Intracortical myelination in musicians with absolute pitch

Seung-Goo (“SG”) Kim & Thomas R. KnöscheMax-Planck Institute for Human Cognitive and Brain Sciences

“The Melodic Mind” organized by Dr. Daniela Sammler2015-08-24

Overview

• Introduction: absolute pitch & myeloarchitecture

• Methods: image acquisition, processing, & inference

• Results: effect of absolute pitch

• Discussion: anterior superior temporal gyrus and ventral pathway

Overview

• Introduction: absolute pitch & myeloarchitecture

• Methods: image acquisition, processing, & inference

• Results: effect of absolute pitch

• Discussion: anterior superior temporal gyrus and ventral pathway

What is absolute pitch (AP)?• Ability to recognize the name (or pitch chroma) of any given tone (“C4” or

“G#3”) without external reference

• Rarely acquired ability (7% of Western musicians, 30% of East Asian musicians [1])

• Related to early musical experience (4~7 year-old [2]), fixed-Do training [3]

• Uncontrollable and instant (e.g., Stroop effect; “Sol” as “Do” in G major [4,5])

• Very accurate at pitch chroma but some of them are not so good at pitch height (e.g., octave errors) [1]

[1] Miyazaki, 2004 [2] Zatorre, 2003 [3] Willson et al., 2012 [4] Itoh et al., 2005 [5] Schultz et al., 2013

• Early perceptual categorization: smaller right-PT [1], larger right-HG [2]; activation in left-PT during passive listening [3,4]

• Late cognitive association to verbal/non-verbal representation: thicker IFG [6]; activation in right DLPFC [2-5]

• Frontotemporal connectivity : phase synchrony [7]

DLPFC

[1] Keenan et al., 2001 [2] Wengenroth et al., 2014 [3] Ohnishi et al., 2001 [4] Willson et al., 2009[5] Zatorre et al., 1998 [6] Dohn et al., 2015 [7] Elmer et al., 2015

Two components: macroscopic findings

HG

PT

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But how does the AP work?• What does distinctive functional activation patterns imply about

the neural mechanism of the AP processing?

• How does macroscopic morphology (e.g. GMD, CT, ROI volume, and so on) contribute to the AP recognition?

• Microscopic investigation powered by ultra-high-field MRI is expected to helpful for better understanding of the AP mechanism.

Intracortical myelination• Long-range connections

• fasten axonal transmissions

• decrease variability of transmission speed thus increasing synchrony

• Still on local connections

• reduce cross-talk so that increasing specificity

• prevent neuroplasticity after critical period [1]

Cyto- Myelo-

Vogt.1903[1] McGee et al., 2005

In-vivo myelin mapping

Wallace et al., 2002 Dick et al., 2012

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Overview

• Introduction: absolute pitch & myeloarchitecture

• Methods: image acquisition, processing, & inference

• Results: effect of absolute pitch

• Discussion: anterior superior temporal gyrus and ventral pathway

Participants• 8 AP musicians (5 women) & 9 non-AP musicians (5 women)

• Age (20~40 y.o) and handedness (≥ 70) matched (p < 0.39)

• Ethnicity and training onset age were not matched (5 Asian musicians with AP, the others were Europeans; Asians started 3 years earlier)

• Self-claimed AP possession was screened by a web-based AP test and later reconfirmed by pitch identification test

Behavioral tests• Pitch identification test using muted digital piano (72 pure tones

+ 72 piano tones across 3 octaves) spacing at least [1]

• Frequency discrimination threshold (FDT) estimated by a staircase procedure (1-up/2-down) with about 100 trials [2]

• Melody part of the Musical ear test (MET) to match musical aptitude between AP and non-AP musicians [3]

• FDT and MET were matched between groups (p<0.11)

[1] Miyazaki 1989 [2] Micheyl et al., 2006 [3] Wallentin et al., 2010

Image acquisition• MP2RAGE (7T), 0.7-mm-isovoxel; Head-coil system: RAPID 8-ch.

