Exam 5--FINAL Flashcards
(385 cards)
1
Q
For the “artificial eyes” discussed in this unit, what kind of damage would they be helpful for?
A
Instances in which the patient still has rods and cones but they no longer appear to be working.
2
Q
electromagnetic spectrum
A
continuum of electromagnetic energy that extends from very-short-wavelength gamma rays to long-wavelength radio waves. Visible light is a narrow band within the spectrum.
3
Q
What kind of damage would “artificial eyes” offer little hope for?
A
People born with cataracts or blind since birth because of completely destroyed or missing rods and cones. And one of the most common genetic forms of blindness, a retina-degrading disease called retinitis pigmentosa, and for people with some rare eye diseases.
4
Q
Nociceptors
A
specialized cell receptors that respond to tissue damage or potential damage
5
Q
What is the direct pathway model of pain? What evidence led researchers to question this model of pain perception?
A
This model says that pain occurs when specific nociceptor receptors in the skin are stimulated and send their signals directly from the skin to the brain. Researchers started questioning this when pain was noted to be affected by factors in addition to stimulation of the skin.
6
Q
What is the gate control model of pain?
A
In this model there are additional pathways that influence the signals sent from the spinal cord to the brain. Nociceptors, mechanoreceptors, and central control impact the transmission cell that “creates” pain.
7
Q
How do nociceptors impact the gate control model of pain?
A
They send excitatory signals to the transmission cell (causing pain). Excitatory signals from the neurons in the dorsal horn “open the gate” and increase the firing of the transmission cells (more pain).
8
Q
Presbyopia
A
the inability of the eye to accommodate due to hardening of the lens and a weakening of the ciliary muscles. It occurs at people get old.
9
Q
How do mechanoreceptors impact the gate control model of pain?
A
When activity in the mechanoreceptors reach the dorsal horn inhibitory signals “close the gate” and decrease the firing of the transmission cells (less/no pain).
10
Q
Central control
A
information related to cognitive functions such as expectation, attention, and distraction
11
Q
How does central control impact the gate control model of pain?
A
Similar to mechanoreceptors, activity coming down from the brain also closes the gate and decreases transmission cell activity, thus decreasing pain.
12
Q
Give an example of when expectation influenced pain
A
the placebo effect makes a patient expect some sort of medical relief, thus creating relief completely or partially. An interesting fact about placebos is that they can attach themselves to particular parts of the body (meaning your hand can be in pain while your foot is impacted by a placebo)
13
Q
Give an example of when shifting attention influenced pain
A
not feeling pain until you see the blood, or playing a video game while changing the bandages of burn victims.
14
Q
Isomerization
A
change in the shape of the retinal part of the visual pigment molecule that occurs when the molecule absorbs a quantum of light. Isomerization triggers the enzyme cascade that results in transduction from light energy to electrical energy in the retinal receptors.
15
Q
Pain matrix
A
subcortical structors (hypothalamus, amygdala, thalamus, and areas of the cortex: somatosensory cortex/S1, anterior cingulate cortex/ACC, the prefrontal cortex/PFC, and the insula)
16
Q
Describe the multimodal nature of pain
A
Pain is made up of both sensory (throbbing, dull, prickly) and emotional/affective (torturing, annoying, sickening) experiences
17
Q
Pain
A
an unpleasant sensory and emotional experience
18
Q
Opiods
A
chemicals such as opium and heroin that impact pain perception and attach themselves to receptor sites. These receptor sites are the same receptors that are activated by endorphines
19
Q
Endorphines
A
endogenous (naturally occurring) morphine
20
Q
Explain how people are impacted by watching other people being touched/hurt/etc.
A
Empathetic people are more likely to experience more pain while watching someone else in pain than people who are not classified as highly empathetic
21
Q
What is the relation between heat and cold receptors–do we use the same receptors to sense both heat and cold?
A
We use thermo-receptors to feel temperature. They do not respond to anything other than temp. And there a different receptors for each. These receptors can feel radiant and touched temp.
22
Q
Visual pigment bleaching
A
the change in the color of a visual pigment that occurs when visual pigment molecules are isomerized by exposure to light.
23
Q
Where do the heat receptors project to? Where do the cold receptors project to?
A
Heat is projected to S1 and cold is projected to SII.
24
Q
As the temperature increases, what happens to the response of a heat receptors? As the temperature decreases, what happens to the response of a cold receptors?
A
1) increase firing rate as temperature rises or falls ( at least to a certain extent)2) continue to fire so long as high/low temperature remains3) decreases firing rate as temperature decreased/increased
25
What is naloxone? How is it used in relation to pain?
A medical drug that is often injected into a person who has overdosed on heroin. It can almost immediately reverse the effects because it attached to the receptor sites that are usually occupied by heroin and blocks the action of the drug.
