L8 - interaction between different sensory systems

Question 1

binaural hearing

Answer 1

hear sounds with both ears
know where sound is
know direction
predict where it moves next 
feel part of 3D world
improves speech understanding

Question 2

monoaural hearing

Answer 2

only hear from one side

don’t know exactly where sound is coming

Question 3

what plane is sound elevation in

Answer 3

vertical plane

Question 4

what plane is sound position in

Answer 4

horizontal position

Question 5

sound elevation

Answer 5

monoaural cues

head related transfer functions

Question 6

sound position

Answer 6

two binaural cues

Question 7

spectral notches function

Answer 7

help to localise sounds in the vertical plane
precisely timed to the onset of sound bouncing of the folds of the outer ear
distorts /alters sound creating a specific patters
all ears are different shapes so spectral notches must be learned by individuals

Question 8

what are IDLs

Answer 8

interaural level differences - difference in the intensity of sound at the two ears (mainly for high frequency sounds)

Question 9

what are ITDs

Answer 9

intramural timing differences - where the brain compares the arrival times of sounds at both ears - as small as 10micro seconds (mainly for lower frequency sounds)

Question 10

outline the auditory pathway

Answer 10

1) cochlea nucleus (DCN and VCN)
2) superior olivary complex (SOC)
3) inferior and superior colliculus
4) medial geniculate nucleus
5) Auditory complex

Question 11

function of the cochlear nucleus

Answer 11

2 pathways
from VCN = sound localisation
from DCN = sound recognition

Question 12

function of the superior olivary complex

Answer 12

sound localisation

Question 13

function of the inferior and superior colliculus

Answer 13

integration with non-auditory input e.g. somatosensory and vision

Question 14

function of the medial geniculate nucleus

Answer 14

involved in learning and memory

Question 15

functions of the auditory complex

Answer 15

cognition, attention, memory, decision making

Question 16

what happens as auditory signals go through the brain

Answer 16

they get more integrated with info from other sensory systems

Question 17

outline the superior olivary complex in the brainstem

Answer 17

the nerve fibres from both ears enter the cochlear nucleus, the 1st nuclei in the CNS
neurons from the anterior ventral cochlear nucleus go. to the superior olivary complex which is composed of the lateral superior olive and medial superior olive and the medial nucleus of the trapezoid body

Question 18

outline the detection of intramural level differences (IDLs)

Answer 18

The IDLs are detected by cells in the LSO called principle cells
The LSO cells receive one excitatory input from aVCN cells on the same side of the head (ipsilateral side of the head)
The same LSO cells receive an indirect ihibitory input from the contralateral side of the head
The inhibtory input, begins as an excitatory fibre from the aVCN, crosses the midline and synapses in the MNTB which forms an inhibitory synapse to the LSO

Question 19

which type of input is received from the ipsilateral ear

Answer 19

excitatory

Question 20

what type of input is received from the contralateral ear

Answer 20

inhibitory

Question 21

which input is. larger ipsilateral or contralateral

Answer 21

ipsilateral

Question 22

what is the overall position of sound encoded by

Answer 22

the balance in average output rate of the LSO channels

Question 23

what are IDLs encoded by

Answer 23

cells in the LSO that compare the coincidence of excitatory ipsilateral and inhibitory contralateral inputs

Question 24

outline the detection of ITDs

Answer 24

the binaural excitatory-excitatory (EE) pathway
ITDs are encoded by cells in the MSO that compare the coincidence of excitatory ipsilateral and contralateral inputs
the two MSOs acts as broad hemispheric channels tuned to sounds from the opposite hemisphere
the overall position of a sound is encoded by the balance between the average population response of the two MSO channels
mainly for LF hearing

Question 25

what do prisms affect

Answer 25

the functional alignment of visual and auditory maps in the midbrain