Visual System Part 2 Flashcards
Retinal ganglion cells axons leave the retina through ___________ and project to the _____________.
Optic nerve
Lateral geniculate nucleus (LGN)
Axons from retinal ganglion cells in the _______________ remain on the same side of the brain and synapse on cells in the ____________(same side) LGN.
Temporal half
Ipsilateral
While cells in the ________ half of the retina cross the midline and synapse on cells in the __________ (other side) LGN.
Nasal
Contralateral
What axons are involved when you see an image on the left visual field?
Hint: What side of the eyeball is involved?
* same for the right visual field
Temporal side of the right eye
Nasal side on the left eye
Information from the (left/right half) of the visual field from both eyes goes to the (left/right side) of the brain
While information from the (left/right) half of the visual field from both eyes goes to (left/right) half of the brain.
Information from the left half of the visual field from both eyes goes to the right side of the brain
While information from the right half of the visual field from both eyes goes to the left half of the brain.
How is the information kept in the LGN?
In layers
Different species have different exact numbers and arrangements of LGN layers. How many LGN layers does a human have?
___ receiving information from each eye.
6 layers
3
True or False: The cells in the LGN have different receptive fields to those of the retinal ganglion cells (RBCs).
They both have center-surround receptive fields.
False
Receptive fields are very similar to the retinal ganglion cells
The second half is true.
Looking at the figure
Which one of these receptive fields will stimulate the strongest action in the On-center ganglion cells?
The first one because the light shines in the middle of the ganglion cell,
which is similar to the Lateral Geniculate Nucleus receptive field
Choose the best option
LGN cells receive (little/various) inputs from RGC
LGN’s receptive field is a bit (more/less) sophisticated
Various
More
What are the various receptive fields that the LGN received?
Hint: There are three receptive fields.
Respond to different wavelengths of light
Broadband center-surround cells
Respond to specific wavelengths of light
Red/green color opponent center-surround cells
Blue color opponent cells
_______________________ (Hint: one of the LGN receptive fields)
receive inputs from both red and green cones but are “color blind” and respond only to light-dark differences.
Broad-band center-surround cells
Which LGN receptive field responds over a broad range of wavelengths?
Broad-band center-surround cells
Answer these fellow examples of broad-band center-surround cells’ receptive fields. Here let’s focus on the on-center field.
If there is a central spot in the on-center field–> ______________.
If there is a peripheral spot in the off area –> _________________.
If there is a central illumination in the on-center field –> _______________.
If there is surround illumination in the off area –> ________________.
If there is a diffuse illumination –>___________________.
Look at image for answer
Answer these fellow examples of broad-band center-surround cells’ receptive fields. Here let’s focus on the off-center field.
If there is a central spot in the off-center field–> ______________.
If there is a peripheral spot in the on area –> _________________.
If there is a central illumination in the off-center field –> _______________.
If there is surround illumination in the on area –> ________________.
If there is a diffuse illumination –>___________________.
What are the three parallel pathways (the different types of ganglion cells and pathway to LGN) of the primate retinal ganglion cells?
Parvocellular
Magnocellular
Koniocellular
True or False: These parallel pathways cross pathways and receive information from both eyes
False
Parallel pathways never cross pathways and receive information from left and right eye
Choose the best option
Parvocellular parallel pathways
(Small/large) cells
(Small/Large) receptive fields
(Is/Not) Color sensitive
(sustained/transient) response ; (slowly/rapidly) adaptation
Signal (Form and Details/Motion)
Small cells
Small receptive fields
Is Color Sensitive
Sustained response; slowly adaptation
the signal form and detail
Choose the best option
Magnocellular parallel pathways
(Small/large) cells
(Small/Large) receptive fields
(Is/Not) Color sensitive
(sustained/transient) response ; (slowly/rapidly) adaptation
Signal (Form and Details/Motion)
Large cells
Large receptive fields
NOT Color Sensitive
Transient response; rapidly adaptation
the signal Motion
Choose the best option
Koniocellular parallel pathways
(Small/large) cells
(Is/Not) Color sensitive
Small cells
Don’t know if it color -sensnitive
True or False: Different RGC types maintain sperate pathways through the lateral geniculate and visual cortex, while also respecting eye-specific pathways.
True
In addition to having eye-specific LGN layers, primates also have _______ layers in LGN which receive input from different types of retinal ganglion cells.
Specific
What are the specific layers in the LGN?
(Hint: Similar to RGC)
Parvocellular
Magnocellular
Kohiocellular
What are the three different terms to describe the Koniocellar, parvocellular, and magnocellular RGC?
