Lecture 29- Thalamus and Striate Cortex Flashcards

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1
Q

Which visual field does the right eye receive information from?

A

Each eye receives information from both visual fields

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2
Q

Which fibers decussate at the optic chiasm?

A

fibers of the nasal retina

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3
Q

What would be the result of damage to the right optic nerve? What about the right optic tract?

A

Right optic nerve damage->lose vision in right eye-maintain vision in both visual fields
Right optic tract damage-> lose vision in left visual field

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4
Q

What results from damage to the optic chiasm region?

A

bitemporal heminopsia- loss of peripheral vision

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5
Q

What is the role of the suprachiasmatic nucleus (SCN) of the thalamus in the visual system?

A

some retinal ganglion fibers synapse there at the optic chiasm to provide light/dark input for circadian rhythms

SCN- SLEEP CLOCK

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6
Q

Where are the 4 places that retinal ganglion cells can synapse?

A

Lateral Geniculate Nucleus (LGN-thalamus)
Superior Colliculus- head movements
Suprachiasmatic Nucleus (SCN-Hypo)- Circaidian
Nuclei of pretectum-pupillary reflex

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7
Q

How many layers are in the lateral geniculate nucleus (LGN)?

A

6 (2 magnocellular, 4 parvocellular)

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8
Q

What are the two layer sub-types in the LGN?

A
Magnocellular Layers (inner 2)
Parvocellular Layers (outer 4)
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9
Q

Which cells in the LGN are more sensitive to rapidly changing or moving visual stimuli?

A
M Cells (Magnocellular layers)
The have larger bodies and receptive fields
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10
Q

Which cells in the LGN are more sensitive to color and detail?

A
P Cells (Parvocellular layers)
They are slower and more concerned with color and spatial resolution
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11
Q

Which layers of the LGN contain information from the contralateral eye?

A

1,4,6

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12
Q

Which layers of the LGN contain information from the ipsilateral eye?

A

2,3,5

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13
Q

What is the primary visual cortex also known as?

A

striate cortex (V1)

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14
Q

What is the name of the fissure that runs through the striate cortex?

A

calcarine fissure

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15
Q

Where does input from the two eyes first come together for processing in the visual system?

A

striate cortex-it is kept separate in the layers of the LGN

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16
Q

What is the best stimulus shape for the receptive fields of the striate cortex?

A

light/dark bar

17
Q

What are the cells of the striate cortex that are sensitive to light/dark edges or bars?

A

simple cells

18
Q

What are the cells of the striate cortex that are sensitive to corners/crosses?

A

complex cells

19
Q

Black ink on white paper is the best stimulus for which type of retinal ganglion cell?

A

OFF-Center Ganglion Cell

20
Q

Where do the compex cells of the striate cortex receive input form?

A

simple cells

21
Q

What is a hyper column?

A

a set of 18 orientation columns and 2 ocular dominance columns

22
Q

How many orientation columns are need to account for all 180 degrees of orientation?

A

18- each accounting for 10 degrees

23
Q

What layer of the striate cortex do cells of the LGN project to?

A

Layer 4