Failures In Somatosensation

Question 1

when do illusions occur

Answer 1

when rules in bodily senses are broken - mismatches etc

Question 2

what kinds of somatosensory illusions are there

Answer 2

tactile illusions
proprioceptive
complex somatosensory
multisensory
thermoception

Question 3

define tactile illusions

Answer 3

depend primarily on cutaneous (skin) inputs

Question 4

describe the cutaneous rabbit

Answer 4

spaciotemporal tactile illusion
geldard and shernick 1972

to sepetate locations on arm are stimulated muliple times in quick succession (p1 & -3)
report feeling in p2 in between sites - like rabbit hopping
“phantom impression”

Question 5

describe blackenburg et al 2006 evidence for the cutaneous rabbit phenomenon

Answer 5

activity in primary somatosensory cortex just as high for p2 as in p1 and p3
primary somatosensory cortex represents the percieved location of stimuli and not the actual location

Question 6

define proprioceptive illusions

Answer 6

depend primarily on non-cutaneous inputs

Question 7

what kind of proprioceptive illusions are there

Answer 7

absence of movement and visual feedback cause things like drift of limbs as proprioceptive info degrades

fool brain into believing muscle is being stretched by vibrating tendons at about 100 Hz

Question 8

define complex somatosensory illusions

Answer 8

depend primarily on cutaneous and proprioceptive inputs

Question 9

describe the aristotle illusion / tactile diplopia

Answer 9

when two fingers are crossed over, can feel two distinct sensations in seperate locations when put obeect between them

panzeo 1910 - middle and ring best but works with others

Question 10

describe lackner 1998 complex somatosensory illusion

Answer 10

vibrate muscle whilst body is in certain positions can induce perceptoin of impossible feeling
msucle movement generates info of proprioceptive misinformation about limb position

Question 11

define multisensory illusion

Answer 11

dependent on somatosensory and/or visual/auditory inputs

Question 12

what kinds of multisensory illusions are there

Answer 12

visual

thermoception

Question 13

describe visual multisensory illusion

Answer 13

hand image makes it appear as though in diff position to reality
perception of hand as in between real and image
works with dummy hand

Question 14

describe botvinik and cohen 1999 visual tactile illusion

Answer 14

pps view dummy hand stroked by paintbrush

feel ldentical stokes on own hand which is out of view

Question 15

describe the thermoception heat grill illusion

Answer 15

warm and cold bars interweaved across skin

report burning heat and freezing cold pains

Question 16

what is craig et al 1996’s perspective on the thermoception illusion

Answer 16

combination of warm and cool activates anterior cingulate - linked to pain

individually this does not occur - sent to insula

Question 17

what is multisensory perception

Answer 17

recieve multiple sensory cues at the same time and there must be coordinated etc
can contradict

Question 18

define visual dominance

Answer 18

visual perception is very compelling

tends to dominate our perception over info from other senses

Question 19

describe the ventriliquist effect

Answer 19

howard and templeton 1966
sound from diff location appears as thought coming from dummy as mouth is moving

tv sounds as though coming from characters when coming from one location

Question 20

describe rock and victor 1964 on visual dominance

Answer 20

visual shape dominates over haptic shape
draw object as view it and not as feel it from tactile senses
unaware of conflict

Question 21

describe shams, kamitani and shimojo 2000 and auditory dominance

Answer 21

pps shown disk flashing on screen with two beeps - report two flashes

as no beeps increases, the illusion stops working - must be in same time frame as visual stimuli

control group with no auditory report correct

Question 22

why do certain senses dominate at certain times

Answer 22

welch and warren 1986
“modality precision”
vision tends to dominate for spacial tasks and autition tends to dominate for temporal judgement

Question 23

describe watkins shams haynes and rees 2005 findings after hams, kamitani and shimojo 2000 study

Answer 23

fmri find increased activity in primary visual cortex during illusion
processing of information changes the perception of the physical stimuli

Question 24

define modality precision

Answer 24

accuracy and precision of sensory modalities can determine the weight of dominance put on a sense

vision tends to be most accurate so rely on more