Brainscape's Knowledge GenomeTM

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


See full index

Psychology of Death and Dying > Perception Midterm > Flashcards

Perception Midterm Flashcards

1
Q

Absolute Threshold

A

the smallest detectable unit of a physical quality

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

Difference Threshold

A

the smallest detectable difference between two physical qualities
so if it says something has a weber fraction of 25% then that means a stimulus must be 25% higher or lower in order to find JND

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

Two types of threshold seeking methods

A

classical and adaptive

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

Three types of classical methods? Describe what they are and their pros and cons.

A

Method of Adjustment: stimuli is adjusted until they can just detect it, fast but not always accurate

Method of Limits: stimuli goes in ascending and descending order and person says whether they can see it or not, easy on observer and fairly fast and accurate

Method of Constant Stimuli: 5 to 9 stimuli of different intensities are presented many times each, in random order, accurate but takes very long

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

what is the relationship between the difference threshold and magnitude of stimulus

A

when magnitude of stimulus increases so does difference threshold

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

response compression

A

(b<1)

as intensity increases, the perceived magnitude increases slower than the intensity

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

response expansion

A

(b>1)

as intensity increases, the perceived magnitude increases faster than the intensity

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

Three main categories of mechanoreceptors

A

encapsulated
accessory-structure-associated
free nerve endings

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

encapsulated types

A

meissner
pacinian
ruffini

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

accessory-structure-associated typed

A

merkel disk

tactile hair

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

what is a receptive field

A

the area of a sense organ affecting the firing of a given neuron

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

spatial resolution

A

how many mechnoreceptors are across an area of a sense organ can determine how precisely one can know where a stimulus occurred

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

temporal resolution

A

how off does a receptor respond to a given stimulus can determine how precisely one can know when a stimulus occurred

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

Two pathways from skin to brain

A

dorsal column-medial lemnisical pathway

anterolateral pathway

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

serial processing

A

neurones connect to one another in a sequences

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

parallel processing

A

several streams or channels bring information to the brain simultaneously and the brain is able to process it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

contralateral processing

A

sensations from left side of the body cross over to right side of the brain and vice versa

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

topographic organization

A

adjacent neurones carry signals from adjacent parts of the body

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

what determines the size of a brain area?

A

the number of receptors in the area, not the size of the area

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

focal dystonia

A

cortical areas fuse together from neural plasticity

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

tactile acuity

A

the ability to locate touch on your body with precision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What area of the body has greatest tactile acuity? Why?

A

the fingers because they have the highest density of SA-1 Merkel mechanoreceptors in them

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

what type of fibres and mechanoreceptors are responsible for perceiving vibration?

A

FA fibres, meissner and pacinian corpuscles

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

sensory channels

A

overall subsystems working together to create sensory behaviour (meissner and pacinian corpuscles creating vibration)

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

envelope function

A

the psychophysical functions associated with sensory channels (the curves of meissner and pacinian working together)

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

what is the perceptual correlate or sensory quality for hearing and touch

A

pitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Which mechanoreceptor is primarily responsible for fine texture discrimination via vibration sense?

A

pacinian corpuscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are the type of thermoreceptors and what fibres are they linked to fibres

A

cold (AS fibres)

warm (C fibres)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

does thermal sensation have response expansion or compression

A

expansion, thermoreceptors respond to reduction of thermal energy, unlike other senses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

opponent process

A

warm and cold receptors compete in an opponent process, adapting one causes the other to become more sensitive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what pathway for thermal sensations?

A

anterolateral pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is proprioception? how is it sensed?

A

the sense of ones own body position and motion. through proprioceptors, responsible for weight discrimination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is kinesthesia?

A

it is part of proprioception, it is the sense of muscle and joint positions in your body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what type of fibres for proprioception?

A

Aa fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

type of proprioceptors?

A

muscle spindle receptors
golgi tendon organs
both have to do with Aa fibres entangling around something since they are accessory structure mechanoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what are corollary discharge signals (CDS’s)?

A

an additional way that body position is signalled, when a motor signal is sent from brain to muscle, a copy of that signal (a CDS) is sent to somatosensory cortex, it is like error checking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is haptic exploration

A

the active exploration of a 3-D object with the hand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

how is shape of an object signaled?

A

through the firing pattern of groups of mechanoreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what type of RF’s are in the thalamus, what other sensation is this parallel to?

A

centre-surround RF’s, vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What are the two major modalities of pain?

A

a sensory component

an emotional component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

what’s the name of the receptors that transduce pain?

A

nocioceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what tare the three types of pain?

A

nocioceptive
inflammatory
neuropathic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

describe nocioceptive pain

A

healthy and protective
usually a result of high intensity stimuli like heat, chemicals, pressure, or cold
it is the response to tissue damage or the threat of tissue damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

describe inflammatory pain

A

healthy and protective but can be pathological (arthritis)

caused by damage to tissue or joints the releases chemicals that activate nocioceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

describe neuropathic pain

A

generally pathological failure of pain systems
caused by damage to the PNS or CNS
carpel tunnel, spinal cord injury, thalamic stroke

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what are some cognitive effects on pain?

A

expectation

shifting attention

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what is gate control theory (GCT)

A

suggests that inputs from nocioceptors can be gated off at the spinal level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What two general influences can modulate pain according to GCT

A

afferent tactile inputs (touching the area)

top-down inputs (shifting attention)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What does Melzack’s “Pain is in the brain” idea mean?

A

pain is not as simple as a reaction to stimuli, pain multimodal and many areas of the brain are involved in it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

opioids

A

exogenous opioids aka painkillers block pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

endorphines

A

endogenous opioids

released by painful experiences or pleasure/relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

naloxone

A

a chemical that blocks opioid receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what are the 4 types of papillae? what do they look like? where are the located?

A

filiform: cone shaped, entire surface
fungiform: mushroom shaped, on tip
foliate: series of folds, back and side
circumvallate: flat mounds, tenches in back

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

what are the different ways of transduction for different tastes

A

salty & sour: ionic channels

bitter & sweet & unami: G protein coupled receptor (GPCR) mechanisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

how do salty & sour ionic channels work

A

positive ions from salt (Na+) and positive ions from sour(H+) travel through ionic channels in the taste cells that depolarize them and lead to neurotransmitter release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

how do sweet GPCR mechanisms work?

