7/23/19

Hearing and Chapter 9

Stimulus for The Auditory Mechanism

Frequency Analysis Garrett: & Behavior 4e Locating with Binaural Cues Language, , and Antecedents 1 Hearing

• A *receptor is a cell or specialized neuron that

• Responds to a particular form of energy 7/23/19 (adequate stimulus). • *converts one form of energy to another

• Intensity and pattern of information makes information meaningful. • “Hearing” vs. “ listening”

• *Sensation- acquisition of information Garrett: Brain & Behavior 4e • *Perception- interpretation of information 2 Hearing Where Sensation Occurs and What is Encoded

Where Physical stimulus is Psychological 7/23/19 Adequate Stimulus modalities converted modalities

(receptor) Hearing Vibration in a • • Pitch

(Ch 9) conducting medium (hair cell) • Intensity or • (air, water, bone) Amplitude Vision Electromagnetic Retina • Wavelengt • Color (Ch 10) radiation in visual (rod , cone) h • Brightness spectrum • Intensity or wavelengths Amplitude Garrett: Brain & Behavior 4e

3 Physical vs. Psychological

• *Amplitude (or • *Loudness 7/23/19 Intensity) • dB- • mV- millivolts • 6dB corresponds to doubling of amplitude • Peak-to-peak • *Frequency • *Pitch • Hz-

• Waves per second • Human hearing range: Garrett: Brain & Behavior 4e *20Hz – 20,000 Hz

4 Hearing Fig 9.2: Alternating Compression & Decompression of Air by a Source Fig 9.3: Examples of Pure Tones (a-d) and Complex (e-f) Sounds (right) 7/23/19

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SOURCE: (LEFT) From Sensation and Perception, 5th ed., by Goldstein, 1999. Reprinted with permission of Wadsworth, a division of Thomson Learning. Hearing Figure 9.4: The Outer, Middle, and Inner Ear 7/23/19

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Oval window Round window Eustachian tube 6 Hearing Figure 9.4: The Outer, Middle, and Inner Ear

• Outer ear 7/23/19 • Pinna • External auditory

canal

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7 Hearing Figure 9.5: Structures of the Middle and Inner Ear.

• Middle ear 7/23/19 • Tympanic membrane • Tensor tympani

• * • hammer, anvil, stirrup • amplify sound from the tympanic membrane to the oval window Garrett: Brain & Behavior 4e • Eustachian tube Stirrup

8 Hearing Figure 9.5: Structures of the Middle and Inner Ear

• Inner ear 7/23/19 • Oval window • Cochlea (Inner Ear) • Vestibular canal

• Cochlear canal • Organ of Corti • Tympanic canal

• Round window

• Auditory nerve Garrett: Brain & Behavior 4e

9 Hearing See Figure 9.6: Electron Microscope view Showing the Hair Cells Attached to the Tectorial Membrane • *Organ of Corti – The receptive Organ of the ear 7/23/19 • Tectorial membrane • *Hair cells – The actual auditory receptors

themselves • *Outer hair cells -> (amplification and sound sharpening) • Inner hair cells (encode sound into

impulses) Garrett: Brain & Behavior 4e • Basilar membrane 10 Hearing The . Figure 9.7: The Auditory Pathway and Auditory Cortex

• Auditory (8th Cranial Nerve) >

• Inferior colliculi (sound from both ears converge) > 7/23/19 • Medial geniculate nucleus (mostly opposite ear information) > • Primary auditory cortex *() • Topographical organization throughout system

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11 Hearing Fig 9.8: The Dorsal “Where” & Ventral “What” Streams of Auditory Processing • What (green) • *Ventral Stream into temporal lobes 7/23/19 • Secondary Auditory Cortical areas • Where (red)

• *Dorsal stream to parietal lobes, then frontal lobes

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12 Hearing Frequency Theories. Figure 9.9: Illustration of Volleying in Neurons • Frequency theory (Rutherford, 1886) • Telephone theory (Wever & Bray, 1930) 7/23/19 • Both of above limited to <500 Hz sounds. Why? • Volley theory (Wever, 1949)

