Increased corpus callosum size in musicians

Modulation of Functional Connectivity in Auditory-Motor Networks in Musicians Compared with Nonmusicians

Correlation of spontaneous fluctuations at rest between anatomically distinct brain areas are proposed to reflect the profile of individual a priori cognitive biases, coded as synaptic efficacies in cortical networks. Here, we investigate functional connectivity at rest (rs-FC) in musicians and nonmusicians to test for differences in auditory, motor, and audiomotor connectivity. As expected, musicians had stronger rs-FC between the right auditory cortex (AC) and the right ventral premotor cortex than nonmusicians, and this stronger rs-FC was greater in musicians with more years of practice. We also found reduced rs-FC between the motor areas that control both hands in musicians compared with nonmusicians, which was more evident in the musicians whose instrument required bimanual coordination and as a function of hours of practice. Finally, we replicated previous morphometric data to show an increased volume in the right AC in musicians, which was greater in those with earlier musical training, and that this anatomic feature was in turn related to greater rs-FC between auditory and motor systems. These results show that functional coupling within the motor system and between motor and auditory areas is modulated as a function of musical training, suggesting a link between anatomic and functional brain features.

Reduced inter-hemispheric interference in ageing: Evidence from a divided field Stroop paradigm

One of the most important structural changes that occur in the brain during the course of life relates to the corpus callosum, the largest neural pathway that connects the two cerebral hemispheres. It has been shown that the corpus callosum, and in particular its anterior sections, endures a process of degeneration in ageing. Hence, a primary question is whether such structural changes in the brain of older adults have functional consequences on inter-hemispheric communication. In particular, whether the atrophy of the corpus callosum in ageing may lead to a higher or lower level of inter-hemispheric interference is currently unknown. To investigate this question, we asked young and healthy older adults to perform modified versions of the classic Stroop paradigm in which the target and distracter were spatially separated. Across two experiments, we found that the Stroop effect was significantly reduced in older adults when the two stimuli were distributed in two different hemifields as opposed to the same single hemifield. This new finding suggests that age-related callosal thinning reduces inter-hemispheric interference by facilitating the two hemispheres to process information in parallel.

Decoding Musical Training from Dynamic Processing of Musical Features in the Brain

Pattern recognition on neural activations from naturalistic music listening has been successful at predicting neural responses of listeners from musical features, and vice versa. Inter-subject differences in the decoding accuracies have arisen partly from musical training that has widely recognized structural and functional effects on the brain. We propose and evaluate a decoding approach aimed at predicting the musicianship class of an individual listener from dynamic neural processing of musical features. Whole brain functional magnetic resonance imaging (fMRI) data was acquired from musicians and nonmusicians during listening of three musical pieces from different genres. Six musical features, representing low-level (timbre) and high-level (rhythm and tonality) aspects of music perception, were computed from the acoustic signals, and classification into musicians and nonmusicians was performed on the musical feature and parcellated fMRI time series. Cross-validated classification accuracy reached 77% with nine regions, comprising frontal and temporal cortical regions, caudate nucleus, and cingulate gyrus. The processing of high-level musical features at right superior temporal gyrus was most influenced by listeners’ musical training. The study demonstrates the feasibility to decode musicianship from how individual brains listen to music, attaining accuracy comparable to current results from automated clinical diagnosis of neurological and psychological disorders.

Improved Digit Span in Children after a 6-Week Intervention of Playing a Musical Instrument: An Exploratory Randomized Controlled Trial

Previous studies have reported that music training not only improves children's musical skills, but also enhances their cognitive functions. However, there is a disagreement about what domain(s) might be affected. Moreover, effects of short-term (<several months) instrumental training have not been examined, although more basic studies have suggested neuroplasticity within several weeks. Consequently, the present exploratory pilot study investigated the effect of a six-week instrumental practice program (i.e., playing the keyboard harmonica) on children's cognitive functions using a randomized controlled trial. Forty children (aged 6–8 years) were randomly assigned to either the experimental group (n = 20), which received a 6-week (12-session) keyboard harmonica curriculum, or an untrained control group (n = 20). Different from traditional instrumental training, the curriculum did not use musical scores to emphasize creating association between sound (auditory modality) and finger movement (somato-motor system). Cognitive measurements included verbal ability, processing speed, working memory, and inhibitory control, which were administered before and after the curriculum in both groups. After the 6-week training, only the experimental group showed a significant improvement in the Digit Span test (especially in the Digit Span Backward) that measures working memory. However, no significant influences were found on the other cognitive tests. The result suggests that several weeks of instrumental music training may be beneficial to improving children's working memory. In addition, we used an inexpensive and portable keyboard harmonica; therefore, our instructional method is easy to apply in classrooms or other circumstances. If the method is applied to music lessons in schools or in the community, it may help improve children's working memory.

