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70 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Describe the responses to the Cortex Cells... - Ganglion and LGN Cells - Simple Cells - Complex Cells - Hypercomplex Cells |
Ganglion responds to spots
Simple Cells responds to lines of specific orientation
Complex Cells respond to lines of specific orientation moving in a specific direction
Hypercomplex Cells respond to lines of a specific length, orientation, and moving in a specific direction |
spots and lines |
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What are the 3 criteria for the hypercomplex cortical cells? |
direction orientation length |
D.O.L |
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What is the criteria for complex cells? |
orientation and direction |
CD rOm |
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What is the criteria for cortical cells? |
bars of light that increase firing rate based on orientation |
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What is Hubel and Wiesel's experiment and discovery? |
after placing an electrode to track neuronal activity when a spot was shined, they only found spontaneous activity until they accidentally used a bar of light found the neuron responded with increased firing |
bars of light |
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What is Stewart's Theory? |
Using curvy lines instead of the straight lines will cause the illusion to disappear disproving the lateral inhibition theory |
counteracts Hermann Grid Illusion |
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What is the Hermann Grid Illusion? |
we see grey blobs on the white lines between the black and white grids, the theory is that the central-surround receptive fields/lateral inhibition play a role |
Total Gridlock |
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How would lateral inhibition play a role in the Hermann Grid Illusion? |
the white area would attract more illuminance and cause increased firing; but there are a lot more dark areas which act as inhibitors so with more inhibitors we would get a grey area because of the black cancelling out the white |
think of darts, the middle is + and out parts are - |
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Describe lateral inhibition. |
neighbouring neurons inhibit eachother |
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What is simultaneous contrast? |
the difference of light caused by the lateral inhibitions in light |
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What is Lateral Inhibition in the Horshoe Crab? |
electrodes record the neuronal activity from one area, as adjacent neurons are stimulated; the firing activity decreases in that neuron |
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Explain centre-surround receptive fields. |
LGN and Ganglion cells are circular, the middle has an on centre (more firing when the light is focused on the center) and when the surrounding is hit, there is a decrease in firing activity. |
think of darts |
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List the types of version eye movements. |
Tremor: maintains vision by providing new stimuli
Nystagmus: the eye movement that occurs when fixated on an object and move your head -optokinetic (OKN) - combination of saccade and smooth pursuit - Vestibular ocular reflex (VOR) : when head is rotated Saccade: quick jerk of both eyes (involuntary) |
Trevor Never Pursues Sacadia |
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What is vergence eye movement? |
Divergence and convergence of eyes when a target is moved farther or closer |
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What is saccadic suppression? |
Reduced visual sensitivity (we don't see a smear, we are focused on the target) |
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Describe the optic flow. |
Optic nerves leave the eye and crosses over at the optic chiasm → 1st synapse is at the Lateral geniculate nucleus (LGN) - in the thalamus → the LGN synapses to the occipital lobe |
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What is the role of the Superior Colliculus? |
allow us recognize objects and their location with respect to ourselves |
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What happens if a person suffers a stroke? |
If a person has a stroke that disconnects the superior colliculus, and the main route is maintained, the individual could recognize objects but can’t tell you where it is; vice versa the person won’t be able to see the object but they will reach out and get it |
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Define Prosopagnosia. |
Inability to recognize faces |
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List the 3 types of neural circuits. |
Linear : one-to-one connection; found mostly in the cones
Convergent: pooling which is most beneficial for low light situations found in the the rods can't tell the difference between stimulated systems
Inhibitory: different neurons with + and - effects if an inhibitory area is stimulated we can a subtracting effect |
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What is the receptive field? |
region of receptive surface on the retina, that influences the rate of neuronal firing when stimulated |
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In theory, which is more important movement or colour? |
Movement is more important because it's universal, not all species can see colour. |
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What are the benefits of eye movement? |
Survival: can spot food and avoid predators
Perception of shapes: we can see thing as they move, but if they stop and they are the same colour we won't see it
Distance and Depth Perception |
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What are the 2 main questions that we ask in vision? |
Image- Retina (IR) System: IS something moving out in the world? *is the image moving on the retina? * if you are tracking something on your fovea, then you won't see the movement * are my eyes moving in my head? * the brain monitors the position of your eyes in your head |
IR and EH |
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What are the 2 competing theories that describe the flow from the optic nerve to the brain? |
Inflow and Outflow Theory |
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How do we see movement? |
Using the Image-Retina system and eye-head movement |
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What are the 2 combinations that allow us to see movement? |
movement on the image-retinal system and not on the eye head system
movement on the eye head system and not on the image-retinal system |
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What are the 2 combinations that allow us to see no movement? |
no movement on the image retinal system or in the eye head movement
movement on the image retinal system and on the eye head system |
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Explain Inflow Theory. |
Inflow theory tells us that in the EH system the motor cortex tells the eye to move which causes the eye muscles to stretch and then send a message to the brain comparator and the image retinal system also sends a message
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Explain Outflow Theory. |
Outflow theory tells us that in the EH system the motor cortex sends a message to the eye muscles and a copy to the brain comparator. The IR system also sends a message to the brain comparator. |
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List some reasons why inflow theory is still accepted. |
We have the mechanism (stretch receptors) which signify some importance.
