Vision Flashcards
What in vision is different in mammals?
Spatial field
What is co processing
When visual information goes into the brain with many co processing
What is the optic chiasm?
At the optic chaism the point where the optic nerve crosses and go to the rear of the brain to visual cortex
What does the visual cortex do?
Visual cortex fuses the information together to make a 3 dimensional image
What is peripheral vision
your side vision, the ability to see things outside of your direct line of sight.
What is the axons on the retinal neurones called?
ganglion cells
What does ganglion cells do?
Carry information from optic nerve to optic chaism
Types of lesions in visual pathway
lesion in the optic nerve causes total loss of vision
lesion in the optic chaism causes loss of half of the visual hemifield
lesion in the optic tract causes loss of vision to the opposite half of the hemifield
3 types of visual perception
Low level- colour, contrast
Medium level- shape discrimination, surface depth
High level-object identification
What does visual perception have to be integrated with
Focus, Light and movement control
What does stimulating retina allow for?
Stimulating retina allows for the recording of activity in the visual cortex
What pathway is involved in recognition?
Ventral pathway is involved in recognition
Retinal ganglion cell
Retinal ganglion cell is connected to different cell types which communicate with photoreceptors
Retinal eccentricity
The area of the retina on which light is focused influences visual acuity, which is sharpest when the object is projected directly onto the central fovea
Ocular dominance
Ocular dominance refers to the preferential use of one eye when performing monocular activities
Ocular dominance columns
Left and right eyes form columns to allow better integration
LGN(Lateral geniculate nucleus)
LGN in 2 signals(p and M channel) sends information to the visual cortex layer 4c
Two types of processing in vision
serial allows only one object at a time to be processed, whereas parallel processing assumes that various objects are processed simultaneously
Tritonopia
lost of blue pigment
What can go wrong with cone pigment in genetics?
Crossover from parents goes wrong causes incorrect gene structure causing problems with vision
dichromate
Loss ff a gene
Intragenic recombination
Anomalous trichromats(gene)
Types of cone pigments
S, M and L
What happens with rhode light
When rhode light comes in rhodopsin switches on the g protein. G protein activates phosphodesterase which catalyses for the destruction of cyclic GMP turning it into GMP which leads to closure of the channel
When continuous light occurs there is a big shut down of channels which leads to low calcium in the cell. There is then high affinity for cyclic GMP, therefore channels open up again. Process can adapt to continuous light.
Photoadaptation
When continuous light occurs there is a big shut down of channels which leads to low calcium in the cell. There is then high affinity for cyclic GMP, therefore channels open up again. Process can adapt to continuous light.
