Lecture 8 Flashcards
What are Basal Processing
(3) Higher Order Processing(2) and association processing of vision?
- Basal processing is thins like angels, colors and lines
- Higher order processing is thins like what and where
- Associating processing is combining it with memory and knowledge about the world
What are the 6 steps from sensation to perception? And what is this for the eye
- Stimulus (light)
- Sense Organ with recptors (eyes with photoreceptors)
- Transduction (Photopigments bleach/split affecting membrane potentials)
- Coding (Light frequency (hue) and intensity (brightness) and pureness (saturation)
- Projection to cortex From the eyes to the LGN to V1
- Higher order processing about what and where an object is.
What are the three kinds of Light Stimuli?
- Light frequency for color (hue)
- Light intensity (brightness), by the size of the wavelength
- Light pureness by the amount of wavbelengths (saturation)
What are the 7 parts of the eye?
- Conjunctiva is the layer that covers your eyes and prevents things from going in
- Cornea or Hoornvlies is what lets trough light
- The Iris is what controls the size of the pupil
- The lens refracts light onto the retina (called accommodation)
- The fovea is the middle part of the retina with a lot of cones
- Ganglion cells are activated by photoreceptors trough bipolar cells
- The optic nerve is where the ganglion cells leave the eye (blind spot)
What are the three cells in the retina?
- Photoreceptors are at the back and detect stimuli
- Bipolar receptors are connected to these receptors and combine them
- Ganglion cells are then connected to these bipolar cells and travel to LGN.
What is the receptive field of a neuron?
The area where a neuron responds to a stimulus.
What is the lamellae in rods and cones?
It is the part that contains the photopigment
What are opsin and retinals of the cones called? What is this system of color detection called.
It is a trichromatic system
1. Cyanolabe + retinal detects blue
2. Chlorolabe + retinal detects green
3. Erythrolabe + retinal detects red
What is the combination of opsin and retinal in the rods Called?
rhodopsin
How do neurons code for brightness?
By their firing rate (rate law)
How do brightness detecting ON and OFF cells react to light. And what does the Mach effect show?
- ON cells are activated by light in the center and inhabited by light in the surround
- OFF cells are inhibited by light in the center and activated by light in the surround
- Mach effect shows that when there is a dark edge next to a bright edge, dark edges and bright edges are increased due to the surround not being inhibited.
What is the rebound effect of brightness or color?
After a specific brightness or color is shown, neurons show the opposite activity when it is taken away.
- So if it was inhibited it now becomes active.
How do two kinds of Ganglion cells use Opponent-processing in red, green, yellow and blue colors?
- There is a RED-GREEN ganglion cell and a YELLOW-BLUE ganglion cell
- RED-GREEN are: activated by red and inhibited by green
- YELLOW-BLUE are activated by green+red and inhibited by blue
How can you cut a Brain (or body) to show the insides?
For the brain:
- The Sagital plane cuts between the left and right hemispheres
- The Coronal Plane cuts between the anterior and posterior regions
- The horizontal/transverse plane cuts between the dorsal and ventral regions.
How do neurons respond to the orientation of objects?
- Specific ON neurons respond to a specific orientation in a specific part of the receptive field.
- They are inhibited by the same orientation in their surround