26
Describe the phantom limb phenomenon in relation to pain
People who have had a limb amputated can often feel as though the limb is still there, as well as, continue experiencing pain in the limb. Removal of pain nerves and cells does not affect the pain, thus informing us that pain is also mental.
27
What is a T-cell (pain section)?
A transmission cell affects pain, as in the increase of activity of a t-cell will result in more pain while a decrease in activity reduces pain.
28
Explain the mirror box treatment associated with phantom limb pain
placing your hand in a box with a mirror that gives the illusion that your other hand is in the box too is know to impact the pain associated with a clenched fist that an amputee might be feeling from their phantom limb. Having a realistic and "perfect" set up is necessary in creating the illusion.
29
Medial lemniscal pathway to the brain
large, fast fibers that are associated with kinesthesis (limb position) and touch. This pathway projects to S1
30
Rod spectral sensitivity curve
the curve plotting visual sensitivity versus wavelength, for rod vision. This function is typically measure when the eye is dark adapted by a test light presented to the peripheral retina.
31
Large-diameter fibers (L-fibers)
are associated with high thresholds and sharp bursts of pain because they adapt more quickly than the slow fibers (meaning they slow back down after the pain starts). They respond to heat and pressure. Mechanoreceptors
32
Small-diameter fibers (S-fibers)
are associated with duller, throbbing, and long-lasting pain. They respond to heat, pressure, cold, and noxious chemicals. Nociceptors
33
What are some of the functions of the odor perception?
not in book
34
What is the difference between the detection threshold and the recognition threshold?
The odor detection threshold is the lowest concentration of a certain odor compound that is perceivable by the human sense of smell. Odor recognition threshold?
35
What are some factors that need to be taken into account when measuring the detection threshold and the difference threshold?
not in book
36
Cornea
the transparent focusing element of the eye that is the first structure through which light passes as it enters the eye. The cornea is the eye's major focusing element.
37
Olfactory Receptor Neurons
There are 350 different types of ORNs in the mucosa in humans and there are about 10,000 of each type (aka millions of ORNs. They are responsible for "coding" each smell molecule that comes in.
38
Glomeruli
small structures in the olfactory bulb that receive signals from similar olfactory receptor neurons. One function of each glomerulus is to collect information about a small group of odorants.
39
Olfactory receptors
a protein string that responds to odor stimuli
40
Optic Nerve
bundle of nerve fibers that carry impulses from the retina to the lateral geniculate nucleus and other structures. Each optic nerve contains about 1 million ganglion cell fibers.
41
What is calcium imaging in regards to odor recognition?
When an olfactory receptor responds, the concentration of calcium ions increases inside the ORN. Calcium images involves soaking olfactory neurons in a chemical that causes the ORN to fluoresce with a green glow when exposed to UV light. Increased calcium decreases the glow.
42
Odorant's recognition profile
The pattern of activation for each odorant, indicating which ORNs are activated by the odorant
43
What is optical imaging in regards to odor recognition?
can be used to measure the activity of large areas of the olfactory bulb by measuring how much red light is reflected from the olfactory bulb. The area of the brain that has been activated will produce less red light.
44
Chemotopic map in olfactory
the pattern of activation in he olfactory system in which chemicals with different properties create a "map" of activation based on these properties. Also called Odor Map.
45
How have optical imaging and the 2-deoxyglucose technique been used to determine a chemotopic map on the olfactory bulb?
These imaging techniques show that certain smells are associated with certain firings from specific groups ORN's thus allowing us to map particular areas associated with different smells.
46
Spectral sensitivity curve
the function relating a subject's sensitivity to light to the wavelength of the light The spectral sensitivity curves for rod and cone vision indicate that the rods and cones are maximally sensitive at 500nm and 560 nm, respectively.
47
Visual acuity
the ability to resolve small details
48
How are odors represented in the piriform cortex and how is it different from the olfactory bulb?
orderly activation pattern in the olfactory bulb no longer exists in the piriform cortex. Activity associated with a single chemical is spread out over a large area, which large spaces between active neurons.
49
What is it like when smelling something for the first time?
This can be compared to creating a new memory. You smell something and the ORNs are alerted, once you smell something again a connection between these ORNs may be present, and then after multiple encounters with the smell you may have the ability to recognize the odor.
50
Retronasal route
The opening from the oral cavity, through the nasal pharynx, into the nasal cavity. This route is the basis for the way smell combines with taste to create flavor.
51
Nasal pharynx
A passageway that connects the mouth cavity and the nasal cavity
52
Flavor
the combination of taste and smell
53
Give an example of when expectations about taste impacted taste judgements and brain response
Wine tasting based on the price of wine impacts your judgement of the taste; however, wine that has not been labeled with price is not
54
Give an example of when satiety impacted flavor
Food appears to have a better taste when you are hungry vs when you are full
55
What is the Proust effect?
the connection between taste and olfaction associated with the recall of a memory. There is a little hard evidence supporting this claim; however, we know it is true.
