Section 3 Flashcards
TRUE/FALSE
Mapping of the visual field is preserved in the primary visual cortex
TRUE
What type of vision has the most cortical space?
Central vision
What is cortical magnification?
The idea that about 50% of V1 is dedicated to 1% of our visual field - the central region of our visual field
What is a consequence of cortical magnification?
visual crowding
what is visual crowding?
Because not as much cortical space is dedicated to the periphery, the reduced visual acuity produces a clutter effect where it becomes more difficult to distinguish one object from another
Which neurons perceive line orientation?
Neurons in V1
How are V1 cells spatially organized?
They organize their center-surround inputs into lines to display an elongated receptive field of a specific orientiation
Where are simple cells located?
Layer 4B of area V1
What layer of V1 do simple cells receive input from?
4C
What determines the firing rate of a simple cell in area V1?
How aligned the light is with the orientation of its receptive field
What is selective adaptation?
When you are exposed to a certain line orientation for an extended period of time, cells whose receptive field align with it will first fire rapidly but with time will adapt and fire less
What is population coding?
the idea that there is a large population of neurons in V1 that will determine your subjective perception of line orientation
Why is it that if you selectively adapt to a 45 degree line orientation you start seeing the line in the opposite direction?
The selective adaptation of neurons will depend on how close their preferred line orientation is to 45 degrees. Overall, this will affect the firing rates across the distribution but more so to those neurons closer to 45 degrees. Neurons beyond 90 degrees are much less affected, so their firing rate remains almost the same while neurons below that are damped, hence we start seeing the line in the opposite orientation
Besides line orientation, what else do neurons in V1 respond to?
directional motion, binocularity, and color sensitivity
Complex cells respond to what?
Motion
Which layers of area V1 have complex cells?
2,3,5,6
TRUE/FALSE
Complex cells do not have a preferential motion orientation
FALSE
How does the receptive field of complex cells compare to that of simple cells?
Complex cells have much larger receptive fields
What are end-stopped cells?
respond to moving light bars of a specific length
What happens if the length of the light bar is longer than the receptive field of the end-stopped cell?
The cell will not fire
What is the main function of end-stopped cells?
Size perception
What does it mean for a V1 neuron to be perfectly binocular?
Will show twice the activity when both eyes are exposed to light compared to only one eye being exposed
Type 1 neurons in V1 are driven exclusively by _________
the contralateral eye
Type 7 neurons in V1 are driven exclusively by _______
the ipsilateral eye