Principles of Neuroscience Lecture 7, Vision, Further pathways Flashcards

0
Q

What are the two types of ganglion cells and describe their features

A

Mango cellular type : large, involved in motion detection, Parasol shape

Parvo cellular : small, involved with colour and visual acuity

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1
Q

Describe the path of information from the retina

A

Retina - photoreceptor cells - optic nerve - Lateral Geniculate nucleus in Thalamus - Primary Visual cortex

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2
Q

Describe the structural arrangement in the Lateral Geniculate Nucleus

A

LGN is located in the thalamus

There are six layers in the LGN that have input from either of the different types of ganglion cell.

Layers 1 & 2 : Magnocellular
Layers 3,4,5 & 6 : Parvocellular

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3
Q

Describe the functional divisions in the occipital lobe

A

V1 : primary visual cortex. Receives information from the thalamus (LGN) by the calcarine fissures
V2,3 : areas to which information travels next.

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4
Q

What is V1?

A

Primary Visual Cortex

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5
Q

Describe the functional layers in V1.

Into which layer does the LGN input information?

A
There are 6 layers of neurons. 
1
2 & 3
4A
4B
4C
5
6

The LGN inputs information into 4C (within 4C are more divisions)

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6
Q

What is important about the organisation of information in V1?

A

Retinotopic organisation : the same mapping from the retina is maintained in V1

Contralateral representation of visual fields

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7
Q

At what point does information from each eye get combined?

A

M - type information : at 4B

P - type information : at 3

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8
Q

What are the pathways that information takes after the Primary Visual Cortex?

A

Dorsal : where is the thing I’m seeing –> motion. Naturally, this comes from M-cells.
Information goes from V1 - V2 - V3 - MT(middle temporal lobe)

Ventral: What is the thing I’m seeing? –> colour and shape.
This is derived from P-type information.
Information feeds from V1 - V2 - V3 - V4 - IT (inferior temporal lobe)

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9
Q

Into which layer does LGN input information in the V1?

Specifically, into which layers is P type and M type information fed?

A

4C.
P - type : 4C beta
M - type : 4C alpha

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10
Q

Which cell is also called midget?

A

Parvocellular ganglion cell

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11
Q

Describe orientational selectivity.

Which neurons exhibit this?

A

Neurons respond most strongly to bars moving at certain rotations

Only the neurons in the visual cortex

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12
Q

Which type of cell is described as parasol

A

Magnocllular ganglion cell

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13
Q

What does orientation all selectivity mean for vision?

A

This means we can see edges of objects clearly

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14
Q

Input from LGN into the V1 is isolated to …

A

Ocular dominance columns

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15
Q

Within a column of the V1, the 6 layers respond to light in … Orientations

A

The same

16
Q

Which region is important for colour, shape, facial recognition, visual memory, visual perception

A

IT

17
Q

Differentiate between the functions of the IT and the MT

A

IT: inferior temporal lobe; colour, shape, visual memory, faces

MT: medial temporal lobe: motion

18
Q

Which region is damaged when people are unable to detect motion?

A

MT

19
Q

Describe the grey hound slide

A

Different columns of neurons detect light at different rotations.

This is then integrated to give a compete image

20
Q

What is the function of the IT?

A

The neurons here respond to shape and colour

Visual memory and perception (especially faces)

21
Q

Which region is damaged when people are unable to recognise faces?

A

IT