Functional connectivity of the cortical network supporting statistical learning in musicians and non-musicians: an MEG study

Statistical learning is a cognitive process of great importance for the detection and representation of environmental regularities. Complex cognitive processes such as statistical learning usually emerge as a result of the activation of widespread cortical areas functioning in dynamic networks. The present study investigated the cortical large-scale network supporting statistical learning of tone sequences in humans. The reorganization of this network related to musical expertise was assessed via a cross-sectional comparison of a group of musicians to a group of non-musicians. The cortical responses to a statistical learning paradigm incorporating an oddball approach were measured via Magnetoencephalographic (MEG) recordings. Large-scale connectivity of the cortical activity was calculated via a statistical comparison of the estimated transfer entropy in the sources' activity. Results revealed the functional architecture of the network supporting the processing of statistical learning, highlighting the prominent role of informational processing pathways that bilaterally connect superior temporal and intraparietal sources with the left IFG. Musical expertise is related to extensive reorganization of this network, as the group of musicians showed a network comprising of more widespread and distributed cortical areas as well as enhanced global efficiency and increased contribution of additional temporal and frontal sources in the information processing pathway.

The music in the brain hemispheres

The mini-review provides an overview on the differences between the right and left hemispheres of the brain. Recent studies highlight the contribution of the two hemispheres to the physical and mental control, and the interaction language-music. We focused the attention on the behaviour of the right and left hemispheres about the music and on what happens when music areas are damaged.

Cerebellar Asymmetry and Cortical Connectivity in Monozygotic Twins with Discordant Handedness

Handedness differentiates patterns of neural asymmetry and interhemispheric connectivity in cortical systems that underpin manual and language functions. Contemporary models of cerebellar function incorporate complex motor behaviour and higher-order cognition, expanding upon earlier, traditional associations between the cerebellum and motor control. Structural MRI defined cerebellar volume asymmetries and correlations with corpus callosum (CC) size were compared in 19 pairs of adult female monozygotic twins strongly discordant for handedness (MZHd). Volume and asymmetry of cerebellar lobules were obtained using automated parcellation.CC area and regional widths were obtained from midsagittal planimetric measurements. Within the cerebellum and CC, neurofunctional distinctions were drawn between motor and higher-order cognitive systems. Relationships amongst regional cerebellar asymmetry and cortical connectivity (as indicated by CC widths) were investigated. Interactions between hemisphere and handedness in the anterior cerebellum were due to a larger right-greater-than-left hemispheric asymmetry in right-handed (RH) compared to left-handed (LH) twins. In LH twins only, anterior cerebellar lobule volumes (IV, V) for motor control were associated with CC size, particularly in callosal regions associated with motor cortex connectivity. Superior posterior cerebellar lobule volumes (VI, Crus I, Crus II, VIIb) showed no correlation with CC size in either handedness group. These novel results reflected distinct patterns of cerebellar-cortical relationships delineated by specific CC regions and an anterior-posterior cerebellar topographical mapping. Hence, anterior cerebellar asymmetry may contribute to the greater degree of bilateral cortical organisation of frontal motor function in LH individuals.

The effects of auditory and visual cues on timing synchronicity for robotic rehabilitation

In this paper, we explore how the integration of auditory and visual cues can help teach the timing of motor skills for the purpose of motor function rehabilitation. We conducted a study using Amazon's Mechanical Turk in which 106 participants played a virtual therapy game requiring wrist movements. To validate that our results would translate to trends that could also be observed during robotic rehabilitation sessions, we recreated this experiment with 11 participants using a robotic wrist rehabilitation system as means to control the therapy game. During interaction with the therapy game, users were asked to learn and reconstruct a tapping sequence as defined by musical notes flashing on the screen. Participants were divided into 2 test groups: (1) control: participants only received visual cues to prompt them on the timing sequence, and (2) experimental: participants received both visual and auditory cues to prompt them on the timing sequence. To evaluate performance, the timing and length of the sequence were measured. Performance was determined by calculating the number of trials needed before the participant was able to master the specific aspect of the timing task. In the virtual experiment, the group that received visual and auditory cues was able to master all aspects of the timing task faster than the visual cue only group with p-values < 0.05. This trend was also verified for participants using the robotic arm exoskeleton in the physical experiment.

Diffusion tensor MRI tractography reveals increased fractional anisotropy (FA) in arcuate fasciculus following music-cued motor training

Auditory cues are frequently used to support movement learning and rehabilitation, but the neural basis of this behavioural effect is not yet clear. We investigated the microstructural neuroplasticity effects of adding musical cues to a motor learning task. We hypothesised that music-cued, left-handed motor training would increase fractional anisotropy (FA) in the contralateral arcuate fasciculus, a fibre tract connecting auditory, pre-motor and motor regions. Thirty right-handed participants were assigned to a motor learning condition either with (Music Group) or without (Control Group) musical cues. Participants completed 20minutes of training three times per week over four weeks. Diffusion tensor MRI and probabilistic neighbourhood tractography identified FA, axial (AD) and radial (RD) diffusivity before and after training. Results revealed that FA increased significantly in the right arcuate fasciculus of the Music group only, as hypothesised, with trends for AD to increase and RD to decrease, a pattern of results consistent with activity-dependent increases in myelination. No significant changes were found in the left ipsilateral arcuate fasciculus of either group. This is the first evidence that adding musical cues to movement learning can induce rapid microstructural change in white matter pathways in adults, with potential implications for therapeutic clinical practice.

