Brain Structures Differ between Musicians and Non-Musicians Christian Gaser and Gottfried Schlaug Su Kyung (Irene) Kim

Introduction Musicians -> Complex motor, auditory, somatosensory skills Skill acquisition -> functional enlargement of the representative area that underlies that particular skill Whole brain space for structural differences b/w musicians and non-musicians Unclear: continued practice or repetition of skills over a long period of time -> structural changes/regional enlargement? Strong association b/w structural differences, musician status, and practice intensity Structural adaptations in response to long-term skill acquisition and the repetitive rehearsal of those skills

Terms/definitions Voxel: a volume element, representing a value on a regular grid in 3D space VBM: Voxel-Based Morphometry -analysis of differences in local gray and white matter volume across the whole brain Morphometrics: field concerned with studying variation and change in the form of organisms or objects; detecting changes in the shape of organisms

Materials & Methods 20 male professional musicians Subjects: 20 male professional musicians (performing artists, full-time music teachers, full-time conservatory students) =high-practicing group 20 male amateur musicians (play musical instrument regularly but profession outside the field of music) =low-practicing group 40 male non-musicians (never played a musical instrument)

Materials & Methods 18 - 40 years Right-handed males ALL Keyboard players & formal training Verbal Intelligence Quotient (IQ) – Shipley Hartford Vocabulary and Abstraction test

Materials & Methods Data acquisition and analysis : High-resolution anatomical images (voxel size, 1mm³) of the whole brain – 1.5T Siemens Vision whole-body scanner Image analysis -> VBM, a fully automatic technique for computational analysis of differences in local gray matter volume Voxel-by-voxel t tests / general linear model

Results Significant (+) correlation: musician status ↔ increase in gray matter volume Musician status Gray matter volume Professional Highest Amateur Intermediate None Lowest

Relative differences in gray matter volume

Perirolandic regions: -1⁰ motor, somatosensory areas -premotor areas -anterior superior parietal areas -inferior temporal gyrus (bilaterally) Additional (+) correlation in: -left cerebellum -left Heschl’s gyrus -left inferior frontal gyrus No significant effects in Planum Temporale (PT) =>Absolute Pitch (AP) No significant correlations b/w white matter volume & musician status

Discussion Premotor & cerebellar cortex (motor) -planning, preparation, execution, and control -cerebellum: cognitive skill learning & music processing Left Heschl’s gyrus (auditory) -neurophysiological source activity differences -listening to tones Superior parietal region/lobe (visual-spatial) -1) integrate multimodal sensory info -2) provide guidance for motor operations -sight-reading Inferior temporal gyrus (visual) -ventral visual stream

Discussion Lack of a finding in white matter -1) plastic changes occur in the cerebral gray matter -2) VBM method insensitive to white matter differences -Diffusion Tensor Imaging (DTI) One gender -1) gender interaction -2) huge gender effects; histological differences -3) microstructural changes ↔ menstrual cycle

Discussion Monotonic relationship b/w musician status and gray matter volume Strong links b/w specialized skills & particular brain structures Anatomical variability -> extraordinary abilities & self-selection for musicianship VS. Adaptations to long-term musical training -> volumetric structural differences

My opinion Comprehensive Intro&discussion section Two different analyses Causal relationships b/w long-term training and related structural changes in specific brain regions Future experiments: relative contribution of predisposition and practice Different instruments (eg. flute, violin, drum) Female musicians