• Volleying fails to follow sounds beyond about 5200 Hz • *groups of neurons follow frequency up to this point though

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13 Hearing Why Frequency Theories are Inadequate

• Why can’t we use frequency theories for encoding high frequency signals? • 1000 Hz is 1000 waves per second, • 1 millisecond between action potentials • Well below absolute refractory period of individual neuron

+20 mV

0 mV -20 mV Absolute -40 mV 14 Threshold (mV) Refractory Period Relative Refractory Period 00 2 1 4 2 6 3 8 4 ms Time between action potentials (ms) Hearing Place Theory. Figure 9.10: Frequency Sensitivity on the Human Basilar Membrane. • *Place Theory • Tonotopic map of basilar membrane • * encoded

by place on membrane

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SOURCE: Animation © 2006 Howard Hughes Medical Institute Hearing Place Theory. Figure 9.11: Tonotopic Map Figure 9.12: “ Tuning Curves” of three Auditory Neurons • Auditory cortex is also *tonotopically organized

• Cells tightly tuned to specific frequencies

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SOURCE: (Bottom) Figure 11.31 from Sensation and Perceptions (5th ed.; p. 331) by E. Bruce Goldstein, 1999, Pacific Grove, CA: Brooks-Cole. © 1999. Reprinted by permission of Wadsworth, a division of Thomson Learning: www.thomsonrights.com. Fax 800-730-2215. Hearing Summary of Frequency vs. Place Theory

• Hair cells fire at same • Basilar membrane frequency as sound sensitive to different wave frequencies • Volley: combining • Tonotopic frequency several hair cells organization • Low frequency • High frequency • Pitch- impulse rate of • Pitch- membrane hair cells location • Loudness- number of • Loudness- firing rate firing hair cells of hair cell 17 Hearing

• However, place theory alone is inadequate. 7/23/19 • Basilar membrane vibrates equally throughout low range of hearing • Frequency-specific neurons have not been found below 200 Hz.

• Frequency-place theory • Frequency encoding at low frequencies (most < 500 Hz) • Place encoding for everything else

Frequency Theories Garrett: Brain & Behavior 4e

Place Theory 18 0 1 2 3 4 5+ kHz Hearing Analyzing Complex Sounds. Figure 9.14: Fourier analysis of a clarinet note

• Analyzing Complex Sounds 7/23/19 • Fourier analysis • Breaking complex sound into component

frequencies • Basal membrane

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SOURCE: From “How Much Distraction Can You Hear?” by P. Milner, Stereo Review, June 1977, pp. 64–68. © 1977. Reprinted by permission of Stereo Review. Hearing Analyzing Complex Sounds Figure 9.15: Areas Involved in Identifying Environmental Sounds • Analyzing Complex Sounds 7/23/19 • Cocktail party effect • Following an auditory object within complex sound background • Selective attention requires directional information as well as

“what” pathway (yellow areas below)

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SOURCE: From “Human Brain Regions involved in Recognizing Environmental Sounds,” by J. W. Lewis et al., 2004, , 14, 1008–1021. Reprinted with permission. Hearing Locating Sounds With Binaural Cues Figure 9.16: Sound Localizing Device Used by 19th-Century Sailors. • Binaural: using both ears • Differences –*Greatest with sounds to our left & right • Difference in Intensity • Difference in Time of Arrival

• Phase Difference

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21 Hearing Locating Sounds With Binaural Cues Figure 9.17: Differential Intensity & Time of Arrival Cues • Difference in 7/23/19 Intensity • High frequencies

• Sound shadow • Difference in Time of Arrival

• Low frequencies • Sound delay Garrett: Brain & Behavior 4e

22 Hearing Figure 9.18: Phase Differences at the Two Ears • Phase difference between ears 7/23/19 • The far ear’s wave will lag behind the nearer one • Only useful < 1500 Hz

