Chapter 6 Flashcards
1
Q
What is the function of the cornea?
A
- Clear outer coating in front of eye
- Starts to focus the image (initial focusing - majority of focusing occurs in lens)
- Protective function as well
2
Q
What is the function of the pupil?
A
- Controls amount of light that enters the eye
(dilates in dim light, constricts in bright conditions) - Pupil reflexes are unconscious reflexes, controlled by signals in brainstem
3
Q
What is the function of the iris?
A
- Contain muscles that help allow the pupil to dilate and constrict
- Coloured part of the eye
4
Q
What is the function of the lens?
A
- Focuses a sharp image onto the back of the eye
- Muscles connected to the lens allow it to bend (change shape for objects closer and further away)
- gets more rigid as ppl age
5
Q
What is the function of the retina?
A
- Where the image is focused on the back of the eye
- Retina is like a curved projection screen
- Thin layer of cells - major type are rods and cones along retina
6
Q
What is the role of rods and cones?
A
Receptors that respond to light and convert it to neural signal - transduction of neural signal is carried out by the receptors
7
Q
What is the blind spot?
A
A gap at the back of the eye where the visual signals leave the eye and travel towards the back of the brain so we can perceive what we are seeing
- part of the retina where axons of the ganglion cells are leaving the eye along the optic nerve (no rods or cones present)
8
Q
What is the fovea?
A
- Part of the retina where the image is projected
- Directly behind the center of your field of view
- Central part of visual field
- Image projected on the fovea is an inverted image - (it is only later in visual pathway that these images are turned right-side up again)
9
Q
What are the 2 problems of focus of the lens?
A
myopia - near-sightedness
hyperopia - far-sightedness
10
Q
What is transduction and where does it occur in the eye?
A
Transduction = conversion of light energy into a neural signal
occurs in rods and cones of retina
11
Q
Rods and cones pass on the transduced neural signal to what cells?
A
to bipolar cells, which pass to ganglion cells
12
Q
Where do neural signals go after the ganglion cells?
A
the neural signals are transmitted to the optic nerve and towards the back of the brain
13
Q
Do we have more rods or cones?
A
many more rods present than there are cones
14
Q
What cells are found in the fovea?
A
only cones (rods are located in the periphery with cones as well)
15
Q
What are the roles of rods and cones?
A
rods: sensitive to motion, allow us to detect motion in visual field (particularly in periphery)
- NOT present in fovea
cones: provide high visual activity, making images very sharp, allow for process of colour
- on found in fovea
16
Q
Where do part of the signals from each eye cross over?
A
at the optic chiasm
17
Q
Where do signals go after passing the optic chiasm?
A
travel to the thalamus, then to visual cortex located in occipital lobe
18
Q
What is the wavelength of visible light?
A
400-700nm
19
Q
What can see UV rays?
What can see infrared radiation?
A
insects - UV rays
snakes - infrared radiation
20
Q
Does physical energy in the environment have perceptual qualities?
A
No
- light waves are not coloured, but wavelength determines the perception of colour
- our nervous system constructs these colours
21
Q
What is colour reflectance?
A
Colour we perceive depends on the quality of the surface or object that the light is being reflected off of.
The colour we see is being reflected, all other wavelengths of light are being absorbed.
22
Q
What is likely the most impressive animal when it comes to changing the colour of its skin?
A
Cuttle-fish
23
Q
Explain how colour is an effective way to communicate information fast and effectively.
A
ex. stop signs - use of colour red
animals also use colours to warn of danger such as poisons and toxins
24
Q
What is trichromatic vision?
A
- Refers to us having 3 different types of cones in our retina; each type of cone responds to a different range of wavelength
Long wavelength cones - respond to wavelengths in upper range (orange, red)
Medium wavelength cones - respond optimally to wavelengths in middle of visual spectrum (greenish)
Short wavelength cones - respond optimally to wavelengths in the low end of visual spectrum (blue)
25
What is dichromatism?
2 types of cones, instead of 3
Often: red-green colour deficiency; person lacks the long-wavelength cones, (contains only medium and short wavelength cones)
- wouldn't see red or orange, and perception of green is not the same (more dull)
26
What is seen with colour afterimages?
colour of afterimages (showing white squares after coloured squares) --> colours are the opposite colours of those that were shown
27
What is opponent process?
