1. Audition Day 8 Music Cognition Harry Howard Tulane University
MUSC , NSCI 466, NSCI
Harry Howard
Barbara Jazwinski
Tulane University

2. Course administration
Spend provost's money
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Music Cognition - Jazwinski & Howard - Tulane University

3. Macrostructure of the brain
The parts of the brain that you can see with the naked eye

4. Music Cognition - Jazwinski & Howard - Tulane University
Questions
What are the axes of the brain?
What are the lobes of the brain and what do they do?
What are the main connections between parts of the brain?
What are the three ways of referring to areas of the brain?
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Music Cognition - Jazwinski & Howard - Tulane University

5. Macrostructure overview
Three axes of the brain
Vertical
Horizontal
Longitudinal
Lateral
Connections
Naming conventions
Gyrii ~ sulcii
Brodmann’s areas
Stereotaxic (“Talairach”) coordinates
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Music Cognition - Jazwinski & Howard - Tulane University

6. Vertical axis: ventral/dorsal
Orientation of picture
Which way is forward?
to the left: cerebellum at back
Which hemisphere do we see?
medial side of right; left is cut away > sagittal view
Vertical axis
Dorsal is up, like dorsal fin (dorsal comes from Latin word for back)
Ventral is down (ventral comes from Latin word for belly)
Cortical vs. subcortical division
Cerebrum vs. cerebellum
Cerebral cortex (neocortex) vs. cerebellar cortex
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Music Cognition - Jazwinski & Howard - Tulane University

7. Longitudinal axis: anterior/posterior
Lobes
Sylvian fissure
Perisylvian area
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Music Cognition - Jazwinski & Howard - Tulane University

8. Longitudinal axis, functions
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Music Cognition - Jazwinski & Howard - Tulane University

9. Lateral axis: left/right
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Music Cognition - Jazwinski & Howard - Tulane University

10. Music Cognition - Jazwinski & Howard - Tulane University
Lateral axis
General
Which way is anterior?
Motor and sensory organs are crossed
Ipsilateral, contralateral LH
Language
Math
Logic RH
Spatial abilities
Face recognition
Visual imagery
Music
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Music Cognition - Jazwinski & Howard - Tulane University

11. Music Cognition - Jazwinski & Howard - Tulane University
Connections
Corpus callosum
Arcuate fasciculus
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Music Cognition - Jazwinski & Howard - Tulane University

12. How to refer to specific areas of the brain
Naming conventions
How to refer to specific areas of the brain

13. Music Cognition - Jazwinski & Howard - Tulane University
Gyrii
AnG - angular gyrus
FP - frontal pole
IFG - inferior frontal gyrus
IOG - inferior occipital gyrus
ITG - inferior temporal gyrus
LOG - lateral occipital gyrus
MFG - middle frontal gyrus
MTG - middle temporal gyrus
OG - orbital gyrus
oper - pars opercularis (IFG)
orb - pars orbitalis (IFG)
tri - pars triangularis (IFG)
poCG - postcentral gyrus
preCG - precentral gyrus
SFG - superior frontal gyrus
SOG - superior occipital gyrus
SPL - superior parietal lobe
STG - superior temporal gyrus
SmG - supramarginal gyrus
TP - temporal pole
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Music Cognition - Jazwinski & Howard - Tulane University

14. Music Cognition - Jazwinski & Howard - Tulane University
Sulcii
cs - central sulcus (Rolandic)
hr - horizontal ramus
ifs - inferior frontal sulcus
ios - inferior occipital sulcus
ips - intraparietal sulcus
syl - lateral fissure (Sylvian)
los - lateral occipital sulcus
ls - lunate sulcus
pof - parieto-occipital fissure
pocs - postcentral sulcus
precs - precentral sulcus
sfs - superior frontal sulcus
tos - transoccipital sulcus
vr - vertical ramus
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Music Cognition - Jazwinski & Howard - Tulane University

15. Music Cognition - Jazwinski & Howard - Tulane University
Brodmann’s areas
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Music Cognition - Jazwinski & Howard - Tulane University

16. Brodmann’s areas, functions
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Music Cognition - Jazwinski & Howard - Tulane University

17. Frequency

18. Music Cognition - Jazwinski & Howard - Tulane University
Sound creation
Sound creation is created in most instruments, including the voice, by turbulent oscillation between phases in which air is compressed and phases in which it is rarefied.
The following figure depicts such a transition, in which increasing darkness symbolizes increasing compression of the airflow.
The heavy line represents the pressure of airflow as a single quantity between a minimum and a maximum.
as air is compressed, its pressure rises;
as air is rarefied, its pressure falls.
A single cycle of compression and rarefication is defined by the distance between two peaks, marked by dotted white lines.
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Music Cognition - Jazwinski & Howard - Tulane University

19. Graph of turbulent oscillation (of vocal air)
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Music Cognition - Jazwinski & Howard - Tulane University

20. Music Cognition - Jazwinski & Howard - Tulane University
Frequency
This cycling of airflow has a certain frequency
the frequency of a phenomenon refers to the number of units that occur during some fixed extent of measurement.
The basic unit of frequency, the hertz (Hz), is defined as one cycle per second.
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Music Cognition - Jazwinski & Howard - Tulane University

21. Two sine functions with different frequencies
A simple illustration can be found in the next diagram. It consists of the graphs of two sine functions.
The one marked with o’s, like beads on a necklace, completes an entire cycle in s, which gives it a frequency of 1.59 Hz.
The other wave, marked with x’s so that it looks like barbed wire, completes two cycles in this period. Thus, its frequency is twice as much, 3.18 Hz.
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Music Cognition - Jazwinski & Howard - Tulane University

