Susie Chapter 6 Flashcards
light enters the eye through the __ and is focused, by the __ and the __, on to the __ at the back of the eye.
pupil, cornea, lens, retina
the pupil is surrounded by a pigmented __ that can expand or contract, making the pupil larger or smaller as light levels vary.
iris
how many photoreceptors are there once focused on the retina?
125 million
this is the most numerous photoreceptor, responsible for black and white, and movements in low light conditions
rods
this photoreceptor is responsible for color vision
cones
the conversion of light into electrical signals in the rods and cones is called…
phototransduction
this is where the fibres of nerve meet, half of them cross to the other side, while the other one stayed uncrossed.
optic chiasm
the bundles of fibres from both eyes form the …
optic tracts
the first relay station on the optic tracts is called…
suprachiasmatic nucleus of hypothalamus
the second synaptic relay station on the optic tracts is called…
lateral geniculate nucleus
the neural representation has inputs from each eye and so the cells in the visual areas at the back of the brain can fire in response to an image in either eye is called…
binocularity
the region of retina over which the cell will respond to the prefered kind of image is called…
receptive field
in this stage, the neurons respond best to lines or edges in a particular orientation. it is responsible for the conscious experience of vision. it also distribute signal to different areas in the brain.
V1
this stage is responsible for the perception of colour
V4
this stage is responsible for the motion of visual stimuli and perceived motion (by the observer).
V5/MT
reactions to perceptual targets that are genuinely ambiguous, the observer is placed in a state of indecision, constantly fluctuating from one interpretation to another.
ex. Necker cube
binocular rivalry
this person contributed to the understanding of how the visual system develops. this includes interactions between different parts of a pathway in the embryonic brain, and axons growing down from the developing cortex to meet other fibres before growing up to the cortex.
Colin Blakemore
these two people discovered orientation selectivity, the columnar organisation of cells and the plasticity of the system in the visual cortex, leading them winning Nobel prize.
David Hubel and Torsten Wiesel.
what visual field deficits would you expect in someone with a stroke destroying their left optic nerve? (blue-red, blue-red)
black-black, blue-red
what visual field deficits would you expect in someone with a stroke destroying their left visual cortex? (blue-red, blue-red)
blue-black, blue-black
what visual field deficits would you expect in someone with a pituitary gland tumour? (blue-red, blue-red)
black-red, blue-black
blindsight is associated with damage in which part of the visual cortex?
V1
the axons of what cell type form the optic nerve?
ganglion cells
name the coloured patchwork design used to study how the brain processes colour.
mondrian
which two parts of the eye focus light on the retina?
cornea, lens
