More brain structure and vision

Question 1

what is hemispatial neglect

Answer 1

lack of awareness to one side of space

Question 2

what side is hemispatial neglect commonly on

Answer 2

lack of attention to left, as right hemisphere is damaged

Question 3

common cause of hemispatial neglect

Answer 3

stroke

Question 4

typical symptoms of hemispatial neglect

Answer 4

ignoring things on affected side, not using limbs or being unaware of limb existence on affected side

Question 5

example of hemispatial neglect

Answer 5

drawing clock with all numbers on one side
only eating from right side of plate

Question 6

what is capgras delusion

Answer 6

belief that a familiar person or pet has been replaced by an imposter

Question 7

what conditions can capgras delusion occur in

Answer 7

schizophrenia, dementia, traumatic brain injury

Question 8

what brain hemisphere is most commonly affected by capgras delusion

Answer 8

right hemisphere

Question 9

what is fregoli delusion

Answer 9

belief that different people are actually one person who can change appearance

Question 10

what can cause fregoli delusion

Answer 10

traumatic brain injury, L-DOPA treatment for Parkinson’s

Question 11

which brain area is linked to fregoli delusion

Answer 11

right frontal and left temporoparietal areas, including the fusiform gyrus

Question 12

what is alien hand syndrome

Answer 12

a condition where hand acts independently without conscious control

Question 13

what hand is typically affected in patients with alien hand syndrome

Answer 13

usually the left hand

Question 14

what can cause alien hand syndrome

Answer 14

damage to frontal lobe, corpus callous, or stroke/tumor

Question 15

what brain disconnect causes alien hand syndrome

Answer 15

disconnection between premotor and primary motor cortex

Question 16

what is cotard’s syndrome

Answer 16

the belief that one is dead or does not exist

Question 17

what is cotard’s syndrome often associated with

Answer 17

psychiatric disorders, neurological symptoms, and right or bilateral hemisphere lesions

Question 18

what was unusual about the man with no brain

Answer 18

he had hydrocephalus as a baby and lived a functional life with a brain mostly filled with CSF

Question 19

what’s the first thing the thalamus does in vision

Answer 19

it processes the visual input before it reaches the cortex

Question 20

what role does the occipital lobe play in vision

Answer 20

recognises what is being seen

Question 21

what does PFC decide in a visual-motor task

Answer 21

whether or not to act based on visual input

Question 22

how long does a visual motor task take

Answer 22

250ms

Question 23

what do rods detect

Answer 23

dim light, night vision

Question 24

what photosensitive protein do rods contain

Answer 24

rhodopsin

Question 25

where are rods located

Answer 25

the periphery

Question 26

what do cones detect

Answer 26

bright light and colour

Question 27

where are cones concentrated

Answer 27

the fovea

Question 28

what photosensitive protein do cones contain

Answer 28

photopsin

Question 29

what does M in M cells stand for

Answer 29

magnocellular

Question 30

what do M cells in the retina do

Answer 30

detect motion and flicker; large receptive fields

Question 31

what does P in P cells stand for

Answer 31

parvocellular

Question 32

are m cells large or small

Answer 32

large

Question 33

are p cells large or small

Answer 33

small

Question 34

what do p cells do

Answer 34

carry colour information, distinguish between red and green cones

Question 35

what is the difference between an On-centre cell and an Off-centre cell

Answer 35

ON - fires more when light hits the centre OFF - fires more when light hits the surround

Question 36

what is retinotopic mapping

Answer 36

adjacent ganglion cells map to adjacent LGN and V1 cells, forming a spatial map of the visual field

Question 37

what happens at the optic chiasm

Answer 37

nasal fibres cross, temporal fibres don't, leading to lateralisation of visual input

Question 38

if the left optic nerve is cut, what is the result

Answer 38

blindness in the left eye

Question 39

if the left optic tract is cut, what is the result

Answer 39

loss of vision in right visual field in both eyes (right homonymous hemianopia)

Question 40

what is the function of the LGN

Answer 40

it acts as a relay station to the primary visual cortex and may filter information

Question 41

how many layers in the LGN

Answer 41

six layers

Question 42

what does each layer process

Answer 42

3 from each eye 2 process M cell input (motion) 4 process P cell input (colour/detail)

Question 42

what is the primary visual cortex specialised in

Answer 42

responds to edges, orientations, motion

Question 43

is the V1 retinotopic

Answer 43

yes