Auditory transduction Sept 6, 2017 – DAY 4 Brain & Language LING 4110-4890-5110-7960 NSCI 4110-4891-6110 Harry Howard Tulane University

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University Course organization http://www.tulane.edu/~h0Ward/BrLg/ Fun with https://www.facebook.com/BrLg17/

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University Review

4 lobes of brain (cerebrum) 9/06/17 Brain & Language - Harry Howard - Tulane University 4 lobes of brain (cerebrum) https://qbi.uq.edu.au/brain/brain-anatomy/lobes-brain http://www.mayoclinic.org/brain-lobes/img-20008887

3 axes (directions) of the brain 9/06/17 Brain & Language - Harry Howard - Tulane University 3 axes (directions) of the brain Longitudinal: rostral (anterior) ↔︎ caudal (posterior) Vertical: dorsal (superior) ↔︎ ventral (inferior) Lateral: left (dominant) ↔︎ right (non-dominant)

Longitudinal axis rostral (anterior) ↔︎ caudal (posterior) 9/06/17 Brain & Language - Harry Howard - Tulane University Longitudinal axis rostral (anterior) ↔︎ caudal (posterior)

Vertical axis dorsal (superior) ↔︎ ventral (inferior) 9/06/17 Brain & Language - Harry Howard - Tulane University Vertical axis dorsal (superior) ↔︎ ventral (inferior)

Lateral axis left (dominant) ↔︎ right (non-dominant) 9/06/17 Brain & Language - Harry Howard - Tulane University Lateral axis left (dominant) ↔︎ right (non-dominant)

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University A sort of summary https://d2gne97vdumgn3.cloudfront.net/api/file/4WiOAg4xQ0mSQK9RxFM2

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University 3 naming conditions Gyrii & sulcii Brodmann's areas Stereotaxic (Talairach) coordinates

Gyri & sulci, lateral view 9/06/17 Brain & Language - Harry Howard - Tulane University Gyri & sulci, lateral view

Brodmann's areas, functions 9/06/17 Brain & Language - Harry Howard - Tulane University Brodmann's areas, functions

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University Slices Any location in the brain can be localized on three planes - the x, y and z planes. The brain is can be cut on any of these planes and are named the coronal plane, the horizontal plane or the sagittal plane. https://faculty.washington.edu/chudler/slice.html

Stereotaxic (Talairach) coordinates 9/06/17 Brain & Language - Harry Howard - Tulane University Stereotaxic (Talairach) coordinates MRI scans vary greatly between individuals due to differences in slice orientation and brain features (i.e. brain size and shape varies across individuals). Therefore, it is generally useful to ‘normalize’ scans to a standard template. Normalization is the process of translating, rotating, scaling, and maybe warping a brain to roughly match a standard template image. After normalization, it is possible to report locations using stereotaxic (“Talairach”) coordinates, which are three numbers (X,Y,Z) that describe the distance from the anterior commissure (the 'origin' of Talairach space). The X,Y,Z dimensions refer to left-right, posterior-anterior, and ventral-dorsal respectively. So 38x-64x58mm refers to a point in right posterior dorsal region of the brain.

Language areas of the brain 9/06/17 Brain & Language - Harry Howard - Tulane University Language areas of the brain What view of the brain is this?

The Broca-Wernicke-Lichtheim model (of the LH) 9/06/17 Brain & Language - Harry Howard - Tulane University The Broca-Wernicke-Lichtheim model (of the LH)

The two main aphasias Ingram p. 49 9/06/17 Brain & Language - Harry Howard - Tulane University The two main aphasias Ingram p. 49 Broca’s Wernicke’s C: What brought you to the hospital? P: yes … ah … Monday … ah … Dad … Peter Hogan, and Dad … ah … hospital … and ah … Wednesday … Wednesday … nine o’clock and ah Thursday … ten o’clock … doctors two … two … an doctors and … ah … teeth … yah … and a doctor an girl … and gums, an I. C: What brings you to the hospital? Boy, I’m sweating, I’m awful nervous, you know, once in a while I get caught up, I can’t mention the tarripote, a month ago, quite a little, I’ve done a lot well, I impose a lot, while on the other hand, you know what I mean, I have to run around, look it over, trebbin and all that sort of stuff.

Hickok & Poeppel (2004)’s model superimposed on the brain 9/06/17 Brain & Language - Harry Howard - Tulane University Hickok & Poeppel (2004)’s model superimposed on the brain Dorsal Ventral

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University Old vs. new

Auditory transduction 9/06/17 Brain & Language - Harry Howard - Tulane University Auditory transduction

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University The vibrating string A simple mode of the vocal folds is a vibrating string, like that of a guitar. The entire string vibrates at a single frequency, called its fundamental frequency, F0.

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry 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.

Two sine functions with different frequencies 9/06/17 Brain & Language - Harry Howard - Tulane University 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 0.628 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.

Graph of two sine functions with different frequencies 9/06/17 Brain & Language - Harry Howard - Tulane University Graph of two sine functions with different frequencies

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University Higher frequencies This brief introduction to the pitch of the human voice leads one to believe that the vocal folds vibrate at a single frequency However, this is but a idealization for the sake of simplification of a rather complex subject. In reality, the vocal folds 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. Here, each half of the string completes a cycle in half the time.

Superposition of frequencies 9/06/17 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”.

Anatomy of the human ear 9/06/17 Brain & Language - Harry Howard - Tulane University Anatomy of the human ear

Pressure equalization within the cochlea 9/06/17 Brain & Language - Harry Howard - Tulane University Pressure equalization within the cochlea

Cochlea uncoiled to show shape of basilar membrane 9/06/17 Brain & Language - Harry Howard - Tulane University Cochlea uncoiled to show shape of basilar membrane

Sample frequency cross-sections of an uncoiled cochlea, in Hertz 9/06/17 Brain & Language - Harry Howard - Tulane University Sample frequency cross-sections of an uncoiled cochlea, in Hertz

Sample frequency cross-sections of the coiled cochlea, in Hertz 9/06/17 Brain & Language - Harry Howard - Tulane University Sample frequency cross-sections of the coiled cochlea, in Hertz

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University Phonation

Three systems involved in speech production 9/06/17 Brain & Language - Harry Howard - Tulane University Three systems involved in speech production Supralaryngeal Laryngeal http://visual.merriam-webster.com/images/human-being/anatomy/respiratory-system/respiratory-system.jpg Respiratory

Vocal folds and their location in the larynx 9/06/17 Brain & Language - Harry Howard - Tulane University Vocal folds and their location in the larynx

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University Phonation Phonation, or speech sound, is created by turbulent oscillation between phases in which the passage of air through the larynx is unconstricted (the expiratory airflow has pushed the vocal folds apart) and phases in which the passage of air is blocked (the vocal folds snap back to their semi-closed position).

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University Complete example Pitch shows fundamental frequency (F0) Spectrogram shows formants (F1-3) Sound wave

Brain & Language - Harry Howard - Tulane University 9/06/17 Brain & Language - Harry Howard - Tulane University NEXT TIME More on speech sounds