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  • 1. Tone deafness: a disorder of the mind’s ear Tim Griffiths Auditory Group, Newcastle University Cognitive Neurology Clinic, Newcastle General Hospital http://www.staff.ncl.ac.uk/t.d.griffiths/tdg.html Supported by the Wellcome Trust (UK)
  • 2. My work: Ordered and disordered acoustic worlds The Ear The person 2. NEUROLOGY Disordered sound pattern analysis Speech Music Environmental Sound The mind’s ear 1. NEUROSCIENCE Ordering of sound pattern
  • 3. How do we explain this? Click picture for sound
  • 4. Famous subjects with tone deafness Che Guevara Milton Friedman
  • 5. Tone deafness: some basic questions His brain? His DNA? His neurons? His deficit?
  • 6. Tone deafness: clues from neuroscience
    • Disorder in the pitch domain: music assessments show input problem with melody perception
    • What is pitch?
    • How does the brain analyse pitch and pitch patterns?
  • 7. Pitch: normal mechanisms
    • Most neuroscience text books are wrong, and so was von Helmholtz
    • It’s not frequency
    • Pitch is a percept not a stimulus property
  • 8. Pitch: normal mechanisms
    • von Helmholtz
    • On the sensation of tone (1862)
  • 9. Construction of the pitch percept 400Hz sine 400Hz fundamental Harmonic 1 - 6 400Hz fundamental Harmonic 4 - 6 frequency (kHz) time (s) frequency (kHz) frequency (kHz) time (s) time (s) 5 5 5 0.1 0.1 0.1 Common pitch explained better by time structure than frequency structure of stimulus
  • 10. Pitch representation in the cortex
    • Functional imaging studies where brain activity measured when time structure of sound and associated pitch strength are varied
  • 11. Individual data: Structural MRI Scan
  • 12. noise - silence fixed pitch – noise Individual fMRI data: Pitch Activation Griffiths et al Nature Neurosci 1998, 2001 Patterson et al Neuron 2002
  • 13.
    • Neural activity corresponding to the pitch of individual notes occurs in secondary auditory cortex
    • Accumulating evidence that activity in this area correlates with the perception of the pitch of sound and is not just a representation of the stimulus
    • Analogy to colour area in visual brain where perceived colour not stimulus wavelength represented
    A ‘pitch centre’ in the auditory cortex?
  • 14. Pitch sequences in the cortex
  • 15. noise - silence fixed pitch – matched noise ‘ lively’ pitch – fixed pitch NB NO TASK Individual fMRI data: Pitch sequence Griffiths et al Nature Neurosci 1998, 2001 Patterson et al Neuron 2002
  • 16. PET group data: Pitch sequence NB TASK Griffiths et al Neuroreport 1999
  • 17. Pitch sequences in the cortex
    • Distributed networks beyond auditory cortex
    • For very high level processing (tonality) frontal processing only: no specific involvement of auditory cortex
  • 18. Pitch: studies of stroke patients Summary data Stewart et al Brain 2006
  • 19. Tone deafness: clues from neuroscience
    • Normal functional imaging and studies of stroke patients broadly congruent
    • Analysis of the pitch of individual notes involves a pitch centre in secondary auditory cortex
    • Highly distributed networks for pitch sequence analysis beyond auditory cortex
    • If the deficit in melody perception in tone deafness is due to abnormal pitch pattern analysis, it is likely to be a problem with cortex beyond primary cortex
  • 20. Tone deafness: what is the pitch deficit? Pitch change and pitch direction analysis Foxton et al Brain 2004 Pitch Change 1 Pitch Change 2 Pitch DIRECTION
  • 21. Tone deafness: what is the pitch deficit?
    • Abnormal perception of pitch direction
    • ‘ Bottom up’ basis for melody deficit: musicology
    • Deficient memory ‘trace’ for pitch –subjects unable to ‘keep track’ of pitch?
  • 22. Tone deafness: Brain structure 1 White matter density: Montreal and Newcastle structural MRI data Hyde, Zatorre, Griffiths, Lerch and Peretz Brain 2006
  • 23. Tone deafness: Brain structure 2 Cortical thickness: Montreal and Newcastle structural MRI data Hyde, Lerch, Zatorre, Griffiths, Evans, Peretz (Human Brain Mapping Meeting 2006)
  • 24.
    • Decreased white matter in right inferior frontal lobe
    • Increased cortical thickness in right inferior frontal lobe and right auditory cortex
    • Single-gene basis for both findings possible (connectivity deficit due to axonal migration disorder or cortex neuronal migration disorder)
    Tone deafness: brain structure
  • 25. Tone deafness: genes? Family undergoing genetic analysis in Newcastle Stewart , McDonald, Kumar, Chinnery, Griffiths (Music and Genetics Meeting Bologna 2007 ) Proband Family
  • 26.
    • Single gene explanations unlikely to be universal explanation for tone deafness
    • Analogy with early onset Alzheimer’s disease (rare single-gene families and more common genes of major effect)?
    Tone deafness : genes?
  • 27.
    • Apart from occasional disturbances of the peace, sufferers are generally useful members of society
    • Model system where we have the potential to explain a complex behaviour in terms of abnormal cortical development and connectivity
    • Other examples of disorders where abnormal connectivity implicated: schizophrenia, autism
    Tone deafness: who cares?
  • 28. Acknowledgements: Current (previous) group members and collaborators
    • Newcastle Auditory Group:
    • Simon Baumann: Freya Cooper; (Jessica Foxton); Manon Grube; (Amanda Jennings); Katharina von Kriegstein; Sukhbinder Kumar; Tobias Overath; (Lauren Stewart)
    • Wellcome Centre for Imaging Neuroscience:
    • Ray Dolan; Richard Frackowiak; Karl Friston
    • Cambridge University (CNBH): Roy Patterson
    • Montreal (BRAMS): Krista Hyde; Isabelle Peretz, Robert Zatorre