Perception and action 2 Flashcards
What are the three ways we stay on course?
Optic flow
Visual direction strategy
Spatial updating
What is visual direction strategy? (simple)
orientating towards goals and away from obstancles
What is spatial updating? (simple)
updating of self-position and target location using motor control and proprioception
Describe the visual direction strategy study
studied walking towards goals and around obstacles using VR
They also looked at route selection
What did the study on visual direction strategy find?
Participants turn body toward a goal
Participants turn body away from an obstacle
Errors are corrected by reorienting towards target
What do the findings of the visual direction strategy study suggest?
human route selection does not require explicit planning but may emerge online as a consequence of elementary behaviours for steering and obstacle avoidance
Dynamic interaction between perception and action
Describe the study on spatial updating
Participants viewed a target, closed their eyes, then tried to walk to target along one of three paths
Blind walking experiment
How did the participants do in the spatial updating study?
did pretty good but worse for farther targets
What did the study on spatial updating find?
We can navigate without immediate visual input
In blind walking, participants depend on:
Initial visually perceived location of target
Response execution
Updating of self-position
Imaginal updating of target location
There is an interaction between motor control and proprioception –> still perception and action interaction
What are some general ways we navigate? Rate them by experience
Initially we depend on a sequence of street names
Then we use a sequence of imagined landmarks
Once it is part of your routine you use first-person imagery of you travelling the route
What are two ways we navigate?
Landmarks
Cognitive maps
Describe the study on landmarks? What were the conditions?
Participants navigated virtual maze full of landmarks
First train (explore), then test (navigate)
Either navigate with all of the landmarks of half of the landmarks
Could be least fixated half or most fixated half of landmarks
When the study on landmarks looked at fixation time during training, which landmarks did people fixate on for the longest?
landmarks at decision points
What were the results of the study on landmarks?
Navigation depended on perception and memory of decision-point landmarks
If they removed the least fixated landmarks it didn’t make any difference
If they removed the most fixated landmarks, it had a significant impact
What did the study on cognitive maps do?
Recording of medial temporal lobe cells while rat navigated
What are medial temporal lobe cells for?
Important for where we are in the world
When did firing increase for the rat in the cognitive map study?
when the rat enters the place cell’s optimal zone
What were the four types of medial temporal lobe cells they found in the cognitive maps study?
Place cells
Grid cells
Head direction cell
Border cell
What are place cells? What would happen if you put animal in a new place?
Place cells fire when an animal is in a particular location
Would develop a new place area in a new environment
What is a grid cell? What are they used for?
Grid cells fire on a regular lattice in the environment
Used to keep track of how we are moving through the environment
What are border cells?
Border cells respond to a boundary at a particular distance and direction from animal
What are head-direction cells?
Respond when animal faces a certain direction irrespective of location
How does the navigation system in the medial temporal lobe allow an animal to keep track of where they are in the environment? What information is being used (5)?
Uses the four types of cells and information from visual input, somatosensory input, proprioceptive input, motor commands, and memory
What are the three ways we interact with objects?
Perceiving actions an object affords (affordances)
Representing those actions (PRR)
Transforming visual input into coordinates for guiding action
What are affordances? Give examples
Potential actions that an object offers to an organism
Perceivable along with physical features
Button- push
Switch - flip
Knob - rotate
Describe the study on affordances? What was the research question?
Do perceived objects prime affordances (activate affordances)?
Primed with an object on the screen (beer mug, teapot, frying pan)
Shown a horizontal or vertical handcue for grasping object
Got the person to perform a hand action to grad two targets
What were the two object primes and hand cue options for the study on affordances?
Cup could be a normal orientation or it could have a rotated orientation
Hand cue could be congruent of incongruent with the orientation of the cup
What were the results of the study on affordances?
Participants actions (reach out and grab) were faster when perceived object primed congruent action than incongruent action
They were faster overall for the normal object rotation
What did the study on affordances discover?
Pictures of handled objects such as a beer mug or frying pan are shown to prime speeded reach and grasp actions that are compatible with the object
Just sight of objects activates representation of grasp for object
What pathway is the parietal reach region found?
Dorsal where
Describe the study on the parietal reach region
Single unit recording in monkey PRR
Monkey looks at fixation light in the dark –> light on and sees object –> lights out and can’t see object –> reaches in dark then grasps object
Shown different objects requiring different grasps
What did the study on the parietal reach region find?
Different neurons appear to encode different grasps
Describe the order that we transform visual inputs into coordinates for guiding action?
Visual target – eye centered coordinates – head centered coordinates — body-centered coordinates — arm-centered coordinates – joint coordinates — movement
What is another way we perceive action?
Mirror neurons
What do mirror neurons respond to?
Both to performance of an action and perception of that action
What did this study on mirror neurons find?
Fires when watching a person pick up a peanut
Fires lots when it picks up a peanut itself
Doesn’t fire much when tool picks up peanut
What did the study on mirror neurons and monkeys find? What were the four conditions?
Response was not specific to any modality
Mirror neurons responding to peanut breaking:
View and sound
View only
Sound only
Motor action ( animal opens nut)
What did the study on mirror neurons in humans find (general)?
Mirror neurons responded to observing actions and executing the actions themselves
What were the four areas tested in the study of mirror neurons in humans?
Left entorhinal cortex, right parahippocampal gyrus, left SMA, left parahippocampal gyrus
What were the two conditions they tested on the left enthorinal cortex for the mirror neurons in humans study? What did they find?
Frown and smile
Showed activation for both doing it and observing someone doing it
What were the two conditions they tested on the right parahippocampal gyrus for the mirror neurons in humans study? What did they find?
whole hand grip movements and precision hand grip movements
Showed activation for both observing and executing the movement
What was the condition they tested on the left SMA for the mirror neurons in humans study? What did they find?
Smile
showed depression in firing for observing and executing the smile
What was the condition they tested on the left parahippocampal gyrus for the mirror neurons in humans study? What did they find?
Frown
Fires less for observing it and more for executing it
Where are mirror neurons found?
In many parts of the brain
Are mirror neurons just for perception and motor pairing?
No they can be for emotions too
How long does a hitter have to decide whether to hit a major league fastball?
100-150 ms
Do baseball players have enough time to think and hit?
No
How do baseball players hit the ball if they don’t have enough time to think and hit?
predict the trajectory in advance and anticipate what will happen
Do baseball players have enough time to separate perception and action?
No, they do both at the same time
How often do baseball players make a hit?
1/4 of the time they get a hit
Are pitchers getting faster overtime? What was the fastest pitch?
Yes, 106 MPH
