1. Visual Perceptions: Motion, Depth, Form
S. J. Potashner, Ph.D

2. Two Visual Pathways in Association Cortex

3. Motion Perception Motion Generated 1. Object moves 2. Observer moves
a. Body moves
b. Head moves
c. Eyes move
3. Combination
eg. Object & eyes move
Optic flow
Motion Analysed
Superior visual pathway
Object movement (MT)
Optic flow (MST)

4. Motion is Represented in the Dorsal Visual Pathway
Primary Visual Ctx MT

5. Object Motion Analysis
Stage 1:
Complex cell
sensitive to
movement of
1 edge
video
Stage 2:
Complex cell
sensitive to
movement of
multiple edges
(entire object)
video

6. Functions of Motion Perception
Movement detection,
awareness & perceptions
Guidance of motor behaviors:
Gaze eye movements
Pursuit eye movements
Limb movements
Trunk & head movements
Locomotion MT
MST

7. Depth Perception is Represented in Both Visual Pathways

8. Depth Perception – Far (monocular) Cues11
Familiar size (2,3)
Occlusion (4,5)
Perspective (1-9)
Illumination (10)
Motion parallax (11) 10

9. Depth Perception – Near (binocular) Cues
Fixation
Far
Near
Zero cell
Near cell
Far cell
In many
visual
cortical
areas R L
L+R

10. Functions of Depth Perception
Depth detection,
awareness & perception
Guidance of motor behaviors:
Vergence eye movements
Limb movements
Trunk & head movements
Locomotion
Near cells
Far Cells
Zero cells
Form vision

11. Form is Represented in the Ventral Visual Pathway

12. Form Perception (Theory)
Primary Visual Cortex
Occipital Assoc. Cortex
Inferior Temporal Assoc. Cortex
(Geons)
(Objects)

13. Form Perception

14. Functions of Form Perception
Detection, awareness,
perception & recognition
of objects in environment
Form vision
Inf. Temp. Assoc.
Ctx.