22. Graph of two sine functions with different frequencies
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Music Cognition - Jazwinski & Howard - Tulane University

23. Fundamental frequency
The pitch of an instrument corresponds to the lowest frequency of oscillation, called fundamental frequency or F0.
Fundamental frequency & gender
the fundamental frequency of a man’s voice averages 125 Hz,
the fundamental frequency of a woman’s voice averages 200 Hz
This 60% increase in the pitch of a woman’s voice can be accounted for entirely by the fact that a man’s vocal folds are on average 60% longer than a woman’s.
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Music Cognition - Jazwinski & Howard - Tulane University

24. The fundamental & higher frequencies
This brief introduction to frequency leads one to believe that an instrument vibrates at a single frequency, that of its fundamental frequency, much as the schematic string on the left side of the next diagram is shown vibrating at its fundamental frequency.
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Music Cognition - Jazwinski & Howard - Tulane University

25. Music Cognition - Jazwinski & Howard - Tulane University
Higher frequencies
However, this is but a idealization for the sake of simplification of a rather complex subject.
In reality, instruments vibrate at a variety of frequencies that are multiples of the fundamental.
The diagram depicts how this is possible – a string can vibrate at a frequency higher than its fundamental because smaller lengths of the string complete a cycle in a shorter period of time.
In the particular case of the central diagram, each half of the string completes a cycle in half the time.
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Music Cognition - Jazwinski & Howard - Tulane University

26. Superposition of frequencies
This figure displays the outcome of superimposing both frequencies on the string and the waveform.
The result is that a pulse of vibration created by the vocal folds projects an abundance of different frequencies in whole-number multiples of the fundamental.
If we could hear just this pulse, it would sound, as Loritz (1999:93) says, “more like a quick, dull thud than a ringing bell”.
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Music Cognition - Jazwinski & Howard - Tulane University

27. Audition

28. Overview of the auditory pathway
CentralAudPath.gif
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Music Cognition - Jazwinski & Howard - Tulane University

29. Auditory transduction: the cochlea
The cochlea is filled with a watery liquid, which moves in response to vibrations coming from the middle ear via the oval window.
As the fluid moves, thousands of "hair cells" are set in motion, and convert that motion to electrical signals that are communicated via neurotransmitters to many thousands of nerve cells.
These primary auditory neurons transform the signals into electrical impulses known as action potentials, which travel along the auditory nerve to structures in the brainstem for further processing.
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Music Cognition - Jazwinski & Howard - Tulane University

30. Cross section of the cochlea
The basilar membrane within the cochlea is a stiff structural element that separates two liquid-filled tubes that run along the coil of the cochlea.
The tubes transduce the movement of air that causes the tympanic membrane and the ossicles to vibrate into movement of liquid and the basilar membrane.
This movement is conveyed to the organ of Corti, composed of hair cells attached to the basilar membrane and their stereocilia embedded in the tectorial membrane.
The movement of the basilar membrane compared to the tectorial membrane causes the sterocilia to bend.
They then depolarise and send impulses to the brain via the cochlear nerve.
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Music Cognition - Jazwinski & Howard - Tulane University

31. Music Cognition - Jazwinski & Howard - Tulane University
Frequency dispersion
The basilar membrane is a pseudo-resonant structure that, like the strings on an instrument, varies in width and stiffness, which causes sound input of a certain frequency to vibrate some locations of the membrane more than others and thus ‘maps’ the frequency domain that humans can hear.
High frequencies lead to maximum vibrations at the basal end of the cochlear coil (narrow, stiff membrane)
Low frequencies lead to maximum vibrations at the apical end of the cochlear coil (wide, more compliant membrane).
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Music Cognition - Jazwinski & Howard - Tulane University

32. The cochlea & basilar membrane
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Music Cognition - Jazwinski & Howard - Tulane University

33. More recent auditory pathway - note complexity
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Music Cognition - Jazwinski & Howard - Tulane University

34. Schematic auditory pathway
AuditoryPathSchematic.gif
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Music Cognition - Jazwinski & Howard - Tulane University

35. Auditory regions of the brain
A lateral view of the cerebral cortex that highlights the prominent neural regions for auditory perception. The temporal lobe is shaded and the numbers refer to the Brodmann areas of primary auditory cortex (area 41) and secondary auditory cortex (areas 22 and 42). The right hemisphere contains homologous regions.
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Music Cognition - Jazwinski & Howard - Tulane University

36. Music Cognition - Jazwinski & Howard - Tulane University
Auditory cortex
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Music Cognition - Jazwinski & Howard - Tulane University

37. Primary auditory cortex (A1)
tonotopic map
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Music Cognition - Jazwinski & Howard - Tulane University

38. Absolute vs. relative pitch
Thus A1 represents absolute pitch
We do not know how relative pitch is represented
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Music Cognition - Jazwinski & Howard - Tulane University

39. Music Cognition - Jazwinski & Howard - Tulane University
Timbre
Different parts of a musical instrument vibrate
with different onsets (attack)
See Levitin’s discussion of Schaeffer’s perceptual experiments on onset (attack), pp
at different frequencies (steady state)
for different durations (flux or decay)
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Music Cognition - Jazwinski & Howard - Tulane University

40. The timbre of the human voice
Supralaryngeal
Laryngeal
Respiratory
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Music Cognition - Jazwinski & Howard - Tulane University

41. Back to our regularly scheduled program

42. Ingredients of music cognition mostly receptive, mostly from Levitin
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Music Cognition - Jazwinski & Howard - Tulane University

43. Go over other musical perceptual attributes §1-2 of Levitin
Next Monday
Go over other musical perceptual attributes
§1-2 of Levitin