Control CS11 visual defects Flashcards
What forms the optic nerve?
Axons of the ganglion cells of the retina
What amino acid is involved in vision?
Glutamate
What vitamin is retinal a form of?
Vitamin A
Where in the retina is retinal found?
Rhodopsin
What happens to glutamate release when light hits the retina?
It decreases causing hyperpolarisation of the retina
What are the two types of bipolar cells?
On = decreased glutamate release causes them to become depolarised in response to light
Off =decreased glutamate release causes them to become hyperpolarised in response to light
How do bipolar cells affect ganglion cells?
Either increases or decreases their firing
What is a receptive field in the retina?
The area of the retina that causes any change in the response of a neuron when simulated.
Why do the adjacent/surrounding ganglion cells of the ganglion cell being simulated also become simulated by a bipolar cell?
Due to the interneurons and amacrine neurones between bipolar cells causing lateral inhibition
What are the two colour opponent pathways?
Red/green
Blue/yellow
What is the 5th photo pigment recent,y discovered in the eye?
Melanopsin
Where is melanopsin found?
In intrinsic photosensitive retinal ganglion cells
What is the role of intrinsic photosensitive retinal ganglion cells?
They encode luminance
Maintaining normal entrainment of the circadian clock
Involved in pupillary light reflex by connecting to the Erdinger-Westphal nuclei
What are the types of layers in the lateral geniculate nucleus?
Parvocellular layers (layers 3-6)
Magnocellular layers (layers 1+2)
Koniocellular layers (very small cell bodies between the other layers)
What are properties of magnocellular ganglion cells?
Larger cell bodies
Large receptive field
Important for detection of movement of stimulus
What are properties of parvocellular ganglion cells ?
small cell bodies
Sensitive to form and fine detail of stimulus
What are the three types of retinal ganglion cells?
M-type aka magnocellular
P-type aka parvocellular
K-type (non-M and non-P)
What are the properties of K-type retinal ganglion cells?
Have medium cell bodies
Involved in detecting lots of different things including objects moving towards us so we can blink in time to protect the eye
How are visual pathways functionally organised in the primary visual/ striate cortex?
In orientation columns
In ocular dominance columns
In colour processing blobs
What part of the striate cortex is thought to process visual motion via the dorsal stream?
Striate cortex towards the parietal lobe
What part of the striate cortex is thought to process object recognition and where things are via the ventral stream?
Striate cortex towards the temporal lobe
