w9 VSE Motion Perception Flashcards
(20 cards)
what does the visual system use to infer motion??
it infers motion from the changing pattern of light on the retina
it motion perception purely visual??
no it’s perceptual, it also integrates info from the vestibular system and eye movement signals
what are smooth pursuit movements for??
tracking moving objects to keep them stationary on the retina
what happens during saccadic movements?
vision esp motion perception is breifly suppressed
which brain area integrates motion signals??
Area MST, near Area MT (V5)
what do MT neurons do ??
they’re velocity-selective (respond to specific speed and direction) and are linked to our perception of motion
what is the “waterfall illusion”?
a motion after-effect: after watching motion in one direction, stationary objects appear to move in the opposite direction
whats an example of induced motion??
sitting in a stationary train while another moves next to u and u feel like ur moving
define Critical Flicker Fusion (CFF)
the highest flicker rate (HZ) thats perceived as non-flickering
whats the average human CFF in bright light??
around 50-60Hz
what law related to luminance to CFF??
Ferry-Porter Law - CFF increases with luminance
why is CFF clinically useful in cataract patients??
CFF is independent of media opacities, so it can assess retinal function even with dense cataracts
what condition shows motion perception loss with normal acuity and colour vision??
Akinetopsia, e.g. patient LM
what is motion parallax??
as u move, closer objects shift more across ur field that distant ones, this is a depth cue
what is optic flow??
a pattern of motion from moving thru the environment helps determine heading direction and distance to objects (as u walk forward, everything moves outward from a focus point(where ur going))
how does motion help with figure-ground segmentation??
moving objects stand out more from the background, especially when static cues aren’t enough
whtas the motion-bounce illusion??
a cognitive effect where auditory and visual cues combine to affect perceived motion outcomes
whats the theory behind motion and myopia??
peripheral hyperopic blur might stimulate eye elongation, and optic flow could be a cue in refractive development
what are the key roles of motion perception??
movement, esp in in ur peripheral vision grabs attention and helps u locate things quickly
moving objects stand out more clearly from the background, even if they have similar colours or patterns
motion helps us work out an objects 3D shape and how far away it is.
2 imp ways we judge distance and move safely are: motion parallax: nearby objects seem to move more than distant ones as we move, optic flow: the pattern of how everything seems to move as u walk or drive.
biological motion lets us easily understand human movement, even with very little visual information, the brain has special areas that process this quickly.
Describe the advantages of using the technique of magnetoencephalography (MEG)
to investigate human brain function
Direct Measure of Neural Function, Extracranial Magnetic Fields reflect neural activity
Magnetic signals reflect neural activity and can be recorded with millisecond precision.
Unlike electrical fields, magnetic fields are not distorted by brain tissue or bone, providing a direct measure of neural sources.
Non-invasive, safe, and does not involve radiation or injections.
Provides whole-brain coverage, capturing neural activity across the entire brain for a comprehensive view of brain networks.
