during aging. The current concept of brain plasticity has wide implication for areas outside neuroscience and for all human life.

FMRI investigation of cross-cultural music comprehension

The popular view of music as a "universal" language ignores the privileged position of the cultural insider in comprehending musical information unique to their own tradition. The purpose of this study was to test the hypothesis that listeners would demonstrate different neural activity in response to culturally familiar and unfamiliar music and that those differences may be affected by the extent of subjects' formal musical training. Just as familiar languages have been shown to use distinct brain processes, we hypothesized that an analogous difference might be found in music and that it may depend in part on subjects' formal musical knowledge. Using fMRI we compared the activation patterns of professional musicians and untrained controls reared in the United States as they listened to music from their culture (Western) and from an unfamiliar culture (Chinese). No overall differences in activation were observed for either subject group in response to the two musical styles, although there were differences in recall performance based on style and there were activation differences based on training. Trained listeners demonstrated additional activation in the right STG for both musics and in the right and left midfrontal regions for Western music and Chinese music, respectively. Our findings indicate that listening to culturally different musics may activate similar neural resources but with dissimilar results in recall performance.

Brain structures differ between musicians and non-musicians

From an early age, musicians learn complex motor and auditory skills (e.g., the translation of visually perceived musical symbols into motor commands with simultaneous auditory monitoring of output), which they practice extensively from childhood throughout their entire careers. Using a voxel-by-voxel morphometric technique, we found gray matter volume differences in motor, auditory, and visual-spatial brain regions when comparing professional musicians (keyboard players) with a matched group of amateur musicians and non-musicians. Although some of these multiregional differences could be attributable to innate predisposition, we believe they may represent structural adaptations in response to long-term skill acquisition and the repetitive rehearsal of those skills. This hypothesis is supported by the strong association we found between structural differences, musician status, and practice intensity, as well as the wealth of supporting animal data showing structural changes in response to long-term motor training. However, only future experiments can determine the relative contribution of predisposition and practice.

Effects of Musical Training on the Auditory Cortex in Children

Several studies of the effects of musical experience on sound representations in the auditory cortex are reviewed. Auditory evoked potentials are compared in response to pure tones, violin tones, and piano tones in adult musicians versus nonmusicians as well as in 4- to 5-year-old children who have either had or not had extensive musical experience. In addition, the effects of auditory frequency discrimination training in adult nonmusicians on auditory evoked potentials are examined. It was found that the P2-evoked response is larger in both adult and child musicians than in nonmusicians and that auditory training enhances this component in nonmusician adults. The results suggest that the P2 is particularly neuroplastic and that the effects of musical experience can be seen early in development. They also suggest that although the effects of musical training on cortical representations may be greater if training begins in childhood, the adult brain is also open to change. These results are discussed with respect to potential benefits of early musical training as well as potential benefits of musical experience in aging.

The musician's brain: functional imaging of amateurs and professionals during performance and imagery

We compared activation maps of professional and amateur violinists during actual and imagined performance of Mozart's violin concerto in G major (KV216). Execution and imagination of (left hand) fingering movements of the first 16 bars of the concerto were performed. Electromyography (EMG) feedback was used during imagery training to avoid actual movement execution and EMG recording was employed during the scanning of both executed and imagined musical performances. We observed that professional musicians generated higher EMG amplitudes during movement execution and showed focused cerebral activations in the contralateral primary sensorimotor cortex, the bilateral superior parietal lobes, and the ipsilateral anterior cerebellar hemisphere. The finding that professionals exhibited higher activity of the right primary auditory cortex during execution may reflect an increased strength of audio-motor associative connectivity. It appears that during execution of musical sequences in professionals, a higher economy of motor areas frees resources for increased connectivity between the finger sequences and auditory as well as somatosensory loops, which may account for the superior musical performance. Professionals also demonstrated more focused activation patterns during imagined musical performance. However, the auditory-motor loop was not involved during imagined performances in either musician group. It seems that the motor and auditory systems are coactivated as a consequence of musical training but only if one system (motor or auditory) becomes activated by actual movement execution or live musical auditory stimuli.

