Topic Test 4 - Part 1 (vision)

Question 1

movement is supported by 3 categories of sensory systems:

Answer 1

motor function is supported by:
- vision
- vestibular
- somatosensory

Question 2

neurons in the visual system create perception of world (images) based on_ (seeing is believing)

Answer 2

electromagnetic radiation
- eyes have evolved to only detect visible light (400-700 nm)
- colour is not inherent in the world (brain’s interpretation of wavelengths)
*we identify the diff types of wavelengths and brain is putting the interpretation of the colours

Question 3

list the very general order of the visual pathway (seeing is believing)

Answer 3

retina>thalamus>primary visual cortex
* we have small sensors (rods/cones) in our eyes in retine, pick up wavelength and send APs along this pathway

Question 4

describe retrifugal projection

Answer 4

retina to thalamus to primary visual cortex (“fugal = fleeing, flees the retina”)
1) retina - receives sensory info
2) optic nerve - before decussation
3) optic chiasm - decussation (partial)
4) Optic tract - after decussation
5) lateral geniculate nucleus
6) primary visual cortex (v1 or brodman’s 17)

Question 5

what is decussation

Answer 5

partial crossing over (ex. optic chiasm decussation = crossing over at optic chiasm)

Question 6

describe primary visual cortex

Answer 6

brodmann’s area 17 in the occipital lobe
- first area of the cortex to receive visual information
- also known as V1, striate cortex
- begins mapping and processing visual information
- 2 main pathways

Question 7

what are the 2 main pathways in the primary visual cortex?

Answer 7

dorsal and ventral stream
* dorsal is info relating to visual motion (navigation, speed of things, moving), helps direct eye movements

Question 8

in clinical cases where dorsal stream was damaged, what happened?*

Answer 8

• can see things that are still but as soon as they move, they dissapear
• can’t process/interpret them
• can’t see coffee when it’s pouring = spills

Question 8

describe the dorsal stream

Answer 8

information passed toward the parietal lobe
- specialized processing of visual motions
> navigation
> directing eye movements
> motion perception

Question 9

describe navigation as a function of the dorsal stream

Answer 9

perceiving the direction and speed of objects helps us navigate safely

Question 10

describe directing eye movements as a function of the dorsal stream

Answer 10

sense motion and quickly react to it

Question 11

describe motion perception as a function of the dorsal stream

Answer 11

interpretation of moving objects

Question 12

describe ventral stream

Answer 12

• information passed toward the temporal lobe
• specialized processing of vision other than motion
  >object perception and facial recognition (only recognize features, but remembering faces)
  *unlike posterior parietal parietal, specifically for visual info (processing shapes, angles, corners, size to come up with object perception and facial recognition)

Question 13

list the concluding remarks on vision

Answer 13

retina>thalamus>primary visual cortex
- maps and processes visual information
- complex integration of parallel sensors and procesing (colour, shape, motion, etc.)
*the idea that we have a bunch of visual sensors that are occuring all at the same time