Motion Perception & Action Flashcards
What is motion perception?
- Movement attracts attention.
- Movement provides information about shape, size and depth.
- Motion helps separate figure from ground.
What is the only type of motion humans can produce and perceive?
Biological motion
What brain area contains mirror neurons?
Central premotor area
When do mirror neurons fire?
- When an action is performed.
- When another organism is observed performing the same action.
What are the functions of the mirror neuron system?
- Identifying the outcome of the observed action and the emotion the other person displays.
- Contributing to representing the other person’s desires, beliefs and intentions.
- Serves as a basic building block allowing for a shared communication system.
What are voluntary movements?
Movements that are under conscious control by the brain.
What are involuntary movements?
- Reflexes.
- Rhythmic movements.
What is the planning system of the planning-control model of goal-directed actions (Glover, 2004)?
Planning system
- Used mostly before the initiation of movement.
- Selects an appropriate target, decides how it should be grasped and works out the timing of the movement.
- Influenced by individual goals and the nature of the target object.
- Relatively slow.
What is the control system of the planning-control model of goal-directed actions (Glover, 2004)?
Control system
- Used during the carrying out of a movement.
- Ensures movements are accurate, making necessary adjustments based on visual feedback.
- Influenced by the target object’s spatial characteristics, but not by the surrounding context.
Fairly fast.
What is personal space?
Refers to spatial position on the body.
What is peripersonal space?
Refers to the spatial realm within arm’s reach, or near space.
What is extrapersonal space?
Refers to the area beyond arm’s reach (far space).
What is defensive peripersonal space (PPS)?
When the peripersonal space contains obstacles or dangers, its function becomes the body’s protection.
How do we predict the moment of contact between us and some object?
By relating the size of an object’s retinal image to its rate of expansion.
- The faster the rate of expansion, the less time there is to contact.
What are affordances?
Affordances refer to the perceived and actual properties of a thing.
- Primarily those fundamental properties that determine how the thing could be used.
What are the two types of grasp?
- Power - Picking up a larger object with all digits so it presses against palm.
- Precision - Picking up tiny objects with thumb and forefinger.
What is kinematic information?
Position, velocity and acceleration of the hand.
What is kinetic information?
Forces generated or experienced by our body.
What are the two stages of reaching movement?
- Transport - Bringing hand next to object (visually guided).
- Grip - Positioning hand and fingers (governed by shape and size of object).
What brain areas are consistently activated during observation of point-light displays?
The posterior superior temporal gyrus and sulcus.
What are examples of motion illusions?
- Motion aftereffect.
- Stroboscoptic motion.
- Wagon wheel effect.
What us akinetopsia?
A disorder in which a patient has difficulty specifically perceiving objects in motion (motion blindness).
What are the two types of akinetopsia?
- Frozen frames - aka cinematographic vision.
- Vanishing objects, as soon as they move.
What is akinetopsia associated with?
Damage to the V5 medial temporal portion of the brain, involving the temporo-parieto-occipital junction.
What is the vision-for-perception system?
(What system)
- Processes information about shape, size, objects, orientation and text.
- Object recognition.
What is the vision-for-action system?
(How system)
- Processes location, distance, position, and motion.
- Visually guided action.
What is optic ataxia?
A condition involving severe problems with the use of vision to guide movements.
- Patients are poor at making precise visually guided movements, but can recognise objects or line drawings.
What is apraxia?
The inability to perform skilled, sequential, purposeful movement that cannot be accounted for by disruptions in more basic motor processes.
- Commonly observed after stroke, traumatic brain injury, and in people with neurodegenerative disorders.
- Typically affects parietal or frontal areas.
