Exam 3 Flashcards
Perceptual process of hearing
1.Sound stimulus is produced
2.Sound travels through the air and is received by the auditory receptors
3.Signals are transduced and sent to the brain
4.Sound information is processed in the brain
5.We perceive the sound
6.We recognize the sound
7.We act on the sound
Physical definition of sound
pressure changes in the air
Perceptual definition of sound
experience we have when we hear
Sound occurs when…
the movement or vibration of an object causes pressure changes in a medium that can transmit vibrations
Condensation
Increase in density
Rarefaction
Decrease in density
Sound wave
pattern of pressure changes
Pure tone
tone with pressure changes that can be described as a single sine wave
Building blocks of sound
Frequency
number of cycles per second that the pressure changes repeat
measured in Hertz (Hz)
Associated with pitch
What range of Hz can humans perceive?
20-20,000 Hz
Amplitude
Size of the pressure change
measured in decibels (dB)
associated with loudness
Decibels increase logarithmically
an increase of 20 dB means the amplitude is 10x greater
Periodic tones
tones with a repeating waveform
Periodic tones have a ____.
Fundamental frequency
Fundamental frequency
Number of times a sound repeats per second
The first harmonic or fundamental of a complex tone, is usually the ___ in the frequency spectrum of a complex tone.
lowest frequency
Higher harmonics
The other components of a tone; frequencies are whole number multiples of the fundamental frequency
Loudness
Perceptual quality most closely related to amplitude of an auditory stimulus
What Hz are humans most sensitive to?
2,000-4,000 Hz
Pitch
quality of a sound ranging from low to high, most closely related to a frequency of a tone
Octave
tones that have frequencies that are binary multiples of each other
Timbre
quality that distinguishes between two tones that sound different even though they have the same loudness, pitch, and duration
Attack
Buildup of sound at the beginning of the tone
Decay
decrease in sound at the end of the tone
Aperiodic sounds
sound waves that do not repeat
Physical qualities of sound
Frequency
amplitude
harmonic structure
Perceptual qualities of a sound
Pitch
loudness
timbre
Three main sections of the ear
Inner ear
middle ear
outer ear
Tympanic membrane
ear drum
What makes up the outer ear?
Pinna
auditory canal
Tympanic membrane
The outer ear is responsible for
resonance
resonance frequency
Resonance
Certain frequencies are enhanced
What makes up the middle ear?
Ossicles
Oval window
middle ear muscles
What are the three parts of the ossicles
Malleus
Incus
stapes
What are the ossicles responsible for
concentrating the vibration of the large tympanic membrane onto the much smaller stapes
middle ear muscles
dampen loud sounds and our own sounds
Parts of the inner ear
Cochlea
cochlear partition- extends from base to apex
organ of Corti
hair cells-stereocilia
basilar membrane
tectorial membrane
Steps of sound transmission
- Stapes vibrates
- Oval window moves back and forth
- Vibrations travel through cochlear fluid
- Basilar membrane moves up and down
5a. Organ of Corti moves up and down
5b. Tectorial membrane move back and forth - Stereocilia of hair cells bend one way
- Tip links stretch
- Tiny ion channels open
- Potassium (K+) flows in
- Electrical signal results
- Neurotransmitters released in synapse
- Stereocilia bend other way
- Ion channels close
Vibrations bend the
stereocilia
bending of stereocilia causes
electrical signals
A sound wave’s frequency determines the ____.
Timing of electrical signals
Phase locking
firing of auditory neurons in synchrony with the phase of an auditory stimulus
Békésy discovered …
how the basilar membrane vibrates like a traveling wave.
Place of greatest vibration depends on…
Frequency
Base (____)
Apex (____)
High frequencies
low frequencies
The basilar membrane has a ___ organization
Tonotopic
Tonotopic map
orderly map of frequencies (tones) along the length of the cochlea
Cochlear amplifier
expansion and contraction of the outer hair cells in response to sound sharpens the movement of the basilar membrane to specific frequencies
Place theory
says that pitch perception is based on the place along the basilar membrane at which the nerve firing is highest
Problem with place theory
amplitude-modulated noise – noise that isn’t associated with vibration of a particular part of basilar membrane, yet still results in pitch perception
Frequency theory
says that pitch perception is based on the frequency of action potentials in auditory nerve neurons, which occur at the same frequency as the sound.