How does it explain colour afterimages?
- Involves processing of the colour signals further down in the visual pathway, within the visual cortex.
- There are opposing channels (red vs. green, blue vs. yellow, achromatic - black vs. white)
○ Opposing colour channels are processed by special neurons located in the visual cortex
With colour afterimages, when you stare at that image, you are exhausting one end of that channel.
○ When original image is removed and there is just a white screen, then the opposite side of the channel is able to be freely expressed, because the other side of the channel being red is exhausted
28
How we see colour involves what 2 systems?
Are both needed for fully-functioning colour vision?
- trichromatic system
- opponent process
both are needed for fully-functioning colour vision
29
How do opponent process neurons work?
by processing the ration of cones responding within the retina
depending on the pattern of the responses, it can reveal the exact wavelength of light that produced it
30
What system allows us to make fine discriminations between colours that are close together within a wavelength spectrum?
Opponent process system
31
Does complex visual perception occur in the occipital lobe?
requires processing that extends beyond the occipital lobe - requires regions of the brain that are involved in higher-level functioning
32
What are the 2 approaches to seeing complex visual images?
Bottom-up approach
Top-down approach (Gestalt)
33
What is the Gestalt theory of visual perception?
perceive whole image first, then look at individual parts
illusory contours
34
What is the guiding principle of the Gestalt theory?
Guiding principle is SIMPLICITY
when looking at an image, the person will make the simplest interpretation
35
What is the Gestalt concept of similarity?
often group things that are similar together
36
What is the Gestalt concept of continuity?
more simple interpretation is to see lines as continuations (continuing behind another object)
37
What is the Gestalt concept of proximity?
when objects are near or close to each other, those objects are thought to "belong" together
38
What is figure-ground segregation?
When we look at an image, we try to extract the object of the image from the background. Separate the figure from the ground.
visual illusions where we can see two different things when you focus on different things as backgrounds
39
What is the main way that we perceive depth in everyday life?
through binocular depth cues
40
What causes binocular depth cues?
results from binocular disparity: when looking at something, the image that enters our left eye is slightly different than the image that enters our right eye. Our brain can then process the differential images and then from that, extracts depth cues.
41
Modern-day 3D movies use what basic concept?
binocular depth cues
The distance between the two cameras mimics the distance between an average person's left and right eye.
42
What did the visual cliff experiment find about babies?
Behaviour of babies had nothing to do with fear of heights, but rather that very young babies have not developed a sense of depth perception and cannot detect change in height. Older babies were more wary of the drop-off in height because they have developed a sense of depth perception.
43
What are monocular depth cues and how do they work?
Doesn't require the interaction of both eyes.
Used to perceive depth from 2D images.
Could close one eye and look at an image like this, and still be able to extract these depth cues.
44
What are the rules we use for monocular depth cues?
relative height
relative size, familiar size
size constancy
45
How do we use relative height to perceive depth?
We use the relative height of images in scene to determine how far away they are
- the higher the image, the further away it is
- in the sky, the higher the image, the closer is it
46
What is the use of relative size and familiar size?
relative: ex. motorcycle closer = bigger image; further motorcycle = smaller image
familiar size: knowledge of how big something is in real life
47
What is size constancy?
Ability to maintain an understanding of the true size of the different images we are looking at even when some appear very large and others appear very small - is what is referred to as size constancy.
48
What is the Ames room and how does it work?
visual illusion due to restrictive viewing angle that a person can see into
Plays on past experiences and our sense of depth, particularly in seeing what we expect to see.
49
How does sound travel?
In waves - different heights and frequencies
50
The physical quality of frequency corresponds with what perceptual quality?
pitch
51
The perceptual quality of loudness corresponds with what physical quality?
amplitude
52
What are the auditory ossicles?
malleus, incus, stapes
smallest bones in the human body
53
Why are there bones in the ear (the auditory ossicles)?
because their role is to transmit sound waves from what is air in middle ear to fluid in cochlea
Because sound waves encounter more resistance travelling through fluid, more force is needed to transmit them through the cochlea
54
Where are receptors for sound found?
in the cochlea (basilar membrane)
55
What is the basilar membrane?
