1. Auditory transduction 2 Sept 8, 2017 – DAY 5
Brain & Language
LING
NSCI
Harry Howard
Tulane University

2. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Course organization
Fun with
I'm slowly getting everyone enrolled.

3. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Computer hygiene
I edit the online book constantly, so you should refresh your browser every now and then.
Restart your computer every now and then!!!

4. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Review

5. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Field
Observations
graphemics
the study of writing systems; a little with visual language
auditory phonetics
yes
articulatory phonetics
phonology
prosody
the study of stress and intonation; yes
morphology
syntax
semantics
pragmatics
a little
lexicography
the study of words; implicit in some of the others
language development
the study of how children learn language; maybe
bi- or multilingualism
the study of people who speak more than one language; a little
sociolinguistics
the study of how language varies by social group; no
dialectology
the study of the language of specific (usually geographically defined) social groups; no
historical linguistics
the study of how languages change; no, neuroscience can’t study dead people, but …
evolution of language
the study of how humans acquired language; maybe – what fun! almost pure speculation
anthropological linguistics
the study of how language varies by social group, usually pre-industrial or non-Western; no

6. Gyri & sulci, lateral view
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Brain & Language - Harry Howard - Tulane University
Gyri & sulci, lateral view

7. Hickok & Poeppel (2004)’s model superimposed on the brain
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Brain & Language - Harry Howard - Tulane University
Hickok & Poeppel (2004)’s model superimposed on the brain
Dorsal
Ventral

8. Graph of two sine functions with different frequencies
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Brain & Language - Harry Howard - Tulane University
Graph of two sine functions with different frequencies

9. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Vibration and standing waves in a string: The fundamental and the first 6 overtones

10. Superposition of frequencies
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Brain & Language - Harry Howard - Tulane University
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”.

11. Practice: wind, meadowlark, bell or speech?
09/08/17
Brain & Language - Harry Howard - Tulane University
Practice: wind, meadowlark, bell or speech?

12. Spectrum of visible light
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Brain & Language - Harry Howard - Tulane University
Spectrum of visible light

13. Brain & Language - Harry Howard - Tulane University
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Brain & Language - Harry Howard - Tulane University
What is this?

14. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Spatial frequency

15. Brain & Language - Harry Howard - Tulane University
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Brain & Language - Harry Howard - Tulane University
Lincoln illusion

16. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
What are these?

17. Three systems involved in speech production
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Brain & Language - Harry Howard - Tulane University
Three systems involved in speech production
Supralaryngeal
Laryngeal
Respiratory

18. Vocal folds and their location in the larynx
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Brain & Language - Harry Howard - Tulane University
Vocal folds and their location in the larynx

19. The three buccal cavities, articulating [i] and [a]
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Brain & Language - Harry Howard - Tulane University
The three buccal cavities, articulating [i] and [a]

20. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Complete example
Pitch shows fundamental frequency (F0)
Spectrogram shows formants (F1-3)
Sound wave

21. Anatomy of the human ear
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Brain & Language - Harry Howard - Tulane University
Anatomy of the human ear

22. Organ of Corti, location in cochlea
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Brain & Language - Harry Howard - Tulane University
Organ of Corti, location in cochlea

23. Pressure equalization within the cochlea
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Brain & Language - Harry Howard - Tulane University
Pressure equalization within the cochlea

24. Sample frequency cross-sections of the coiled cochlea, in Hertz
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Brain & Language - Harry Howard - Tulane University
Sample frequency cross-sections of the coiled cochlea, in Hertz

25. Sample frequency cross-sections of an uncoiled cochlea, in Hertz
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Brain & Language - Harry Howard - Tulane University
Sample frequency cross-sections of an uncoiled cochlea, in Hertz

26. Auditory transduction 2
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Brain & Language - Harry Howard - Tulane University
Auditory transduction 2

27. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Organ of Corti, close-up transduction of mechanical to electrical signals
Wave energy from the cochlea causes the basilar membrane to vibrate, bending hair cells.
The hair cells depolarize their membranes; action potentials travel down the auditory nerve to the brainstem & beyond.
outer hair cells
inner hair cell

28. Bending of basilar membrane translated to stereocilia tips
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Brain & Language - Harry Howard - Tulane University
Bending of basilar membrane translated to stereocilia tips

29. A close-up of a bundle of stereocilia
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Brain & Language - Harry Howard - Tulane University
A close-up of a bundle of stereocilia
) Less
1000 x KB
abovethemessycloud.blogspot.com

30. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
An inner hair cell
The deflection of the hair-cell stereocilia opens mechanically gated ion channels that allow any small, positively charged ions (primarily potassium and calcium) to enter the cell.
Unlike many other electrically active cells, the hair cell itself does not fire an action potential.
Instead, the influx of positive ions from the endolymph in the scala media depolarizes the cell, resulting in a receptor potential.
This receptor potential opens voltage gated calcium channels; calcium ions then enter the cell and trigger the release of neurotransmitters at the basal end of the cell.
The neurotransmitters diffuse across the narrow space between the hair cell and a nerve terminal, where they then bind to receptors and thus trigger action potentials in the nerve.

31. Hair cells along the basilar membrane
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Brain & Language - Harry Howard - Tulane University
Hair cells along the basilar membrane

32. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
Outer hair cells
They can contract, and therefore act as motor units that amplify the movement of the basilar membrane in response to a stimulus.
Think of a swing: if a person sitting on a swing (basilar membrane) pumps his legs (OHC), the amplitude of the swing motion is increased in response to a push (sound stimulus)

33. Outer hair cell "Rock around the clock"
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Brain & Language - Harry Howard - Tulane University
Outer hair cell "Rock around the clock"

34. Brain & Language - Harry Howard - Tulane University
09/08/17
Brain & Language - Harry Howard - Tulane University
NEXT TIME
P1: 10 multiple choice questions
The fields of linguistics
The macrostructure of the brain
Sound
Speech sounds and their articulation
Auditory transduction
More on speech sounds