A

wide variety of sweet tastants trigger GPCR to release a cAMP mechanism in sweetness-detecting cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

how do bitter GPCR mechanisms work?

A

wide variety of bitter tastants trigger GPCR to release calcium (Ca++) in bitter-detecting cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

taste pathway

A

VII, IX,X>NST>VPMN>PGC>SGC of OFC>hypothalamus and amygdala

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

physical definition of sound

A

sound is pressure changed in the air or other medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

perceptual definition of sound

A

sound is the experience of we have when we hear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

what are sound waves

A

they are what make up sounds, they are longitudinal waves which means variations in intensity (air density) are the parallel to the direction the wave is travelling in

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

transverse waves

A

water or light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What moves through the air in a sound wave?

A

air PRESSURE, not the actual air, so it is like wave at sports stadium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is a pure tone? what qualities define it?

A

a pure tone is the simplest form of a sound wave, the pressure variations are sinusoidal
amplitude (uPa) = subjective loudness
frequency (Hz) = subjective pitch
all other sounds are made up of many pure tones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Discuss taste quality and methods to assess it

A

no simple relationship between molecular structure and taste quality so it is hard to measure
Henning’s taste pyramid thing
MDS
Star Charts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

what is hedonics

A

the study of of the pleasurable or unpleasurable aspects of taste

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

what is PTC how many people can taste it?

A

a chemical put in toxic products to make it taste bad
75% can taste
6% of them are supertasters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

route of odour stimuli affecting taste

A

odour stimuli>retronasal route>olfactory mucosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

pheromones

A

messenger chemicals that are released to control the 4 F’s

possible existence of CN0 involved in human pheromonal control of sexual arousal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What are olfactory stimuli

A

odourants that are found in the air, the concentration of them decides the subjective intensity of the smell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

what is the relationship between chemical structures and odour qualities?

A

it is complex, the same looking chemicals could produce different smells, or vice versa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

amplitude

A

the difference in sound pressure between high and low peaks of a wave (Ps)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

db=20 x log10 (Pr/Ps)

A

decibels formula

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

what is frequency? how is it measured?

A

number of amplitude cycles within a given period of time
measured in Hertz (Hz)
1 Hz=1 cycle per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

what are complex sounds?

A

a combination of pure tones, each with its own amplitude and frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

what is a fundamental frequency?

A

the lowest frequency element of a set of tones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

overtone

A

the higher frequency elements of a tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

harmonic/harmonic overtone

A

a frequency that is a whole integer multiple of the fundamental frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

what is attack/decay?

A

attack: the buildup of sound at the beginning of a tone
decay: the decrease in sound at the end of a tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

what are periodic sounds? examples?

A

sounds that have patterns that repeat across time

musical notes, vowels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

what are aperiodic sounds? examples?

A

sounds that have no repeating patterns

hissing, thumps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

What is the basic idea behind Fourier Analysis?

A

That any function can be broken down into a series of sine waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Fourier Synthesis?

A

that any function can be built up from a series of sine waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

relationship between tones, frequencies, and amplitudes

A

multiple amplitudes make up one frequency

multiple frequencies make up one tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

fourier spectrum

A

shows the the amplitude for each frequency that make up a tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

how are oldfactory signals coded?

A

through cross-fibre coding
each odourant has a number of molecular components (different shapes of different colours creates molecule)
each shape can activate a different receptor
(receptors with different shapes indented in them)
this creates a pattern of activated receptors that signal a specific scent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

what are enatiomers?

A

molecules that are exactly the same except they are mirror images of each other
challenges malnic’s olfactory coding theory because they have the same molecular components but they create different scents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

what are two methods to measure the quality of smells? pros and cons?

A

2AFC vial sniffing: given two options, one has stimulus in it one does not, must say which one has the stimulus
it is simple but noisy due to difference in sniff volumes and rates
Olfactometer: a machine that gives controlled bursts of air into nose with smells in them
stimuli is well-controlled but it is very complex machine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

odourants experience response compression or expansion?

A

compression (b<1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

Odour Primaries

A

Henning’s created odour prism with the odour primaries

flowery, spicy, putrid, burning, burnt, resinous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

what is easy and what is difficult in odour identification?

A

detecting that an odour is there is easy, but naming them is difficult

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

What is sensitivity?

A

one’s ability to detect a signal (the simulus)

d’ (dee-prime)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

How do you measure sensitivity?

A

You make the four possible result squares
the stimulus is either present (test trials) or not (catch trials)
and the person either says they hear it or not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

What do we call it when the stimulus is present and the person says they do detect it? How is this used in measuring sensitivity

A

a hit

we look proportions of hits (Ph)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

What do we call it when the stimulus is not present and and the person says they do detect it? How is this used in measuring sensitivity

A

a false alarm

we look at proportions of false alarms (Pfa)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

What is criterion?

A

a person’s tendency to say yes a lot or no a lot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

What is it called when someone tends to say yes more? Why would they do this?

A

A Lax Criterion
If the cost (punishment) of a miss is raised
If the reward (benefit) of a hit is raised
You will say yes more because you do not want to miss it and you want to get them right when they are there

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

What is it called when someone tends to say no more? Why would they do this?

A

A Balanced Criterion
If the cost of a false alarm is raised
If the reward for a correct rejection is raised
You will say no more

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

When c<0, yes __ no

When c>0, yes__no

A

When c<0, yes>no
When c>0, yes<0
The lower the criterion value, the more of a chance that someone will say yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

What happens when you increase d’ in SDT?

A

Increasing d’ means that the two sounds sound nothing alike (increases distance between probability distributions) so you are more likely to hear the signal even with the noise with a neutral c (no tendency to say yes or no)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

What happens when you decrease d’ in SDT?

A

The two sounds sound very similar (the probability distributions will be very close together)
so you are more likely to have false alarms or misses regardless of where c is

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

physical definition of sound

A

pressure changes in the air or medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

perceptual definition of sound

A

the experience we have when we hear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

what are sound waves? what kind of waves are they? how do they work?

A

objects make sounds by moving back and forth through a medium (air)
longitudinal waves
compression and rarefaction cycle creates high and low pressure regions that travel through air
variations in intensity (air density) are parallel to the wave’s direction of travel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

what moves through the air in a sound wave?

A

sound pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

pure tones

A

the simplest form of a sound wave
pressure variations are sinusoidal
all other sounds are

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

2 defining qualities of pure tones and what are they

A

1) amplitude (uPa): subjective loudness

2) frequency (Hz): subjective pitch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

what is amplitude and how do we measure it?

