vision

Question 1

primary visual cortex

Answer 1

occipital lobe, striate cortex, receives input from visual relay nuclei of thalamus (afferent nerves)

Question 2

secondary visual cortex

Answer 2

pre striate cortex, receives input from primary visual cortex

Question 3

visual association cortex

Answer 3

inferotemporal cortex and posterior parietal cortex, recieves input from secondary visual cortex

Question 4

Scotoma

Answer 4

areas of blindness in corresponding areas of visual field, caused by damage to primary visual cortex. Scotomas are plotted with perimetry tests

Question 5

completion

Answer 5

Brain builds up a visual field despite we have a blind spot, might be because of residual visual capacaties in the scotoma but also without it (example, patients who are hemianopsic (having a scotoma covering half of the visual field)
may see an entire face when they focus on a person’s nose, even when the side of the
face in the scotoma has been covered by a blank card)

Question 6

blindsight

Answer 6

the ability to respond to visual stimuli in a scotoma with no conscious
awareness of them, this supports the parallel models rather than serial.

Two neurological interpretations of blindsight have been proposed:
o striate cortex is not completely destroyed, remaining
islands of functional cells are capable of mediating some visual abilities in the
absence of conscious awareness.
o The visual pathways that ascend directly to the secondary visual
cortex from subcortical visual structures without passing through the primary
visual cortex are capable of maintaining some visual abilities in the absence of
cognitive awareness.

Question 7

Dorsal stream

Answer 7

primary visual cortex to the dorsal prestriate cortex (V2) to the posterior parietal cortex (association cortex).
- where pathway, visual spatial perception
- control of behavioral pathway, visually guided behavior

Question 8

ventral stream

Answer 8

primary visual cortex –> ventral prestriate secondary cortex –> association cortex of inferotemporal cortex
- what pathway, visual pattern recognition
- conscious visual perception

Question 9

prosopagnosia

Answer 9

Fusiform Face Area (FFA & OFA on the ventral surface of the
temporal lobe and occipital lobe)
- maybe neurons in inferotemporal cortex
- Confirmed prosopagnosia sufferers could recognize
faces unconsciously (No conscious recognition but
different skin conductance
responses for familiar faces.)

Question 10

akinetopsia

Answer 10

Deficiency in the ability to see smooth movement
- Can be triggered by high doses of antidepressants.
- Damage to medial temporal area (MTA or V5).
- Each MT neuron has a large binocular receptive field, allowing it to track movement over a
wide range.
- * Primary Visual Cortex neurons also
respond to movement but not to direction.
* 95% of MT neurons (large binocular
receptive fields) respond to direction

Question 11

Licht kan je op twee verschillende manieren beschouwen:

Answer 11

 Photons: discrete particles of energy (300.000 km/sec)
 Energiegolven

Question 12

Licht heeft bepaalde belangrijke eigenschappen:

Answer 12

 Golflengte > kleuren
 Intensiteit > helderheid

Question 13

Het aanpassen van de configuratie van de lens om scherp beeld op retina heet

Answer 13

accommodation en wordt gereguleerd door de ciliary muscles:
 Object dichtbij > natuurlijke cilinder-vorm lens > refract (buigen) light
 Object ver weg > lens wordt plat

Question 14

Er is echter altijd een verschil in de positie van hetzelfde beeld op de twee netvliezen:

Answer 14

binocular disparity, omdat je ogen de wereld niet van precies dezelfde positie bekijken
 Dit verschil is groter voor objecten dichtbij
 De mate van binocular disparity kan gebruikt worden om een 3D-beeld te construeren uit 2D beelden van retina
 Cocktail Sausage: als wijsvingers bijna tegen elkaar, armen strekken, kijken in de verte > er ontstaat een ‘sausage’ tussen je vingers (werkt niet als 1 oog open)

Question 15

het proces waarmee we oppervlakken waarnemen, het visuele systeem extraheert informatie over randen en daaruit leidt tot het uiterlijk van grote oppervlakken

Answer 15

surface interpolation

Question 16

duplexity theory

Answer 16

De theorie dat kegeltjes en staafjes verschillende soorten zicht mediëren:
 Phototopic vision: cone-mediated zicht bij goed licht > high acuity, kleur
 Scotopic vision: rod-mediated zicht bij slecht licht > low acuity, geen kleur
 Bij zwak licht kunnen kegeltjes niet worden geactiveerd, staafjes gevoeliger

Question 17

Er zijn verschillen in de verdeling van rods/cones over retina:

Answer 17

 Kegeltjes: in fovea, daalt enorm bij grenzen fovea
 Staafjes: niet in fovea, aantal stijgt enorm bij grenzen fovea, maximum bij 20
graden van centrum fovea
 Meer staafjes in nasal hemiretina (deel retina naast neus) dan in temporal hemiretina (deel retina naast ‘temples’)

Question 18

De overgang van phototopic naar scototopic vision

Answer 18

Purkinje effect:

Question 19

Transduction

Answer 19

de omzetting van de ene vorm van energie in de andere
 Visuele transductie: omzetting van licht in neurale signalen door visuele receptoren

Question 20

mach bands

Answer 20

Adjacent to each edge, the brighter stripe looks brighter than it really is and the darker stripe looks darker than it really is. The nonexistent stripes of bright- ness and darkness running adjacent to the edges. –> they enhance the contrast at each edge and make the edge easier to see.

–> contrast enhancement

Question 21

on center cells & off center cells

Answer 21

On-center cells respond to lights shone in the central region of their receptive fields with “on” firing and to lights shone in the periphery of their receptive fields with inhibi- tion, followed by “off” firing when the light is turned off.

Off-center cells display the opposite pattern: They respond with inhibition and “off” firing in response to lights in the center of their receptive fields and with “on” firing to lights in the periphery of their receptive fields.