Gray Matter Differences between Musicians and Nonmusicians

Musicians learn complex motor and auditory skills at an early age and practice these specialized skills extensively from childhood through their entire careers. Using a voxel-by-voxel morphometric technique, we found gray matter volume differences in motor as well as auditory and visuospatial brain regions comparing professional musicians (keyboard players) with matched amateur musicians and nonmusicians. These multiregional differences might represent structural adaptations in response to long-term skill learning and repetitive rehearsal of these skills. This is supported by finding a strong association between structural differences, musician status, and practice intensity as well as by a wealth of supporting animal data showing structural changes in response to long-term motor training.

Mapping perception to action in piano practice: a longitudinal DC-EEG study

BACKGROUND

Performing music requires fast auditory and motor processing. Regarding professional musicians, recent brain imaging studies have demonstrated that auditory stimulation produces a co-activation of motor areas, whereas silent tapping of musical phrases evokes a co-activation in auditory regions. Whether this is obtained via a specific cerebral relay station is unclear. Furthermore, the time course of plasticity has not yet been addressed.

RESULTS

Changes in cortical activation patterns (DC-EEG potentials) induced by short (20 minute) and long term (5 week) piano learning were investigated during auditory and motoric tasks. Two beginner groups were trained. The 'map' group was allowed to learn the standard piano key-to-pitch map. For the 'no-map' group, random assignment of keys to tones prevented such a map. Auditory-sensorimotor EEG co-activity occurred within only 20 minutes. The effect was enhanced after 5-week training, contributing elements of both perception and action to the mental representation of the instrument. The 'map' group demonstrated significant additional activity of right anterior regions.

CONCLUSION

We conclude that musical training triggers instant plasticity in the cortex, and that right-hemispheric anterior areas provide an audio-motor interface for the mental representation of the keyboard.

Mapping perception to action in piano practice: a longitudinal DC-EEG study

BACKGROUND

Performing music requires fast auditory and motor processing. Regarding professional musicians, recent brain imaging studies have demonstrated that auditory stimulation produces a co-activation of motor areas, whereas silent tapping of musical phrases evokes a co-activation in auditory regions. Whether this is obtained via a specific cerebral relay station is unclear. Furthermore, the time course of plasticity has not yet been addressed.

RESULTS

Changes in cortical activation patterns (DC-EEG potentials) induced by short (20 minute) and long term (5 week) piano learning were investigated during auditory and motoric tasks. Two beginner groups were trained. The 'map' group was allowed to learn the standard piano key-to-pitch map. For the 'no-map' group, random assignment of keys to tones prevented such a map. Auditory-sensorimotor EEG co-activity occurred within only 20 minutes. The effect was enhanced after 5-week training, contributing elements of both perception and action to the mental representation of the instrument. The 'map' group demonstrated significant additional activity of right anterior regions.

CONCLUSION

We conclude that musical training triggers instant plasticity in the cortex, and that right-hemispheric anterior areas provide an audio-motor interface for the mental representation of the keyboard.

Enhancement of neuroplastic P2 and N1c auditory evoked potentials in musicians

P2 and N1c components of the auditory evoked potential (AEP) have been shown to be sensitive to remodeling of the auditory cortex by training at pitch discrimination in nonmusician subjects. Here, we investigated whether these neuroplastic components of the AEP are enhanced in musicians in accordance with their musical training histories. Highly skilled violinists and pianists and nonmusician controls listened under conditions of passive attention to violin tones, piano tones, and pure tones matched in fundamental frequency to the musical tones. Compared with nonmusician controls, both musician groups evidenced larger N1c (latency, 138 msec) and P2 (latency, 185 msec) responses to the three types of tonal stimuli. As in training studies with nonmusicians, N1c enhancement was expressed preferentially in the right hemisphere, where auditory neurons may be specialized for processing of spectral pitch. Equivalent current dipoles fitted to the N1c and P2 field patterns localized to spatially differentiable regions of the secondary auditory cortex, in agreement with previous findings. These results suggest that the tuning properties of neurons are modified in distributed regions of the auditory cortex in accordance with the acoustic training history (musical- or laboratory-based) of the subject. Enhanced P2 and N1c responses in musicians need not be considered genetic or prenatal markers for musical skill.