A

difference in sound pressure between high and low peaks of a wave
sound pressure (P) is measured in (uPa)
sound intensity, related to subjective loudness, is a square of P (I=P squared)
ratio of squared pressures (Ps squared/ Pr squared)
Pr=reference pressure typically 20 uPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

sound pressure level (SPL)

A

20 uPa is the lowest pressure variation amplitude detectable by an average human at 1000 Hz frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

decibels

A

The range of pressure ratios that humans can hear covers 7 orders of magnitude (i.e., from 1 to 10000000)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

how do we measure decibels?

A

dB = 20 × log10(Ps/Pr)
Ps: difference between mac and min pressure
Pr: is SPL usually 20 uPa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

what is frequency? how do we measure it?

A

number of amplitude cycles within a given time period
measured in Hz
1 Hz= 1 cycle/minute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

complex sounds

A

natural sounds do not have a single freq and/or amplitude
made up of complex sets of combined pure tones
each of these pure tones has its own freq and amp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

the doppler effect

A

When a sound source approaches at high speed, its sound
seems to increase in frequency, then decrease as it passes
due to compression and expansion of sound waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

fundamental frequency

A

the lowest frequency element of a set of tones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

overtone

A

higher frequency elements of a sound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

harmonic

A

overtones whose frequency is a whole integer multiple of the fundamental frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

frequency spectrum

A

the tones that together make up a sound, partly responsible for a sounds timbre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

attack of tones

A

quality of timbre

buildup of sound at the beginning of the tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

decay of tones

A

quality of timbre

decrease in sound at the end of the tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

periodic sounds

A

have patterns that repeat across time

ex: musical notes, vowels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

aperiodic sounds

A

have so repeating sounds

ex: thumps, contants, hissing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q

fourier analysis

A

any function can be be mathematically broken down into a series of sine wave elemets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

fourier synthesis

A

any function can be built up from a series of sine waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

fourier spectrum

A

shows lines, the heights of the lines indicate the amplitude

of each of the frequencies that make up the tone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

what does the speed of sound transmission depend on?

A

the density and the elasticity of the medium it is traveling through (air)
More dense = slower transmission
More elastic = faster transmission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

what happens with sound and objects

A

objects will absorb, reflect, transmit, or diffract sound based on their physical properties

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

when do objects absorb sound?

A

the larger and denser the object is, the more it will absorb sound
the shape of the object also affects it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

when do objects reflect sound?

A

the more elastic the object is, the more it will reflect sound
the shape of the object also affects it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
130
Q

when do objects diffract sound?

A

occurs when sound encounters an object, sound waves will re-form on the other side of small objects but not large ones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
131
Q

inverse square law

A

As sound moves out from a point source, its energy is
spread over a larger and larger area
Area is proportional to square of the relative distance
2×distance = 1/4 intensity
3×distance = 1/9 intensity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
132
Q

If the sound intensity is 180 units at distance

10 m, what will it be at 30 m?

A

30m/10/=3
3x30=90
180/90=20 sound intensity units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
133
Q

outer ear parts and functions

A

pinna: helps with sound localization
auditory canal: approx 3 cm long tube,
protects tympanic membrane at the end of the canal

134
Q

resonance frequency of outer ear

A

amplifies frequencies between 2000 and 5000 Hz

135
Q

middle ear function and parts

A

≈2 cm3 cavity separating inner from outer ear
three ossicles: malleus, incus, stapes
eustachian tube: equalizes pressure

136
Q

ossicles function

A

outer and inner ear are filled with air and inner ear is filled with fluid that is denser than air, this causes poor pressure changes from air to fluid
ossicles act in two ways to amplify the vibration for better transmission to the fluid

137
Q

ossicles condensation effect

A

force is concentrated down on a smaller area to create higher pressure
larger of the 2 effects, 25 dB

138
Q

ossicles lever effect

A

ossicles are set up like a lever arm
allows weaker force of air vibrations to move liquid to cochlea
smaller effect, 2 dB

139
Q

inner ear parts

A

cochlea: fluid like structure set into vibration by the stapes

140
Q

structure of the cochlea

A

divided into 3 canals by 2 membranes

canals: scala vestibuli, scala media, scala tympani
membranes: reissner’s membrane, cochlear partition

141
Q

cochlear partition structure

A

cochlear partition: narrow at the apex and wide at base
basilar membrane: wide at apex and narrow at base
spiral lamina: makes up rest of cochlear partition

142
Q

other cochlea structure, the organ of corti description and function

A

has inner and outter hair cells and their supporting structure

rests on basilar membrane which vibrates in response to sound stimuli, activating hair cells

inner hair cells are receptors for hearing

Tectorial membrane extends over the hair cells

Transduction at the hair cells takes place due to
the bending of tectorial and basilar membranes

143
Q

Two theories of how nerve fibres signal frequency

A

1) Place theory

2) Frequency Theory

144
Q

place theory

A

see which fibres are firing since different hair cells along the OoC fire to different sound frequencies

Hz of sound is coded by the place on the organ of corti that has the greatest vibration, and thus greatest stimulation of neurones

Békésy suggested that sounds produce a travelling wave along the basilar membrane

The peak of this wave occurs at the point where the
membrane’s resonant frequency matches that of the sound’s frequency

the resonant frequency of the base of the basilar membrane is much higher than the apex

145
Q

frequency theory

A

how fibres are firing, rate or firing patter of nerve impulses

proposed that all hair cells fire to every sound, and their rate of vibration indicates frequency of sound

action potentials from IHCs are found to be phase locked to the sound signals

146
Q

phase locking

A

phase is a characteristic of sine waves describing where the wave starts

IHCs spike when a pure tone is at highest compression
but max firing rate is 500 spikes/sec, so how to code for higher frequencies? volley theory

147
Q

volley theory

A

no single neurone can signal each pressure maximum for
tones above about 500 Hz

by aliasing and firing out of phase with one-another,
several neurones can together encode high frequencies.

148
Q

synthesis

A

For sounds below 1000 Hz, only volley theory
applies
For those between 1000 and 5000 Hz, both place
and volley theory apply
For 5000 Hz and above, only place theory applies

149
Q

which end of the basilar membrane codes

for low frequency sounds and which for high?

A

low=apex

high=base

150
Q

where does transduction occur for hearing and how does it happen?

