reverse terms Flashcards
1) something moves in the world - image moves across the retina
2) Things not explained by above
Examples:
something moves and we track it - doesn’t move across the retina
We move our eyes or body – movement of the image across the retina but we don’t perceive movement
Real movement
Assume that detector cell (D) responds when it receives simultaneous input from receptors R1 and R2.
By introducing a delay element (t), detector would only respond to a target moving in one direction
directionally selective circuit:
Specialized motion sensitive mechanisms must represent speed & direction
Reichardt detectors - most modern models elaborate on this type of detector
Retinal Image Motion
The impossibility of determining the actual direction of motion of a stimulus by the response of a single neutron that sees the stills only through a small window and sees inly the component of motion in the bourbons preferred direction.
Solution: Responses of a number of V1 neurons are pooled
This may occur in the medial temporal (MT) cortex, which is located in the where/action stream
Aperture Problem
depends on three signals
-Motor signal (MS) - signal sent to eyes to move eye muscles
-??? - copy of the motor signal
-Image movement signal (IMS); movement of image stimulating receptors across the retina
Movement is perceived when comparator receives input from either ??? or image movement signal
Movement is not perceived when comparator receives input from both ??? and image movement signals
Corollary Discharge Theory
A case in which we see motion when there is none present
Motion aftereffects
occurs when 2 or more lights are flashed in sequence
Depending on the interstimulus interval and the spatial arrangement of the lights, different forms of illusory movement are seen
Apparent Motion
apparent motion tends to occur on the shortest path between two stimuli
Shortest-path constraint
is the incorrect attribution of movement e.g. sitting next to train that moves, moon in clouds, etc.
Occurs typically when larger object moves relative to a smaller one (frame of reference)
Induced movement:
When the shadow of a rotating 3D object is cast on a screen, it looks three-dimensional, even though the shadow is flat.
The kinetic depth effect
structure created by surfaces, textures, and contours, which change as the observer moves through the environment
optic array
Representations provided by perceptual system
Take action capabilities into account.
Capture the relationship between your environment and your abilities.
Action-specific perception
Refers to visual information used to control an ongoing movement
Involves complex and precise coordination of incoming visual information with outflowing muscle commands
Visual feedback
involved in planning reach movements
Medial intraparietal area (MIP)
involved in grasping movements.
Anterior intraparietal area (AIP)