56
Can newborns taste?
Yes, we know this because of facial expressions. We also know that during pregnancy and during breast-feeding, a baby is influenced by the health choices that the mother makes.
57
Across-fiber patterns
the pattern of nerve firing that stimulus causes across a number if neurons. Also referred to as distributed coding.
58
Amiloride
a substance that blocks the flow of sodium into taste receptors
59
Amygdala
a subcortical structure that is involved in emotional responding and in processing olfactory signals
60
Anosmia
loss of the ability to smell due to injury or infection
61
Bimodal neuron
a neuron that responds to stimuli associated with more than one sense.
62
Primary cells
?
63
Macrosmatic
having a keen sense of smell; usually important to an animal's survival
64
Microsmatic
having a weak sense of smell; this usually occurs in animals like humans, in which the sense of smell is not crucial for survival
65
Neurogenisis
the cycle of birth, development, and death of a neuron. This process occurs for the receptors of olfaction and taste.
66
Nontaster
a person who cannot taste the compound phenylthiocarbamide
67
Nucleus of the solitary tract
the nucleus in the brain stem that receives signals from the tongue, the moth and the larynx transmitted by the chorda tympani, glossopharyngeal, and vagus nerves
68
Olfactory mucosa
the region inside the nose that contains the receptors for the sense of smell. There are 4 zones and a particular ORN type can be found in only one zone.
69
Olfactory receptor neurons (ORNs)
sensory neurons located in the olfactory mucosa that contain the olfactory receptors
70
Orbital frontal cortex (ORC)
an area in the frontal love, near the eyes, that receives signals originating in the olfactory receptors. Also known as the secondary olfactory cortex.
71
Papillae
ridges and valleys on the tongues, some of which contain taste buds. There are four types of papillae: filiform, fungiform, foliate, and circumvallate
72
Pheromone
chemical signal released by an individual that affects the physiology and behavior of other individuals
73
Piriform cortex (PC)
an area under the temporal love that receives signals from glomeruli in the olfactory bulb. Also called the primary olfactory cortex.
74
Supertaster
a person who is especially sensitive to 6-n-prophylthiouracil (PROP), a bitter substance. More prevalent in females.
75
Taste bud
a structure located within papillae on the tongue that contains the taste cells
76
Taste cell
cell located in taste buds hat causes the transduction of chemical to electrical energy when chemicals contact receptor sites or channels located at the top of this cell.
77
Taste pore
an opening in the taste bud through which the tips of taste cells protrude. When chemicals enter a taste pore. they stimulate the taste cells and result in transduction
78
Taster
a person who can taste the compound phenylthiocarbimide. They typically have a higher density of taste buds than non-tasters and have specialized receptors that non-tasters lack.
79
Odetype
group of odorants with a specific chemical feature that determines firing rate
80
What are the 5 taste receptors?
bitter, sweet, sour, salty, umami
81
Describe the relation between signals from the mechanoreceptors, signals from the nociceptors, the medial lemniscal pathway, and the spinothalamic pathway
Signals from the mechanoreceptors are carried primarily on the medial lemniscal pathway and those from the nociceptors primarilybon the spinothalamic pathway
82
In which brain structure do we find first find cells that are sensitive to input from both olfaction and taste?
The orbitofrontal cortex
83
What is sound?
1) physical sound is pressure changes in the air or other medium2) perceptual sound is the experience we have when we hear
84
Describe sound in terms of pressure changes in the air
a sound stimulus occurs when the movements or vibrations of an object cause pressure changes of condensations and rarefactions.
85
Condensations in sound creation
the act of pushing the surrounding air molecules together as the diaphragm of the speaker moves out which causes a slight increase in the density of molecules near the diaphragm.
86
Rarefactions in sound creation
when the speaker diaphragm moves back in causing air molecules that were spread out to fill in the increased space
87
Pure tone
occurs when changes in air pressure occur in a pattern described by a mathematical function called a sine wave
88
Sound frequency
the number of cycles per second that the pressure changes repeat which is measured in hertz (Hz)
89
Sound amplitude
the size of the pressure change which is measured in decibels (dB) which are scaled down via Log because they grow exponentially. Amplitude and loudness is a perceptual sensation, not a physical one.
90
Audibility curve
a curve that indicates the sound pressure level (SPL) at threshold for frequencies across the audible spectrum.
91
Tone height
the perceptual experience of increasing pitch that accompanies increases in a tone's fundamental frequency
92
Tone chroma
the perceptual similarity of notes separated by one or more octaves.