A

in the inner hair cells (IHCs)

1) stereocilia in the IHCs are bent
2) tip links (tiny filaments in stereocila) are pulled
3) tip links open ionic channels
4) causing the IHC to alternately hyperpolarize and depolarize

151
Q

what is active response where does it occur and how?

A

in the outer hair cells (OHCs)
do not transduce sound by boost IHC response
1) sound stimulates OHCs
2) OHCs rhythmically contract and expand like muscles
3) this amplifies the motion of the basilar ad tectorial membranes
4) this actively stimulates the IHCs

152
Q

amplitude transduction

A 
a single class of neurones cannot code for the whole range
so instead different hair cells code for different limited ranges of amplitude

“A” codes for a low range, starting at ≈10 dB & saturating at ≈50 dB. It has a high resting response rate
“B” responds only to upper range, starting at ≈50 dB and
saturating at ≈100 dB

153
Q

what does it mean to say that the basilar

membrane performs Fourier analysis?

A

the basilar membrane shows the highest response in auditory nerve fibers with characteristic frequencies that correspond to the sine wave components of complex tones
In this sense the basilar membrane does a Fourier
Analysis of the incoming sound signal, breaking it down
into component pure tones

154
Q

what are the subcortical structures in the pathway from the cochlea to cortex

A

C? SONIC MG is A1!

1) Cochlear nucleus
2) Superior olivary nucleus (in the brain stem)
3) Inferior colliculus (in the midbrain)
4) Medial geniculate nucleus (in the thalamus)
5) Auditory receiving area (A1 in the temporal lobe)

155
Q

cochlear nucleus

A 
has tonotopic organization:
Ventral = low Hz
Dorsal = high Hz
contains 3 types of cells
1) bushy cells
2) stellate cells
3) octopus cells
156
Q

cochlear nucleus: bushy cells function

A

code for different frequencies and inhibit one another to get sharper frequency tuning

157
Q

cochlear nucleus: stellate cells function

A

fire for duration of stimulus (slow adapting)

their rate indicates intensity of the sound

158
Q

cochlear nucleus: octopus cells function

A

fire at sound onset/offset (fast adapting)

may provide sound timing information

159
Q

superior olivar nucleus

A 
located in the brain stem
tonotopic organization
first site of binaural activity 
integrate signals from both ears
first analysis of sound direction (horizontal only) via analysis of time and intensity differences between both ears
160
Q

inferior colliculus

A

located in the midbrain
receives inputs from higher areas like AI

may be a “switchboard” for regulating auditory attention

also an integrating area for multi-modal
perceptual responses such as startle reflexes
and reflexive looking

161
Q

medial geniculate nucleus

A 
nucleus of the thalamus 
tonotopic organization
processes all aspects of sound
may be the first site of complex pitch (as opposed to
simple frequency) perception
162
Q

descending pathways function

A

olivocochlear neurones–going from superior olivary down to cochlea–can turn down the gain on IHCs to allow them to process higher sound volumes

descending connections also cause contractions in small
muscles attached to ossicles, causing them to be less mobile and thus “turning down the volume” on high amplitude sounds

163
Q

AI primary auditory cortex

A

located in the temporal lobe

processes relatively simple sound information regarding frequency and location

164
Q

AI organization

A

organized in isofrequency sheets which run left to right

neurones within a sheet have the same characteristic frequency (Hz to which the cell is most sensitive; lowest
threshold)

transverse to the sheets are aural dominance
columns and suppression/summation columns

suppression, sum, right, left, binaural for different Hz

165
Q

“what” stream for hearing

A

starts in the anterior temporal lobe and extends to the prefrontal cortex
responsible for identifying sounds

166
Q

“where” stream for hearing

A

starts in the posterior temporal lobe and extends to the parietal and prefrontal cortex
responsible for locating sounds

167
Q

what is loudness? what is it most related to?

A

the subjective perceptual quality of sound

pressure or intensity, also depends on frequency, etc

168
Q

what is the max sensitivity to loudness?

A

2-5 kHz (human speech)

169
Q

psychometric function

A

function on physical quantity of a behaviour, shows one threshold

170
Q

psychophysical function

A 
function of 2 physical quantities
shows hows threshold on 1 quantity varies as a function of the other
171
Q

other factors affecting loudness

A

binaural vs monaural presentation (spatial integration)

duration of sound (temporal integration)

172
Q

the dynamic range

A

interval between the softest and loudest sound that the ear can hear (100-500)x10

173
Q

minimum audibility curve

A

threshold of hearing vs frequency

174
Q

spatial and temporal integration

A

any sensor (biological or artificial) must integrate (add up) signals across a certain range

175
Q

longer/larger integration=?

A

higher sensitivity, lower acuity

176
Q

what are sound masking experiments? what are the two types? what are the two methods used?

A

psychophysical experiment examining how one sound affects perception of another

types:
1-tonal masking
2-noise masking

methods:
1-constant target Hz with varying masker Hz, mainly used with tonal masking
2-varying target Hz with constant masker Hz, mainly used with noise making

177
Q

tonal masking

A

asking how much one pure tone impairs perception of another
test tone of fixed frequency chosen
series of masking tones of different frequencies presented
for each masking tone, observer adjusts its intensity (dB) until it drowns out the the test tone
most effective masking is at the same frequency as the test tone

178
Q

noise masking

A

asking how much do aperiodic sounds impair perception of tones
constant mask is used, usually a narrow-band white noise, which is aperiodic sound with frequency in a certain range
subtract the baseline from the masked constant masked audibility curve and you get the get how much the threshold was elevated by the noise mask
noise mask shows asymetry

179
Q

describe 410 +/- 45Hz

A

has centre frequency of 410 and a bandwith of 90Hz

180
Q

why masking asymmetries occur

A

because of asymmetries in how the basilar membrane responds to pure tones
the travelling wave builds up gradually then collapses suddenly

181
Q

what will be the response to test and masking tones due to asymmetries?

A

A-more similar if mask is < the test in frequency

B- more different if the mask is > test in frequency

182
Q 
If a masking tone is 500 Hz in frequency:
What Hz of target tone will it most
effectively mask?
Which target tone will it mask more:
A 400 Hz tone, or a 600 Hz tone?
A 
500 Hz
400 Hz (?)
183
Q

how are frequency and pitch related?

