Vision Flashcards
achromatopsic
• Damage to V4 =achromatopsic
○ No representation of colour (see in black and white)
○ Not the same as colour blindness (lacking cones in retina)
Fail to see colour, but the retina and V1 cells are still responding to different wavelengths of light
akinetopsic
• Bilateral V5/MT damage= akinetopsic
○ See the world in a series of still frames
• Can still detect movement in other senses
○ i.e. hearing something scrap along a wall
Suggest V5/MT is specialized to vision, not other senses
parvocellular/P layer
○ Upper 4 layers have parvocellular/P layer
§ Contain small cell bodies
Responds to detail and colour
magnocellular/M layers
○ Lower 2 layers have magnocellular/M layers
§ Larger cell bodies
§ More sensitive to movement than colour
Respond to large areas of the visual field
konio/K cells
○ Between the magno and parvo layers are konio/K cells
§ Less functional specificity than magno or parvo cells
Have a different pattern of connectivity
Hemianopia
○ Cortical blindness restricted to one half of visual field
Associated with damage to V1 in one hemisphere
Quadrantanopia
○ Cortical blindness restricted to a quarter of the visual field
○ Partial damage to V1 can affect one subregion of space
i.e. Upper part of V1 represents bottom side of space
Scotoma
Small region of cortical blindness
Apperceptive agnosia
Failure to understand the meaning of objects due to a deficit at the level of object perception
Associative agnosia
Failure to understand meaning of objects due to a deficit at the level of semantic memory
Facial recognition units (FRUs)
§ Stored knowledge of the 3D structure of familiar faces
Familiar faces are recognized by matching to a store of FRUs
Person identity nodes (PINs)
Abstract description of people that links together perceptual knowledge (i..e faces) with semantic knowledge (i.e. their occupation)
Categorical perception
Tendency to perceive ambiguous or hybrid stimuli as being either one thing or another, instead of a blend of the two
