Topic 3- The visual cortex and beyond Flashcards
How are both eyes able to see both visual fields?
What’s an example of contralateral processing?
Right visual field: Information from the right side of what you see goes to the left side of your brain.
Left visual field: Information from the left side of what you see goes to the right side of your brain.
This is why if you damage one side of your brain, you might lose vision in the opposite side of your field of view.
Both eyes can see both visual fields.
True or false
Give an example.
True
If you cover one eye and hold your finger up, and look directly at it you can still see the left and right side of your finger
Where does the signal travel after the LGN?
The signal travels to the occipital lobe, specifically the primary visual receiving area also called V1
What is the pathway to the brain?
- Vision leaves the back of the eyes through the optic nerves
- meets/ crosses at optic chiasm
- 90% goes to thalamus, more specifically the lateral geniculate nucleus “sensory relay station”
- Other 10% proceeds to superior colliculus which is in the midbrain nuclei (tectum) for eye movement and orienting movements
What are simple cortical cells?
A neuron in the visual cortex that best responds to bars of a particular orientation
What are complex cortical cells? Why are they important?
3 points
A neuron in the visual cortex that best responds to moving bars of a particular orientation
- This is crucial for being able to see movement. Imagine walking around in a world where nothing is ever moving.
What are end-stopped cells?
Neurons in visual cortex that respond to movement but only bars of certain lengths
List the 3 cortical cells called feature detectors?
- Simple cortical cells
- Complex cortical cells
- End-stopped cells
What happens if the brain has fully developed and you try to show a human or animal an orientation they’ve never seen before, ex- horizontal lines
Why does this happen?
They are blind to that orientation because the neurons that respond to that orientation were never developed
What is a retinotopic map?
It’s a map in the visual system that corresponds to locations on the retina
When you look at an object light….
Finish the sentence.
bounces off the object
The image in our retina starts off as BLANK, then BLANK back to right side up in the BLANK
flipped/inverted, flips, brain
What is the topographic organization of V1 (primary visual receiving area)
2 points
Fovea= posterior
Periphery = anterior
How are we able to perceive all orientation around us?
We have a part of our brain for every orientation
What are orientation columns?
Neurons in the visual cortex that are designed to detect lines and edges at a particular angle
What does V1 stand for?
2 points
- Primary visual receiving area
- Striate cortex
Where do the signals from the striate cortex (V1) travel to after?
V1:
V2:
V3:
V4:
V5:
Other cortical regions for further visual processing.
V1: preliminary visual processing; moves to V2
V2: initial processing of shape, color, and motion; moves to V3, V4, or V5
V3: shape (particularly when in motion)
V4: color
V5: motion
Once the signal leaves the occipital lobe which two visual streams or pathways does it go to?
4 points
Some info goes to the temporal lobes –> “What?”
- Identify objects, what am i looking at
Some info goes to the parietal lobes –> “Where/How?”
- Where am i looking, how do i reach it
What is it called to lose the “what” stream?
Temporal ablation
What is it called to lose the “where/how” stream?
Parietal ablation
What are the 3 complex stimuli that the temporal pathways respond to?
PPA: responds/fires in response to place, scenery, landmarks
EBA: responds/fires in response to shapes of the human body
FFA: responds/fires in response to face perception
