Theories of Color Vision
What phenomenon of color vision does trichromatic theory fail to explain?
Negative color afterimages
_____________________ are visual receptors that contribute to the perception of color. They are mostly concentrated in the fovea.
Cones
This is a developmental stage when experiences have especially strong and lasting effects on the brain, largely influenced by inhibitory neuron activity. After this stage, experiences can still shape responses, but the effects become progressively weaker.
These cells are responsive to stimulus at specific orientation and location
-see box shaped, NOT complex things like faces
Simple Cells
Damage to areas MT and MST, which normally respond strongly to moving objects, can cause this condition where a person can see objects but cannot perceive their motion or direction.
Motion Blindness
The ability to recognize the color of an object despite changes in lighting is due to
Color Constancy
This part of the eye responds to faint light but is not useful in daylight because bright light bleaches them.
-abundant in the periphery of retina
Rods
In the videos of cats shown during visual system experiments, what was all the “noise” that researchers were recording?
Action Potentials
These visual cortex cells respond to a bar-shaped pattern of light in a particular orientation, but only if it does not extend beyond a certain point.
-have inhibitory end
Hypercomplex cells
Damage to the ventral stream can lead to this condition, characterized by the inability to recognize faces.
Propagnosia
According to this theory, certain neurons are excited by one color in a pair and inhibited by the other. For example, staring at a blue image for a long time fatigues the blue response, and when you shift your gaze to a white surface, the brain swings to the opposite—you see yellow instead. This explains negative afterimages, where prolonged exposure to one color causes you to see its opposite afterward.
Opponent-process theory
This small area near the center may be tiny but it is very important as 70% of input to the brain comes from this area. It specializes in detailed vision.
-each cone is connected to own ganglion
Fovea
Cortical neurons in the visual cortex of a kitten or a cat will lose the ability to respond to stimuli in one eye if the eye is sutured shut for how long?
The first month of life
These cells respond to the same orientation but also track motion.
-Orientation selective, lose positional sensitivity
Complex cells
Damaging primary visual cortex in the left hemisphere would result in blindness which area?
The right visual field
According to this theory of color vision, our perception of color depends on the relative activity of three types of cones.
Trichromatic Theory
These ganglion cells are located in or near the fovea, specialize in visual detail, and have smaller receptive fields.
Parvocellular Ganglion Cells
What was the method for the experiment manipulating the visual experience of kittens?
Expose cat only to lines of a particular orientation
These cells excite both horizontal and bipolar cells.
Photoreceptors
Damage to the dorsal stream can cause this condition, in which a person can perceive individual objects but cannot see them together as part of a whole scene (context).
Simultanagnosia
This theory explains color constancy. If you wear green-tinted glasses or replace your white light bulb with a green one, you still identify bananas as yellow, paper as white, and so forth. Your brain compares the color of one object with the color of another, in effect subtracting a certain amount of green from each
-retina+cortex as visual perception requires reasoning
Retinex Theory
The back surface of the eye that contains photoreceptors is called the ____?
What were the results of the experiment manipulating the visual experience of kittens?
Cats only see lines they were exposed to
These cells inhibit bipolar cells.
Damage to the ventral stream can lead to this condition, characterized by the ability to see objects, but not recognize them.
Visual Agnosia