Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

year 1 - biological bases of behaviour > How do we see? > Flashcards

How do we see? Flashcards

1
Q

What is vision?

A

How we transduce light energy - assists with locating objects in collaboration with other senses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens to light as it enters the cornea to the retina?

A

It is refracted by the cornea and travels through the pupil and then refracted again by the lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is accommodation?

A

Eye muscles adjust lens curvature for focusing on objects at different distances.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is significant about the curvature of the cornea?

A

Its fixed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What causes vision problems?

A

When the focal point of light refraction is in front or behind the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What causes astigmatism?

A

cornea or lens is rugby-ball shaped, not rounded. This prevents part of it from focusing light onto the retina. The result is a blurred area within an otherwise clear image.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the emmetropic eye?

A

normal vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is hyperopia and what are the cause and correction?

A

long-sighted vision (the hypermetropic eye) - the lens is too weak/eyeball is too short/cornea is too flat.
Can be corrected by a converging lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is myopia and what are the cause and correction?

A

short-sighted vision (the myopic eye) - lens is too strong/eyeball too long/cornea too curved
Can be corrected by a diverging lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is presbyopia and what are the cause and treatment?

A

The ability to see things up-close getting worse with age (presbyopic eye) - lens no longer flexible enough for accommodation
Corrected by reading glasses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the retina composed of?

A

Photoreceptors with a layer of neurons connected on top. These neurons are transparent so light can pass through, which is translated to action potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the fovea?

A

The centre of the retina & vision field - 0.3mm dimple in retina with denser receptors at centre. Sharpest vision, densest colour receptors (better than periphery) and makes reading possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the blind spot?

A

An area of the retina with no photoreceptors where blood vessels enter and exit the eye. Fibres leading from retinal neuron form optic nerve going to the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do photoreceptors do?

A

Convert light to chemical energy and then neural activity - light triggers chemical reactions - change membrane potential (electric charge)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 2 types of receptors?

A

Rods - longer, cylindrical shape at one end ~ 120million
Cones - tapered at end 6-7million

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the 6 ways photoreceptors are connected to ganglion cells?

A
  1. Horizontal cells
  2. Glial gells
  3. Amacrine cells
  4. Bipolar cells
  5. Rods
  6. Cones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is colour vision enabled by?

A

Three cone types (red, green, blue).
Different combinations interpret a wide range of colors.
Roughly equal red and green
Less blue - not as sensitive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is what colour we see determined by?

A

The absorption range of photoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do we see a range of hues across visual field?

A

Cones are distributed across field of vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which chromosome are cones coded on and what implications does this have?

A

x-chromosome meaning that men are more likely to be colour-blind and women can have more distinctive colour vision than men because of an extra red pigment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 4 types of neurons in retina?

A
  1. bipolar
  2. horizontal
  3. amacrine
  4. ganglion cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How are retinal neurons arranged?

A

2 layers going from rods and cones to retinal surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the 2 categories of retinal ganglion cells in primates?

A

Magnocellular (M-cells) and parvocellular (P-cells) cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are M-cells sensitive to and where do they get their information from?

A

Sensitive to light, movement and low contrast NOT colour or fine detail and get info mostly from rods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where are M-cells present?

A

throughout retina, including periphery.
Axons (mostly) project to magnocellular layer of lateral geniculate nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are P-cells sensitive to and where do they mostly get their info from?

A

Sensitive to colour and fine detail (weak response to changes in contrast), info mostly from cones

27
Q

Where are P-cells present?

A

Mostly in fovea
Axons project to parvocellular layer of lateral geniculate nucleus

28
Q

What are receptive fields?

A

The region of space in which stimuli will alter a sensory neuron’s firing rate

29
Q

What characterizes neurons at different levels of processing in the visual system?

A

Neurons at different levels of processing in the visual system exhibit varying receptive fields, influencing their response to stimuli.

30
Q

How many types of receptive fields do bipolar cells in the visual system have, and how do they respond to light?

A

Bipolar cells in the visual system have two types of receptive fields, each responding differently to light.

31
Q

What are concentric receptive fields, and where do they play a role in the visual system?

A

Concentric receptive fields are a type of receptive field where stimuli alter a sensory neuron’s firing rate within a circular area.

32
Q

In on-centre receptive fields, how does the cell respond to light hitting the center, and what neurotransmitter is involved?

A

a light hitting the centre of its receptive field (receives less glutamate) excites the cell

33
Q

For off-centre receptive fields, what triggers the cell’s response, and which neurotransmitter is involved?

A

turning off light in the centre of its receptive field (receives more glutamate) excites the cell

34
Q

When there is bright light on centre, what happens in cells on-centre/off-surround field AND off-centre/surround field?

A

Excites cells on-centre/off-surround field and inhibits cells off-centre/surround field

35
Q

When there is bright light onto surrounding, what happens in cells on-centre/off-surround field AND off-centre/surround field?

