Sensation and perception Flashcards
1
Q
Which cells in the retina fire action potentials?
A
ganglion cells
2
Q
Scotopic system
A
rods - works in dim light
3
Q
Photopic system
A
cones- require more light and require more light
4
Q
The visual system responds to a band of electromagnetic radiation, measured in
A
quanta
5
Q
Each quantum has a
A
wavelength
6
Q
Quanta of light energy with visible wavelengths are called
A
photons
7
Q
Retina contains
A
both rods and cones
8
Q
The fovea contains
A
only cones
9
Q
The retina contains stacks of disks that react to light and release neurotransmitters onto
A
bipolar neurons
10
Q
In rods, quanta of light are captured by the photopigment
A
rhodopsin
11
Q
Photopigments consist of two parts
A
Retinal and opsin
12
Q
When light activates rhodopsin, retinal
A
dissociates and the opsin is activated
13
Q
A cascade of events produces a ____ of rods or cones.
A
hyperpolarization
14
Q
The magnitude of the hyperpolarization determines the
A
reduction in neurotransitters
15
Q
The visual system tracks changes in
A
light
16
Q
receptive field of a sensory cell
A
consists of the stimulus region and the features that excite or inhibit the cell
17
Q
At rest, photoreceptors
A
steadily release glutamate
18
Q
Glutamate depolarizes some bipolar cells and hyperpolarizes others, depending on
A
the type of glutamate receptor the cell possesses.
19
Q
On-center bipolar cells
A
turning light on in the center excites them
They receive less glutamate, which normally inhibits on-center bipolar cells.
20
Q
Off-center bipolar cells
A
turning off light in the center of the field excites the cells
They receive more glutamate and are depolarized
21
Q
Bipolar cells release glutamate, which always depolarizes
A
ganglion cells
22
Q
On-center bipolar cells excite
A
on-center ganglion cells when light is turned on
23
Q
Off-center bipolar cells excite
A
off-center ganglion cells when light is turned off
24
Q
Range fractionation
A
receptors with different thresholds handle different intensities.
25
Two main factors contribute to photoreceptor adaptation
Calcium (Ca2+) regulation
Amount of photopigment available
26
Visual field
The whole area you can see without moving your head or eyes
27
Visual acuity
Sharpness of vision; falls off towards the periphery of the visual field
28
Visual acuity is best in the
fovea
29
Optic disc
where blood vessels enter and leave the eye
30
Blind spot
due to lack of photoreceptors in the optic disc/ optic nerve
31
Rod input converges on
ganglion cells in the scotopic system.
32
Saccades
constantly shift the eyes so that adaptation doesn’t cause the scene to disappear
33
Information from nasal half of retina crosses to opposite hemisphere at
the optic chiasm
34
90% of axons go to
Lateral geniculate nucleus (LGN), V1 (primary visual receiving area of the cortex)
35
10% of axons go to
Superior colliculus (SC), Pulvinar nucleus of the thalamus
36
Striate cortex
primary visual cortex (v1)
37
extrastriate cortex
visual cortical areas outside of the striate cortex
38
Ventral pathway
"what" pathway
object identification
39
Dorsal pathway
"where" pathway
object location or motion
40
Sensation
The registration of physical stimuli from the environment by the sensory organs
41
Perception
Subjective interpretation of sensations by the brain
42
Perception involves an interaction between
physical stimuli and the context surrounding them (including our previous experiences)
43
Luminance
Physical measure of light intensity
44
Brightness
The perceptual experience of light and dark elicited by different intensities of light
45
Hue
perceptual process of viewing color
"color" is a hue
46
Color has three perceptual qualities
Hue
Saturation
Brightness
47
V4
primary receiving area for color
48
lesions to v4 cause
achromatopsia- see in shades of light to dark
49
illusory motion leads to neural activity
in motion areas
50
Sound wave
wave-like changes in air pressure
51
A pure tone is described by two measures
amplitude and frequency
52
Amplitude
loudness, measured in decibels (dB)
53
Frequency
number of cycles per second
pitch- measured in hertz (Hz)
54
Complex sounds can be broken down into their component frequencies
A sound contains a fundamental, or basic, frequency—harmonics are multiples of that frequency.
55
Timbre
Characteristic sound quality of an instrument, related to the intensities of harmonics.
56
Sound, a mechanical force, is ____ into neural activity.
transducted
57
The external ear and the pinna funnel sound waves into the
ear canal
58
middle ear
concentrates sound energies.
59
Three ossicles
malleus, incus, and stapes—connect the tympanic membrane (eardrum) to the oval window.
60
Inner ear structures
convert sound into neural activity.
61
Mammals have a fluid-filled
cochlea
62
parts of the cochlea
base and apex.