An MRI study of the corpus callosum in monkeys: Developmental trajectories and effects of neonatal hippocampal and amygdala lesions

This study provides the first characterization of early developmental trajectories of corpus callosum (CC) segments in rhesus macaques using noninvasive MRI techniques and assesses long-term effects of neonatal amygdala or hippocampal lesions on CC morphometry. In Experiment 1, 10 monkeys (5 males) were scanned at 1 week-2 years of age; eight additional infants (4 males) were scanned once at 1-4 weeks of age. The first 8 months showed marked growth across all segments, with sustained, albeit slower, growth through 24 months. Males and females had comparable patterns of CC maturation overall, but exhibited slight differences in the anterior and posterior segments, with greater increases in the isthmus for males and greater increases in the rostrum for females. The developmental changes are likely a consequence of varying degrees of axonal myelination, redirection, and pruning. In Experiment 2, animals with neonatal lesions of the amygdala (n = 6; 3 males) or hippocampus (n = 6; 4 males) were scanned at 1.5 years post-surgery and compared to scans of six control animals from Experiment 1. Whereas amygdala damage yielded larger rostral and posterior body segments, hippocampal damage yielded larger rostrum and isthmus. These differences demonstrate that early perturbations to one medial temporal lobe structure may produce extensive and long-lasting repercussions in other brain areas. The current findings emphasize the complexity of neural circuitry putatively subserving neurodevelopmental disorders such as autism spectrum disorder and Williams syndrome, which are each characterized by malformations and dysfunction of complex neural networks that include regions of the medial temporal lobe.

Connectivity patterns during music listening: Evidence for action-based processing in musicians

Musical expertise is visible both in the morphology and functionality of the brain. Recent research indicates that functional integration between multi-sensory, somato-motor, default-mode (DMN), and salience (SN) networks of the brain differentiates musicians from non-musicians during resting state. Here, we aimed at determining whether brain networks differentially exchange information in musicians as opposed to non-musicians during naturalistic music listening. Whole-brain graph-theory analyses were performed on participants' fMRI responses. Group-level differences revealed that musicians' primary hubs comprised cerebral and cerebellar sensorimotor regions whereas non-musicians' dominant hubs encompassed DMN-related regions. Community structure analyses of the key hubs revealed greater integration of motor and somatosensory homunculi representing the upper limbs and torso in musicians. Furthermore, musicians who started training at an earlier age exhibited greater centrality in the auditory cortex, and areas related to top-down processes, attention, emotion, somatosensory processing, and non-verbal processing of speech. We here reveal how brain networks organize themselves in a naturalistic music listening situation wherein musicians automatically engage neural networks that are action-based while non-musicians use those that are perception-based to process an incoming auditory stream. Hum Brain Mapp 38:2955-2970, 2017. © 2017 Wiley Periodicals, Inc.

Volume and density of microglomeruli in the honey bee mushroom bodies do not predict performance on a foraging task

The mushroom bodies (MBs) are insect brain regions important for sensory integration, learning, and memory. In adult worker honey bees (Apis mellifera), the volume of neuropil associated with the MBs is larger in experienced foragers compared with hive bees and less experienced foragers. In addition, the characteristic synaptic structures of the calycal neuropils, the microglomeruli, are larger but present at lower density in 35-day-old foragers relative to 1-day-old workers. Age- and experience-based changes in plasticity of the MBs are assumed to support performance of challenging tasks, but the behavioral consequences of brain plasticity in insects are rarely examined. In this study, foragers were recruited from a field hive to a patch comprising two colors of otherwise identical artificial flowers. Flowers of one color contained a sucrose reward mimicking nectar; flowers of the second were empty. Task difficulty was adjusted by changing flower colors according to the principle of honey bee color vision space. Microglomerular volume and density in the lip (olfactory inputs) and collar (visual inputs) compartments of the MB calyces were analyzed using anti-synapsin I immunolabeling and laser scanning confocal microscopy. Foragers displayed significant variation in microglomerular volume and density, but no correlation was found between these synaptic attributes and foraging performance. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1057-1071, 2017.

Altered microstructure rather than morphology in the corpus callosum after lower limb amputation

The corpus callosum (CC) has been implicated in the reorganization of the brain following amputation. However, it is unclear which regions of the CC are involved in this process. In this study, we explored the morphometric and microstructural changes in CC subregions in patients with unilateral lower limb amputation. Thirty-eight patients and 38 age- and gender-matched normal controls were included. The CC was divided into five regions, and the area, thickness and diffusion parameters of each region were investigated. While morphometric analysis showed no significant differences between the two groups, amputees showed significant higher values in axial diffusivity, radial diffusivity and mean diffusivity in region II of the CC, which connects the bilateral premotor and supplementary motor areas. In contrast, the mean fractional anisotropy value of the fibers generated by these cortical areas, as measured by tractography, was significantly smaller in amputees. These results demonstrate that the interhemispheric pathways contributing to motor coordination and imagery are reorganized in lower limb amputees.