Koniocellar –> bisttratified
parvocellular –> midget
magnocellular –> parasol
Different RGC project to different LGN layers such that
midget ganglion cells project to _________________.
parsol ganglion cells project to ________________.
bistraitifed ganglion cell project to ___________________.
parvocellular layers
magnocellular layers
; konicoeullar layers
The arrangement of RGC to different LGN layers has been well characterized and linked to visual ___________ that remain anatomically separate LGN and into the primary visual cortex.
(don’t cross each other)
parallel pathways
Choose the best option
Magnocellular cells in LGN have
(Small/Large) receptive fields
(Yes/No) Color Blind cells
Involved in processing _________.
Large
Yes
visual motion
Choose the best option
Parvocellular cells in LGN have
(Small/Large) Receptive fields
(Yes/No) Color-opponent
in processing _________.
Small
Yes
Form visions
True or False: LGN cells axons project to the Contralateral (different side) primary visuals cortex (V1)
False
LGN cells axons project to the ipsilateral (same side) primary visuals cortex (V1)
Where is the first place where the visual information from the two eyes comes together?
Primary visual cortex
What is the inter-ocular transfer?
Only occur at a cell receiving information from both eyes (binocular) this is seen in the primary visual cortex.
The flag color affects illusion (does/does not) show inter-ocular transfer.
Does not
The flag color effect illusion can be due to either ___________ that adapted or the __________ that adapted but can not be due to ___________ that adapted to this illusion.
(inter-ocular transfer)
Retinal cells
LGN cells
Cortisol cells (in the primary visual cortex)
What is motion aftereffect illusion?
After viewing a ________visual stimulus for a time with stationary eyes and then fixating a stationary stimulus.
The stationary stimulus appears to move in the ________ direction to the original stimulus
The cells which adapt to cause motion aftereffects illusion is at ____________.
After viewing a moving visual stimulus for a time with stationary eyes and then fixating a stationary stimulus.
The Stationary stimulus appears to move in the opposite direction to the original stimulus.
The cells which adapt to cause motion aftereffect illusion is at cortical neurons.
Motion aftereffect illusion (does/does not) show inter-ocular transfer
Does
Cells in the primary visual cortex (do/do not) have center-surround receptive fields.
Do not
What does the primary visual cortex have instead of center-surround receptive fields?
They have elongated fields –> respond best not to spots of light but rather to moving bars or edges oriented at a particular angle in the visual fields.
What are simple cells?
Simple cells, whose receptive fields are elongated are not center-surround but still have distinction and off areas in their receptive fields.
Simple cells respond best when a ________ at a vertical angle moves through the on a portion of its receptive field.
Light Bar
It is thought that simple cell receptive fields are constructed from ____________ by each cortical cells receiving inputs from several LGN cells whose receptive fields are aligned in space.
LGN inputs
Where are complex found?
Found in primary visual cortex
Complex cells also have ____________ but unlike simple cells they ________________.
Orientation-specific repetitive fields
do not have separate on and off areas.
Complex cells respond to either ______________ anywhere in their receptive fields
Light or dark edges
Complex cells are often sensitive to __________________.
Direction of motion of a moving bar
Complex cells receptive fields are thought to be constricted by each complex cell receiving inputs from _____________ with __________ but with overlapping on and off regions
Several simple cells
Same orientation
True or False:
Cells in the primary visual cortex are highly organized into maps, columns, and layers like cells in the somatosensory cortex.
True
There is a _______________ of visual space across the cortex.
Topographic map
There are ________ of the cortex, each with different inputs and outputs.
6 layers
There are ___________ –> cell which response best to ispliateral side and contertateral side.
Ocular dominance columns
There are _____________. Cells that respond to the same angle of stimulus are found in the same columns and orientation is mapped fairly smoothly across the surface of the cortex.
Orientation columns
What are blobs?
Special columns in the primary visual cortex
which are cytochrome oxidase-positive contain color-sensitive cells which are poorly tuned for orientation
What do functional imaging studies reveal?
Reveal that, rather than simple rows or slabs of differing orientation preference, cells in our brain are arranged in pinwheels.
What is hypercolumn?
Containing both the ocular dominance and orientation-selective columns and color selective blobs (poorly tuned for orientation)
What is functional imaging?
Overlay of ocular dominance columns and pinwheels.
Most orientation domains are split into ipsilateral and contralateral halves and thus serve the two eyes for that region of visual space.
