week 10

Question 1

question: is motion detection or object recognition evolutionarily older? why?

Answer 1

• motion = older
  ⤷ less complex
• object recog. needs temporal processing + higher acuity
  ⤷ higher lvl function built upon the basic motion detecting abilities

Question 2

name: parts of ventral stream + what they encode

Answer 2

V3 = dynamic form
⤷ perception of objects that change over time
V4 = colour form

Question 3

name: parts of dorsal stream + what they encode

Answer 3

V5 = motion
V3A = form

Question 4

define: monocular blindness

Answer 4

• loss of sight in one eye
• damage to retina or optic nerve

Question 5

define: bitemporal hemianopia

Answer 5

• loss of vision in both temporal fields
• often bc tumour in pituitary -> psi on medial optic chiasm

Question 6

define: right nasal hemianopia

Answer 6

• loss of vision in R nasal field
• from lesion in lateral optic chiasm

Question 7

define: homonymous hemianopia

Answer 7

• loss of vision in 1 visual field (both R or both L)
• damage can be either optic tract, LGN, V1

Question 8

define: quadrantanopia

Answer 8

• loss of vision in one quarter of vis. field
• often be visual cortex lesions
  ⤷ hard to pin point (need imaging)

Question 9

define: macular sparing

Answer 9

• macula is spared
• can be lesions in optic tract or thalamus (cortical)

**often spared bc macula might get double vascular supply from medial and cerebral arteries

Question 10

define: scotoma

Answer 10

• blind spot
• from small vic. cortex lesions
  ⤷ particularly near calcarine sulcus

Question 11

define: blindsight

Answer 11

• conscious vision
  ⤷ indicates probably damage to V1
• can respond to vis. stim. in their blind fields without consciously perceiving them
• ex. quadrantanopia
  ⤷ could see prior location one the light moved into a visual quadrant

Question 12

define: angioma

Answer 12

• benign tumour of blood vessels or lymph vessels

Question 13

define: optic ataxia

Answer 13

• deficit in visually guided hand movements
• impairment in using vis. info to guide motor

Question 14

question: what can a right occipitotemporal lesion lead to?

Answer 14

• prosopagnosia

**left = alexia

Question 15

question: what can bilateral hemorrhages in occipitoparietal regions lead to?

Answer 15

• optic ataxia

Question 16

question: what can damage to area V5 lead to?

Answer 16

• V5 = MT (middle temporal area)
• loss of movement vision

Question 17

question: what can a left occipitotemporal lesion lead to?

Answer 17

• alexia
  ⤷ unable to read

**left = language -> reading -> alexia
**right = prosopagnosia

Question 18

define: visual agnosia

Answer 18

• neurological condition that affects a person’s ability to recog./interpret vis. info
  ⤷ despite normal vision

Question 19

name: types of visual agnosia (6)

Answer 19

1. apperceptive
   ⤷ difficulty w/ tasks
2. simultagnosia
   ⤷ can’t perceive more than 1 at a time
3. associative agnosia
   ⤷ can perceive, can’t ID
4. prosopagnosia
   ⤷ faces
5. alexia
   ⤷ reading
6. visuospatial agnosia
   ⤷ inability to find way + other deficits

Question 20

explain: apperceptive agnosia

Answer 20

• difficulty w/ tasks
  ⤷ matching, ID objects (shape, size, colour)
• from gross bilateral damage to occipital
  ⤷ a lot of damage

Question 21

explain: simultagnosia

Answer 21

• difficulty w/ tasks that req. processing multiple objects
• can’t perceive more than one object at a time
• from gross bilateral damage to occipital

Question 22

explain: associative agnosia

Answer 22

• difficulty in recog. objects
  ⤷ bc problem w/ connecting visual information w/ knowledge about the object
• can perceive but can’t ID
• from lesions to anterior temporal lobes

Question 23

explain: prosopagnosia

Answer 23

• can’t recog. faces
  ⤷ even if previously known
• from bilateral damage in temporal cortex

Question 24

explain: alexia

Answer 24

• visual agnosia
• inability to read
• from left fusiform and lingual areas

Question 25

explain: visuospatial agnosia

Answer 25

- topographic disorientation ⤷ inability to find one's way - often accompanied by other visual deficits - from damage to occipitotemporal regions and medial fusiform and lingual areas **often a symptom of dementias (ex. alzheimer)