Week 2: Perception Flashcards
Why must Sensory Information be Interpreted?
1) Incomplete Information
2) Information Overload
3) Extract Important or Dangerous Information
Vision
The only sense (out of 5 senses) to have an entire brain lobe dedicated to it (occipital lobe or cortex).
It is not a simple process of capturing images; it’s a complex construction built by the brain based on sensory input.
Visual Cortex / Occipital Lobe
Region of the brain that shows the complexity of vision and reveals how it’s not simply a passive projection of the outside world into the brain.
Retina
Located in the back of the eyes.
These are where all the rods and cones are.
Rods and Cones
The light receptor cells that we need to see.
Rods
They work when we have very little light available in the visual field.
They’re not sensitive to color information, and so vision in the dark is black and white.
Cones
Are sensitive to colour information.
They only work in well-lit conditions and enable colour vision.
They are found only on the part of the retina labelled fovea in the figure right at the back of the eye in the middle.
Fovea
Central part of the retina with the highest concentration of cones.
Visual Field
The area we can see without moving our head.
The center is processed by both eyes (binocular vision), while the sides are processed by only one eye.
Optic Nerve
Carries visual information from the retina to the brain.
Optic Chiasm
Where the optic nerves cross, separating information from the left and right visual fields.
Thalamus
A hub for sensory information entering the brain
relaying incoming input to relevant parts of the cortex for more detailed processing.
Lateral Geniculate Nucleus (LGN)
Part of the thalamus specifically concerned with visual information.
Primary Visual Cortex (V1)
Sometimes called Striate Cortex.
The initial processing area for visual information in the occipital lobe.
Binocular Vision
Limited to the central part of the visual field.
Colour Vision
Primarily based on information from the fovea.
2 Principles of Vision
- Hierarchical Processing: Vision starts with simple elements (dots, lines) and gradually builds up to complex objects and motion.
- Modular Organization: Different parts of the visual cortex handle specific aspects of vision (e.g., color, motion).
Key Areas of Vision
V1 (Primary Visual Cortex): Basic visual information (lines and edges). Damage leads to blindness.
V2 (Secondary Visual Cortex): Contour integration, Texture perception, Illusion perception, Color processing (with V4). Damage results in impaired texture perception.
V3: Form perception (shapes and objects), Depth perception (3D), Motion analysis (w V5). Damage results in impaired depth perception
V4: Handles color information. Damage results in color blindness.
V5: Processes motion. Damage causes motion blindness.
Dorsal
Refers to locations nearer the top of the brain
Ventral
Refers to locations nearer the bottom of the brain.
Dorsal Stream (Where stream)
Runs from V1 to the parietal cortex.
Concerned with spatial information, location
judgments, and motion
Spatial Information
Where things are in the world around you where they
are compared to you and where they are in relation to one another
Ventral Stream (What stream)
Runs from V1 to the temporal cortex.
Concerns what the visual elements are, and is important in object recognition decisions.
Visual Elements
Starts with the construction of simple forms, then shapes, and finally whole objects. This includes
some dedicated processing of category-specific information, for example, faces.
