W5 REDONE Flashcards
(17 cards)
Where does motion processing occur in the brain?
In the visual cortex: V1, V2, V3, MT (V5), and MST.
How does the brain detect motion?
Using a delay and compare mechanism: one cell detects initial motion, another detects delayed motion, and a third compares both. These are direction-selective cells, especially in MT (V5).
What is real motion vs. apparent motion?
Real motion: object physically moves over time. Apparent motion: no actual movement; motion is perceived from sequential static images.
What is apparent motion?
Illusion of motion when static images are shown rapidly in sequence. The brain fills in gaps to perceive continuous movement.
What is illusory motion?
Perception of motion in static images due to visual properties or eye movements. Examples: Pinna, Enigma illusions.
What is the Pinna illusion?
A static image appears to rotate when you move your eyes. Caused by differing motion signals in central vs. peripheral vision.
What is the Enigma illusion?
A static image with concentric patterns appears to move. Believed to result from microsaccades triggering motion detectors.
What are motion aftereffects?
Illusions of motion after prolonged viewing of motion. Example: Waterfall illusion. Explained by neural adaptation.
What is the waterfall illusion?
After staring at downward motion, stationary objects appear to move upward. Caused by adaptation of motion-sensitive neurons.
What is induced motion?
A stationary object appears to move due to movement of the background. Example: The moon appears to move through clouds.
What is vection?
The illusion of self-motion when you are still. Example: feeling like you’re moving when a nearby train moves.
What is motion contrast?
Enhanced motion perception when object moves against an oppositely moving background. Helps distinguish object from background.
What are opponent motion cells?
Neurons that compare motion in opposite directions. Found in MT. Help determine net direction of motion.
What is the aperture problem?
Ambiguity in motion direction when viewing part of an object through a small window. Resolved by combining input from multiple neurons.
What is biological motion?
Motion patterns typical of living beings. Recognized from point-light displays. Involves STS and MT.
What is Area MT (V5)?
A brain region specialized for motion processing. Contains direction- and speed-sensitive neurons. Damage can cause akinetopsia.
Is motion perception fully understood?
No. Current models are helpful but incomplete. Low-level neural mechanisms are still being studied.
