LECTURE 25 - closed-loop control **

Question 1

what are four structures that support closed-loop control ?

Answer 1

• vision
• proprioception - muscles spindles, GTO
• vestibular
• somatosensory - haptic

Question 2

what is the closed-loop control all about ?

Answer 2

regulating an ongoing movement

Question 3

how does this closed-loop control move ?

Answer 3

system goal → reference mechanism → executive level → effector level → environment (feedback arrow back up to reference mechanism)

Question 4

what does the closed-loop control monitor ?

Answer 4

the effectiveness of your of your movement while performing the actual task

Question 5

what are the two pathways of vision in the closed-loop control ?

Answer 5

geniculostriate and retinotectal pathway

Question 6

what is the genuculostriate pathway ?

Answer 6

a relatively “low-level” visual pathway, involved in the processing of basic visual features and the detection of simple visual stimuli

Question 7

what is the retinotectal pathway ?

Answer 7

is a neural pathway found in some non-mammalian vertebrates, such as fish, amphibians, reptiles, and birds. It plays a crucial role in the control of visual processing and the guidance of eye movements

Question 8

how does the genuculostriate pathway travel ?

Answer 8

• begins in the retina (back of the eyes)
• projects to the superior colliculus (structure in the midbrain that is involved in the control of eye movements and other visual behaviors)
• continues to the the thalamus,
• from there, the pathway projects to the visual cortex, where it provides inputs to regions involved in the processing of visual information

Question 9

how does the retinotectal pathway travel ?

Answer 9

• dynamic visual cue from the visual stimulus
• to the retina
• to the SC
• to the brainstem
• to the eye (dynamic moving stimulus)

Question 10

what are the two kinds of photoreceptors in vision ?

Answer 10

cones and rods

Question 11

what are rods ?

Answer 11

• achromatic
• equally dispersed about retina
• low spatial resolution
• respond to low light levels
• provides night vision
• scotopic vision

Question 12

what are cones ?

Answer 12

• chromatic
• largely located in the center of the retina (central vision)
• high spatial resolution
• do not operate in low light levels
• photopic vision

Question 13

between cones and rods which are slow acting and fast acting ?

Answer 13

slow acting = rods
fast acting = cones

Question 14

between cones and rods which are colour and black/white ?

Answer 14

black & white = rods
colour = cones

Question 15

what is the back of the eye called ?

Answer 15

retina

Question 16

what is achromatopsia ?

Answer 16

a rare visual disorder that affects color perception

Question 17

what do individuals with achromatopsia experience ?

Answer 17

have a complete absence or severe reduction in the ability to perceive colors, which can make the world appear in shades of gray and sensitivity to colour

Question 18

what cause achromatopsia ?

Answer 18

acquired from a injury (e.x., stroke)

Question 19

perception of colour comes from what pathway ?

Answer 19

ventral visual pathway

Question 20

what is a way to test for colourblindness ?

Answer 20

The Ishihara test (circular plate with number within)

Question 21

what are the three cones in the colourblind test?

Answer 21

L-cone, M-cone and S-cones

Question 22

what colour is the L cone ?

Answer 22

red

Question 23

what colour is the M cone ?

Answer 23

green

Question 24

what colour is the S cones ?

Answer 24

blue

Question 25

does everyone have the same concentration of colour mosaic’s ?

Answer 25

no, people have different concentrations of colour mosaics

Question 26

what are the two related concepts in vision science that are related to the way the brain processes information from the two eyes ?

Answer 26

binocular rivalry and strereopsis

Question 27

what is binocular rivalry ?

Answer 27

• seeing two images
• phenomenon in which a visual perception alternates between the different images presented to the eyes
• very small differences between the two eyes yield stereopsis
• eye dominance

Question 28

what is strereopsis ?

Answer 28

• without stereopsis depth determination is impaired
• motion parallaz
• remember “magic eye” : it is an example of an autosterogram
• refers to the perception of depth or three-dimensionality that arises from the slightly different perspectives provided by each eye

Question 29

what does enucleated mean ?

Answer 29

an individual has had an eye removed (due to an injury or a disease)

Question 30

what is it called when an individual has had an eye removed ?

Answer 30

enucleated

Question 31

what were some in class examples of binocular rivalry ?

Answer 31

• buny or seagull
• vase or faces
• golfer or spartan

Question 32

what was the “grandparent of them all” in regards to binocular rivalry ?

Answer 32

the necker cube (cube moves ; depth determination)

Question 33

what is the first region of the brain to receive visual information from the eyes ?

Answer 33

The primary visual cortex (V1)

Question 34

how does the geniculostriate pathway travel (simple) ?

Answer 34

retina → SC → pulvinar →Posterior parietal cortex

Question 35

how does the retinotectal pathway travel (simple) ?

Answer 35

retina → LGNd → primary occipital cortec (area V1) → (dorsal) posterior parietal cortex or (ventral) inferotemporal cortex

Question 36

what is the posterior parietal cortex responsible for ?

Answer 36

action

Question 37

what is the inferotemporal cortex responsible for ?

Answer 37

perception

Question 38

what is allocentric frame of reference ?

Answer 38

• objects and locations are described in relation to other objects and locations in the environment, independent of the observer’s own position or movements.

Question 39

what is vision for perception ?

Answer 39

identify, determine size, shape or properties of object

Question 40

what is vision for action ?

Answer 40

reach or point to an area in space to control action

Question 41

what is egocentric frame of reference ?

Answer 41

• representation of space describes objects or locations in relation to the observer’s own body position and movements

Question 42

what are allocentric and egocentric frame of reference ?

Answer 42

allocentric and egocentric are two different ways of representing spatial information in the brain