Exam 1 - Chapter 4 - Part 2 Flashcards
two visual systems
Focal system
Ambient system
focal system
ambient system
- “what”
- “where”
theories of visual perception
Cognitive or Indirect theory of visual perception
Ecological or Direct theory of visual perception
cognitive theory
Visual perception is based on one’s understanding of the environment through deductive internal processes
Requires cognitive activity, thus perception is indirect - NOT directly apparent from the visual scene
visual guidance of action
Vision provides us with higher-level proprioceptive sensitivity
Provides exproprioceptive information
reaching and grasping
Upright posture is maintained by cutaneous, proprioceptive, vestibular and visual information
locomotion
Role of vision in locomotion varies with the movement situation - smooth vs uneven terrain; daylight vs darkness
Vision serves a feedforward mechanism
sensorimotor approach to treating patients with damage to the visual areas in the cortex
Some people have visual damage to the occipital lobe; Can be restored through stimulation
- Use this to help correct visual impairments
time-to-contact information and tau
An optical variable used to predict time to contact
- Information used for coordinating movement (dodge an object flying in your direction)
visual dominance and sensory conflict
Vision is about 80% of the sensory information we get
- 80% of the nerves are based on vision; guiding transmitting visual inputs
vestibular system (semicircular canals and two otolith organs-utricle and saccule)
Ascending Pathways
Descending Pathways
ecological theory
Visual information can be directly extracted from the environment
The optic array provides all the necessary information to guide movement
Does NOT require any intervening cognitive processes to determine meaningfulness
eye movements
Vestibular Occular Reflex (VOR) Optokinetic Reflex (OKR) Smooth pursuit Saccades Vergence -Convergence -Divergence