Other muscles in the body use feedback loops but the eye doesn't have constant load so it doesn't need the feedback. |
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According to the analogy of looking at the eye as the perfect child, which theory describes the role of a parent that checks in? |
Inflow theory because of the feedback loop. |
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Why are messages transmitted faster in outflow theory? |
Both messages are transferred from the motor cortex at the same time; one message goes to the brain comparator and one to the eye muscles. |
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Why is the outflow theory supported when an athlete's eye muscle is detached and the visual field completely moves right? Why does this refute the inflow theory? |
This supports the outflow theory because a copy of the message is sent directly to the brain comparator despite the detached eye muscle. This refutes the inflow theory because a message from the eye muscle should be sent to the brain comparator. |
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Describe an experiment that supports Outflow theory and refutes Inflow theory. |
closing one eye and tapping the open eye causes the prof to appear to move. this leads to eye movement on the RH and not on the EH, this supports the outflow theory because the MC send a message to the brain compartor
this refutes inflow theory because the way in which the eye muscles is stretched doesn't matter - the eye head messages are not sent to the brain comparator |
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What is the range of colour that humans can see? |
380nm (violet) - 760 nm (red) |
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Describe Induced Movement. |
when a small object is within a larger object like a frame; we think the smaller object is moving. |
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Describe Apparent Movement (Phi Phenomenon). |
2 balls flickering on and off creates the motion of moving from left to right |
Phi Phenomenon |
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Describe movement aftereffect. |
too much stimulation in one direction causes you to see motion in the opposite direction |
Water fall illusion |
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Describe the physical and psychological affects of light. |
Wavelength impacts hue (colour) Intensity impacts Brightness Purity affects Saturation |
Similar to auditory system; frequency
WIP HBS |
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What are the 2 main theories in colour? |
Young-Helmholtz's Trichromatic Theory
Hering's Opponent-Process Theory |
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What is trichromatic theory? |
There are 3 cones receptors, Red (760 nm), green (middle) and blue (380 nm) that capture light rays and bounce rays back accordingly. |
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Mixing lights together is called... |
pigment addition |
white light |
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Mixing pains together is called... |
pigment subtraction |
dark paint |
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What is Hering's Opponent-Process Theory? |
Certain receptors fire more frequently when exposed to red light but decrease when exposed to green light.
These cells also have combinations for after images Red and Green; and Yellow and Blue |
+B/-Y or +R/-G or -B/+Y or -R/+G |
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How does the Hering's Opponent-Processs theory refute the Trichromatic Theory? |
Yellow is not a colour, yet it appears as an after image. |
looking at the dot for a while and one side looks green and then it looks red |
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What is the compromise theory for the Hering's Opponent-Processs theory and the Trichromatic Theory? |
Both systems work together but it depends on which level of the visual system. |
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What is the test for colour blindness (the recessive trait that lies on the X chromosome). |
random red dots with green dots are present; if the person can't see the green dots then they are colour blind |
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What is relative direction task? |
Localizing objects with respect to each other. |
we're really good at this |
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What hints do we have to indicate our hyperacuity (how well we would see relative direction)? |
the spacing between the rods and cones |
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What is absolute direction task? |
where is the object with respect to us
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we're not good at it think peripheral vision |
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Describe Hearing's experiment. |
Hearing's looked off into the distance through a window and closed one eye put a dot at the object he saw. He repeated with the other eye without moving his head. Everything shifted when he opened both eyes. |
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What were some other experiments we used to test the cyclopean eye? |
Magic Lines
Silly Sausage
Dancing Digit |
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Describe the magic lines experiment. |
Magic Lines: looked at the red and green lines on a cardboard, when we look with both eyes the lines appear to have shifted behind our ears |
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Describe the dancing digit. |
when you put one finger in front of you and alternate which eye you open, the finger appears to move. |
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Describe the silly sausage. |
holding out 2 fingers in front of each other in the distance causes you to see an additional filler/sausage in between |
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What are Oculomotor Cues? |
the information that our eye gets causes it to converge or diverge |
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What are pictorial cues? |
alterations in a picture that allow us to see depth |
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What is stereokinetic? |
when the brain translates motion signals into a depth signal |
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Give examples of pictorial cues |
linear perspective: when the lines converge in the distance
interposition: where things are placed in a picture
shading and lighting: to create craters
texture gradients |
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Describe motion parallax |
when travelling on a train for instance and fixating on one object in the middle, the objects in the distance, behind the fixated point will appear to travel in the same direction at a faster rate, while the objects in front of the fixated object appear to travel slowly in the opposite direction |
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What is binocular disparity? |
the difference between the 2 eyes |
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What is a horopter? |
the imaginary circle that cuts through a fixed point - they are seen as the same distance |
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Describe crossed and uncrossed disparity in terms of horopter. |
when something is close you cross your eyes which narrows the focus of the horopter to one spot, when you look into the distance the eyes uncross so you see 2 different points on the horopter |
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What is occlusion? |
A way to analyze depth by obstructing parts of an object. |
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What is the difference between distal and proximal stimulus? |
Distal stimulus is anything in the world and proximal stimulus is an image on the retina. |
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What is Ponzo illusion? |
The bar placed in the distance appears to be larger than the closer one. |
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What is Size Distance Invariance Hypothesis and how does it explain the moon illusion? |
For a fixed sized object, if it is closer to us appears smaller and when it's farther away it seems larger. people think the moon is closer when they look at the sky so it appears smaller, when it's on the horizon it looks farther so it appears larger |
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What's Gibson's approach? |
Direct approach; we have enough information on the retina, we use higher order variables |
Direct |
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What is Helmholtz's approach? |
We use past information because we experience equivalent configurations on the retina yet we're able to decipher them. |
Indirect |
