Tut 7 Completly done

Question 1

Definition of sound (physical and perceptual )

Answer 1

Physical: Sound is pressure changes in the air do to vibrations
Perceptual: Sound is our experience when we hear.

Question 2

How do we change pressure ?

Answer 2

Due to consideration and rarefaction.

Question 3

What is consideration ?

Answer 3

Vibrations which pushes air molecules together which leads to an increase in air pressure.

Question 4

What is rarefaction ?

Answer 4

Air molecules move back out (seperate again)

- Decrease in air pressure

Question 5

How does sound energy travel ?

Answer 5

Trough out waves

• Transverse (up and down) and
• longitudinal(back and forth) waves
• > Not really common

Question 6

What is a sine wave ?

Answer 6

A pure tone (one wave)

Question 7

Tell the structure of a complex tone:

Answer 7

• A complex tone is divided in a one fundamental frequency (lowest tone or base)
• Partial top layers
• Mostly they are harmonics of the fundamental frequencys (muliplies of FF)

Question 8

A sound wave is made up off 2 parts:

Answer 8

• Amplitude

- Frequency

Question 9

What is amplitude ?

Answer 9

Size of pressure changes (How far waves goes up and down)

• Also called intesity so how loud
• Meassured in DB (logorith function not proportional)
• 6 DB seem to be doubling the amount of loudness

Question 10

What is frequency ?

Answer 10

Number of times per second in which the sound waves repeats

• Meassured in Hz
• 1Hz = 1 cycle per second
• The higher the pitch the higher the frequency
• we can perceive frequency till 20000 Hz

Question 11

Define Fourier analysis

Answer 11

its a sinus function which divides a complex tone into many simple sin waves 
(frequencys)
- which is needed for simplification 
- shown as a single line in a Diagramm 
- that is what the cochlear does for us.

Question 12

structure of the outer ear ?

Answer 12

1. sound waves pass trough the pinna
2. then it passes trough the auditory canal
3. which then reaches the tympanic membrane which starts to vibrate

Question 13

What is the pinna ?

Answer 13

Outer structure of the ear which is good for object location

Question 14

What is the auditory canal good for?

Answer 14

-For protection of the middle ear

Question 15

What is the function of the tympanic membrane ?

Answer 15

Receives sound and transmit it.

Question 16

Structure of the middle ear ?

Answer 16

formed by 3 ossicles

• Maleus (gets set into vibration)
• Incus (transmits vibration
• Stapes (pushing the oval window to transmit the signal)
• All of them increase the sound pressure

Question 17

Structure of the inner ear ?

Answer 17

• Cochlea snai like structure
• only part with liquid
• when stapes moves against the oval window liquid is set into vibration
• has an tonotopic organization high frequencies at the beginning

Question 18

What is an tonotopic organization ?

Answer 18

• goes from high to low Hz

- so as farther the liquid goes the lower the Hz

Question 19

What is the actual sound procedure ?

Answer 19

• Stapes creates movement of liquid
• Cochlear partition moves which sets structure such as basilar membrane in movement
• movement against tectorial membrane leads to bending of hair cells
• movement of hair cells in one dircetion leads to the opening channel
• Ions can flow into the hair cells (afferent and effernt) and transmitter are released.

Question 20

Define what phase locking is:

Answer 20

Neurons fire in synchrony with the auditory stimuli

- Till 1000 Hz

Question 21

Define what volley locking is:

Answer 21

If neurons can not keep up with the frequency:

• Group of neurons are combined to still work in synchrony with the auditory stimuli (4000Hz)
• Its due to relaxation time of neurons

Question 22

Name the sonicmg pathway:

Answer 22

• it is the pathway from cochlea to cortex
• goes from:
  1. cochlear nucleus
  2. Superior olivary nuclei
  3. inferior colliculus
  4. Medial Geniculate nucleus
  5. Primary auditory cortex
• vision has less stages only optic nerve

Question 23

Name the parts of the auditory cortex:

Answer 23

• it lays under the temporal lobe
• it is hierarchical organized
• Corea area
  (simple tones)
• belt area (complex sound)
  -parabelt area (most complex sound and combines information with other senses

Question 24

Define the where (dorsal) pathways:

- After sonicmg

Answer 24

Good for locating sound

- Start behind parts of the core and belt area and goes to prefrontal cortex

Question 25

Define the what (ventral) pathway | - after sonicmg

Answer 25

Identifying sound in general | - Starts infront of the core and belt area and goes to the prefrontal cortex

Question 26

What is conductive hearing loss ?

Answer 26

- Damage on the outer middle ear but cochlea is still intact - Basicaly sound does not reach the receptors (hair cells) no action potential - everything is quite - solution hearing aid

Question 27

What is Sensorineural hearing loss ?

Answer 27

Inner ear problems - Destruction of hair cells due to loud noise - Treat is cochlear implant which translates sound energy into nerve impulses

Question 28

What types of hearing loses do we have ?

Answer 28

1. Conductive hearing loss 2. Sensorineural hearing loss 3. Hidden hearing loss:

Question 29

What is hidden hearing loss ?

Answer 29

Loud noise leads to damage on the ear nerve cells - Which are the connection between cochlea and brain - its often under diagnosed because they can hear quite and loud frequencys but not with background noises

Question 30

How is a cochlear implant structured ?

Answer 30

- microphone on the extrernal ear - speech processor converts the sounds into digital signals and sends it to the internal implant - internal implant converts signals into electrical energy - electrical energy go to the injected electrodes in the cochlea - the electrodes bypass the damaged hair cells and stimulate the auditory nerve fibers

Question 31

What if a cochlear implant does not work ?

Answer 31

- Auditory nerves are destroyed - We need: Auditory brainstem implants (ABIs) that bypass nerve fibers - They directly stimulate the ventral cochlear nucleus

Question 32

What does the audibility curve do ?

Answer 32

- Plots the relationship between intensity and frequency - Also identifies tresholds of hearing (Low dB and high frequencies) - Shows the perfect sound to be perceived regarding aplitude lvk and frequencys.

Question 33

What is frequency coding? (How to endcode fequencies)

Answer 33

Place coding: - higher frequency = more vibration on the base of basilar membrane - less frequency more vibration on the apex Tonotopy - We have to mirror tonotopy structure And also time coding/temporal coding:

Question 34

What are harmonics:

Answer 34

Multiple Hz of fundamnetal frequency.

Question 35

How is doubling the sound pressure perceived:

Answer 35

- 6 db for physical | - 10 db for perceived loudness

Question 36

What does the inner hair cells do:

Answer 36

They have a long and a short hair (called cilia) on hair cells, which are connected via a (rope) when long hair cell bends then the connection point on the short hair where rope is connected open the channels.

Question 37

What does the outer hair cells do:

Answer 37

- monulate action potentail | - sharpen the procces

Question 38

What is auditory maksing (pure tone):

Answer 38

- Overlaping tone of sound - The mask of a tone strongest from low to high. - relationship between mask and tone

Question 39

What does turnning curve show:

Answer 39

- Neurons have specialized preferrention.