Visual Perceptions: Motion, Depth, Form S. J. Potashner, Ph.D sjp9713@neuron.uchc.edu

Two Visual Pathways in Association Cortex

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)

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

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

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

Depth Perception is Represented in Both Visual Pathways

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

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

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

Form is Represented in the Ventral Visual Pathway

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

Form Perception

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