Focal dystonia: advances in brain imaging and understanding of fine motor control in musicians

This article reviews the neuroanatomic and neurophysiologic foundations of music performance and learning. Music performance is regarded as complex voluntary sensorimotor behavior that becomes automated during extensive practice with auditory feedback. It involves all motor, somatosensory, and auditory areas of the brain. Because of the life-long plasticity of neuronal connections, practicing a musical instrument results first in a temporary and later in a stable increase in the amount of nerve tissue devoted to various component tasks. Motor and somatosensory brain regions corresponding to specific subtasks of music performance are larger in musicians starting younger than age 10 years than in the general population. In rare cases, overuse of movement patterns may induce a degradation of motor memory that results in a loss of voluntary control of movements, called musician's cramp. Specific therapeutic options for this condition are reviewed.

Music training improves verbal but not visual memory: cross-sectional and longitudinal explorations in children

The hypothesis that music training can improve verbal memory was tested in children. The results showed that children with music training demonstrated better verbal but not visual memory than did their counterparts without such training. When these children were followed up after a year, those who had begun or continued music training demonstrated significant verbal memory improvement. Students who discontinued the training did not show any improvement. Contrary to the differences in verbal memory between the groups, their changes in visual memory were not significantly different. Consistent with previous findings for adults (A. S. Chan, Y. Ho, & M. Cheung, 1998), the results suggest that music training systematically affects memory processing in accordance with possible neuroanatomical modifications in the left temporal lobe.

The fate of sounds in conductors' brains: an ERP study

Professional music conductors are required to home in on a particular musician but at the same time have to monitor the entire orchestra. It was hypothesized that this unique experience should be reflected by superior auditory spatial processing. Event-related brain potentials were obtained, while conductors, professional pianists, and non-musicians listened to sequences of bandpass-filtered noise-bursts presented in random order from six speakers, three located in front and three to the right of the subjects. In different runs, subjects either attended the centermost or the most peripheral speaker in order to detect slightly deviant noise-bursts. For centrally located speakers, the ERPs showed a typical Nd attention effect for the relevant location with a steep decline for the neighboring speakers in all subject groups. For peripheral speakers, only the conductors showed attentional selectivity, while the Nd effect was of similar size for all three peripheral speakers in the other two groups. These ERP effects were paralleled by an enhanced behavioral selectivity in peripheral auditory space in conductors. Moreover, the pre-attentive monitoring of the entire auditory scene indexed by the mismatch negativity was superior in musicians compared to non-musicians. In conductors, the MMN was followed by a positivity suggesting an attention shift towards the deviant stimuli in this group only.

Neuromuscular and musculoskeletal problems in instrumental musicians

Over the past 20 years, there has been increasing interest in the medical problems of performing artists. In this review, the major playing-related disorders seen in instrumental musicians are discussed. Among the 1353 instrumentalists personally evaluated, the major diagnoses included musculoskeletal disorders in 64%, peripheral nerve problems in 20%, and focal dystonia in 8%. Of these instrumentalists, 60% were women, although men were the majority in the group with focal dystonia. The average age at the time of evaluation was 37 years for men and 30 years for women. Among musculoskeletal disorders, regional muscle pain syndromes, particularly of the upper limb, upper trunk, and neck, were most common. Specific entities such as tendinitis and ligament sprain were less common. Frequent peripheral nerve disorders included thoracic outlet syndrome, ulnar neuropathy at the elbow, and carpal tunnel syndrome. Each instrument group showed a characteristic distribution of symptoms and signs that appeared to be directly related to the static and dynamic stresses inherent in the playing of the instrument. Electrodiagnostic studies are an important part of the evaluation of these disorders, particularly nerve entrapment syndromes. With carefully designed treatment, the majority of instrumental musicians can return to full and pain-free playing. Nerve entrapment syndromes have the highest treatment success rate, followed by musculoskeletal pain syndromes. Despite some recent innovative approaches, focal dystonia remains largely resistant to therapy.

