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  • THE NEUROSCIENCES AND MUSIC II I: DISORDERS AND PLASTICITY

    The Effects of Musical Training on StructuralBrain Development

    A Longitudinal Study

    Krista L. Hyde,a Jason Lerch,b Andrea Norton,c

    Marie Forgeard,c Ellen Winner,d Alan C. Evans,a

    and Gottfried Schlaugc

    aMontreal Neurological Institute, McGill University, Montreal, Quebec, CanadabMouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada

    cDepartment of Neurology, Music and Neuroimaging Laboratory, Beth Israel DeaconessMedical Center and Harvard Medical School, Boston, Massachusetts, USA

    dDepartment of Psychology, Boston College, Chestnut Hill, Massachusetts, USA

    Long-term instrumental music training is an intense, multisensory and motor experi-ence that offers an ideal opportunity to study structural brain plasticity in the developingbrain in correlation with behavioral changes induced by training. Here, for the first time,we demonstrate structural brain changes after only 15 months of musical training inearly childhood, which were correlated with improvements in musically relevant motorand auditory skills. These findings shed light on brain plasticity, and suggest that struc-tural brain differences in adult experts (whether musicians or experts in other areas)are likely due to training-induced brain plasticity.

    Key words: brain plasticity; development; music; children; MRI

    Introduction

    Studies comparing adult musicians withmatched nonmusicians have revealed structuraland functional differences in musically relevantbrain regions, such as sensorimotor brain ar-eas,13 auditory areas,47 and multimodal in-tegration areas.811 However, no studies haveyet examined structural brain and behavioralchanges in the developing brain in response tolong-term music training to specifically addressthe question of whether structural brain differ-ences seen in adults (comparing experts withmatched controls) are a product of nature ornurture.

    Addresses for correspondence: Krista L. Hyde, Montreal NeurologicalInstitute, McGill University, 3801 University Street, Montreal, Quebec,H3A 2B4, Canada. [email protected] and Gottfried Schlaug,Department of Neurology, Music and Neuroimaging Lab, Beth IsraelDeaconess Medical Center and Harvard Medical School, 330 BrooklineAvenue, Boston, MA 02215. [email protected]

    As part of an ongoing longitudinal study ofthe effects of music training on brain, behav-ioral, and cognitive development in young chil-dren,12,13 here we investigated structural brainchanges in relation to behavioral changes inyoung children who received 15 months of in-strumental musical training relative to a groupof children who did not. We used deformation-based morphometry (DBM),14 an unbiased andautomated approach to brain morphology, tosearch throughout the whole brain on a voxel-wise basis for local brain size (voxel expansionsor contractions) differences between groupsover the 15 months.

    Materials and Methods

    Participants

    The Instrumental group consisted of 15 chil-dren (mean age at start of study: 6.32 years old,

    The Neurosciences and Music III: Disorders and Plasticity: Ann. N.Y. Acad. Sci. 1169: 182186 (2009).doi: 10.1111/j.1749-6632.2009.04852.x c 2009 New York Academy of Sciences.

    182

  • Hyde et al.: Music and Structural Brain Development 183

    SD 0.82 years) who received private keyboardinstruction for 15 months. The Control groupconsisted of 16 children (mean age at start ofstudy: 5.90 years old, SD 0.54 years) who didnot receive any instrumental music trainingduring this 15-month period, but did partici-pate in a weekly group music class in school(i.e., singing and drums). The Instrumental andControl children were all right-handed andmatched as closely as possible in gender, ageat the start of the study, and socioeconomic sta-tus. At time 1, all children were tested on a se-ries of behavioral tests, and underwent an MRIscan (scan 1). At time 2 (15 months later), allchildren were retested on the behavioral testsand underwent a second MRI scan (scan 2).This research was approved by the ethics com-mittees of the Beth Israel Deaconess MedicalCenter.

    Behavioral Tests

    Children were tested individually at times1 and 2 on two musically relevant behavioraltasks: a 4-finger motor sequencing test for theleft and right hands assessing fine finger motorskills, and a custom-made Melodic and Rhyth-mic Discrimination Test Battery, assessingmusic listening and discrimination skills. Fivenonmusical tasks were also administered: theObject Assembly, Block Design, and Vocabu-lary subtests of the WICS-III,15 the RavensProgressive Matrices,16 and the Auditory Anal-ysis Test17 (see Refs. 12 and 18 for details). Be-havioral difference scores measuring the dif-ference in performance on the behavioral testsfrom time 1 to time 2 were calculated and thencorrelated with brain deformation measures.