TR / TE / TI1 / TI2= 5000 / 2.45 / 900 / 2750 msec FA1/FA2= 5/3 degrees; dimension: 320 x 320 x 240 voxels

1st inversion 2nd inversion Quantitative T1 Uniform contrast

Image processing

• Cortical surface reconstruction using FreeSurfer

• qR1(=1/qT1) values sampled directly from 0.7-mm volume at 25, 50, 75 % of cortical thickness along outward normal vectors

qR1(1=1/qT1) values over layers

Statistical inference• SurfStat MATLAB toolbox used for 2-D random field theory

(RFT)-based family-wise error rate (FWER) control at cluster-level (alpha=0.05)

• Iterative surface-based smoothing corresponding to a 2-D Gaussian kernel with a FHWM of 7 mm

• Inferior regions (such as temporal pole, fusiform gyrus) excluded from search region for signal dropout in 7T images

Overview

• Introduction: absolute pitch & myeloarchitecture

• Methods: image acquisition, processing, & inference

• Results: effect of absolute pitch

• Discussion: anterior superior temporal gyrus and ventral pathway

AP-test confusion matrix

qR1 examples

qR1 = β0 +β1age+β2sex +β3ethnicity +β4AP + ε

qR1 = β0 +β1age+β2sex +β3AP + ε

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qR1 = β0 +β1age+β2sex +β3ethnicity +β4AP + ε

qR1 = β0 +β1age+β2sex +β3ethnicity +β4AP +β5(− logFDT)+ ε

Overview

• Introduction: absolute pitch & myeloarchitecture

• Methods: image acquisition, processing, & inference

• Results: effect of absolute pitch

• Discussion: anterior superior temporal gyrus and ventral pathway

• Early perceptual categorization: smaller right-PT [1], larger right-HG [2]; activation in left-PT during passive listening [3,4]

• Late cognitive association to verbal/non-verbal representation: thicker IFG [6]; activation in right DLPFC [2-5]

• Frontotemporal connectivity : phase synchrony [7]

DLPFC

HG

[1] Keenan et al., 2001 [2] Wengenroth et al., 2014 [3] Ohnishi et al., 2001 [4] Willson et al., 2009[5] Zatorre et al., 1998 [6] Dohn et al., 2015 [7] Elmer et al., 2015

Two components via dorsal pathway

PT

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• PT is sensitive to: spatial information, speech perception, acoustic pattern analysis, music perception [1]

• PP is sensitive to:identity of auditory object [2], voice identity [3], physical property of vocal tract [4], salience of pitch [5], and pitch chroma [6]

PP

PT

Planum temporale vs. planum polare

HG

[1] Griffiths & Warren, 2002 [2] Zatorre et al., 2004 [3] Belin et al., 2001 [4] Kriegstein et al., 2006 [5] Penagos et al., 2004 [6] Warren et al., 2003

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Pitch chroma & pitch height• Scientific pitch notation: A4 = 440 Hz• Pitch chroma: 12 tones consist 1 octave

e.g. A, A#, B, C, C#, …, G#

• Pitch height: integer index of octave e.g. (0, 1, 2, …, 8) for 88-key (full scale) piano

Warren et al., 2003https://en.wikipedia.org/wiki/Piano

Pitch chroma vs. pitch height

Warren et al., 2003

Octave errors• APs make errors in pitch height with almost no errors in pitch

chroma) suggesting distinctive processes of pitch chroma and pitch height [1-4]

[1] Miyazaki, 1988 [2] Deutsch, 2013 [3] Deutsch & Henrhotn, 2004 [4] Takeuchi & Hulse, 1993

• APs’ behaviors shows higher sensitivity to pitch chroma [1]

• PP is sensitive to pitch chroma [2] and related to auditory object recognition [3,4]

• And greater cortical myelin in the right PP in APs [5], which prohibits plasticity after the critical period [6]

• Conjecture: “Recognition of pitch chroma may occur as an auditory object recognition”

DLPFC

PP

PT

Ventral pathway for pitch chroma

HG

[1] Miyazaki, 1998 [2] Warren et al., 2003 [3] Zatorre et al., 2004 [4] Kriegstein et al., 2006 [5] Kim et al., 2015ht

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On-going analyses for further evidence• Functional/anatomical

connectivity

Resting-state functional connectivity seeding from the right PP

(our data)

Non-AP (n=1) AP (n=1)

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Octave-tuned voxels in non-musicians (Moerel et al., 2015)

• Tonotopy mapping to find pitch chroma sensitive voxels

Thank you for attention!