Week 6 key terms Flashcards
What is a retina?
The light sensitive part of the eye
what is the retina made up of? (2)
photoreceptors
Layers of neurons on the top
What neurons is the retina made up of? (4)
- ganglion cells
Horizontal
Bipolar
Amacrine
What is the fovea?
The central potion of the retina
what is the fovea packed of?
photoreceptors
What is the lens?
A structure in the eye that helps focus an image on the retina
What are the main terms for vision problems? (3)
The hypermetropic eye
The myopic eye
The presbyopic eye
What is a hypermetropic eye?
Long sighted vision- lens does not bend enough
what is a myopic eye?
short-sighted eye- lens bends too much
what is a presbyopic eye?
Lens no longer flexible enough to focus clearly
What are ohotoreceptors?
Retinal receptors that convert might into neural activity
What are cones?
Photoreceptor’s that respond to colour and bright lights
what are rods?
photoreceptors that respond to dim light and Black and white
What are bipolar cells?
A retinal neuron that uas 2 different types of receptive fields that each respond differently to light
What are the 2 receptive fields in the bipolar fell?
- on-centre
- off-centre
What is an on-centre receptive field?
When light hits the eye, less glutamate is received exciting the cell
What is an off-field receptive field?
When light id turned off, more glutamate is received exciting the cell
What are the 2 different types of cells in the Retinal ganglia?
Magnocellular cells (M-cells) Parvocellular cells (P-cells)
What are magnocellular cells sensitive to? (3)
Where do they get info from?
Sensitive to light not colour
Sensitive to movement and low contrast not colour and fine detail
where are magnocellular cells present in the eye?
Present throughout retina and periphery
What are parvocellular cells sensitive to? (2)
Where do they get info from?
Sensitive to colour and rich detail
Get most of its information from cones
Where are parvocellular cells present in the eye?
Mostly the fovea
What is the blind spot?
Area in the retina where blood flow enters and exit but has no photoreceptors
What do the fibers in the retina form?
optic nerves that goes to the brain
What is the optic chiasm?
Where the pathways from each eye cross
What is the geniculostriate system?
1 of 2 routes that information from the eye is sent to the brain
What is the geniculostriate system made up of?
some M and P ganglion cells
What is the route of the geniculostriate system?
Goes from retina to lateral geniculate nucleus of thalamus and via optic radiations to layer 4 of the primary visual cortex
What is the primary visual cortex also known as?
striate cortex
where is the primary visual cortex?
in the occipital lobe
What is the primary visual cortex?
First stage of visual informstion processing
What V striate is the primary visual cortex?
V1 striate
Where is the primary visual cortex located?
Located in and around the calcarine fissure in the occipital lobe
What does the V1 striate do? (4)
Atunes to; Position Orientation Spatial temporal frequency
What does the V2 extrastriate area do?
The cells are tuned to spatial mapping as well as V1 properties
What does the V3 extrastriate area do?
Receives input from V1 and V2
Dorsal part projects to parietal cortex
Ventral part projects to inferior temporal cortex
What does the V4 extrastraite area do?
Receives input from V1 and V2
Strong projects to inferior temporal cortex
Attuned to simple shapes and colour
What does the V5 straite do?
Receives input from V1, V2 and V3
Plays a major role in the perception of motion
Where is the V5 striate located?
Mid-temporal visual area
What does the calcarine fissure do?
Seperates the first and second visual areas on each side of the brain
What is retinotopic?
Area in the brain that contains a complete map of the visual field covered by the eyes
What is the tectopulvinar system?
Other path from the eye to the brain
What is the tectopulvinar system made up of?
Remaining M ganglion cells
What is the route the tectopulvinar system takes?
Sends axons to superior colliculus where it sends connections to the pulvinar region of the thalamus
Pulvinar sends info to parietal and temporal lobe
What is the ventral pathway used for?
the WHAT?
Colour and form
What is the pathway that the central pathway takes?
1- Retinal P-cells 2- Parvocellular LGN 3- V1 4- V2 5- V4 6- inferior temporal cortex
What is the dorsal pathway for?
The WHERE?
For space and motion
What path does the dorsal pathway take?
1-Retinal M-cells 2-Magnocellular LGN 3- V1 4-V2 5-V3 6-V5 7- posterior parietal cortex
Where in the temporal lobe is specialised for processing vision?
Fusiform face ar
Parrahippocampul place area
Where in the parietal lobe is specialised for vision processing?
Intrapareital sulcus areas (Control eye movement and visual hrasping) Parietal region (visual control of reqching)