    Brain Analyses

    T1-weighted anatomic MRI scans were ob-tained for all children on a 3T General ElectricMRI scanner. Automated deformation brainanalyses were performed on the T1 MRI datafor each child using MNI autoreg tools.14 Statis-tical analyses were performed according to the

    general linear model and results were thresh-olded using random field theory cluster thresh-olding.19

    Results and Discussion

    There were no behavioral or brain differ-ences between the Instrumental and Controlchildren at base line (prior to any music train-ing). These results support the view that braindifferences seen in adult musicians relative tononmusicians are more likely to be the productof intensive music training rather than biologi-cal predispositions to music.12,13

    As predicted, Instrumental children showedgreater behavioral improvements over the15 months on the finger motor task and themelody/rhythmic tasks, but not on the non-musical tasks. In addition, Instrumental chil-dren showed areas of greater relative voxel sizechange over the 15 months as compared toControls in motor brain areas, such as the rightprecentral gyrus (motor hand area, Fig. 1A),and the corpus callosum (4th and 5th seg-ment/midbody, Fig. 1B), as well as in a right pri-mary auditory region (Heschls gyrus, Fig. 1C).These brain deformation differences are con-sistent with structural brain differences foundbetween adult musicians and nonmusicians inthe precentral gyri,2 the corpus callosum,2022

    and auditory cortex.2,4,23

    The brain deformation changes found be-tween Instrumental and Control childrenin motor and auditory brain areas, werepredicted by behavioral improvement scoreson the finger-motor (Fig. 1A and B) andmelody/rhythmic tasks (Fig. 1C), respectively.These results are important from a functionalperspective since these brain regions are knownto be of critical importance in instrumental mu-sic performance and auditory processing. Forexample, the primary motor area plays a criti-cal role in motor planning, execution, and con-trol of bimanual sequential finger movementsas well as motor learning,24,25 and intense bi-manual motor training of musicians could play

  • 184 Annals of the New York Academy of Sciences

    Figure 1. Group brain deformation differences. The brain images in panels A, B, andC show areas of significant brain deformation (DBM) differences over 15 months in Instru-mental (n = 15) versus Control (n = 16) children in terms of a t-statistical color map of thesignificant clusters superimposed on an average MR image of all children. The significantpositive correlations of relative voxel size with behavioral difference scores (from time 1 totime 2, either on the left-hand motor task or the melody/rhythmic task) for each child areplotted at the peak (most significant voxel shown by the yellow arrow) in the right primarymotor area (precentral gyrus; x = 40, y = 7, z = 57; t = 4.2, P < 0.05 at whole-braincluster threshold) in panel A, in the corpus callosum (x = 14, y = 24, z = 30; t = 5.2,P < 0.05 at whole-brain cluster threshold) in panel B, and in the right primary auditory area(Heschls gyrus; x = 55, y = 8, z = 10; t = 4.9, P < 0.1 at a priori cluster threshold) inpanel C. A relative voxel size of 1 indicates no brain deformation change from time 1 andvalues greater than 1 indicate voxel expansion, whereas values less than 1 indicate voxelcontraction. For example, a value of 1.1 at voxel X indicates a 10% expansion from time 1,whereas 0.9 indicates a 10% contraction. (In color in Annals online.)

    an important role in the determination of cal-losal fiber composition and size.21 The correla-tion found between the brain deformation mea-sures and the melody/rhythmic test battery in

    the right primary auditory region is consistentwith functional brain mapping studies that havefound activity changes using auditory-musicaltests in similar auditory regions.26

  • Hyde et al.: Music and Structural Brain Development 185

    While structural brain differences were ex-pected in motor and auditory brain areas, un-expected significant brain deformation differ-ences were also found in various frontal areas,the left posterior peri-cingulate, and a left mid-dle occipital region. However, none of theseunexpected deformation changes were corre-lated with motor or auditory test performancechanges. These findings indicate that plasticitycan occur in brain regions that control primaryfunctions important for playing a musical in-strument, and also in brain regions that mightbe responsible for the kind of multimodal sen-sorimotor integration likely to underlie instru-mental learning.

    These results provide new evidence fortraining-induced structural brain plasticity inearly childhood. These findings of structuralplasticity in the young brain suggest that long-term intervention programs can facilitate neu-roplasticity in children. Such an interventioncould be of part

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