Effect of skilled reaching training and enriched environment on generation of oligodendrocytes in the adult sensorimotor cortex and corpus callosum

Background

Increased motor activity or social interactions through enriched environment are strong stimulators of grey and white matter plasticity in the adult rodent brain. In the present study we evaluated whether specific reaching training of the dominant forelimb (RT) and stimulation of unspecific motor activity through enriched environment (EE) influence the generation of distinct oligodendrocyte subpopulations in the sensorimotor cortex and corpus callosum of the adult rat brain. Animals were placed in three different housing conditions: one group was transferred to an EE, a second group received daily RT, whereas a third group remained in the standard cage. Bromodeoxyuridine (BrdU) was applied at days 2–6 after start of experiments and animals were allowed to survive for 10 and 42 days.

Results

Enriched environment and daily reaching training of the dominant forelimb significantly increased the number of newly differentiated GSTπ⁺ oligodendrocytes at day 10 and newly differentiated CNPase⁺ oligodendrocytes in the sensorimotor cortex at day 42. The myelin level as measured by CNPase expression was increased in the frontal cortex at day 42. Distribution of newly differentiated NG2⁺ subpopulations changed between 10 and 42 days with an increase of GSTπ⁺ subtypes and a decrease of NG2⁺ cells in the sensorimotor cortex and corpus callosum. Analysis of neuronal marker doublecortin (DCX) showed that more than half of NG2⁺ cells express DCX in the cortex. The number of new DCX⁺NG2⁺ cells was reduced by EE at day 10.

Conclusions

Our results indicate for the first time that specific and unspecific motor training conditions differentially alter the process of differentiation from oligodendrocyte subpopulations, in particular NG2⁺DCX⁺ cells, in the sensorimotor cortex and corpus callosum.

Electronic supplementary material

The online version of this article (doi:10.1186/s12868-017-0347-2) contains supplementary material, which is available to authorized users.

Musicians react faster and are better multisensory integrators

The results from numerous investigations suggest that musical training might enhance how senses interact. Despite repeated confirmation of anatomical and structural changes in visual, tactile, and auditory regions, significant changes have only been reported in the audiovisual domain and for the detection of audio-tactile incongruencies. In the present study, we aim at testing whether long-term musical training might also enhance other multisensory processes at a behavioural level. An audio-tactile reaction time task was administrated to a group of musicians and non-musicians. We found significantly faster reaction times with musicians for auditory, tactile, and audio-tactile stimulations. Statistical analyses between the combined uni- and multisensory reaction times revealed that musicians possess a statistical advantage when responding to multisensory stimuli compared to non-musicians. These results suggest for the first time that long-term musical training reduces simple non-musical auditory, tactile, and multisensory reaction times. Taken together with the previous results from other sensory modalities, these results strongly point towards musicians being better at integrating the inputs from various senses.

Tapping Speed Asymmetry in Drummers for Single-Hand Tapping with a Stick

The purpose of this study was to investigate tapping speed asymmetry in 13 right-handed drummers and 13 right-handed nondrummers. The participants executed single-hand tapping with a stick as fast as possible for 10 sec. with the left and right hand. There was no significant difference in the tapping speed of the right hand between the drummers and the nondrummers, whereas in the left hand, the drummers tapped significantly faster than the nondrummers. Drummers showed less tapping speed asymmetry than nondrummers. These results suggest that the tapping speed of the nonpreferred hand progressed nearly to the level of the preferred hand through daily drum training.

A Pilot Study of a Possible Effect from a Motor Task on Reading Performance

This pilot study examined the influence of participation in a 6-week bimanual coordination program on Grade 5 students' reading achievement. Twenty Grade 5 students participated in a bimanual activity (sport stacking) and were tested whether reading achievement scores were significantly different from the scores for 21 control students. The experimental group consisted of 20 students (11 boys, 9 girls) from one intact classroom cohort; the control group consisted of 21 students (12 boys, 9 girls) from one intact classroom cohort. Students in both groups ranged in age from 10 to 11 years. The intact classroom cohorts were randomly assigned to experimental and control groups. Reading achievement was measured by differences in pre- and posttest scores from the GMRT-4 Decoding and Comprehension skill subtests. Group by sex analyses of covariance, using pretest scores as covariates, indicated that there were no significant differences by group or sex for decoding skills. A significant increase was found for the experimental group on Comprehension skills. Therefore, participation in a bimanual coordination program, using sport stacking as the activity, may improve Grade 5 students' reading comprehension skills, regardless of sex.

Musical training shapes neural responses to melodic and prosodic expectation

Current research on music processing and syntax or semantics in language suggests that music and language share partially overlapping neural resources. Pitch also constitutes a common denominator, forming melody in music and prosody in language. Further, pitch perception is modulated by musical training. The present study investigated how music and language interact on pitch dimension and whether musical training plays a role in this interaction. For this purpose, we used melodies ending on an expected or unexpected note (melodic expectancy being estimated by a computational model) paired with prosodic utterances which were either expected (statements with falling pitch) or relatively unexpected (questions with rising pitch). Participants' (22 musicians, 20 nonmusicians) ERPs and behavioural responses in a statement/question discrimination task were recorded. Participants were faster for simultaneous expectancy violations in the melodic and linguistic stimuli. Further, musicians performed better than nonmusicians, which may be related to their increased pitch tracking ability. At the neural level, prosodic violations elicited a front-central positive ERP around 150 ms after the onset of the last word/note, while musicians presented reduced P600 in response to strong incongruities (questions on low-probability notes). Critically, musicians' P800 amplitudes were proportional to their level of musical training, suggesting that expertise might shape the pitch processing of language. The beneficial aspect of expertise could be attributed to its strengthening effect of general executive functions. These findings offer novel contributions to our understanding of shared higher-order mechanisms between music and language processing on pitch dimension, and further demonstrate a potential modulation by musical expertise.

