Lecture 12: Motion Flashcards
Damage to the _________________ in humans leads to perception of movement of stationary environment with movement of eyes.
Medial superior temporal area
When do real movement neurons respond/not respond?
- respond when a stimulus moves
- do not respond when eyes move
What are reichardt detectors? Describe in detail.
- model of a simple neural circuit that could fire in response to movement in one direction
- neuron A and B send signals to OUTPUT UNIT, which compares to see if the signals are synchronized
- neuron A signal goes through DELAY UNIT before output unit
- motion is perceived if signals from neuron A and B are received by the output unit at the same time (i.e. signals from A and B are multiplied, and the neuron fires if >0…does not fire if = 0)
Where does perception of motion begin?
Striate cortex (V1)
What do complex cortical cells respond to?
Movement of the ends of objects
Which area of the brain is implicated in other aspects of motion perception?
Middle temporal area
Normal monkeys can detect motion with coherence of 1-2%. Monkeys with lesions in _______________ cannot detect motion until the coherence is 10-20%.
Middle temporal cortex
_________________ applied to _____________ in humans disrupts ability to perceive direction in a random pattern of moving dots.
Transcranial magnetic stimulation (TMS); MT area
Review slide 13
Slide 13
What is the shortest path constraint?
Apparent movement tends to occur along the shortest path between 2 stimuli
FMRI shows that motor cortex is activated for perception of ____________ movement only.
Possible (vs. Impossible)
What is biological motion?
Self-produced motion of a person or other living organism
What is the point-light walker stimulus?
Created by placing lights on the joints of a living organism, which convey their pattern of movement (and biological movement)
Which area is most active for biological motion?
- Superior temporal sulcus (STS)
- others show activation of mirror neurons in FFA AND PFC
TMS applied to the _______________ impairs detection of biological motion.
Superior temporal sulcus
What are the functions related to motion in the striate cortex?
Direction of motion across small receptive field
What are the functions related to motion in the middle temporal area?
Direction and speed of object motion
What are the functions related to motion in the medial superior temporal area?
Processing optic flow; locating moving objects; reaching for moving objects
What are the functions related to motion in the superior temporal sulcus?
Perception of biological motion (animal/human)
What is implied motion?
Conveyed by still pictures that depict an action which involves motion
What is representational momentum?
Implied motion depicted in a photo an be “carried out” or continue in the observer’s mind
When looking at still pictures, do people take longer to time-forward or time-backward pictures?
time-forward because the anticipation interferes with responding
What finding can provide evidence for the fact that perception of biological motion may not depend on visual experience?
newly hatched chicks have a preference for biological motion
