C3.P3 Flashcards
Summarize the four steps involved in sensing vision
First, the eye must gather light. Second, the eye bends the light to the retina. Third, photoreceptors transduce the light energy and communicate with bipolar sensory neurons who will transmit it into a neural signal . Fourth, the brain will process the information
Do we see the light an object holds or reflects?
The light the object is reflecting
What are the two sides of the electromagnetic spectrum?
Gamma rays to long radio waves
What is the visible light spectrum?
The relatively narrow range of colored light we are able to sense and perceive (ROYGBIV)
What are the two ways humans differentiate light color and brightness?
Wavelength and amplitude
What is wavelength?
It is used to determine color. The shorter the wavelength the closer to violet, the longer the wavelength the closer to red
What is amplitude?
Determines the light’s intensity/brightness. It measures the height of the wave
Who introduced the trichromatic theory?
Hermann von Helmoltz
What is the trichromatic theory?
The eye has three types of receptors, one sensitive to blue, one to red, and one to green, which can work together to help us experience color
What is a disadvantage to the trichromatic theory?
It cannot explain afterimages
Who introduced the opponent-process theory?
Ewald Hering
What is the opponent-process theory?
There are three channels for processing color information from cones in the retina and thalamus. A color can activate and deactivate others, creating a spectrum
What happens when someone is missing one or more types of cones?
They are color blind
What is the most common type of color blindness?
Dysfunction in the reddish green channel
What causes red-green blindness?
It is carried by a gene in the X chromosome
Who is more likely to have red green blindness?
Males
What starts formed perceptions?
The primary visual cortex constructs perceptions using bottom up and top down processing
Who studied feature detectors with frogs?
Jerome Letvin
Frog
Frog :)
Are there feature detectors in the human retina?
No
Who identified that there are feature detectors in the brain?
Hubel and Wiesel
What are feature detectors?
Several neurons connecting forming feature detector neural networks that fire selectively in response to specific shapes, angles, edges, movement, and gradient patterns
What are supercell clusters?
Integrates data from multiple feature detectors and learn to fire in response to certain patterns
What is the dorsal path?
Moves sensory information from the PVC to association areas in the parietal lobe where its processed. This locates spatial objects
What is the ventral path?
From PVC to lower portions on the temporal lobe, association areas are linking the incoming sensory information with memory. Determines what things are
Do supercells work in a top-down or bottom up fashion?
Top-down
