Chapter Six Flashcards

1
Q

Transduction

A

physical stimulation –> brain activity

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2
Q

In humans, which sensation has more brain devoted to it?

A

Vision

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3
Q

In rodents, which sensation has more brain devoted to it?

A

olfaction

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4
Q

what exactly is light?

A

a wave of which we see a narrow range

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5
Q

Sclera

A

the white membrane on outside of eye; not transparent-no light can pass through

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6
Q

Cornea

A

transparant film on the front of the eye; one of the fastest repairing tissues

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7
Q

Iris

A

muscle that regulates amount of light that comes into the eye; changes size of pupil

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8
Q

Pupil

A

hole in the front of the eye

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9
Q

Lens

A

directly behind the pupil; focuses light waves as they come into the eye

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10
Q

Accommodation

A

the lens literally changes shape

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11
Q

Vitreous Humor

A

gel-like; allowed eye to keep spherical shape

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12
Q

Retina

A

nervous tissue; where light (which comes in right to left) gets focused

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13
Q

Retina is made up of three cell types

A

photoreceptors, bipolar cells, ganglion cells

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14
Q

Photoreceptors

A

very back of the retina; rods & cones

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15
Q

Bipolar cells

A

middle

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16
Q

Ganglion cells

A

front of the retina; axons make up the optic nerve

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17
Q

Rods

A

(120 mil) outside edge of retina; seeing with low light levels

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18
Q

Cones

A

(6 mil) middle of retina; color vision, visual acuity-seeing in detail

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19
Q

Pigment in the photoreceptors

A

Opsin (protein) and retinal (lipid)

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20
Q

What are the colors of cones?

A

red, blue, and green

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21
Q

What does contact with light do to the photopigment?

A

splits the photopigment

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22
Q

What does the split in the photopigment cause?

A

change in release of glutamate (excitatory) , which causes chain reaction

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23
Q

What is the end result with the photoreceptors?

A

ganglion cells are stimulated and these cells make up the optic nerve

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24
Q

Once the retina is stimulated, where does the nerve impulse travel?

A
  1. ) dorsal lateral geniculate nucleus (thalamus) and 2.) optic radiations carry signal to the primary visual cortex (AKA striate nucleus)
25
Q

Optic radiatons

A

the pathway from 1-2 (dorsal lateral geniculate nucleus–> primary visual cortex

26
Q

Receptive Field

A

part of environment that stimulates neurons-group on retina; the part of the visual field that a neuron “sees”

27
Q

Fovea

A

has the greatest concentration of cones; absolute dead center of the retina

28
Q

How many ganglion cells does each cone have?

A

One

29
Q

In the periphery, how many rods does each ganglion cell connect to?

A

there may be 10 rods to each ganglion cell

Why visual acuity is better at the fovea

30
Q

Three varieties of ganglion cells

A

ON, OFF, ON/OFF

31
Q

What do receptive fields look like?

A

they have a center that is surrounded by a ring

32
Q

When you mix red, blue, and green light, what do you get?

A

White

33
Q

Trichromatic Theory

A

we see color because we have three different kinds of cones

34
Q

Where does perception come from?

A

the stimulation of cones (3 types)

35
Q

How many of each color of cones are there?

A

Red and green equal each other, there are fewer blue ones

36
Q

How are different colors seen?

A

because of different ratios and intensities; cones are stimulated in different ways

37
Q

Color blindness

A

deficiency in number of cones of chemical

38
Q

Protanopia

A

confusion of red/green; see world as yellows and blues

39
Q

Deuteranopia

A

green cones filled with red photopigment

40
Q

Tritanopia

A

rarest form; deficient in blue cones; see world as red and green

41
Q

Ganglion cells

A

also involved in color processing; they follow a center-surround orientation

42
Q

What explains negative afterimages?

A

ganglion cells; when stimulation is taken away, the other color in the pair rebounds

43
Q

Primary Visual Cortex (striate cortex)

A

found next to calcarine fissure, occipital lobe.

44
Q

What do cells in the primary visual cortex respond to?

A

specific bits of information

1/4 is devoted to fovea

45
Q

Orientation of lines

A

different lines turn on different cells in the PVC

46
Q

Retinal Disparity

A

because two eyes are separated; each eye sees a slightly different image; cells in PVS respond vigorously when each eye receives a slightly different image

47
Q

CO blobs

A

further interpretation of color

48
Q

Organization of PVC

A

organized in modules (columns)- 25,000 modules each with 150,000 neurons; 1/2 mm x 3/4 mm and analyze features from that part of the visual field

49
Q

What does the PVC provide?

A

color, input to orientation, texture, disparity

50
Q

Visual Association Cortex

A

this lies outside of the occipital lobe

51
Q

Ventral Stream

A

WHAT-temporal lobe

52
Q

Dorsal Stream

A

WHERE-parietal lobe

53
Q

Form Perception

A

temportal lobe-ventral stream based; region combines info bout color, form, and dimension; neurons respond to 3D objects

54
Q

Agnosia

A

disruption of form perception; cannot recognize visually-body makes appropriate gestures for object; can use other non-visual senses to recognize

55
Q

Apperceptive Agnosia

A

cannot draw or copy

56
Q

Associative Agnosia

A

can copy, but now draw from memory

57
Q

Prosapagnosia

A

the recognition deficit is very specific to a certain object; can see individual features but cannot recognize; can use other sensory modalities to recognize (walk, etc.)

58
Q

What does evidence show the right temporal cortex is most important for?

A

face recognition; faces may be special, as cases of object agnosia, but face recognition was left intact