A 
tone height (aspect of pitch): increases linearly as frequency increases
tone chroma (aspect of pitch): increases in a circular fashion as frequency increases
184
Q

auditory space

A

surrounds an an observer and exists where there is sound

185
Q

what are location in auditory space defined by?

A

1) azimuth coordinates=left and right
2) elevation coordinates=up and down
3) distance coordinates=position from observer

186
Q

what are the cues for sound localization?

A

1-Binaural Cues (ITD, IID)

2-Monaural Cues (HRTF)

187
Q

binaural cues

A

location cues based on comparison of the signals received by the left and right ears
ITD=difference between the time sounds reach the two ears
IID=difference in sound pressure level reach the two ears

188
Q

what affects ITD?

A

when source is to the side, times will differ

when distance to each ear is the same, no difference in time

189
Q

what affects IID?

A

head casts an acoustic shadow
reduction in intensity occurs for high frequency sound for the FAR ear
there is no reduction in intensity for low frequency sounds as they diffract around the head

190
Q

what are cones of confusion?

A

a given ITD/IID on its own cannot tell you WHERE a sound is coming from
can only tell you it’s coming from somewhere on a particular cone of points

191
Q

monaural cues

A

as sounds encounter the head, they are modified by its structures (bones, muscles, etc) especially the pinna

some frequencies are reduced in amplitude, others are increased due to resonance and constructive interference

HRTF=the pattern of increases and decreases of frequencies’ amplitudes

192
Q

what makes HRTF differ?

A

the elevation of the sound source
the head and pinna leave a unique “fingerprint” on sounds based on the elevation
this helps to resolve which point on the cone is the source of the sound but doesn’t solve distance

193
Q

explain Hoffman’s experiment on judging elevation

A

experiments investigated spectral cues
put moulds in their pinnae
right after moulds were inserted, performance at locating sounds at different elevations was poor
after 19 days, close to original performance
once removed, performance stayed high

194
Q

what does Hoffman’s experiment suggest?

A

that there might be two different sets of neurones, one for each set of HRTF cues

195
Q

what are the distance cues for sound?

A

1) spectrum
2) loudness
3) movement
3) reflection

196
Q

spectrum distance cue

A

for sound with known spectrum like speech, distance can be estimated by degree of muffling
high Hz sounds are more quickly damped by air, so distant sources of sound are muffled

197
Q

loudness distance cue

A

self-explanatory

198
Q

movement distance cue

A

motion parallax=nearby sound sources pass faster than distant ones

199
Q

reflection distance cue

A

in enclosed areas, direct sound arrives at ears without being reflected at the wall
reflected sound arrive later, after bouncing off walls
ratio between direct and reflect arrival time can give an indication about the distance of a sound source

200
Q

two methods for measuring sound location accuracy

A

1) free-field presentation

2) headphone presentation

201
Q

what is free-field presentation? advantages/disadvantages

A

sounds are presented by speakers located around listeners head in a dark sound-proof room
indicates location by pointing, giving azimuth and elevation coordinates
advantage=high naturalistic
disadvantage=expensive equipment and some lack of control over exact sound contents

202
Q

headphone presentation advantages/disadvantages

A

advantage=precise control over sounds and cheaper
disadvantage=cues from pinna (HRTF) are eliminated, results in sound being internalized
sounds can be externalized by measuring each subjects’ HRTF and applying it to presented sounds

203
Q

physiological representations of auditory space

A

1) interaural time-difference detectors: panoramic neurones

2) topographic map

204
Q

panoramic neurones

A

neurones that respond to specific ITDs, found in the auditory cortex at the first nucleus (superior olivary), in the system that receives input from both ears

signal location by their pattern of firing

205
Q

topographic maps as psychological representation of auditory space

A

neural structure that responds to location in space, these neurones have RFs for sound location
barn owls have in the MLD
mammals have in subcortical structures like the inferior collicus

206
Q

auditory scene

A

array of all sound sources in a listener’s environment

207
Q

auditory scene analysis

A

process by which sound sources in the auditory scene are separated into individual perception

does not happen in the cochlea as simultaneous sounds are combined together in the pattern of vibration of the basilar membrane

segregation of sound signal into those coming from different sources

grouping of separate sounds into those coming from one given source

sound localization

208
Q

gestalt heuristics

A

heuristic=rule of thumb used by a system (ex. brain)

gestalt heuristics=a rule of thumb applied to organizing sensory inputs to make determinations

which elements of a scene belong to which objects, which elements represent edges between an object and its background

ex: proximity and similarity principles

209
Q

auditory grouping

A

sound stimuli perceptually organized according to certain heuristics

210
Q

principles of auditory group (3)

A

1) proximity: sounds from a single source tend to come from one location
2) similarity: sounds from a single source tend to be similar in pitch, loudness, etc
3) smoothness: sounds from a single source change in pitch, loudness, etc, in a smoother and continuous way

211
Q

auditory streaming as auditory scene analysis

A

when sound A and B are similar in pitch, they are grouped together in a single “galloping” sound stream based on proximity in time and timbre

when sound A and B are different in pitch, they are grouped into 2 separate streams
changing the speed does the same

212
Q

Deutch’s melodic channeling experiment method, results, reason for results?

A

stimuli were 2 sequences alternating between the right left ears

listeners perceive 2 smooth sequences by grouping the sound by similarity in pitch

caused by proximity and smoothness heuristic

213
Q

what does wessel’s timbre illusion demonstrate?

A

demonstrates how heuristics can compete with each other

smoothness heuristic: tries to group by smoothly changing pitch, dominates at low speeds

similarity heuristic: tries to group by timbre, dominates at high speeds

214
Q

Bregman continuation heuristic demonstration

A

tones were presented interrupted by either gaps of silence or by noise

silence condition= perceived sound stopped during the gaps

noise condition=perceived the sound continues behind the noise

215
Q

Dowling effects of experience experiment methods, results, meaning

A

used 2 interleaved melodies (three blind mic and mary had a little lamb)

listeners reported hearing meaningless jumble of notes
once they were to listen for the melodies, they were able to hear them by using a melody schema

this shows how heuristics can be affected by learning and knowledge

216
Q

interactions between vision and sound

A

visual capture or the ventriloquist effect: an observer perceives the sound as coming from the seen location rather than the source for the sound

217
Q

Sekuler experiment on interactions between vision and sound

A

balls moving without sound appeared to move passed each other

balls with added “click” appeared to collide

218
Q

what is light

A

a form of electromagnetic (EM) radiation

219
Q

how does electromagnetic radiation vary? (3)

A

1) wavelength
2) intensity
3) polarity

220
Q

1) wavelength? measured? causes?

