PSC1002/L26 The Eye II Flashcards
What is the effect of glutamate on bipolar cells?
Excitation
What is the role of bipolar and retinal ganglion cells? (2)
Bipolar cells excite or inhibit retinal ganglion cells
Retinal ganglion cells give rise to optic nerve fibres
What is the role of horizontal and amacrine cells?
Carry signals horizontally across retina
What is the immediate response of photoreceptors to light?
Reduced NTM (glutamate) release
Describe the on centre type of rod ganglion cells. (2)
Centre excited by light
Outside inhibited by light
Give 2 benefits of centre surround organisation of rod ganglion cells.
Helps to emphasise contrast
Important for identifying shapes
Form of surround inhibition
Basis for some visual illusions
Give the 2 types of cone ganglion cell with cell centre surround organisation.
Red (L) - Green (M)
Blue - Yellow
Where do fibres from the nasal retina of each eye cross?
Optic chiasm
Where do the left eye temporal and right eye nasal end?
Left LGN and cortex
Where do the right eye temporal and left eye nasal end?
Right LGN and cortex
How are projections from each eye kept separate?
Contralateral and ipsalateral layers
What are the 5 areas of the visual cortex?
V1-5
What is the role of the primary visual cortex?
Maintains topographic mapping of visual world
What is the more cortical area of the primary visual cortex devoted to?
Centre of vision
What are the selective responses of neurons in the visual cortex?
Prefer bars and edges not spots
Prefer specific position of stimulus in receptive field
OR
Bright bar in specific orientation
Prefer stimulus moving in specific direction