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23 Quality Stimulates *A Cochlear bone *Hearing aids Application: Restoring Hearing is about conduction issues

hair cells the Implant Device same directly useful for as through a telephone

losses implanted for associated call problems receiver/stimulator with with hair middle cells

ear

24 Garrett: Brain & Behavior 4e Hearing A Brain Circuit for Detecting Time Differences Figure 9.19: Difference in Time of Arrival Circuit • Coincidence detectors and delay lines 7/23/19 • Longer pathway from one ear compensates for sound delay to the other ear. • Cell fires most when inputs from both ears arrive at the same time.

• Each detector is specialized for a particular angle of sound.

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SOURCE: Based on the results of Carr and Konishi (1990). Hearing Application: I Can Hear a Tree Over There • Echolocation • Emit sound, echoes coming off objects are “seen” • , dolphins, whales, some birds, submarines • Occasionally a blind human!

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SOURCE: From Figure 3, Thaler, L., Arnott, S. R., Goodale, M. A. (2011). Neural correlates of natural human echolocation in early and late blind echolocation experts. PLoS ONE, 6, e20162, DOI: 10.1371/journal.pone.0020162. Figure was edited to highlight only the later views of Participant EB and control Participant C1 Defined Language •

written, Language: • • •

Impairment- Brain Acquired

areas

spoken,

generation

through responsible

Aphasia and learning gestural and

for understanding language communication.

of

27 Garrett: Brain & Behavior 4e 7/23/19 Language Broca’s Area. Figure 9.20: Language-Related Areas of the Cortex • Broca (1861): Stroke patient with *frontal lobe

damage anterior to motor cortex (Broca’s area) 7/23/19 • Broca’s (Expressive) • *Non-fluency (selecting the right word) • Anomia • *Inarticulate (pronunciation) • Agrammatic

28 Figure Wernicke Language •

temporal Wernicke •

Wernicke’s 9.20: • •

’ *Fluent forms Unable s Language-Related Area.

lobe (1874):

to and

understand (Receptive)

Articulate, damage Left Areas *Posterior language of but Aphasia (Wernicke the meaningless Cortex in

written

superior ’s

“word area) or spoken salad” 29 Garrett: Brain & Behavior 4e 7/23/19 SOURCE: Figure Language

Adapted 9.21: from “Specializations The Wernicke-Geschwind of the Human Brain, ” by N. Geschwind, Model

of

Scientific Language American,

241 (9), pp. 180–199.

30 Garrett: Brain & Behavior 4e 7/23/19 Major ’s Broca Wernicke’s Agraphia Aphasia Alexia Type

Aphasia

forms

imbalanced language impaired output impaired Inability Impaired Inability (meaningless Articulate, agrammatic difficulty Nonfluent of to

to to

with visual language

reading centers motor

Symptoms , yet write read

language visual

“Word articulation, agrammatic input due systems due due

inputs anomia, center to Salad”) to to to

deficits Planum Broca’s or Brain ’s Wernicke

larger temporal Angular Angular

Areas temporale

Area lobe on

gyrus gyrus right

Involved

of

Area lobe frontal side equal of 31 Garrett: Brain & Behavior 4e 7/23/19 SOURCE: Area Figure Language

Based on 9.22: Hécaen Frequency and Angelergues of

(1964). Language Deficits Resulting

From Damage in

Each 32 Garrett: Brain & Behavior 4e Language Reading, Writing, and Their Impairment

• Angular gyrus 7/23/19 • Connects the visual projection area to auditory and visual association areas. • *Alexia: the inability to read • Input through angular gyrus • Dyslexia- impaired reading