A

measured in lambda
measured in units of distance (nanometers)
variations in wavelength cause colour experience

221
Q

range of visible light to human? why is there this limit?

A

400nm-700nm
bc where most of the energy is sunlight is
other ranges can be damaging (UV)
or pass through objects too easily (radio)

222
Q

natural light

A

have ranges of lambdas

each with its own intensity

223
Q

laser lights

A

single lambda

224
Q

what is a light’s subjective colour determined (in

part) by

A

by its intensity spectrum

225
Q

what are spectral functions

A

describes some property of a stimulus as a function of wavelength or frequency
This can be wavelengths of light, sound, physical vibration, etc.
Most stimuli have a broad range of wavelengths, each with
its own amplitude.
A spectral function can describe properties of emission, transmission, scatter, etc. but also detection/differentiation

226
Q

2) intensity

A

variations of intensity cause the sensation of brightness, but relationship is nonlinear

measured in units of power per area (candela (cd)/m2)

Human vision can handle between about 10-6 and 107 cd/m2 (beyond this, damage occurs)

227
Q

3) polarity

A

Polarity refers to the angle (e.g., in degrees) other electric component

228
Q

emitted light

A

light is emitted from a s source and travels in all diffraction until it is either absorbed, refracted, or reflected

At a sufficient distance(called optical infinity):
Spherical wave fronts can be treated as flat
Light rays can be treated as parallel
By convention, optical infinity is said to be 6 m

229
Q

light’s journey to the eye (6)

A

1-light is emitted by a source
2-transmission through a medium (lightbulb, sun, etc)
3-interaction with surfaces or objects
4- transmission through a medium again (air, water, etc)
5-interactions with outer structure of the eye
6-interactions with structures of the retina

230
Q

what can happen to light at each stage of its journey to the eye?

A

1) Transmission: refraction or scatter
2) Absorption
3) Reflection: specular or body

231
Q

what is the difference between specular and

body (a.k.a. diffuse) reflection?

A

body: light scattered in all directions
specular: light reflect at opposite angle

232
Q

what is focus? how do you do it? 2 methods?

A

an acute image system (camera or eye) form a sharp image on it imaging system (film or retina)

to do so must direct the light from each point in its field of view to a small patch on the imaging system

can accomplish focus by 2 methods

1) pin-hole light gathering
2) lenses

233
Q

pin-hole light gathering to get focus, problem?

A

sharpen light by allowing light to reach the imagine surface via only one small opening

problem: only allows a small amount of light in, creating dim images

234
Q

lenses, how is lens strength measure?

A

transparent surface that transmits and refracts light to sharpen image

measured in diopters (dp)

235
Q

different types of lenses (2)

what are their measurements in dp?

A

convex lens: gathers light to a focal point (magnifying glasses, reading glasses, etc)
positive dp

concave lens: spreads light beams apart, so no real focal point (glasses to correct myopia)
negative dp

236
Q

calculating focal distance (F) formula

A

F= 1/dp therefore dp=1F

237
Q

combining pinholes and lenses

A

small pinhole: focus is ok, but image is dark due to the small amount of light allowed to enter

large pinhole: focus is poor but image is bright due to the large amount of light allowed to enter

large pinhole with lenses: focus is excellent and image is bright due to the large amount of light allowed to enter

238
Q

combining lenses

+3dp lens on top of +5dp lens
+3 dp len and -3dp lens

A

= +dp lens

= 0, cancels each other out

239
Q

what does the cornea and crystalline lens do?

A

focus images on the retina

The cornea is (on average) a +43 dp lens
The crystalline lens is also a lens that can vary its shape/power from +15 to +25 dp

Total focussing power is thus 43+15 = 58 dp
when lens is relaxed and 68 dp at maximum accommodation

Eye is about 25 mm in diameter, but distance
from lens to retina is about 18 mm (≈1/58 m).

240
Q

emmetropic /emmetropia eye

A

relaxed states of eye

light rays are focus to a point on the retina
light rays parallel from optical infinity

20/20 vision

241
Q

myopia/myopic eye

A

light focussed in front of retina

eye has too strong a lens for its length

causes near-sightedness

242
Q

hyperopia/ hyperopic eye

A

lens not power enough for length of eye so images are blurred

causes far-sightedness

corrected by convex (+dp) lenses

243
Q

accomodation

A

when objects are closer than optical infinity, light rays from points are not parallel
therefore a blue is produced
crystalline lenses can change shape to accommodate this

244
Q

the near point

A

the distance at which objects get too close and the crystalline lens cant accommodate so it defocusses

245
Q

presbyopia

A

as we age, the lens becomes harder and accommodation becomes limited, so the near point gets further away

a convex (+dp) lens can correct for this

246
Q

the retinal image

A

extended objects consists of a large number of point sources

due to the way lenses work ,the imagine on the retina is upside-down and backwards but not pose a problem for analysis of the info

the image on the retina is of higher quality in the centre of the retina

the distribution RFs in the centre is sparser too

Objects at distances other than the depth off focus are blurred
The degree of blur depends on pupil size

Thus, we have greater depth of field under bright conditions than dim ones

247
Q

anatomy of the retina (4)

A

1) macula
2) fovea
3) optic disc
4) peripheral retina

248
Q

layers of the retina back-front (4)

A

1) pigment of epithelium
2) photoreceptor layer
3) inner nuclear layer
4) ganglion cell layer

249
Q

photoreceptors (4)
function
size amount of each

A

1) rods: night vision
2) S-cone: day vision
3) M-cone: day vision
4) L-cone: day vision

rods larger and more numerous than cones
120 million rods, 6 million cones

250
Q

Distribution of Rods & Cones Across Retina

A

fovea: rods=none, cone=max density
macula: rods=max density, cones=?
optic dic: rodes=none, cones=none
peripheral retina: rods and cones= drops rapidly as we move out towards it

251
Q

the blind spot

A

optic disc is where optic nerves leaves eye
no receptors here

create hole in our vision
but one eye covers the blind spot of the other

It is located in the periphery, where acuity is
low anyway
The brain “fills in” the spot