Contralateral activity in a homologous hand muscle during voluntary contractions is greater in old adults

This study compared the amount of contralateral activity produced in a homologous muscle by young (18-32 yr) and old (66-80 yr) adults when they performed unilateral isometric and anisometric contractions with a hand muscle. The subjects were not aware that the focus of the study was the contralateral activity. The tasks involved the performance of brief isometric contractions to six target forces, slowly lifting and lowering six inertial loads, and completing a set of 10 repetitions with a heavy load. The unintended force exerted by the contralateral muscle during the isometric contractions increased with target force, but the average force was greater for the old adults (means +/- SD; 12.6 +/- 15.3%) compared with the young adults (6.91 +/- 11.1%). The contralateral activity also increased with load during the anisometric contractions, and the average contralateral force was greater for the old subjects (5.28 +/- 6.29%) compared with the young subjects (2.10 +/- 3.19%). Furthermore, the average contralateral force for both groups of subjects was greater during the eccentric contractions (4.17 +/- 5.24%) compared with the concentric contractions (3.20 +/- 5.20%). The rate of change in contralateral activity during the fatigue task also differed between the two groups of subjects. The results indicate that old subjects have a reduced ability to suppress unintended contralateral activity during the performance of goal-directed, unilateral tasks.

Size of the human corpus callosum is genetically determined: an MRI study in mono and dizygotic twins

The factors determining the large variation seen in human corpus callosum (CC) morphology are as yet unknown. In this study heritability of CC size was assessed by comparing the concordance of CC midsagittal area in 14 monozygotic and 12 dizygotic twin pairs with a mean age of 27 years, using magnetic resonance imaging and various methods of calculating trait heritability. Heritability was high regardless of method of assessment. The application of a structural equation model resulted in the estimate that 94% of the variance in CC midsagittal size is attributable to the genome. This indicates that under normal conditions and before the effects of normal aging, there is very modest influence of the environment on CC morphology. The results suggest that correlates of CC size, such as the pattern of cerebral lateralization, cognitive abilities and neuropsychiatric dysfunction may be associated with the genetic determinants of CC morphology.

Corpus callosum: musician and gender effects

Previously we found that musicians have significantly larger anterior corpus callosum (CC). In the current study, we intended to replicate and extend our previous results using a new and larger sample of gender-matched subjects (56 right-handed professional musicians and 56 age- and handedness-matched controls). We found a significant gender x musicianship interaction for anterior and posterior CC size; male musicians had a larger anterior CC than non-musicians, while females did not show a significant effect of musicianship. The lack of a significant effect in females may be due to a tendency for a more symmetric brain organization and a disproportionately high representation of absolute pitch (AP) musicians among females. Although a direct causal effect between musicianship and alterations in the midsagittal CC size cannot be established, it is likely that the early commencement and continuous practice of bimanual motor training serves as an external trigger that can influence midsagittal CC size through changes in the actual callosal fiber composition and in the degree of myelinization, which will have implications for interhemispheric connectivity.

Voxel-based morphometry reveals increased gray matter density in Broca's area in male symphony orchestra musicians

Broca's area is a major neuroanatomical substrate for spoken language and various musically relevant abilities, including visuospatial and audiospatial localization. Sight reading is a musician-specific visuospatial analysis task, and spatial ability is known to be amenable to training effects. Musicians have been reported to perform significantly better than nonmusicians on spatial ability tests, which is supported by our findings with the Benton judgement of line orientation (JOL) test (P < 0.001). We hypothesised that use-dependent adaptation would lead to increased gray matter density in Broca's area in musicians. Voxel-based morphometry (VBM) and stereological analyses were applied to high-resolution 3D MR images in male orchestral musicians (n = 26) and sex, handedness, and IQ-matched nonmusicians (n = 26). The wide age range (26 to 66 years) of volunteers permitted a secondary analysis of age-related effects. VBM with small volume correction (SVC) revealed a significant (P = 0.002) region of increased gray matter in Broca's area in the left inferior frontal gyrus in musicians. We observed significant age-related volume reductions in cerebral hemispheres, dorsolateral prefrontal cortex subfields bilaterally and gray matter density in the left inferior frontal gyrus in controls but not musicians; a positive correlation between JOL test score and age in musicians but not controls; a positive correlation between years of playing and the volume of gray matter in a significant region identified by VBM in under-50-year-old musicians. We suggest that orchestral musical performance promotes use-dependent retention, and possibly expansion, of gray matter involving Broca's area and that this provides further support for shared neural substrates underpinning expressive output in music and language.