L07: Sensation & Perception Flashcards
1
Q
Sensation
A
The ability to detect a stimulus. Features of the environment that are used to create understanding of the world.
2
Q
Perception
A
The act of giving meaning to a detected stimulus. Combining of sensations arriving from the sensory system with prior knowledge.`
3
Q
Transduction
A
Process where stimuli are converted to neural electrochemical energy.
4
Q
Psychophysics
A
The science of defining quantitive relationships between physical & psychological events. Relates physical stimuli to the contents of consciousness.
5
Q
Absolute Threshold
A
Level of stimulus intensity requires to create conscious experience.`
6
Q
Signal Detection Theory
A
Accounts for individual biases
7
Q
Just Noticeable Difference (JND)
A
the amount something must be changed in order for a difference to be noticeable, detectable at least half the time
8
Q
Bottom-up processing
A
Processing the elementary messages from the environment
9
Q
Top-down processing
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Applying memory, knowledge, etc. to understand and create perception
10
Q
Extromission theory of vision
A
Eyes send out vision beans, which seize objects. Plato & Galen
11
Q
Intromission theory of vision
A
Visual perception comes from some representation of the object entering the eyes
12
Q
What is light
A
Electromagnetic energy that exists as particles (photons) and waves
13
Q
Wavelength
A
Perceived hue (shade)
14
Q
Frequency
A
Cycle rate
15
Q
Amplitude
A
Perceived intensity
16
Q
Cornea
A
Transparent tissue which allows light rays to enter the eye and focus on objects
17
Q
Iris
A
Coloured part of the eye consisting of muscular diaphragm which regulates light entering the eye
18
Q
Pupil
A
Centre of the iris
19
Q
Lens
A
Crystalline lens inside the eye that enables the changing of focus
20
Q
Retina
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Contains photoreceptors
21
Q
Photoreceptors
A
Light sensitive neurons that transduce light into neural activity
22
Q
Fovea
A
Smallest pit that contains the highest concentration of colour sensitive light receptors
23
Q
Neuron Signal Pathway
A
- Photoreceptors
- Bipolar cells
- Ganglion cells
24
Q
Rods- Function
A
- responsible for night vision
- dim light
- low resolution
25
Cones- Function
- responsible for daylight vision
- bright light
- sensitive to blue, red, and green
- high resolution
26
Blindspot
Where the optic nerve leaves the eye. no photoreceptors in this area, so the visual system usually fills in the area with info about the surroundings
27
3 types of cones
s- cones
m- cones
l- cones
28
s- cones
short wave cones
| blue light
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m- cones
medium wave length cones
| yellow & green light
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l- cones
long wave length
| red light
31
Bipolar cells
Intermeditate cells that determine the info from photoreceptors to ganglion cells
32
Two types of bipolar cels
diffuse bipolar cells
| midget bipolar cells
33
Diffuse bipolar cells
Convergence of info in the periphery.
| 1 diffuse bipolar cell = 50 rods
34
Midget bipolar cells
Found in the fovea.
| 1 midget bipolar cell= 1 cone
35
Ganglion cells
Final layer of the retina
36
M-cell
diffuse bipolar cells synapse onto m- cells
37
P-cell
midget bipolar cells -> p- cell
38
Retinal ganglion cell (RGC)
axons for the optic tract
39
Receptive field
the region on the retina in which the visual stimuli influence the neural firing rate
40
Retinal ganglia
receptive fields of individual retinal ganglion cells. conveys patterns of life
41
ON-centre, OFF-surround cell
A ganglion cell that increases firing in response to an increase in light intensity
42
OFF-centre, ON-surround cell
A ganglion cell that increases firing in response to a decrease in light intensity in its receptive field
43
Trichromatic Theory
Colour vision occurs by comparing the activation of 3 different cones
44
Opponent process theory
p-cells fire rapidly to one wavelength and reduce to another, forming pairs of colours (red-green, blue-yellow, black-white)
45
The visual pathway
1. information from the retina leaves the eye via the optic nerve.
2. information from the optic nerve travels to the optic chasm (cross-over)
3. information reaches the lateral geniculate nucleus (LGN) of the thalamus
4. information reaches the visual striate cortex then the occipital cortex to be processed
46
Feature detectors
receptive fields of individual neurons in the visual cortex
47
Simple cells
neurons fire vigorously when the line is orientated vertically but reduce firing horizontally
48
Complex cells
Fire most when lines are in certain motion
49
Ventral Pathway
What stream
| Ventural -> temporal lobe -> object recognition
50
Dorsal Pathway
Where stream
| Dorsal -> parietal lobe -> location of objects in space
51
Gesalt Psychology
Describes how people tend to organize visual elements into whole entities
1. figure-ground law
2. principle of proximity
3. principle of similarity
4. principle of closure
5. principle of continuation
6. principle of common fate
52
Figure-ground law
a form is naturally perceived as a figure while its surrounding area is perceived as ground
53
principle of proximity
elements placed close together are perceived as a group
54
principle of similarity
similar objects are perceived as a group
55
principle of closure
people perceive the whole by filling in missing info
56
principle of continuation
the eye is compelled to move through one object and continue to another object
57
principle of common fate
objects moving together are grouped together
58
biological motion
the pattern of movement of living beings
59
blindsight
damage to one of the visual cortexes leads to conscious blindness. typically only on one side. when patients are asked to identify visual stimuli in their blind field, they can do so with accuracy above change, suggesting conscious and unconscious vision
60
visual agnosia
inability to recognize visual objects. associated with issues in the ventral pathway
61
prosopagnosia
inability to recognize faces. associated with issues in the ventral pathway. shows emotional responses to very close relatives, suggesting unconscious vision
62
akinetopsia
inability to detect motion, associated with issues in the dorsal pathway. patients see life in a series of snapshots.