63
the cochlea has three parallel canals
Scala vestibuli—vestibular canal
Scala media—middle canal
Scala tympani—tympanic canal
64
round window
membrane that separates the scala tympani from the middle ear
65
organ of Corti has three main structures
-Sensory cells, or hair cells
-Framework of supporting cells
-Basilar membrane, which vibrates in response to sound
66
Sound vibrations cause the basilar membrane to
oscillate
67
High frequency sound displaces the narrow base of
basilar membrane
68
Low frequency sound displaces the
wider apex
69
The organ of Corti has two sets of sensory cells:
Inner hair cells (IHCs)
Outer hair cells (OHCs)
70
Stereocilia
protrude from each hair cell
71
OHCs extend into the
tectorial membrane, which is on top of the organ of Corti.
72
Afferent nerve fibers carry messages from
hair cells to the brain.
73
Efferent nerve fibers send messages from
the brain to hair cells
74
Tip links
Thin fibers that run across the tips of the hair cell’s stereocilia
75
Vibration makes stereocilia sway, creating tension on the tip links that then open the
ion channels
76
The hair cell depolarizes, and calcium influx at the base of the cell causes
neurotransmitter release
77
Output of the cochlear nuclei travels to multiple targets:
Superior olivary nuclei—receive bilateral input
Inferior colliculi—in the midbrain
Then to the medial geniculate nuclei in the thalamus
Then to auditory cortical areas
78
~60% of auditory information goes to the
contralateral auditory cortex
79
All levels of the auditory pathway have
tonotopic organization
-arranged in a map according to the frequencies to which they respond
80
A1
primary receiving area for auditory information
81
Sound has 3 physical properties:
Frequency
Amplitude
Complexity
82
three perceptual qualities of sound
Pitch
Loudness
Timbre
83
Three kinds of taste papillae are distributed on the tongue:
Circumvallate papillae
Foliate papillae
Fungiform papillae
84
Each papillae holds one or more
taste buds
sit between the crevices of the papillae
85
taste buds consist of 50-100
taste receptor cells
86
Taste cells extend cilia into the
taste pore
87
taste pore 👅
the opening at the surface of the taste bud, to expose them to tastants.
88
Five basic tastes:
salty
sour (acidic)
sweet
bitter
Umami (savory)
89
Salty taste is due to
Sodium (Na+) ions are transported across taste cell membranes, causing depolarization that sends information to the brain.
90
Sour ☣️
-All acids release hydrogen ions (H+).
-Sour taste cells all seem to contain the PKD2LI ion channel protein.
This same receptor detects carbonation in drinks.
-H+ ions block K+ channels, preventing K+ from leaving the cell
-Results in depolarization, opens voltage-gated Ca2+ channels, causes neurotransmitter release
91
sweet, bitter, and umami 🚸
all appear to stimulate G-protein-coupled receptors that cause a cascade of intracellular events.
92
Sweet tastants are detected by
a heterodimer of two T1R receptors: T1R2 and T1R3.
93
Bitter is detected by
T2R receptors
94
Umami is a meaty, savory flavor detected by
a type of metabotropic glutamate receptor.
-Monosodium glutamate (MSG) stimulates this receptor.
-A second probable umami receptor is a heterodimer of T1R1 and T1R3 receptors.
-Selectively responds to most of the 20 standard amino acids in our diet.
95
Gustatory Pathway
Cranial nerves
Nucleus of the solitary tract in the medulla
Ventral posterior medial nucleus of thalamus
Primary gustatory cortex
Insula and frontal operculum
Secondary gustatory cortex
Orbitofrontal cortex
96
Pattern coding
Tastes may be based on temporal patterns of action potentials
97
Taste may be a system of labeled lines
inactivating one taste quality leaves the perception of other taste qualities intact.
98
Flavour is the perception of
taste and smell together
99
The sense of smell starts with receptor neurons in the nose—within the
olfactory epithelium.
100
Three types of cells in the epithelium
Olfactory receptor neurons
Supporting cells
Basal cells
101
Each olfactory receptor cell has an apical dendrite that extends to the
mucosal surface.
102
Cilia emerge from the
dendritic knob
103
Curved surfaces in the nasal cavity, called ____, direct airflow.
turbinates
104
Once at a receptor cell, odorants interact with receptors on the
cilia and dendritic knob.
105
The G olf protein is activated, triggering production of
second messengers
106
Olfactory receptor cell axons end in the
olfactory bulb
107
The olfactory bulb is organized into many ____ :roughly spherical units
glomeruli
108
Olfactory receptor axons synapse onto the dendrites of
mitral cells within the glomeruli and conduct smell information directly to cortex and other brain regions
109
Primary olfactory (pyriform or piriform) cortex
Primarily ipsilateral
Junction of frontal and temporal cortices
Goes to medial dorsal nucleus of the thalamus AFTER processing in piriform cortex
110
Secondary olfactory cortex is in the
orbitofrontal cortex
111
Superior colliculus
separates visual only and multimodal layers
spatial maps of visual, auditory, and tactile space
information is integrated if spatially and temporally aligned
112
Junctions of cortical areas
parieto-occipital and tempo-parietal
113
synesthesia
inappropriate connections between modalities that leads to abnormal perceptions
114
possible cause of synesthesia
improper synaptic pruning during infancy, likely a genetic component
115
most common type of synesthesia
color-grapheme
vision-audition also common