A

Inhibits cells on-centre/off-surround field and excites cells off-centre/surround field

36
Q

When there is no illumination/diffuse illumination, what happens in cells on-centre/off-surround field AND off-centre/surround field?

A

Weak response from both (basal rate)

37
Q

How is shape coded in the retina?

A

Cells in the retina cant detect shape - their receptive fields are tiny dots that respond to presence/absence of light (info about luminance contrast) related to the arrangement of the cells’ receptive field - helps to detect edges

38
Q

What do the retinal cell ganglia form?

A

The optic nerve

39
Q

Where do the pathways from each eye intersect?

A

The optic chiasm

40
Q

What happens to the medial path of each retina (nasal) at the optic chiasm?

A

It crosses to the opposite side.

41
Q

What happens on the lateral (temporal) visual pathway?

A

Stays in the ipsilateral side

42
Q

What is the consequence of the crossing paths at the optic chiasm?

A

Information from each visual field is represented on the opposite side of the brain.

43
Q

What is the Geniculostriate system in the visual pathway?

A

It is a pathway where all P ganglion cells and some M ganglion cells separate from retinal cell ganglia axons. It extends from the retina to the lateral geniculate nucleus of the thalamus and then to layer 4 of the primary visual cortex (striate cortex) in the occipital lobe.

44
Q

What information does the Geniculostriate system convey to the visual cortex?

A

It carries information about color, form, and motion to the visual cortex.

45
Q

What characterizes the Tectopulvinar system in the visual pathway?

A

It is another pathway formed by the remaining M ganglion cells. Axons from this system travel to the superior colliculus (tectum) in the midbrain, and from there, connections are sent to the pulvinar region of the thalamus.

46
Q

Where does the Tectopulvinar system send information after reaching the pulvinar region of the thalamus?

A

The pulvinar sends information to the parietal and temporal lobes.

47
Q

What is the primary visual area (v1, striate)?

A

First stage of cortical processing of visual information.
Located in and around the calcarine fissure in the occipital lobe.
Retinotopic: Contains a complete map of the visual field covered by the eyes
V1 neurons are selective for basic visual properties: position, orientation, spatial and temporal frequency

48
Q

What characterises the extrastriate area V2?

A

Cells are tuned to similar properties as V1; spatial map.

49
Q

What characterises the extrastriate area V3?

A

receives input from V1 and V2; dorsal part projects to parietal cortex;
ventral part to inferior temporal cortex.

50
Q

What characterises the extrastriate area V4?

A

receives input from V1 and V2; strong projects to inferior temporal
cortex. Colour vision and simple shapes.

51
Q

What characterises the extrastriate area V5?

A

(mid-temporal visual area, MT): receives input from V1, V2 and V3.
Major role in the perception of motion.

52
Q

What is the ventral pathway?

A

Visual stream known as the what pathway - for form and colour.
Retinal P-cells → Parvocellular LGN → V1 → V2 → V4→ Inferior Temporal Cortex

53
Q

What is the dorsal pathway?

A

Visual stream known as the where pathway - for space and motion.
Retinal M-cells → Magnocellular LGN → V1 → V2 → V3 → V5/MT →
Posterior Parietal Cortex

54
Q

What is the significance of brain regions along the ventral and dorsal streams in visual processing?

A

These regions have specialized visual functions.

55
Q

In the temporal lobe, what specific pathway is associated with processing information about ‘what’?

A

The ventral pathway.

56
Q

What is the role of the Fusiform Face Area (FFA) in visual processing?

A

It is specialized for processing faces

57
Q

What is the specialized function of the Parahippocampal Place Area (PPA) in visual processing?

A

It is specialized for processing places.

58
Q

In the parietal lobe, what specific pathway is associated with processing information about ‘where’?

A

The dorsal pathway.

59
Q

What role do areas in the Intraparietal Sulcus play in visual processing?

A

They are involved in controlling eye movements and visual control of grasping.

60
Q

What is Optic Ataxia, and what brain region is implicated in this condition?

A

Optic Ataxia is a high-order deficit in visual reaching related to lesions in the posterior parietal cortex (PPC).

61
Q

What is Motion Blindness, and which brain area is affected in patient ‘LM’?

A

Motion Blindness results from damage to MT (middle temporal area), and patient ‘LM’ experienced this condition.

62
Q

What is retinotopic mapping in visual processing?

A

It is the organization of neurons in lower visual areas according to the 2D representation of the image formed on the retina.

63
Q

What does retinotopy involve?

A

remapping of retinal image onto cortical surface
Each point of the visual field maps onto a local group on neurons in V1
Neighbouring regions of the image are represented by neighbouring regions
of cortex
Representation is distorted; fovea represented by larger area (greater
magnification factor)

year 1 - biological bases of behaviour (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions