Week 2 : Vision Flashcards
What are rods and how many are there?
Responsive for light and movement and 125 million
What are cones and how many are there?
Responsible for colour and sharpness and 6 million
What is visual light?
Electromagnetic waves of the spectrum
What light in the human eye is most sensitive?
Green light
What is the Trichromatic theory?
All colour are made from three colours
What does the eye respond to?
the eye responds to different wave lengths through a process called photoreceptors
What are the three different wavelengths?
short - red, medium - yellow or green and long - blue
What is the opponent processing theory?
You cannot process an object as green/red
What is colour constancy?
The wavelengths are different but your eye sees them as the same colour
What is the respective field?
The retina
What happens after the retina?
two pathways
What is the Magnocelluar Pathway?
mp - is the pathway for motion from the rods
What is the Pavo-cellular pathway?
pp - is the pathway for colour from the cones
What happens after the PP and MP after the retina?
Optic nerve, Optic chasm, Optic tract, LGN, optic radiation and primary visual cortex
What is Retinotopy?
the retina sees things next to each other in the visual field and the neurons next to each other process the objects
What is lateral inhibition?
Reduction in activity because of a neighbouring neuron (lateral being right next to each other)
What is the primary visual cortex V1?
Extracts information from the visual field
What does damage to the V1 do?
Blindness
What is the functional Specialisation theory?
Every part of the visual cortex is specialisation for different functions
What is every function from V1 to V5?
V1/V2 is sensory information, V3 is form of an object, V4 is colour and V5 is motion
What is cortical Achromatopsia?
Colour blindness
What is Ankinetopsia?
Deficit in ability to detect motion/motion blindness
What is the model of object recognition?
stage 1 is colour, motion and shape. stage 2 is perceptual segregation (separating objects to make them make sense) stage 3 is structural descriptions and stage 4 is semantic meaning
What is Agnosia?
can’t recognise objects/impairment
What are the two types of agnosia?
associative and apperceptive
What is associative agnosia?
Deficit in the ability to attach meaning to objects
What is apperceptive agnosia?
Deficit in the ability to identify an object
What is perceptual organisation?
Separating visual input into individual objects with their own meanings
What is Gestalts laws of perceptual organisation?
Law of proximity, law of continuation, law of closure, law of similarity
What are some problems with this?
Only descriptive, aren’t always bottom up processes.
What is figure-ground segregation?
Being able to see two images from one ambitious image
What are some caveats in perception studies?
Mostly male participants and European.
What is facial recognition?
A within category discrimination process
What is prosopagnosia?
Not being able to identify faces
