LEC6: sensation & perception (sounds)

Question 1

what is sound?

Answer 1

air moves around and changes air pressure (the waves)

Question 2

transdunction

Answer 2

the process of converting outside stimuli, such as light of air pressure, into neural activity

Question 3

tympanic membrane

Answer 3

the eardrum
- structure that separates outer ear from middle ear (ossicles) and vibrates in response to sound waves.

Question 4

function of ossicles

Answer 4

to transmit and amplify vibrations from eardrum to the inner ear

Question 5

cochlea

Answer 5

coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

Question 6

basilar membrane

Answer 6

structure that runs length of cochlea in inner ear and holds auditory receptors called hair cells.
responds by moving in wave.
diff sections sensitive to diff frq

Question 7

basilar membrane freq sensitivity

Answer 7

base: high frq (narrow, thick and stiff)
apex: low freq (wide,thin and floppy)

Question 8

oval window

Answer 8

membrane at enterance to cochlea thru which ossicles transmit vibrations

Question 9

where do hair cells sit

Answer 9

on top of basilar membrane

Question 10

what is on hair cells

Answer 10

stereocilia

Question 11

stereocilia

Answer 11

hairlike extensions on tips of hair cells in cochlea that initiate opening of ion channels

Question 12

place code

Answer 12

diff frq of sound represented by type brain according to where along basilar membrane stimulated

Question 13

rate code

Answer 13

diff intensities (amplitude) of souonds represented by brain by firing rate of auditory nerve neurons

Question 14

temporary ringing in ears caused by

Answer 14

hair cells being knocked down and kept down
(keeping ion channels open)
producing ring

Question 15

spiral ganglion cells

Answer 15

group of nerve cells that serve sense of hearing by sending representation of sound from cochlea to brain

Question 16

structures in brain stem that audio travels through first

Answer 16

1. dorsal cochlear nucleus (medulla)
   OR
2. ventral cochlear nucleus and superior olive

Question 17

inferior colliculi

Answer 17

protrusions on top of midbrain; part of auditory system
reflexes

Question 18

MGN (medial geniculate nucleus)

Answer 18

relay center in thalamus receiving auditory input from inferior colliculus

Question 19

studying auditory processing w Event-Related Potentials (ERPs)

Answer 19

using EEG
finding avg of signal in response to stimuli ABR (auditory brainstem response)

Question 20

auditory brainstem response (ABR)

Answer 20

technique used to record electrical activity in auditory nerve, brainstem and cortical ease of brain.
useful in detecting brainstem diseases
also very helpful in testing hearing of newborn infants

Question 21

A1

Answer 21

primary auditory cortex

Question 22

A2

Answer 22

secondary auditory cortex

Question 23

location of A1

Answer 23

(core) deep w/in sulcus (sylvia’s fissure)
anterior/apex: low frq (0.5/far left)
posterior/base: high frq (16/far right)
simple tones

Question 24

tonotopic map

Answer 24

representation in auditory cortex of diff sound frqs

Question 25

location of A2

Answer 25

belt (complex sounds) below sylvian fissure

Question 26

tuning curve

Answer 26

graph of responses of single auditory nerve or neuron to sounds that vary in frq and intensity

Question 27

two main cues to help us infer spatial location

Answer 27

interaural timing diff (ITD) interaural intensity diff (IID)

Question 28

interaural time difference (ITD)

Answer 28

diff when signal arrives to each ear not perfect (pt A in the front)

Question 29

interaural intensity difference (ITD)

Answer 29

difference in intensity of signal at each ear (pt B towards the side w/ acoustic shadow)

Question 30

acoustic shadow

Answer 30

an area on other side of head from sound source in which loudness of sound is reduced bc sound waves are partially blocked by head; has much greater effect on high-frq sounds than on low-frq sounds (IID concept)

Question 31

coincidence detectors and delay lines

Answer 31

cells in superior olive are stimulated along delay lines from each ear should hit certain cell at same time to determine where stimulus (sound) came from

Question 32

where are more complex tonal patterns processed

Answer 32

post A1 areas (A1 mainly just frq based) tonal space and music (certain keys) shown to activate diff places in brain thru fMRI (janata et al., 2002)

Question 33

somatosensation

Answer 33

skin sensations: touch/pressure. warmth, cold and pain

Question 34

mechanoreceptors

Answer 34

detect touch/pressure/vibration of skin

Question 35

nociceptors

Answer 35

detect tissue damage/extreme temp/pain

Question 36

thermoreceptors

Answer 36

cells that detect ranges of temp

Question 37

proprioceptors

Answer 37

cells that detect how much diff muscles in body stretched/relaxed

Question 38

unique quality of nocieption

Answer 38

pain sensation quick reflexes due to complete system w/in spinal cord rather than traveling to brain (no cortex needed) sensory neuron - interneuron - motor neuron

Question 39

proprioception

Answer 39

ability to tell where one's body is in space. some have simple spiral cord circuits and some go to cortex

Question 40

ascending proprioceptive pathwys

Answer 40

up from spinal cord to cortex sometimes crosses in spinal cord sometimes crosses in brainstem (medulla)

Question 41

homunculus

Answer 41

rendering of body in which each part is shown in proportion to show how much of somatosensory cortex is devoted to it

Question 42

olfactory receptor cells

Answer 42

sensors responsible for smell hang into nasal cavities (thru cribriform plate) and make contact w molecules

Question 43

cribriform plate

Answer 43

horizontal plate of ethmoid bone separating cranial cavity from nasal cavity, olfactory receptor cells integrated through

Question 44

is olfactory sensory contralateral

Answer 44

no. it's ipsilateral

Question 45

does olfactory pathway go through thalamuus?

Answer 45

no

Question 46

olfactory pathway

Answer 46

- molecules inhaled into nasal passages - contact olfactory nerves in olfactory epithelium - receptor cells activated - signal is sent to olfactory bulb - signals relayed to higher regions of brain via olfactory tract (not thalamus - orbitofrontal olfactory cortex, piriform cortex, amygdala)

Question 47

are taste buds neuronal cells

Answer 47

no; synapse w sensory neurons

Question 48

is taste contralateral

Answer 48

no it's ipsilateral

Question 49

the insula

Answer 49

located deep w/in sylvian fissure

Question 50

where are taste buds located

Answer 50

papillae of tongue (w/in bumps)

Question 51

taste pathway

Answer 51

taste buds on papillae --> cranial nerves 7,9,10 --> brainstem (medulla) --> taste center in thalamus --> gustatory cortex (anterior insula - frontal operculum)