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Melodic expectancy influences the processing of prosodic expectancy.

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Musical expertise modulates pitch processing in music and language.

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Musicians have a more refined response to pitch.

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Musicians' neural responses are proportional to their level of musical expertise.

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Possible association between the P200 neural component and behavioural facilitation.

The Case for Musical Instrument Training in Cerebral Palsy for Neurorehabilitation

Recent imaging studies in cerebral palsy (CP) have described several brain structural changes, functional alterations, and neuroplastic processes that take place after brain injury during early development. These changes affect motor pathways as well as sensorimotor networks. Several of these changes correlate with behavioral measures of motor and sensory disability. It is now widely acknowledged that management of sensory deficits is relevant for rehabilitation in CP. Playing a musical instrument demands the coordination of hand movements with integrated auditory, visual, and tactile feedback, in a process that recruits multiple brain regions. These multiple demands during instrument playing, together with the entertaining character of music, have led to the development and investigation of music-supported therapies, especially for rehabilitation with motor disorders resulting from brain damage. We review scientific evidence that supports the use of musical instrument playing for rehabilitation in CP. We propose that active musical instrument playing may be an efficient means for triggering neuroplastic processes necessary for the development of sensorimotor skills in patients with early brain damage. We encourage experimental research on neuroplasticity and on its impact on the physical and personal development of individuals with CP.

Short-Term Memory Performance in 7- and 8-Year-Old Children: The Relationship Between Phonological and Pitch Processing

PURPOSE

The relationship between short-term memory for phonology and pitch was explored by examining accuracy scores for typically developing children for 5 experimental tasks: immediate nonword repetition (NWR), nonword repetition with an 8-s silent interference (NWRS), pitch discrimination (PD), pitch discrimination with an 8-s silent interference (PDS), and pitch matching (PM).

METHOD

Thirty-six 7- and 8-year-old children (21 girls, 15 boys) with normal hearing, language, and cognition were asked to listen to and repeat nonsense words (NWR, NWRS), make a same versus different decision between 2 tones (PD, PDS), and listen to and then vocally reproduce a tone (PM).

RESULTS

Results showed no significant correlations between tasks of phonological memory and tests of pitch memory, that participants scored significantly better on nonword repetition tasks than PD and PM tasks, and that participants performed significantly better on tasks with no silent interference.

DISCUSSION

These findings suggest that, for typically developing children, pitch may be stored and rehearsed in a separate location than phonological information. Because of fundamental task differences, further research is needed to corroborate these data and determine the presence of developmental effects and neuroanatomical locations where a potential language/music overlap is occurring in children.

Sensory Re-education Today and Tomorrow: A Review of Evolving Concepts

Following surgical repair of major nerve trunks there is a rapid functional reorganisation in the brain, characterised by a changed cortical mapping of the hand secondary to incorrect reinnervation of peripheral targets. Sensory re-educational programmes are used in the rehabilitation phase to facilitate and positively influence the re-learning process, which is required to make possible an adaptation to the new synaptic organisation and to improve the recovery of functional sensibility - tactile gnosis. However, the outcome is often disappointing, especially in adults. The design of sensory re-education programmes has not changed for several decades. The purpose of this paper is to review evolving concepts in neuroscience and cognitive science, present a rationale for a modified approach to classic sensory re-education, and suggest new strategies for enhanced sensory re-learning following nerve repair.

The EyeHarp: A Gaze-Controlled Digital Musical Instrument

We present and evaluate the EyeHarp, a new gaze-controlled Digital Musical Instrument, which aims to enable people with severe motor disabilities to learn, perform, and compose music using only their gaze as control mechanism. It consists of (1) a step-sequencer layer, which serves for constructing chords/arpeggios, and (2) a melody layer, for playing melodies and changing the chords/arpeggios. We have conducted a pilot evaluation of the EyeHarp involving 39 participants with no disabilities from both a performer and an audience perspective. In the first case, eight people with normal vision and no motor disability participated in a music-playing session in which both quantitative and qualitative data were collected. In the second case 31 people qualitatively evaluated the EyeHarp in a concert setting consisting of two parts: a solo performance part, and an ensemble (EyeHarp, two guitars, and flute) performance part. The obtained results indicate that, similarly to traditional music instruments, the proposed digital musical instrument has a steep learning curve, and allows to produce expressive performances both from the performer and audience perspective.

