Stimulus Identification/processing Visual Information Flashcards
What factors effect stimulus identification
Clarity
Intensity
Modality
Explain stimulus clarity
How defined or unambiguous
Reduces uncertainty, faster and more accurate reactions
Explain stimulus intensity
Strength or magnitude of a stimuli
More intense = faster e.g startle, faster than voluntary reaction times, mediated by brainstem
Auditory startle faster at RT
Up to a certain point
Explain stimulus modality
The type or form of a stimulus, corresponding to the system it activates
- visual
- auditory
- tactile
Explain modality specific reaction times
Auditory - 85-100ms
Visual - 100-180 ms
Tactile - 120-150 ms
Due to times for systems processing
What are the sources of sensory information
Exteroception - from outside the body
- vision
- audition
Interoception
- inside body
Proprioception
What are the sources of proprioception
Muscle spindles (detect changes in muscle length and tension
Gogli tendon organs (monitor tension in tendons)
Vestibular apparatus
Joint receptors (joint angles and movements)
Cutaneous receptors
Explain interactions between sources of sensory information
Catch ball
Vision
Proprio to track hands position
Intero to sense muscle strain
How does light pass through the eye
- Entry through the cornea
- refracts light to focus it toward centre of eye - Pass through pupil
- regulates how much light enters the eye - Further refraction by lens (behind pupil)
- Retina
Firms upside down image
Has Ross and comes
Explain Rods and Cones
Convert light to electrical signal when it hits the photoreceptor cells
Rods:
- low light
- highly sensitive to light but do not detect colour
- peripheral vision and motion detection
- more rods
Cones:
- specialised for vision in bright light
- colour vision and fine detail
- concentrated in fovea in centre of retina, why we have to move head to see detail
Explain projection of visual field
Info from left visual field hits right side of each eyes retina
Image flipped upside down and reversed when it hits the retina
Info from right visual field sent to left side of brain
Brain fixes the image
Explain binocular vision
Info from visual fields of both eyes in combined
Sent to back of brain Brain due
Occipital lobe
Combines field of view, aids with depth perception, fuses images
What are the two visual streams
Dorsal and ventral
Explain the dorsal stream
Where
Parietal lobe
- optical flow
- central and peripheral visual field
- no conscious
- process spatial information
- important for guiding motor actions
Combines info from both eyes to create a sense of depth and motion
Explain the ventral stream
Temporal lobe
- what, identification
- central visual field
- conscious
- recognition, shape
What is optical flow
As light enters the eye it creates patterns on the retinas, it is how those patterns change = optical flow
As objects move/ you move
Interpret speed and direction
Close to you = move fast
Speed, direction and distance
What is the time to contact equation
T contact = size of image / rate of expansion
As rate of expansion gets bigger, time ti cobtact becomes smaller
Which is the focal vision, which is ambient
Focal - ventral
Ambient - dorsal
Which visual stream includes optical flow
Dorsal
What is interceptive control
The ability to guide your movements to interact with moving table at the right time and place = intercept it
Timing
Prediction, based on speed and direction of object
Motor adjustment
What is it called when you are late or early in interceptive control
Temporal error
What are the key events during interceptive tasks
Target visible
Viewing period (vp)
Triggering quantity (TQ crit) - the point at which you decide to move
PT-TT, perceptual time, transition time = commands triggered
Movement onset
Movement time
Contact
