Units 5-9 Psychology 230 Flashcards
The Auditory System
What is sound?
Sound as a stimulus
Sound stimulus
Periodic variations in air pressure traveling out from a source
Sound waves
The waves of pressure changes that occur in the air as a function of the vibration of a source
Medium of Sound
It is necessary to conduct air; sound, water
The Relation of Physical and Perceptual Attributes of Sound
Pure tones
Sound waves in which air pressure changes follow a sine wave pattern
Amplitude
Difference between the maximum sound and minimum sound pressures
Loudness
Perceptual experience of an amplitude
Loud sounds can be dangerous
Prolonged contact to sounds over 85 decibels can eventually cause hearing loss
Frequency or Wavelength of Sound
What is frequency of sound?
One it can be measured in cycles, the amount of time between one peak of high pressure and the next, and the amount of cycles in a sound stimulus that occur in 1 second
What is Pitch?
The subjective experience of a frequency
What Unit is used to measure sound amplitude?
dB
What is the hearing range of humans?
Humans hearing can range from 20 Hertz (Hz)-20,000 Hertz, as you get older your hearing will diminish
How does hearing change with age?
But by age 50 humans can hear only up to about 12,000 Hz
Anatomy of the Ear
Outer Ear
Pinna
Collects sound and funnels it into the auditory canal
External auditory canal
Conducts sound to the tympanic membrane
Tympanic membrane
Thin elastic sheet
The Middle Ear
Eustachian tube
Connects the middle ear with the pharynx
Tensor tympani
Muscles attached to the malleus and the stapes
Stapedius
Muscles attached to the malleus and the stapes
Ossicles
Transmit sound via chain reaction of vibrations that connect to the eardrum
Malleus (Hammer)
Magnifies the oscilliations and sends the information to the inner ear
Incus (Anvil)
Magnifies the oscillations and sends the information to the inner ear
Stapes (Stirrup)
Magnifies the oscillations and sends the information to the inner ear
Inner Ear
Functions of inner ear
Transduces sound into a neural signal
Cochlea
Snail-shaped structure of the inner ear that houses the hair cells
Tympanic canal
Three-liquid filled chambers
Middle canal
Three-liquid filled chambers
Vestibular canal
Three-liquid filled chambers
Reissner’s membrane
Sits in the cochlea, and transmits vibrations from fluid in the vestibular duct to the cochlear duct
Basilar membrane
Composed of fibers, the Organ of Corti lies on it
Tectorial membrane
Sits in the organ of the Corti, and mainly stimulates hair cells
The Organ of Corti
Allows for transduction of auditory signals into nerve’s action potential
Hair cells
Stereocilia
Hair cells that respond to fluid motion
Inner hair cells
Convey information to the brain
Outer hair cells
Receives information from the brain
Actions of hair cells
Vibrations, transducing signals, sending info to the brain
How is Amplitude Coded?
Small amplitude sounds
Small displacement along the cochlea, the tectorial membrane will shear across the organ of Corti less forcefully, less NT is released
Large amplitude sounds
Large displacements along the cochlea, the tectorial membrane will shear across the organ of Corti more forcefully, more NT is released
How and Where is Frequency Coded?
It is coded in the nervous system, and it is based on the threshold
Place code theory
Different locations along the basilar membrane respond to different frequencies
The Basilar Membrane of the Cochlea
At the base, the basilar membrane is thicker and stiffer, at the apex it is thinner and less stiff
Characteristic frequency
The frequency to which any particular location on the basilar membrane responds best
Frequency and Displacement along the Basilar Membrane
Temporal code theory
Frequency representation occurs because of a math between sound frequency and the firing rates of the auditory nerve
Tuning Curve for an Auditory Nerve Fiber
Find the lowest point on the cone, read the frequency
Cochlear nucleus
Senses as a lateral inhibition function
Trapezoid body
Important for determining the direction of sound
Superior Olive
Receives information from both ears; critical for sound localization
Inferior colliculus
Serves as a the main auditory (sound) for the body
Medial geniculate nucleus
Two pair of nuclei found in the thalamus, which process auditory information
The Auditory Pathway
Primary auditory cortex
Located in the temporal lobe, allows both ears to project on both sides
Tonotopic organization
Similar frequencies are coded by neurons close to each other in the brain
What and Where Pathways of hearing
What pathway
Basis for speech perception and music perception
Where pathway
Localization of sound in space
Conductive hearing loss
Sound does not properly arrive at the cochlea, blockage of the auditory canal, or tympanic membrane, or damage to the ossicles
Otosclerosis
Calcification of the ossicles, making them less conducive to sound
Sensorineural hearing loss
Damage to the cochlea, auditory nerve, or primarily auditory cortex
Tinnitus
The condition when people perceive sounds when none are present
Hearing Aids
Cochlear Implant
An implant in the ear to help people who are deaf
Understanding the World Through Sound
Harmonic Spectrum
Containing only frequency components whose frequencies are whole number multiples of the fundamental frequency
Missing Fundamental Effect
If the lower harmonics are not produced you still hear the tone as having the pitch of the nonexistent fundamental because of the presence of these beat frequencies
Timbre
Psychological sensation that combines tonality and harmonic spectrum of a sound as a whole
Onset and offset sounds
They change the quality of sounds as well
How sound Localization works
What is interneural difference?