Executive Function, Visual Attention and the Cocktail Party Problem in Musicians and Non-Musicians

The goal of this study was to investigate how cognitive factors influence performance in a multi-talker, “cocktail-party” like environment in musicians and non-musicians. This was achieved by relating performance in a spatial hearing task to cognitive processing abilities assessed using measures of executive function (EF) and visual attention in musicians and non-musicians. For the spatial hearing task, a speech target was presented simultaneously with two intelligible speech maskers that were either colocated with the target (0° azimuth) or were symmetrically separated from the target in azimuth (at ±15°). EF assessment included measures of cognitive flexibility, inhibition control and auditory working memory. Selective attention was assessed in the visual domain using a multiple object tracking task (MOT). For the MOT task, the observers were required to track target dots (n = 1,2,3,4,5) in the presence of interfering distractor dots. Musicians performed significantly better than non-musicians in the spatial hearing task. For the EF measures, musicians showed better performance on measures of auditory working memory compared to non-musicians. Furthermore, across all individuals, a significant correlation was observed between performance on the spatial hearing task and measures of auditory working memory. This result suggests that individual differences in performance in a cocktail party-like environment may depend in part on cognitive factors such as auditory working memory. Performance in the MOT task did not differ between groups. However, across all individuals, a significant correlation was found between performance in the MOT and spatial hearing tasks. A stepwise multiple regression analysis revealed that musicianship and performance on the MOT task significantly predicted performance on the spatial hearing task. Overall, these findings confirm the relationship between musicianship and cognitive factors including domain-general selective attention and working memory in solving the “cocktail party problem”.

Motor Cortical Plasticity to Training Started in Childhood: The Example of Piano Players

Converging evidence suggest that motor training is associated with early and late changes of the cortical motor system. Transcranial magnetic stimulation (TMS) offers the possibility to study plastic rearrangements of the motor system in physiological and pathological conditions. We used TMS to characterize long-term changes in upper limb motor cortical representation and interhemispheric inhibition associated with bimanual skill training in pianists who started playing in an early age. Ipsilateral silent period (iSP) and cortical TMS mapping of hand muscles were obtained from 30 strictly right-handed subjects (16 pianists, 14 naïve controls), together with electromyographic recording of mirror movements (MMs) to voluntary hand movements. In controls, motor cortical representation of hand muscles was larger on the dominant (DH) than on the non-dominant hemisphere (NDH). On the contrary, pianists showed symmetric cortical output maps, being their DH less represented than in controls. In naïve subjects, the iSP was smaller on the right vs left abductor pollicis brevis (APB) indicating a weaker inhibition from the NDH to the DH. In pianists, interhemispheric inhibition was more symmetric as their DH was better inhibited than in controls. Electromyographic MMs were observed only in naïve subjects (7/14) and only to voluntary movement of the non-dominant hand. Subjects with MM had a lower iSP area on the right APB compared with all the others. Our findings suggest a more symmetrical motor cortex organization in pianists, both in terms of muscle cortical representation and interhemispheric inhibition. Although we cannot disentangle training-related from preexisting conditions, it is possible that long-term bimanual practice may reshape motor cortical representation and rebalance interhemispheric interactions, which in naïve right-handed subjects would both tend to favour the dominant hemisphere.

White matter microstructural properties correlate with sensorimotor synchronization abilities

Sensorimotor synchronization (SMS) to an external auditory rhythm is a developed ability in humans, particularly evident in dancing and singing. This ability is typically measured in the lab via a simple task of finger tapping to an auditory beat. While simplistic, there is some evidence that poor performance on this task could be related to impaired phonological and reading abilities in children. Auditory-motor synchronization is hypothesized to rely on a tight coupling between auditory and motor neural systems, but the specific pathways that mediate this coupling have not been identified yet. In this study, we test this hypothesis and examine the contribution of fronto-temporal and callosal connections to specific measures of rhythmic synchronization. Twenty participants went through SMS and diffusion magnetic resonance imaging (dMRI) measurements. We quantified the mean asynchrony between an auditory beat and participants' finger taps, as well as the time to resynchronize (TTR) with an altered meter, and examined the correlations between these behavioral measures and diffusivity in a small set of predefined pathways. We found significant correlations between asynchrony and fractional anisotropy (FA) in the left (but not right) arcuate fasciculus and in the temporal segment of the corpus callosum. On the other hand, TTR correlated with FA in the precentral segment of the callosum. To our knowledge, this is the first demonstration that relates these particular white matter tracts with performance on an auditory-motor rhythmic synchronization task. We propose that left fronto-temporal and temporal-callosal fibers are involved in prediction and constant comparison between auditory inputs and motor commands, while inter-hemispheric connections between the motor/premotor cortices contribute to successful resynchronization of motor responses with a new external rhythm, perhaps via inhibition of tapping to the previous rhythm. Our results indicate that auditory-motor synchronization skills are associated with anatomical pathways that have been previously related to phonological awareness, thus offering a possible anatomical basis for the behavioral covariance between these abilities.

Neural Mechanisms Underlying Musical Pitch Perception and Clinical Applications Including Developmental Dyslexia

Music production and perception invoke a complex set of cognitive functions that rely on the integration of sensorimotor, cognitive, and emotional pathways. Pitch is a fundamental perceptual attribute of sound and a building block for both music and speech. Although the cerebral processing of pitch is not completely understood, recent advances in imaging and electrophysiology have provided insight into the functional and anatomical pathways of pitch processing. This review examines the current understanding of pitch processing and behavioral and neural variations that give rise to difficulties in pitch processing, and potential applications of music education for language processing disorders such as dyslexia.

The "silent" imprint of musical training

Playing a musical instrument at a professional level is a complex multimodal task requiring information integration between different brain regions supporting auditory, somatosensory, motor, and cognitive functions. These kinds of task-specific activations are known to have a profound influence on both the functional and structural architecture of the human brain. However, until now, it is widely unknown whether this specific imprint of musical practice can still be detected during rest when no musical instrument is used. Therefore, we applied high-density electroencephalography and evaluated whole-brain functional connectivity as well as small-world topologies (i.e., node degree) during resting state in a sample of 15 professional musicians and 15 nonmusicians. As expected, musicians demonstrate increased intra- and interhemispheric functional connectivity between those brain regions that are typically involved in music perception and production, such as the auditory, the sensorimotor, and prefrontal cortex as well as Broca's area. In addition, mean connectivity within this specific network was positively related to musical skill and the total number of training hours. Thus, we conclude that musical training distinctively shapes intrinsic functional network characteristics in such a manner that its signature can still be detected during a task-free condition. Hum Brain Mapp 37:536-546, 2016. © 2015 Wiley Periodicals, Inc.

Role of α4-containing GABAA receptors in limiting synaptic plasticity and spatial learning of female mice during the pubertal period

Expression of α4βδ GABA_A receptors (GABARs) increases at the onset of puberty on dendritic spines of CA1 hippocampal pyramidal cells. These receptors reduce activation of NMDA receptors (NMDARs), impair induction of long-term potentiation (LTP) and reduce hippocampal-dependent spatial learning. These effects are not seen in the δ-/- mouse, implicating α4βδ GABARs. Here we show that knock-out of α4 also restores synaptic plasticity and spatial learning in female mice at the onset of puberty (verified by vaginal opening). To this end, field excitatory post-synaptic potentials (fEPSPs) were recorded from the stratum radiatum of CA1 hippocampus in the slice from +/+ and α4-/- pubertal mice (PND 35-44). Induction of LTP, in response to stimulation of the Schaffer collaterals with theta burst stimulation (TBS), was unsuccessful in the +/+ hippocampus, but reinstated by α4 knock-out (~65% potentiation) but not by blockade of α5-GABARs with L-655,708 (50nM). In order to compare spatial learning in the two groups of mice, animals were trained in an active place avoidance task where the latency to first enter a shock zone is a measure of learning. α4-/- mice had significantly longer latencies by the third learning trial, suggesting better spatial learning, compared to +/+ animals, who did not reach the criterion for learning (120s latency). These findings suggest that knock-out of the GABAR α4 subunit restores synaptic plasticity and spatial learning at puberty and is consistent with the concept that the dendritic α4βδ GABARs which emerge at puberty selectively impair CNS plasticity. This article is part of a Special Issue entitled SI: Adolescent plasticity.

Music and Dyslexia: A New Musical Training Method to Improve Reading and Related Disorders

Numerous arguments in the recent neuroscientific literature support the use of musical training as a therapeutic tool among the arsenal already available to therapists and educators for treating children with dyslexia. In the present study, we tested the efficacy of a specially-designed Cognitivo-Musical Training (CMT) method based upon three principles: (1) music-language analogies: training dyslexics with music could contribute to improve brain circuits which are common to music and language processes; (2) the temporal and rhythmic features of music, which could exert a positive effect on the multiple dimensions of the “temporal deficit” characteristic of some types of dyslexia; and (3) cross-modal integration, based on converging evidence of impaired connectivity between brain regions in dyslexia and related disorders. Accordingly, we developed a series of musical exercises involving jointly and simultaneously sensory (visual, auditory, somatosensory) and motor systems, with special emphasis on rhythmic perception and production in addition to intensive training of various features of the musical auditory signal. Two separate studies were carried out, one in which dyslexic children received intensive musical exercises concentrated over 18 h during 3 consecutive days, and the other in which the 18 h of musical training were spread over 6 weeks. Both studies showed significant improvements in some untrained, linguistic and non-linguistic variables. The first one yielded significant improvement in categorical perception and auditory perception of temporal components of speech. The second study revealed additional improvements in auditory attention, phonological awareness (syllable fusion), reading abilities, and repetition of pseudo-words. Importantly, most improvements persisted after an untrained period of 6 weeks. These results provide new additional arguments for using music as part of systematic therapeutic and instructional practice for dyslexic children.