63
Optic Nerve
a paired cranial nerve that transmits visual information from the retina to the brain
64
Rods- Distribution
- found in the periphery
- around 100 million in each eye
- one photopigment
65
Cones- Distribution
- multiple photopigments
- around 5 million in each eye
- spike in the number of cones by the fovea
66
Visible light spectrum
We only detect b/n 400-700nm of light
| 400- ultraviolet, 700- infrared
67
Optic Chiasm
X-shaped structure formed by the crossing of the optic nerves in the brain
68
Lateral geniculate nucleus
a relay center in the thalamus for the visual pathway
69
Visual Striate Cortex
The part of the visual cortex that is involved in processing visual information and first receives info from the lateral geniculate nucleus.
70
Occipital Cortex
primarily responsible for visual processing. It contains the primary and association visual cortex
71
Sound
Vibrations in a medium that cause pressure changes or waves
72
Frequency
The number of times per second that a pattern of pressure change repeats. Perceived as pitch
73
Amplitude
The magnitude of displacement of a sound pressure wave. Perceived as loudness
74
Outer ear
Contains the pinna and tympanic membrane
75
Pinna
the outer segment of the ear, shaped to collect and funnel sound toward the tympanic membrane
76
Tympanic Membrane
also known as the eardrum. Transfers sound energy from air to the ossicle
77
Hair Cells
Transduce mechanical movement from sound waves into neural activity
78
Place Theory
The brain uses the location of neural firing to understand sound
79
Frequency Theory
the more rapidly the cells fire, the higher the perception of the pitch
80
Interpreting sound
2 theories: place & frequency theory
81
Thermoreceptors
Signals info about changes in skin temp. Also responds to chemical stimuli. 2 distinct populations: warm and cold fibers
82
Nociceptors
Transmit info about painful stimulation that causes damage to the skin. Mix of signals transduced: mechanical, thermal, and chemical
83
Middle Ear
Contains 3 ossicles, tiny bones responsible for amplifying sound arriving at the eardrum to the oval window (small membrane) of the cochlea
84
Ossicles
Malleus
Incus
Stapes
85
Inner ear
Helps you hear and maintain your balance. Contains the cochlea
86
Cochlea
Fluid-filled, coiled structure with two membranes, creating 3 canals
87
Basilar Membrane
Where the hair cells (sound transduction) are located
88
Tectorial Membrane
Floats above and connects to hair cells
89
Sound localization
Detecting objects' location in space requires binaural cues
90
Binaural cues (def)
Auditory cues that require comparison from both ears
91
Interaural time differences
differences in arrival times at each ear
92
Interaural level differences
differences in the intensity of sounds that reach each ear
93
Phantom words
Although everyone hears the same stimulus, perceptions differ based on our prior knowledge.
94
Tonotopic organisation:
The spatial organization of the basilar membrane is maintained through the auditory pathway
95
The auditory pathway
1. Auditory information travels to the medial geniculate nucleus of the thalamus.
2. Info then travels to the auditory cortex in temporal lobes.
96
Mechanoreceptors (def)
transduce mechanical stimulation (pressure) into touch sensation
97
Mechanoreceptors (types)
Merkel receptor, Meissner Corpuscle, Ruffini cylinder, Pacinian corpuscle
98
Merkel receptor
Application and removal of pressure (constant firing while pressure applied)
99
Meissner Corpuscle
Application and removal of pressure (fire only during the application and removal –changes in pressure)
100
Ruffini cylinder
Interpret stretch of skin
101
Pacinian corpuscle
Vibration and texture
102
Somatosensory Pathway
Info is relayed via the thalamus to the contralateral parietal lobe.
103
Somatotopic homunculus
- Spatial mapping of the somatosensory cortex in correspondence to spatial events on the skin
- Adjacent points on your skin are represented by adjacent points on the somatosensory cortex
104
Body Schema Modifications
visual input integrates with and even overrides our conscious body image
105
Split Brain Patients
Corpus callosum is severed –communication between the left and right hemisphere is impaired
If a split-brain patient sees an object in the right visual field, this is projected to the left hemisphere and they are able to name the object. When a patient sees an object with their left visual field (which projects to the right hemisphere) they cannot name the object (no access to language system on left hemisphere)
106
What hemisphere is the language center located in
Left
107
The interpreter
The neuro-psychological concept proposed by Michael Gazzaniga to explain narrative. Causal explanations (narrative) are generated by the left-hemisphere