- considered the best theory
Damage to inner hair cells
loss of sensitivity
Damage to outer hair cells
loss of sensitivity and loss of sharp frequency tuning (cochlear amplification)
Auditory pathway
Cochlea
Auditory nerve
Cochlear nucleus
Superior olivary nucleus
Inferior colliculus
Medial geniculate nucleus (thalamus)
A1 (primary receiving area)
Other areas in cortex
Presbycusis
hearing loss caused by hair cell damage resulting from cumulative effects over time
caused by noise exposure, drugs that damage hair cells, and age-related degeneration
affects men more than women
Greatest loss of hearing for Presbycusis
greatest loss for high frequencies
Noise-induced hearing loss
occurs when loud noises cause degeneration of the structures involved in hearing
Noise-induced hearing loss can involve damage to
Organ of Corti
hair cells
auditory nerve fibers
Cochlear implants
use electrodes inserted into the cochlea to create hearing by electronically stimulating auditory nerve fibers.
Parts of cochlear implant
- microphone
- sound processor
- transmitter
- array of electrodes
essentially acts as the hair cells
Auditory localization
perception of the location of a sound source
Auditory space/ scene
the sound environment, which includes the locations and qualities of individual sound sources
Location cues
characteristics of a sound that provide info regarding location of the sound source
Binaural cues
require two ears
determine the azimuth of sounds
monaural cues
requires only one ear
Three dimensions in auditory space
Azimuth
elevation
distance
Azimuth
left-right sound cues
Elevation
up-down sound cues
Distance
how far or close the sound is
Interaural time difference (ITD)
difference between when a sound reaches the left ear and when it reaches the right ear
between-ear sound difference
What is ITD best for
low-frequency sounds
most important binaural cue
Interaural level difference (ILD)
difference in sound pressure level (amplitude of the sound reaching the two ears)
Acoustic shadow
The head blocks the ear, resulting in the sound appearing quieter in the opposite ear
ILD is best for
high-frequency sounds
The ILD and the ITD leave ____ ambiguous
elevation
Cone of confusion
surface in the shape of a cone that extends out from the ear; sounds originating from different locations on this surface all have the same ITD and ILD, so location info provided by these cues is ambiguous
The anterior auditory cortex is important for
pitch perception
A1 travels to other cortical auditory areas
core area
belt area
parabelt area
Core area
A1 and nearby
Belt area
surrounds and receives signal from core
Spectral cue
distribution of frequencies reaching the ear that are associated with specific locations of a sound, caused by interaction of sound with head and pinnae
important for elevation
Parabelt area
receives signals from belt area
Hoffmann et al.
demonstrated the importance of the pinnae for localization of elevation
The Jeffress neural coincidence model
neural circuit for processing the interaural time difference
neurons are wired to each to receive signals from the two ears, so that different neurons fire to different ITDs
Coincidence detectors
neurons detecting the coincidence of both ears firing together
Mammals have much broader
ITD tuning curves
Location of sound indicated by a ratio of responding in groups of
broadly tuned neurons
A1 and other areas are involved in
sound localization
evidence from ablation and cortical cooling, single electrode recordings
Posterior belt
precise info about location of a sound
Two auditory pathways extend from the
temporal lobe to the frontal lobe
What pathway
Identifying sounds
Where pathway
Localizing sounds
Direct sound
from sound source
Indirect sound
reflections of sound
Precedence effect
when two identical or very similar sounds reach a listener’s ears separated by only a short time interval, the listener hears the first sound that reaches his or her ears
Architectural acoustics
study of how properties of a room affect the quality of a sound.
