Multimodal investigation of the visual system

Question 1

inflating the brain

Answer 1

• first step in map understandings
  -Allows brain surface hidden in the folds to be revealed

Question 2

Lateralisation of visual system

Answer 2

• contralateral
• All info from left eye goes to right hemisphere

Question 3

Localisation of visual field

Answer 3

• Medial surface (bottom) of occipital lobe at the bottom correlates to upper visual field

Question 4

Holmes Visual Field Map

Answer 4

• If damage is at back themes a central visual field deficit
• shows localisation brain area to visual field

Question 5

Post-Mortem anatomy in humans with 1 eye

Answer 5

• Examine humans who lost the use of one eye
• Tissue shows some features of lack of input from 1 eye
• primary visual cortex has zebra stripes shows input layers from different eyes

Question 6

functional modules in VI electrophysiology

Answer 6

• There are blobs
• colour code indicates orientation preference
• sophisticated pattern of organised columns
• functional properties of the cells cluster
  -very invasive mainly done on animals
• single unit recording

Question 7

summary

Answer 7

-changes in perception when brain is lesioned gives insight into mapping + functional specialisation of different visual areas
- single unit electro physiology helps explore functional properties of visual system in animals

Question 8

FMRI visual field mapping

Answer 8

• Eccentricity
• Have people look at visual stimulus in FMRI Scan
• stimulus starts in centre + progressively moves out
• wave of activity spreads across occipital lobe

Question 9

Multiple visual field maps

Answer 9

• measures responses to different visual attributes
• Apply magnetic field to disrupt in specific maps to see how they are causally involved in processing

Question 10

How a small central region of blindness occurs

Answer 10

• some indivs have only functioning rods so have small central regions of blindness from birth
• leaves a small region of blindness when light levels are low
• The very centre of retina doesn’t have rods so when you direct your eye it will no longer be visible

Question 11

Remapping

Answer 11

• Those that have hole in vision at birth have remapped visual maps
• maximises allocation to remaining vision

Question 12

Does age matter

Answer 12

• congenital visual deficits lead to visual cortex remapping
• macular degeneration = visual deficit often age dependent
• Retinal lesions in adulthood doesn’t result in remapping like at birth
• So for remapping age doesmatter