Depth & Motion Flashcards
What do smaller and higher objects in the visual field generally indicate?
That they are further away.
What do finer textures generally indicate?
That something is further away.
What type of borders generally appear closer?
Sharply defined ones.
How can shadow indicate depth?
Light typically comes from above, so we interpret images this way.
What difference between the eyes is used to interpret depth?
Angular distances.
What is the name for the cue which utilises the slightly different images from mammal’s eyes?
Binocular disparity.
How do we know depth is processed before form?
When objects cannot be identified, depth can still be perceived.
What is the first area where neurons respond to input from the eyes?
V1.
How do left and right eye neuron’s receptive fields signal disparity?
Their centre-surrounds are shifted so can be in different spatial locations.
What is animacy?
Simple motion displays that convey intention.
What is akinetopsia?
A disorder when people cannot are any motion.
What is damaged in akinetopsia?
MT.
What detectors are used in motion space-time turning?
Moving bar detectors.
Describe moving bar detectors.
They are sensitive to lines, oriented in space and time, at particular directions and speeds.
Describe the motion after-effect.
Motion sensitive mechanisms adapt and reduce their response, the balance between responses changes, and so when a static image is shown, motion is perceived in the opposite direction.
What is the aperture problem?
Small, localised receptive fields perceive motion in only one, tiny region of space.
How is the aperture problem solved?
Several local motions are fed into neurons with larger receptive fields and integrated.
What type of motion is processed in V1?
Component motion.
What type of motion is processed in MT?
Global motion.
What is the name for the cue from object motion that indicates depth and shape?
Kinetic depth effect.
What pathway is used for motion processing?
Dorsal.
Describe the hierarchy of motion sensitive areas.
Neurons response to more complex motions as the hierarchy is climbed along the dorsal stream.
What is the hierarchy of motion sensitive areas, in terms of specific brain areas?
V1 - V2 - V3 - MT - MST
Define the motion coherence threshold.
The point at which direction of motion can be just detected.