Reverberation time
the time it takes for the sound to decrease to 1/1000th of its original amplitude
Auditory scene analysis
sounds produced by different sources become perceptually organized into sounds at different locations and into separated streams of sound
Melody
sequence of pitches perceived as belonging together
Music
sound organized in a way that creates a melody.
Rhythm
the time pattern of durations created by notes
Beat
equally spaced intervals of time
Listening to a beat activates
motor areas
Meters
the organization of beats into bars or measures.
acoustic signal
pattern of frequencies and intensities of the sound stimulus
The sound that’s produced from the voice depends on the shape of the
vocal tract
articulators
structures involved in speech production
vowel sounds are produced by
vibrating the vocal cords
the specific sound of each vowel is created by
changing the overall shape of the vocal tract, changes resonant frequency which changes sounds.
Each vowel sound has a characteristic series of
formants
formant
horizontal band of energy in speech spectrogram associated with vowels
sound spectrogram
shows the pattern of intensities and frequencies for a speech stimulus
consonants are produced by
constricting or closing the vocal tract
formant transitions
rapid shifts in frequency that precede or follow a formant
speech sounds are described by the manner and place of articulation, as well as
being voiced or unvoiced
Place of articulation
Lips /b/
alveolar ridge /d/
soft palate /g/
manner of articulation
stopped /b/
partially obstructed /s/
initially blocked /j/
nasal /n/
voiced or unvoiced
voiced- b, a, e, i, o u
unvoiced- p, t, k
phoneme
shortest segment of speech that, if changed, would change the meaning of the word
speech sound, not letter
different languages have ____ of phonemes
different numbers
variability problem
there is no simple relationship between a particular phoneme and the acoustic signal
coarticulation
overlapping articulation that occurs when different phonemes follow one another in speech
two sources of variability in the variability problem
variability from context (surrounding phonemes) and the acoustic signals.
variability in pronunciation
pitch, speed, accent
categorical perception
we only perceive phonemes in discrete categories, even though phonetic features may vary continuously
voice onset time
time delay between when the sound begins and when the vocal cords begin vibrating
phonetic boundary
the Voice onset time when perception changes from one speech category to another
How does the speech perception system solve the variability problem?
categorical perception, info provided by the face, info from our knowledge of language.
speech perception is aided by info from
faces
McGurk effect
speech perception is influenced by both auditory and visual stimuli
Speech perception is influenced by both
top-down and bottom-up processing
speech segmentation
perceiving individual words from continuous flow of speech signals
Transitional probabilities
chances that one sound will follow another sound
aphasia
difficulty speaking or understanding speech due to brain damage
Broca’s aphasia
problems with speech production and grammar
Wernicke’s aphasia
problems with speech comprehension
Areas of the brain involved in speech perception
Parietal lobe, STS, temporal lobe
Parietal lobe damage
difficulty discriminating between syllables
STS
activated more by voices than other sounds
Temporal lobe
Voice cells respond more strongly to recordings of monkey calls
dual-stream model of speech perception
Ventral- recognizing speech
Dorsal- Linking acoustic signals to movements used to produce speech
speech perception development involves
learning the sounds of a language
somatosensory system
sensation of the body and its movements
Proprioception
ability to sense the position of the body and limbs
Kinesthesia
ability to sense the movement of the body and limbs
Cutaneous senses
sensations from receptors in the skin
Functions of the skin
-holding in bodily fluids
-protection
-warnings and other info
Layers of the skin
epidermis
dermis
hypodermis
4 types of mechanoreceptors
-Merkel receptor
-Messiner corpuscle
-Ruffini cylinder
-Pacinian corpuscle
Merkel receptor
fine detail
course texture
Ruffini cylinder
stretching of skin
Pacinian corpuscle
Vibration, fine texture
Messiner Corpuscle
grip control
Medial lemniscal
large fibers,
touch, proprioception
fast
Spinothalamic pathway
smaller fibers
pain, temperature
slower
Primary somatosensory cortex (s1)
somatotopic organization
example of cortical magnification
cortical body maps demonstrate
plasticity
people can detect very small
tactile details
tactile acuity
ability to detect details on the skin
tactile acuity is better in some areas than others
ex. better in fingertips that palms
tactile acuity responds to
representation space in the brain
tactile acuity also depends on
cortical receptive field size
three elements that tactile acuity depends on
receptor spacing
cortical representation
receptive field size
duplex theory of texture perception
says that our perception of texture depends on both spatial cues and temporal cues
Spatial cues
from large surface elements, can be detected with or without motion
temporal cues
from fine-grained surface elements, can only be detected with motion
Neuropathic pain
damage to the nervous system
Nociceptive pain from nociceptors
detects heat, chemicals, pressure, cold
direct pathway model of pain
pain occurs when nociceptors are stimulated and they send signals directly from the skin to the brain
fine textures are detected by
Pacinian corpuscles
coarse textures are detected by
Merkel receptors
Phantom limb syndrome
when someone continues to perceive a limb after it has been amputated
Active touch
when a person actively explores an object
Passive touch
when touch stimuli are applied to the skin
haptic perception
perception in which 3-D objects are explored with the fingers and hand
exploratory procedures
used to investigate objects
gate control model of pain
pain perception is determined by a neural circuit that takes into account signals from nociceptors, mechanoreceptors, cortex
4 exploratory procedures
lateral motion, pressure, enclosure, contour following
Social touch
one person touching another
Placebo effect
relief from symptoms resulting from a substance that has no pharmacological effect
mechanoreceptors are concentrated in
glabrous (non- hairy) skin
C-Tactile (CT) afferent nerve fibers
found in hairy skin and respond to gentle stroking
Social touch hypothesis
CT afferents are responsible for social touch
Pain matrix
network of brain structures involved in pain perception
S1, Thalamus, amygdala, insula, ACC, PFC, hippocampus
pain is multimodal, it involves both
sensory and affective components
Opioid
chemical that reduces pain and induces feelings of euphoria
work by taking the place of endorphins
Social touch involves the ____ of touch rather than the ____ that mechanoreceptors produce
affective function, discriminative function
CT fibers are specially sensitive to
slow stroking
Endorphins
natural pain relievers in the brain
endogenous morphines
Naloxone (Narcan)
Blocks endorphin receptors to block opioids
can reverse opioid overdose
Social touch activates the
insula
Placebos can result in the release of
endorphins
social touch perception is influenced by
top-down processing
four types of papillae on the tongue
filiform, fungiform, foliate, circumvallate
which papillae does not contain taste buds?
filiform
each taste bud contains
50-100 taste cells
taste pathway
-taste cells
-chorda tympani & other cranial nerves
-nucleus of the solitary tract (brain stem)
-ventral posterior nucleus (thalamus)
-insula and frontal operculum (primary taste cortex)
population coding for taste
taste quality is signaled by the pattern of activity distributed across many neurons
Specificity coding
taste quality is signaled by activity in individual neurons tuned to respond to specific qualities
Olfactory and taste receptors undergo
neurogenesis
evidence for population coding
across-fiber patterns
Erickson (1963)
5 (or 6) basic tastes
salty
sour
sweet
bitter
umami
(fats-oleogustus)
taste acts as a gatekeeper of
what to eat and what to avoid
Evidence for specificity coding
genetic cloning experiments
PTC-bitter
tips of taste cells protrude through
taste pores
Transduction occurs when chemicals contact
receptor sites on tips
basic taste qualities are determined by
specificity coding
subtle differences in taste are determined by
population coding
there are differences in taste perceptions across different
species and people
Olfaction can act as a
warning system
Macrosmatic vs microsmatic animals
macrosmatic have a strong, keen sense of smell important for their survival
microsmatic have a less keen sense of smell, not as important for survival
Anosmia
inability to smell
pheromones are detected via the
vomeronasal organ
humans do not have a functioning
vomeronasal organ, but we can detect odors related to fertility