• Agraphia: the inability to write Garrett: Brain & Behavior 4e • Output through angular gyrus • Dysgraphia- impaired writing 33 Language Reading, Writing, and Their Impairment Figure 9.24: Anomalies in the Dyslexic Brain • Dyslexia- impaired reading • Right planum temporale (Wernicke’s Area) is larger or equal in size. • Left planum temporale neurons lack orderly arrangement. • Prenatal: Genes identified involve neuronal guidance and migration. • More prevalent in complex • Phonological hypothesis- impaired phoneme processing

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34 Normal brain Dyslexic brain

SOURCE: Courtesy A. M. Galaburda, Harvard Medical School. • *Words shiftingormoving aroundonthepage • *Letterreversals: may read‘bog’ ‘now’ • *Word reversals :mayconfuse‘won’with Someone withDyslexiawilloftenexperience: Dyslexia Language

related

issues with

Reading

as ‘’

35 Garrett: Brain & Behavior 4e Language Mechanisms of Recovery from Aphasia

• Left hemisphere damage: 7/23/19 • Early in life: Right side can take over language functions, since it already is responsible for • * (intonation, emphasis, and rhythm of speech) • Figurative nature of language (non-literal interpretations)

• Late in life: Language control shifts into Garrett: Brain & Behavior 4e bordering areas. 36 Language A Language-Generating Mechanism? Figure 9.26: Babies of Signing Parents Babble with their Hands • Language acquisition device 7/23/19 • Brain area dedicated to learning & controlling language.

• Same rules whether it is written, spoken, or signed. • Biological mechanisms

• Left hemisphere shows *language dominance for 90% of right handers, and 66% of lefties Garrett: Brain & Behavior 4e • *right hemisphere for Prosody • Response to language seen even before birth 37

SOURCE: Petitto, Holowka, Sergio, & Ostry, 2001. Photo courtesy of Dr. Laura-Ann Petitto, University of Toronto. Language A Language-Generating Mechanism? Figure 9.27: Language Areas in Hearing and Deaf Individuals • Spoken (left) and signed (right) language processed in same areas of brain

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SOURCE: Reprinted with permission from H. J. Neville et al., “Cerebral Organizations for Language in Deaf and Hearing Subjects: Biological Constraints and Effects of Experience,” Proceedings of the National Academy of Sciences, USA, 95, pp. 922–929. Copyright 1998 National Academy of Sciences, USA. Language Figure 9.28: Brain Areas Activated by Different Languages in Bilingual Individuals • Languages activate separate areas 7/23/19 • Green- English • Yellow- Spanish

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SOURCE: From “Mapping of Receptive Language Cortex in Bilingual Volunteers by Using Magnetic Source Imaging,” by P. G. Simon et al., 2001, Journal of Neurosurgery, 95, pp. 76–81. Language Language in Nonhumans

• Behaviors that humans and animals share 7/23/19 • Tool use • Self-recognition

• Creativity • Language?

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40 Language Language in Nonhumans See Figure 9.29: Language Research With Chimpanzees and Bonobos 7/23/19

• Chimps and Bonobos •

Can learn many different ASL symbols • Can teach each other how to sign • Can have conversations among themselves • Alex the parrot • Could answer complex language tasks Garrett: Brain & Behavior 4e

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SOURCES: (a) Susan Kuklin/Photo Researchers; (b) © Frans Lanting/Corbis. Language Neural and Genetic Antecedents

• Animals share some of the brain organization 7/23/19 associated with human language. • Left-hemisphere dominance for meaningful sounds or

gestures. • Both likely provide pre-language communicative abilities. • Genetic correlates:

• FOXP2, the language gene, found in apes as well as Neanderthal remains. Garrett: Brain & Behavior 4e

42 Language Neural and Genetic Antecedents . Figure 9.32: Overlap Between Language Areas and Areas Involved with Imitation. • We share mirror neurons with other species 7/23/19 • May be critical to the development of language. • Below, overlap of speech and imitation areas (brown)

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SOURCE: Image provided courtesy of Dr. Marco Iacoboni. From “The , ” by C. Holden, 2004, Science, 303, p. 1318.