252
Q

specialization across the retina

A

fovea= detailed vision

periphery=low-light vision

253
Q

averted vision

A

look slightly away from things at night to see them better

254
Q

phototransduction

A

the process of transducing light energy into bioelectrical signal in neurones
odd, backwards

255
Q

transduction of light

A

photoreceptors (rods and cones) have inner and outer segments

outer segments contain visual pigments:
rods=rhodopsin
cones= 3 types of photopsin

these “opsins” are GPCRs

256
Q

the dark current (in darkness)

A

sodium ions (Na+) flow into outer segments of photoreceptors

potassium ions (K+) flow out into the inner segment

sodium-potassium pumps keeps potential at steady -40mV

sodium inflow can only happen with the help of cGMP

257
Q

the phototransduction cascade

A

1) light is absorbed by an opsin, isomerizing it into an active form
2) activates cGMP
3) activates an enzyme that converts cGMP to GMP
4) makes for less cGMP, sodium (Na+) channels shut down

Thus more light means lower positive inflow
The end result of all this is greater polarization
Down to -70 mV from -40 mV!

258
Q

Name two weird things about how the

receptors work

A

1) More light = less neurotransmitter release from
the photoreceptors
And it’s glutamate, which is normally excitatory

2) This is all rectified by the fact that ON bipolars are weird and fire more when they get less glutamate

259
Q

only _____ absorbed by an ______ are traduced into neural signals

A

photons, opsin

260
Q

what does number of photons absorbed depend on? (2)

A

1) number of photons hitting retina
more photons present = more photons absorbed
2)wavelength of photons
each photoreceptor has a lamba it absorbs best

261
Q

how do you get the absorption spectra of photopigments?

A

shine a laser through a vil of rhodopsin or cones
measure how much is transmitted
do this across the of lambdas (400-700nm)

262
Q

peak absorption for each photopigment

A

rhodopsin=400nm
S-cone= 440 nm
M-cone= 530
L-cone=560 nm

263
Q

absorption spectra and human sensitivity spectra

A

to see if a.s. relates to variations in human sensitivity across the spectrum

264
Q

how do we measure absorption spectra and human sensitivity spectra

A

have to measure 2 human Spectral Sensitivity Functions (SSFs)
compare a.s. of the various photopigments to the SSFs

265
Q

what is an SSF

A

a psychophysical function, two physical units
it shows sensitivity as a function of wavelength
sensitivity (S) as the inverse of of the threshold (T)
S=1/T therefore T=1/S

266
Q

S=1/T therefore T=1/S

what is this for

A

Spectral Sensitivity Functions

to see if absorption spectra relates to variations in human sensitivity across the spectrum

267
Q

what are the two types of SSFs and how do you do them

A

Scotopic=rods, night vision
in low light levels
place stimulus just off fixation

Photopic=cones, day vision
make stimulus small
place stimulus directly at fixation

268
Q

how do rods and cones a.s. match the SSF

A

rods a.s. matches well to SSF

the 3 cone functions must be combines to explain the SSF, specifically M and L cones, little input from S

269
Q

the Purkinje Shift

A

at twilight/night, blue/grreen things brighter while red/yellow things look darker
rods more sensitive to light around 500 nm (blue/green)
cones more sensitive to light around 550 nm (yellow)

270
Q

compare cones when it comes to night/day vision, sensitivity, acuity, and colour sense

A

rods=night vision, more sensitive, no colour sense

cones-day vision, better acuity, provide colour sense

271
Q

what is photopic? what happens to both cones and rods when this occurs?

A

when light levels are > 1cd/m squared
rods=bleached (all photopigments are isomerized)
only cones function

272
Q

what is scotopic? what happens to both cones and rods when this occurs?

A

when light levels are <0.01/m squared
rods=regenerated and become functional
cones=available but not sensitive enough to detect such low light levels

273
Q

what is mesopic? what happens to both cones and rods when this occurs?

A

when light levels are 0.01 to 1 cd/, squared

274
Q

what is odd about colour vision and photoreceptors

A

all 3 receptor types work at once

275
Q

dark adaption

A

the process of switching from cone vision to rod vision

not due to pupil dilation, retinal phenomenon

276
Q

time course of dark adaption

A 
takes 20 min or more
cone adaption (5 min)
rop adaption (20 min)
277
Q

what are the three experiments to measure time course of dark adaption, what do all three have in common method wise

A

1) rods and cones: stim placed at side of fixation
2) cones only: stim light right at fixation
3) rods only: test colour-blind person

exposed to bright light so cones and rods are bleached
then lights turned off, measure absolute threshold for light brightness at various time intervals thereafter

278
Q

light adaption

A

the process of switching from rod vision to cone vision

not due to pupil dilation, retinal phenomenon

279
Q

time course of light adaption

A

takes less than a min

280
Q

why does dark adaption take longer than light adaption?

A

LA only require that pigments be bleached (used up)

DA takes takes longer bc pigments must be regenerated after being bleached

281
Q

neural circuits

A

a group of neurones connected by excitatory and inhibitory links

282
Q

what are the three principles of of neural circuits

A

1) linearity
2) convergence
3) lateral inhibition

283
Q

why is stim placed on the side of fixation for rods and cones experiment of time course of dark adaption

A

to stimulate both rods and cones
the peripheral sees things on the sides
the fovea sees thing in the centre but only has cones

284
Q

what type of neural circuits contain all three principles

A

centre-surround circuits

285
Q

what is a linear circuit?

A

simply a chain of neurones, one stimulating the next
input into each receptor has no effect on the output of neighbouring cells
each circuit can only indicate single spot of stimulus

286
Q

what is a convergent circuit?

A

a chain of neurones where input from each receptor summates into the next neurone in the circuit
output varies based on input
increases output as stimulus increases in some characteristics like length and bandwith

287
Q

what does greater convergence lead to? (3) why?

A

greater convergence=more receptors feeding into one neurone

1) higher sensitivity to faint signals because high rod to ganglion cell ratio and rods are sensitive to light
2) less specificity/ acuity of signal detail/ reduces detail because foveal cones need more light to respond that rods, they are less sensitive
3) greater spatial summation

288
Q

what is lateral inhibition in neural circuits? what does this result un?