Auditory Profiles of Classical, Jazz, and Rock Musicians: Genre-Specific Sensitivity to Musical Sound Features

When compared with individuals without explicit training in music, adult musicians have facilitated neural functions in several modalities. They also display structural changes in various brain areas, these changes corresponding to the intensity and duration of their musical training. Previous studies have focused on investigating musicians with training in Western classical music. However, musicians involved in different musical genres may display highly differentiated auditory profiles according to the demands set by their genre, i.e., varying importance of different musical sound features. This hypothesis was tested in a novel melody paradigm including deviants in tuning, timbre, rhythm, melody transpositions, and melody contour. Using this paradigm while the participants were watching a silent video and instructed to ignore the sounds, we compared classical, jazz, and rock musicians' and non-musicians' accuracy of neural encoding of the melody. In all groups of participants, all deviants elicited an MMN response, which is a cortical index of deviance discrimination. The strength of the MMN and the subsequent attentional P3a responses reflected the importance of various sound features in each music genre: these automatic brain responses were selectively enhanced to deviants in tuning (classical musicians), timing (classical and jazz musicians), transposition (jazz musicians), and melody contour (jazz and rock musicians). Taken together, these results indicate that musicians with different training history have highly specialized cortical reactivity to sounds which violate the neural template for melody content.

Structural and functional plasticity specific to musical training with wind instruments

Numerous neuroimaging studies have shown structural and functional changes resulting from musical training. Among these studies, changes in primary sensory areas are mostly related to motor functions. In this study, we looked for some similar functional and structural changes in other functional modalities, such as somatosensory function, by examining the effects of musical training with wind instruments. We found significant changes in two aspects of neuroplasticity, cortical thickness, and resting-state neuronal networks. A group of subjects with several years of continuous musical training and who are currently playing in university wind ensembles showed differences in cortical thickness in lip- and tongue-related brain areas vs. non-music playing subjects. Cortical thickness in lip-related brain areas was significantly thicker and that in tongue-related areas was significantly thinner in the music playing group compared with that in the non-music playing group. Association analysis of lip-related areas in the music playing group showed that the increase in cortical thickness was caused by musical training. In addition, seed-based correlation analysis showed differential activation in the precentral gyrus and supplementary motor areas (SMA) between the music and non-music playing groups. These results suggest that high-intensity training with specific musical instruments could induce structural changes in related anatomical areas and could also generate a new functional neuronal network in the brain.

Cortical entrainment to music and its modulation by expertise

Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta-theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15-30 Hz)-often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition.

Action in Perception: Prominent Visuo-Motor Functional Symmetry in Musicians during Music Listening

Musical training leads to sensory and motor neuroplastic changes in the human brain. Motivated by findings on enlarged corpus callosum in musicians and asymmetric somatomotor representation in string players, we investigated the relationship between musical training, callosal anatomy, and interhemispheric functional symmetry during music listening. Functional symmetry was increased in musicians compared to nonmusicians, and in keyboardists compared to string players. This increased functional symmetry was prominent in visual and motor brain networks. Callosal size did not significantly differ between groups except for the posterior callosum in musicians compared to nonmusicians. We conclude that the distinctive postural and kinematic symmetry in instrument playing cross-modally shapes information processing in sensory-motor cortical areas during music listening. This cross-modal plasticity suggests that motor training affects music perception.

Musical training as an alternative and effective method for neuro-education and neuro-rehabilitation

In the last decade, important advances in the field of cognitive science, psychology, and neuroscience have largely contributed to improve our knowledge on brain functioning. More recently, a line of research has been developed that aims at using musical training and practice as alternative tools for boosting specific perceptual, motor, cognitive, and emotional skills both in healthy population and in neurologic patients. These findings are of great hope for a better treatment of language-based learning disorders or motor impairment in chronic non-communicative diseases. In the first part of this review, we highlight several studies showing that learning to play a musical instrument can induce substantial neuroplastic changes in cortical and subcortical regions of motor, auditory and speech processing networks in healthy population. In a second part, we provide an overview of the evidence showing that musical training can be an alternative, low-cost and effective method for the treatment of language-based learning impaired populations. We then report results of the few studies showing that training with musical instruments can have positive effects on motor, emotional, and cognitive deficits observed in patients with non-communicable diseases such as stroke or Parkinson Disease. Despite inherent differences between musical training in educational and rehabilitation contexts, these results favor the idea that the structural, multimodal, and emotional properties of musical training can play an important role in developing new, creative and cost-effective intervention programs for education and rehabilitation in the next future.

Neuroplasticity beyond Sounds: Neural Adaptations Following Long-Term Musical Aesthetic Experiences

Capitalizing from neuroscience knowledge on how individuals are affected by the sound environment, we propose to adopt a cybernetic and ecological point of view on the musical aesthetic experience, which includes subprocesses, such as feature extraction and integration, early affective reactions and motor actions, style mastering and conceptualization, emotion and proprioception, evaluation and preference. In this perspective, the role of the listener/composer/performer is seen as that of an active “agent” coping in highly individual ways with the sounds. The findings concerning the neural adaptations in musicians, following long-term exposure to music, are then reviewed by keeping in mind the distinct subprocesses of a musical aesthetic experience. We conclude that these neural adaptations can be conceived of as the immediate and lifelong interactions with multisensorial stimuli (having a predominant auditory component), which result in lasting changes of the internal state of the “agent”. In a continuous loop, these changes affect, in turn, the subprocesses involved in a musical aesthetic experience, towards the final goal of achieving better perceptual, motor and proprioceptive responses to the immediate demands of the sounding environment. The resulting neural adaptations in musicians closely depend on the duration of the interactions, the starting age, the involvement of attention, the amount of motor practice and the musical genre played.