Quiz 1: Pyschophysics and Audition Study Guide Flashcards
What are the 3 main psychophysical methods to determine thresholds?
-method of limits
-method of adjustment
-method of constant stimuli
Method of limits
a psychophysical method in which particular dimension of a stimulus, or the difference between two stimuli, is varied incrementally until the participant responds differently
Method of adjustment
the method of limits for which the subject controls the change in the stimulus
-attempts to improve accuracy with subject-controlled change
-LEAST PRECISE of the 3 methods because the subject can unreliably adjust the stimulus to the same threshold across trials
Method of constant stimuli
a psychophysical method in which many stimuli, ranging from rarely to almost perceivable, are presented one at a time at random
Who is Gustav Fechner?
Creator of psychophysics- a way to test a person’s perception of a stimulus
Made the formula S= k log R
What is the difference between the logarithmic scale and the linear scale?
Logarithmic scale for psychophysics
S= k log R
Sensory receptor- sensitive to small stimuli but activation maxes out eventually
Increases by a factor making large numbers appear smaller
Better representation of values with a high range without sacrificing resolution at the low end
Linear scale
Y-axis increases by addition
(i.e. you perceive a wide range of physical stimuli)
What are the two qualities of sound waves?
Amplitude and Frequency
Amplitude
Loudness or intensity
Amount of change in pressure in a sound wave
Measured in dB
Frequency
Pitch
Rate of recurrence of oscillations/ vibrations in a sound wave
Measured in Hz
Middle ear and the in-between (before the inner ear)
Ossicles
oval window/ round window
Structure of the Outer ear and the in-between (before middle ear)
Pinna, Ear canal
Tympanic membrane
Structure of the Inner ear
Cochlea
Vestibular system (semicircular canals)
Organ of corti
What does tonotopic mean?
= the organization of neurons according to their characteristic frequency
The primary auditory cortex contains a topographic map of the cochlear frequency spectrum
Pathway of sound waves from physical vibration to electrical signals in the brain
Pinna>Ear canal>Tympanic membrane>Ossicles>oval window>cochlea>round window>vestibular canal>middle canal>Organ of Corti>hair cells>auditory nerves>cochlear nucleus>superior olives>lateral lemniscus>inferior colliculus>medial geniculate nucleus>primary auditory cortex
How does the tonotopic organization relate to the cochlea and the auditory cortex?
All structures in the auditory system show an organizational pattern where neurons are aligned respective to the frequencies that they are most sensitive
What happens inside the cochlea? Specifically how does transduction occur in the cochlea?
1- Ossicles hit the oval window with pressure
2-Oval window moves
3-Traveling waves of the fluid inside the cochlea, flowing down the vestibular canal
4-Vestibular canal bulges, placing pressure on middle canal
5-Middle canal displaces the cochlear partition
-depends on frequency (High= near oval, low= near round)
What are the different types of deafness?
Sensorineural hearing loss
Conductive hearing loss
Mixed hearing loss
Bilateral hearing loss
Unilateral hearing loss
Sensorineural hearing loss
Occurs as a result of damage to the auditory nerve or when hair cells are damaged
-most common type of hearing loss
Conductive hearing loss
Occurs when the ossicles become unable to convey vibrations to the oval window
Mixed hearing loss
Occurs when you have both sensorineural and conductive issuesBilat
Bilateral hearing loss
Hearing loss in both ears
Unilateral hearing loss
Hearing loss in one ear
Typical human hearing range and different ways it is measured
20-20,000 Hz
Measured:
3 psychophysical methods
Audiometer
Habituation
Participant hesitates to switch his/her response
Participant continues responding Y or N too long
i.e. they “get used to” responding a certain way
-they forget, zone out, tune out
Expectation
Participant expects the stimulus to increase (or decrease) and thinks that the stimulus should now be detectable and thus responds it did increase or decrease even if the stimulus is not yet at threshold
i.e. jumping the gun
Interaural time delay
= the difference in time between a sound arriving at one ear compared to the other
-varies for different sound source positions
-Medial superior olive
-Excitatory input from the two ears arrives coincidentally at one of an array of cells inn the MSO
Interaural level difference
= the difference in intensity between a sound arriving at one ear compared to the other
-Lateral superior olive
-Excitatory input from ipsilateral ear and inhibitory input from the contralateral ear (sound from that side will be stronger)
Know the auditory pathways from the vestibucochlear nerve through the auditory cortex
ECO-LIMA
Ear (pinna, etc.)
Cochlear nucleus
Superior olive
Lateral Lemniscus
Inferior Colliculus
Medial Geniculate Nucleus
Primary auditory cortex
Cochlear nucleus
=the first processing stage with many different types of specialized cells
Superior olive: Medial and Lateral
- important role in the localization of sound
-projections from cochlear nucleus to superior olive also cross over to the opposite side of the brain
Medial Superior Olives
-Interaural time differences primarily occur
Lateral Superior Olives
-hold neurons sensitive to intensity differences
-Interaural Level Difference
Lateral Lemniscus (Fiber tract)
-contains axons from cochlear nucleus, superior olive, and the nucleus of the lateral lemniscus
-projects to the inferior colliculus
Inferior Colliculus
-Signal integration, frequency recognition, and pitch discrimination
-Second level of processing
Medial Geniculate Nucleus
-Part of the Thalamus that relays auditory signals to the cortex
Primary Auditory Cortex
-processing of tones; tonotopic organization