A

adjacent receptors inhibit one another
results in a strong response from stimuli have a given narrow range of a particular characteristic (size, frequency, sweetness, etc)
weaker response from stimulus close to range
no response from stimulus outside of range

289
Q

retinal ganglion cells (RGCs)

A

type of neurone throughout the retina
photoreceptors send signals to RGCs via neural circuits
125 million of each convergence 100:1

290
Q

RFs of RGCs

A 
almost all are centre-surround
small near fovea
large in peripheral 
half ON/OFF, half OFF/ON
this is why visual acuity so much greater near the centre of visual field
291
Q

centre-surround RFs firing

A

fire maximally to stimulus of just the right size

fire less if stimulus is smaller or bigger

292
Q

types of RGCs (2) what are they and percentage of them

A

1) midget: small cells with small RFs, 70%

2) parasol: big cells with big RFs, 30%

293
Q

what are inner nuclear layer cells and what how are they set up

A

between photoreceptor layer and RGC layer is inner nuclear layer
1) bipolar cells
2) horizontal cell
3) amacrine cells
all set up in such a way that give the RGCs a centre-surround RF

294
Q

what are bipolar cells in the inner nuclear layer?

A

carry info vertically from receptors to RGCs
on=light
off=dark
decides whether an RGCs Rf has an on centre or off centre response

295
Q

horizontal cells in the inner nuclear layer?

A

obvious
inhibitory=off surround response
excitatory= on surround response

296
Q

amacrine cells in the inner nucleus layer?

A

carry info horizontally across ganglion cells

many roles

297
Q

what is A=2xarctan[(S/2)/D]

A

visual angle calculation

298
Q

why is acuity best in the fovea? (3)

A

1) densest possible receptor mosaic
3) smallest RFs
3) best optical quality image

299
Q

what is MAR how do you calculate it?

A

measures acuity
20/20 vision means being able to resolves 1 min of angle (1/60th of a degree)
20/60 means only resolve 3 min of angle (60/20=3)

300
Q

what is grating acuity

A

measures the min contrast needed to detect a grating across the spatial frequency spectrum

301
Q 
what do each of these things detect?
RGCs
VI
V4
temporal lobe
A

dot detectors
line orientation, motion, colour
shapes
objects, faces

302
Q

who is the brain organized? (4)

A

1) modules
2) streams
3) columns
4) maps

303
Q

what are the two streams of vision processing?

A

1) dorsal: where pathway, motion processing

2) ventral: what pathway, object identification

304
Q

explain contrlaterality in vision

A

right nasal visual filed—->temporal retina—–>ipsilateral hemisphere
right temporal visual field—>nasal retina—>contralateral hemisphere

305
Q

what are the two paths from the eye to cortex?

A

1) geniculocortical pathway: LGN—>VI (90% of RCGs)

2) testopuvin pathway: superior colliculus—>pulvinar nucleus in visual cortex (10%)

306
Q

what is the LGN, where is it, how is it organized?

A

in the thalamus
the nuclei for early sensory processing
a module organized in layers and columns

307
Q

what are the layers of the LGN?

A

1&2: magnocellular
3&4&5&6: parvocelular
1&4&6: contralteral
2&3&5: ipsilateral

308
Q

the LGN’s retinoptic map

A

adjacent neurones in LGN have adjacent neurone on the retina

309
Q

how do we know about retinoptic maps and location columns in LGN?

A

single-cell recording experiments on monkeys

310
Q

superior colliculus

A

small branch from optic tract goes to to here
receives descending signals from visual, auditory, and somatosensery cortices
integrates all of them to coordinate eye and body movement towards stimuli

311
Q

layers of VI

A

1: no neurones, just fibres from neurones below
2 and 3: communicate horizontally with other visual cortical areas
4A and 4B: received input from LGN
4alpha: receives LGN’s magnocellular inputs
4beta: receives LGN’s parvocellular inputs
5 and 6: sends descending communications back to subcortical areas (LGN and SC)

312
Q

difference between minocular/bionocular neurones

majority in VI?

A

mino=respond to stim of only one eye
bino=respond to stim of either eye
mostly bionocular

313
Q

what is orientation selectivity of VI?

A

most VI neurones have elongated RFs that are like rectangles
each neurone responds best to a line of light or dark of given orientation
draw the model showing this

314
Q

M vs. P channels

A

two channels that start in the retina
M channel—>MT—->dorsal stream
P channel—>V4—>ventral stream

315
Q

where does the ventral stream mostly engage in vision?

A

the inferior temporal area (IT)

316
Q

what are the 3 zone of the the inferior temporal area (IT)

A

1) PIT: complex form procession tasks
2) CIT: complex form processing tasks
3) AIT

317
Q

what are some examples of complex form procession tasks done by the PIT/CIT of the IT

A

inverse projection: determining 3D shape from 2D info
segmentation: differentiating objects from background and each other
viewpoint invariance: objects look different from different viewpoints

318
Q

what are the two models of viewpoint invariance?

A

1) structural description models: geons

2) image description models: identify 3D objects from stored 2D viewpoints from different perspectives

319
Q

prosopagnosia

A

inability to recognize faces

often due to damage in AIT

320
Q

five ways to perceive movemnt

A

1) real movement
2) apparent movement
3) induced movement
4) movement aftereffect
5) movement illusion in static stimuli

321
Q

motion agnosia

A

damage to cortex causing inability to perceive movement

322
Q

two approaches to studying motion

A

1) ecological

2) physiological

323
Q

local distubrance

A

occurs in the optic array, causes other motion

an object moves relative to a static background and vice versa

324
Q

global optic flow

A

causes self motion

overall movement of the whole optic ray indicates the observer is moving

325
Q

corollary discharge theory signals (3)

A

1) motor signal (MS): signal sent to eyes to move eye muscles
2) corollary discharge signal (CDS): copy of the motor signal
3) image movement signal (IMS): movement of image stimulus receptors across the retina

326
Q

the aperture problem

A

complex cortical cells respond to an orientated bar moving in a specific direction
observation of small portion of larger stimulus leads to misleading/incomplete info about the direction of movement

327
Q

solution to the aperture problem

A

VI complex cells with different direction sensitivities are pooled
may occur in MT cortex

328
Q

how is shown that the ventral stream processes motion

A

the MT is part of it

lesions in monkey’s MT led to motion detection issues

329
Q

apparent motion

A

biological plausibility
one object must have occluded the other
shortest-path constraint

330
Q

implied motion

A

pics that are stations that depict an action that involves motion
MT/MST fire

331
Q

representational motion

A

reed and vinson experiment with rocket and dumbells

Psychology of Death and Dying (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions