The aperture problem describes
an effect by which a contoured stimulus, moving behind an aperture with both ends occluded, appears to move in a direction perpendicular to its own orientation
.
What is the aperture problem in motion perception quizlet?
The aperture problem is the fact that when a moving object is viewed through an aperture
(or a receptive field), the direction of motion of a local feature or part of an object may be ambiguous
.
What is the aperture problem?
The aperture problem implies that
motion sensitive neurons in the visual primary cortex will always respond to a contour that crosses their receptive field
, independently of its true length and orientation, as long as its direction is consistent with the preferred direction of the neuron.
What causes the aperture problem?
The local motion information from a single neuron is inherently ambiguous with respect to the global motion. That is,
many different motions on the retina could cause the same response in a single motion sensitive neuron with a small receptive field
. This is called the aperture problem.
What is the consequence of the aperture problem?
The “aperture problem” indicates that
a local reading of the velocity of an oriented contour is inherently ambiguous, insufficient by itself to recover the velocity of image points
.
What is the aperture problem group of answer choices?
The aperture problem is the fact that
when a moving object is viewed through an aperture (or a receptive field)
, the direction of motion of a local feature or part of the object may be ambiguous.
Which brain region is most specialized for motion processing?
Area V5
, specialized for visual motion, is probably the most celebrated area of the primate brain. It is characterized by neurons selective for the direction of motion of the stimulus (14), with responses that follow the animal’s performance in direction-discrimination tasks (15).
What does tau τ represent in motion perception?
The parameter tau (τ) is proportional to
the observer’s spatial uncertainty
(specifically, it is the spatial standard deviation divided by the low-speed prior standard deviation).
How does the visual system overcome the aperture problem?
Because neurons in the primary visual cortex (V1) have small receptive fields, this “aperture problem” (Marr, 1982) must be overcome
if the visual system is to function properly
. … End-stopped neurons respond well to short contours, but the responses are suppressed by long contours.
In which brain area is the aperture problem likely resolved?
Similar effects of contour orientation have been found in humans8,9. Our results suggest that
cortical area MT
is likely to be involved in solving the aperture problem.
What is an aperture and what does it do?
Aperture refers
to the opening of a lens’s diaphragm through which light passes
. … Lower f/stops give more exposure because they represent the larger apertures, while the higher f/stops give less exposure because they represent smaller apertures.
What is the corollary discharge signal?
A corollary discharge (CD) is
a copy of a motor command that is sent to the muscles to produce a movement
. … The CD signal, like that sent to the motor neurons driving the muscles, occurs before the movement actually occurs, and is an internal signal that does not leave the brain.
What is area MT?
The middle temporal visual area (MT or V5) is
a region of extrastriate visual cortex
. In several species of both New World monkeys and Old World monkeys the MT area contains a high concentration of direction-selective neurons.
What is the motion parallax?
Motion parallax refers to the fact that
objects moving at a constant speed across the frame will appear to move a greater amount if
they are closer to an observer (or camera) than they would if they were at a greater distance. … Motion parallax diagram.
Is the illusion that a stationary object is moving and occurs after prolonged exposure?
Motion aftereffect
: The illusion of a stationary object that occurs after prolonged exposure to a moving object.
