Evidence in animals and humans indicates that there are sensitive periods during development, times when experience or stimulation has a greater influence on behavior and brain structure. Sensitive periods are the result of an interaction between maturational processes and experience-dependent plasticity mechanisms. Previous work from our laboratory has shown that adult musicians who begin training before the age of 7 show enhancements in behavior and white matter structure compared with those who begin later. Plastic changes in white matter and gray matter are hypothesized to co-occur; therefore, the current study investigated possible differences in gray matter structure between early-trained ET; 7 musicians, matched for years of experience. Gray matter structure was assessed using voxel-wise analysis techniques optimized voxel-based morphometry, traditional voxel-based morphometry, and deformation-based morphometry and surface-based measures cortical thickness, surface area and mean curvature. Deformation-based morphometry analyses identified group differences between ET and LT musicians in right ventral premotor cortex vPMC, which correlated with performance on an auditory motor synchronization task and with age of onset of musical training. In addition, cortical surface area in vPMC was greater for ET musicians. These results are consistent with evidence that premotor cortex shows greatest maturational change between the ages of 6-9 years and that this region is important for integrating auditory and motor information. We propose that the auditory and motor interactions required by musical practice drive plasticity in vPMC and that this plasticity is greatest when maturation is near its peak.

Early musical training is linked to gray matter structure in the ventral premotor cortex and auditory-motor rhythm synchronization performance

Experience-dependent modulation of right anterior insula and sensorimotor regions as a function of noise-masked auditory feedback in singers and nonsingers

Despite considerable research on experience-dependent neuroplasticity in professional musicians, detailed understanding of an involvement of the insula is only now beginning to emerge. We investigated the effects of musical training on intrinsic insula-based connectivity in professional classical musicians relative to nonmusicians using resting-state functional MRI. Following a tripartite scheme of insula subdivisions, coactivation profiles were analyzed for the posterior, ventral anterior, and dorsal anterior insula in both hemispheres. While whole-brain connectivity across all participants confirmed previously reported patterns, between-group comparisons revealed increased insular connectivity in musicians relative to nonmusicians. Coactivated regions encompassed constituents of large-scale networks involved in salience detection (e.g., anterior and middle cingulate cortex), affective processing (e.g., orbitofrontal cortex and temporal pole), and higher order cognition (e.g., dorsolateral prefrontal cortex and the temporoparietal junction), whereas no differences were found for the reversed group contrast. Importantly, these connectivity patterns were stronger in musicians who experienced more years of musical practice, including also sensorimotor regions involved in music performance (M1 hand area, S1, A1, and SMA). We conclude that musical training triggers significant reorganization in insula-based networks, potentially facilitating high-level cognitive and affective functions associated with the fast integration of multisensory information in the context of music performance. Hum Brain Mapp 38:4834-4849, 2017. © 2017 Wiley Periodicals, Inc.

Insula-based networks in professional musicians: Evidence for increased functional connectivity during resting state fMRI.

Interoception is the process of perceiving afferent signals arising from within the body including heart rate (HR), gastric signals, etc., and has been described as a mechanism crucially involved in the creation of self-awareness and selfhood. The heartbeat perception task is a tool to measure individuals' interoceptive accuracy (IAcc). IAcc correlates positively with measures of self-awareness and with attributes including emotional sensitivity, empathy, prosocial behavior, and efficient decision making. IAcc is only moderate in the general population, and attempts to identify groups of people who might have higher IAcc due to their specific training (e.g., yoga, meditation) have not been successful. However, a recent study with musicians suggests that those trained in the arts might exhibit high IAcc. Here, we tested IAcc in 20 professional dancers and 20 female control participants on a heartbeat perception task. Dancers had a higher IAcc, and this effect was independent of their lower heart rates (a proxy measure of physical fitness), counting ability, and knowledge about HR. An additional between-groups analysis after a median split in the dancer group (based on years of dance experience) showed that junior dancers' IAcc differed from controls, and senior dancers' IAcc was higher than both junior dancers and controls. General art experience correlated positively with IAcc. No correlations were found between IAcc and questionnaire measures of empathy, emotional experience, and alexithymia. These findings are discussed in the context of current theories of interoception and emotion-highlighting the features of arts training that might be related to IAcc.

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I can feel my heartbeat: Dancers have increased interoceptive accuracy

Neuroanatomical substrate of noise sensitivity

Interoception is defined as the perceptual activity involved in the processing of internal bodily signals. While the ability of internal perception is considered a relatively stable trait, recent data suggest that learning to integrate multisensory information can modulate it. Making music is a uniquely rich multisensory experience that has shown to alter motor, sensory, and multimodal representations in the brain of musicians. We hypothesize that musical training also heightens interoceptive accuracy comparable to other perceptual modalities. Thirteen professional singers, twelve string players, and thirteen matched non-musicians were examined using a well-established heartbeat discrimination paradigm complemented by self-reported dispositional traits. Results revealed that both groups of musicians displayed higher interoceptive accuracy than non-musicians, whereas no differences were found between singers and string-players. Regression analyses showed that accumulated musical practice explained about 49% variation in heartbeat perception accuracy in singers but not in string-players. Psychometric data yielded a number of psychologically plausible inter-correlations in musicians related to performance anxiety. However, dispositional traits were not a confounding factor on heartbeat discrimination accuracy. Together, these data provide first evidence indicating that professional musicians show enhanced interoceptive accuracy compared to non-musicians. We argue that musical training largely accounted for this effect.

/pdf/evidence-for-enhanced-interoceptive-accuracy-in-professional-3q89zptxm1.pdf

Katharina L. Schirmer-Mokwa

Papers

Evidence for Enhanced Interoceptive Accuracy in Professional Musicians.