What is the difference between tuning at apex vs. base of membrane?
- found along cochlea
- houses receptors for sound
- apex of membrane is tuned for low frequency sounds
- base of membrane is tuned for higher frequency sounds
- medium frequencies engage basilar membrane at the midpoint
56
What nerve transports signals from the ears to the brain?
auditory nerve
57
Where do auditory neural signal originate?
Where do they travel to to get to the brain for processing?
From the cochlea, travel along auditory nerve, up brainstem, connections made in thalamus, temporal lobe, primary auditory cortex
58
Where does the conscious perception of sound occur?
In auditory cortex
59
What are the 2 types of hearing problems?
Conductive: disruption of sound signal within the ear
- can occur in auditory canal, problem with tympanic membrane, or conduction with the auditory ossicles
- sound signals are not transmitted properly to cochlea
- less serious, can be treated
Sensorineural:
- more serious
- issue with neural processing of sound waves
- could be caused from damage to sound receptors or to auditory nerve fibres
- limited hearing or totally deaf
60
What is one type of treatment for hearing loss?
a cochlear implant
- transmits neural signals within cochlea that are no longer being transmitter on their own
61
How does a cochlear implant potentially help with speech production?
- One of the things we need to produce speech is to hear our own voice
○ People who become totally deaf find it extremely difficult to produce language, because they can't get that feedback of their own voice
- Cochlear implant allows ppl to hear their own voice when speaking
62
How can we taste?
- Chemical contents of the food react with taste receptors within our mouths
63
Are taste buds visible bumps?
No, but bumps may mean that there are more taste buds located beneath
64
What is the evolutionary purpose of a liking for salty and sweet foods?
These foods typically contain a lot of calories - high energy
65
Why do humans evolutionarily have less of a preference for sour or bitter tastes?
tend to have more of a negative response because these foods are associated with toxic or poisonous foods
66
What are the 5 tastes?
Salty
Sweet
Sour
Bitter
Umami
67
What are supertasters and non-tasters?
Supertasters:
- More tastebuds than the average person
- Can be identified by putting dye on a person's tongue and counting the number of bumps on their tongue
Non-tasters:
- Comparatively fewer tastebuds compared to the rest of the population
- Biggest difference between supertasters and non-tasters are foods with a bitter taste to them
68
Is there a difference between supertasters and non-tasters for sweet foods?
no - ex. chocolate
69
Olfactory receptors send neural signals to where?
to olfactory bulb, which then send signals to higher regions of the brain to perceive what we are smelling
70
What parts of the brain are involved with determining the pleasantness and/or emotional reaction of a smell?
Signals travel to orbitofrontal cortex:
- Decision-making part of the brain
- Area where we decide whether or not an odour is pleasant or unpleasant
Signals can also travel to amygdala:
- Smells can impact emotional state
- It allows us to have an emotional reaction to the smell - can be positive, or negative if it is a bad smell
71
What are mechanoreceptors?
receptors in skin that respond to pressure and temperature changes against the skin
72
What nerves carry touch perception signals to the brain?
cranial and spinal nerves - bring signals to somatosensory cortex
73
What are the 2 types of nociceptors?
- 1 travels along fast fibres to the brain; this pathway is reserved for sharp and immediate pain
○ Ex. touch hot frying pan
2nd travels along slow fibre pathway; this pathway transmits more lingering kinds of pain (ex. slow ache)
74
What is the Gate Control Model?
Pain signals travel to the brain via the spinal cord
- additional signals influence pain signals (ex. cognitive state)
- can act to open or close a "gate"
- pain signals can be influenced by person's cognitive state; what they think of or are paying attention to can influence amount of pain they feel
- opening = feel pain; closing = reduced or no pain
75
The Gate Control Model can influence what effects?
- placebo effect
- or continuing to play with injury and not feeling pain
- why things like meditation, acupuncture, or hypnosis can relieve pain even without having strong scientific reasons for why they should be effective