Is a binaural cue for high-frequency sounds only
What is interaural time difference?
When concerning humans or animals, is the difference in arrival time of a sound between two ears
How is interaural time difference computed in the medial superior olives?
The way in which superior olive does this is by measuring the differences in time between two ear signals recording the same stimulus
Cone of confusion
Collection of locations in the world that produce the same ITD
Elevation Perception
An emotional response to moral beauty
Echo
Echo is a long reflection of sound on a far hard surface
Reverberation
While reverb has a way shorter reflection time
Relationship between sound frequency and its travel distance
Frequency and distance are directly proportional the higher the frequency the more distance for the sound to dissipate the lower the frequency the shorter the distance for the sound to dissipate
What is an echo?
An echo occurs when two vibrations are close together like a mic and the speaker
Auditory Scene Analysis
Spatial segregation
Refers to the distribution of social groups or any other elements in space
Temporal segregation
This is the result of the target being neither temporally integrated with nor segregated from the mask
Spectral sensitivity
Spectral sensitivity is the extent that light of different wave lengths is absorbed by the photopigments of the retina
Sound restoration
Effect refers to the tendency for people to hallucinate a phoneme replaced by a non-speech sound
The Vestibular system
Vestibulo-spina reflex
Controls balance and postural control
Visual stability
Balance postural control
Regulation of blood pressure
Vestibulo-spinal reflex
Vestibulo-autonomic relfex
Balance and spatial orientation
What information does the Vestibular system provide?
The nervous system provides us with the awareness of the spatial position of our head and body (proprioception) and self-motion (kinesthesia)
Location of the Vestibular system in the human body
Located in the nervous system
What are vestibular organs?
Organs located in the inner ear
Vestibular organs and sensitivity to sensitivity changes
They detect changes in accleration
Function of hair cells in the vestibular organs
Transduce the mechanical movements into neural energy
Resting state
Observed when stereocilia are not bent
Depolarization
Observed when stereocilia bend in the direction opposite to the kinocilium
Utricle
Contains 30,000 hair cells that detects changes in acceleration along the horizontal plane
Saccules
Vertical acclerations
Otoconia
Crystals lying on the top of a gelatinous layer
Striola
Bond that determines the direction of the kinocilium
Hair cells
Embedded in the gelatinous layer
Ampulla
Each canal has an ampulla containing acupula which is a gelatinous membrane
Cupula
The bottom part of the cupula (crista) contains the hair cells involved in the process of transduction
Hair cells
As the fluids move in the canals, they will push on the cupula like wind on a windsurf sail, and the hair cells’ stereocilia will bend
What different rotational movement cause changes in semicircular canals?
Anterior, posterior, and horizontal
Push-pull effects in the two ears
Effects in the two ears; the arrangement of the hair cells within the two depolarized, the other is hyperpolarized
Low vs. High Amplitude Movements
The more the hair cells bend, the larger the change in voltage
Sinusoidal Changes in Angular Acceleration
Used for vestibular testing
Deflection of the Cupula after Acceleration
Cupula bends when we accelerate one way and then goes to the usual position and then when we stop the cupula is deflected in the opposite direction
Experienced Speed of Turning
We are spinning then after 30 seconds at constant velocity we feel as though we are no longer spinning then when the cupula deflects, we are going to feel like we are now opposite direction until the cupula returns to the original condition
Exponent for turning sensation?
About 1.3 response expansion as we increase speed of rotation the experience increases
What is passive translation?
You do nothing and people move you we are good at estimating how far we moved, how fast and at what speed
Vertigo
Sensation of feeling off-balance, dizzy
Symptoms of vertigo
Nausea, Difficulty with vision, no change in hearing
Vestibular neuritis
Inflammation of the vestibular nerve
Labyrinthitis
Inflammtion of the vestibular and cochlear nerve
Motion sickness
Disagreement between vestibular organs and vision
Illusion of self-motion
Not moving but you think you are because the fluids in the semicircular canals think you are
Wavelength
Distance between peaks
Intensity
Height of the wave
Frequency
Number of waves per unit of time
Properties of light
Scattered/diffracted; absorbed; reflected; transmitted; refracted
Reflected light enters the eye through the pupil
Human field of view
Is a perspective that emphasizes looking at the whole person, and the uniqueness of each individual
Anatomy of the eye
Sclera, Cornea, Anterior chamber, Iris, Pupil
Pupillary reflex
Automatic process
Accommodation
Rapid process of adjusting the lens so that both near and far objects can be seen
Near point
The closest distance at which an eye can focus
Presbyopia
Light focuses behind the retina; difficulty focusing on close objects
Retina
The inner-most light-sensitive layer of tissue of the eye
Fovea
When we look at objects, their image is projected on it, it is at the center of the retina
Optic disc
No receptor cells; optic nerve leaves the eye
Photoreceptors
Cones; rods located at the very end of the eye
Cones
Help us see in low levels of light
Horizontal cells
Are located in the retina along with retinal bipolar cells and amacrine cells. they a part of the indirect pathway only, as opposed to bipolar cells which are part of the indirect and direct pathways in the eye
Bipolar cell
1 cone—> 1 bipolar cell
Amacrine cells
Interneurons in the retina
Ganglion cell
P: 1 cone—–> 1 bipolar cell——> P ganglion cell
M cell
Input from—–> 50 photoreceptors—–> diffuse bipolar cell—-> M ganglion cell
Transduction of light
Photopigment; opsin; classes of receptors
Duplex Theory of Vision
Photopic vision; Scotopic vision
Receptive field
A spatial entity ( a portion of the visual field or retina, or a portion of the body surface); that makes the most sense in the visual and somatosensory systems
On-center ganglion cell
A retinal ganglion cell which is aroused by light in the core of its receptive region but is hindered by light in the surrounding region
Off-center ganglion cell
A retinal ganglion cell which is hindered by light in the core of its receptive region but is aroused by light in the surrounding region
Lateral inhibition
A type of cell-cell interaction, during asymmetric cell division one daughter cell adopts a particular fate that causes it to be a copy of the original cell, and the other daughter cell is inhibited from becoming a copy
Myopia
Nearsightedness cannot see objects far away
Hyperopia
Farsightedness cannot see objects close up
Astigmatism
A defect in the eye or in a lens caused by a deviation from spherical curvature, which results in distorted images, as light rays are prevented from meeting at a common focus
Cataract
The cladding of the eye
Macular degeneration
Affects central vision, blurring our perception of whatever it is we are trying to look at
Retinitis pigmentosa
Affects peripheral vision, creating a “tunnel” vision effect in which we see what are we looking at with normal acuity, but cannot see what surrounds our focus
Vision Protheses
Devices intended to restore visual function to blind individuals
The Visual System and the Brain
Work by Torsten Wiesel and David Hubel
Work on anatomy and physiology of the visual cortex
Optic nerve
Is a paired cranial nerve that transmits visual information from the retina to the brain
Optic chiasm
An X-shaped space, located in the forebrain, directly in front of the hypothalamus
Optic tract
A large bundle of nerve fibers of the visual pathway
Optic radiation
A projection tract that connects the lateral geniculate nucleus to the primary visual cortex in the occipital lobe
Superior Culliculi
Structure out the top of the brainstorm
Function
Control of rapid eye movements
Saccades
Sudden eye movements used to ook from object to another
Smooth-pursuit eye movements
Voluntary tracking eye movements
Visual cortex
Layers; Reinotopic map; Cortical magnification; Visual crowding
Bar detector
Mounted towards the eye with the division of between the two photosensitive surfaces
Simple cells
A simple cell in the primary visual cortex is a cell that responds primarily to oriented edges and gratings (bars of particular orientations)
Orientation tuning curve
The unit measures the cellular response as a function of the orientation or movement of a visual stimulus
Complex cells
Can be found in the primary visual cortex, it responds to oriented edges and gratings
End-stopped cells
Striate cells that examine a monocular response and the dominant eye to half its maximal amplitude
Hypercolumn
A group of nerve cells in the brain that helps us interpret what we see by enabling us to analyze the size, shape, speed, and direction of visual stimuli
V2
It affects how light is refracted
Ventral pathway
The (what, parvo pathway) sits in the temporal lobe, it affects how we see color and process shapes and sizes
Dorsal
The (where, magno pathway) sits in the parietal lobe, and it helps us with motion and spatial relations
Experiment on monkeys
The experiment on monkeys showed, direction, length, orientation, and color of moving bar stimuli
Where does vision come together?
It comes together in the retina, lens, optic nerve it transduces signal and transmits it from our brain into the nerve endings
The Kitten Carousel Experiment
This experiment took into account guided behavior when a hand is waved in front of them
Critical Period
When the nervous system is primed and sensitive to environmental experiences
Visual acuity
How small are the spatial details that our visual system can resolve
Spatial frequency
How many alterations of black and white can we fit in a fixed amount of space
Development of spatial frequency in children
Low spatial frequency stimuli at 9 weeks old, but reach adult levels, at 3-4 years old children reach adult levels, because the fovea needs time to develop
Tilt aftereffect
The vertical bars should appear to be slightly tilted to the left (opposite to the previous orientation)
Color aftereffect
Color depth (or bit depth) is the number of bits per channel used to represent the color of a pixel
Spatial frequency aftereffect
Is manipulated so that the magnitude of the aftereffect can be assessed as a function of spatial frequency
Blindsight
Unconscious residual visual capacities shown by cortically blind patients