93
Timbre
the quality that distinguishes between two tones that have the same loudness, pitch, and duration, but still sound different
94
Describe the sensitivity of human hearing
People are least sensitive at low and high frequencies and most sensitive at middle frequencies
95
Generally speaking, what is the psychological correlate of frequency of a pure tone?
Pitch
96
Generally speaking, what is the psychological correlate of amplitude of a pure tone?
Loudness
97
Pinna
The part of the ear that is visible on the outside of the head. It helps people localize sounds
98
Auditory canal
The canal through which air vibrations travel from the environment to the tympanic membrane. It amplifies sounds at its resonance frequency, thus making them more audible
99
Ossicles
Three small bones in the middle ear that transmit vibrations from the outer to the inner ear. One of the functions of these bones is to concentrate the sound pressure from a relatively large area on the tympanic membrane onto a much smaller area on the oval window.
100
In the middle ear, there are small muscles attached to the ossicles. What function does contraction of these muscles have?
It dampens very loud sounds, thus protecting the ear from potential damage
101
What is the role of the envelope on the traveling wave?
It traces out the point of maximum displacement to a particular sound along the length of the basilar membrane
102
What causes the de-polarization of a hair cell?
The bending of the cilia in one particular direction
103
What are the two primary factors that influence our perception of the timbre of a sound, such as a musical note?
1) Harmonic structure2) Attack and decay
104
What does the pitch we perceive corresponds to?
The rate at which the waveform repeats itself
105
What does the main characteristic frequency of an auditory neuron refer to?
The frequency of sound to which the neuron is most sensitive
106
Explain the periodicity theory of pitch perception
the pitch we perceive corresponds to the rate at which the waveform repeats itself
107
Bandpass filter
has the role of passing all frequencies between two bounds, blocking frequencies below the lower bound and above the upper bound
108
Phoneme
The smallest unit of sound that distinguishes the meaning of two words in a language
109
What is the difference between the formation of vowels and consonants?
Vowels are made with an open vocal tract; consonants are made with at least a partially closed tract
110
Fourier analysis
The idea that the basilar membrane breaks the sound down into its component frequenciesand that auditory neurons signal those individual frequencies to the brain
111
Apex (of the cochlear)
the end of the cochlear furthest from middle ear
112
Attack and Decay (in regards to sound)
Attack = the build up of sound at the beginning of the toneDecay = the decease in sound at the end of the tone.They are one of the two primary factors that influence perception of timbre.
113
Auditory receiving area (A1)
The area of the cortex, located in the temporal lobe, that is the primary receiving area for hearing.
114
Base (of the cochlea)
The part of the cochlea nearest the middle ear
115
Basilar membrane
a membrane that stretches the length of the cochlea and controls the vibration of the cochlear partition
116
Belt area
Auditory area in the temporal love that receives signals from the core area and sends signals to the parabelt area
117
Cilia
fine hairs that protrude from the inner and outer hair cells of the auditory system. Bending the cilia of the inner hair cells leads to transduction.
118
Cochlea
The snail-shaped, liquid-filled structure that contains the structures of the inner ear, the most important of which are the basilar membrane, the tectorial membrane, and the hair cells.
119
Cochlear implant
a device in which electrodes are inserted into the cochlea to create hearing by electrically stimulating the auditory nerve fibers. This device is used to restore hearing in people who have lost their hearing because of damaged hair cells.
120
Cochlear partition
A partition in the cochlea, extending almost its full length, that separates the scala tympani and the scala vestibuli. the organ of Corti, which contains the hair cells, is part of the cochlear partition.
121
Decibel (dB)
A unit that indicates the pressure of a sound stimulus relative to a reference pressure: dB=20log(P/Psub0) whee P is the pressure of the tone and Psub0 is the reference pressure.
122
Tympanic membrane/Eardrum
The membrane located at the end of the auditory canal that vibrates in response to pressure changes. This vibration is transmitted to the bones of the middle ear.
123
Equal loudness curves
A curve that indicates the sound pressure levels that result in a perception of the same loudness at frequencies across the audible spectrum.
124
First harmonic/Fundamental Frequency
The first harmonic of a complex tone; usually the lowest frequency in the frequency spectrum of a complex tone. The tone';s other components, called higher harmonics, have frequencies that are multiples of the fundamental frequency.
125
Frequency spectrum
A plot that indicates the amplitude of the various harmonics that make up a complex tone. Each harmonic is indicated by a line that is positioned along the frequency axis, with the height of the line indicating the amplitude of the harmonic.
126
Hair cells (ear)
Inner - auditory receptor cell in the inner ear that is primarily responsible for auditory transduction and the perception of pitchOuter - auditory receptor cells in the inner ear that amplify the response of inner hair cells by amplifying the vibrations of the basilar membrane.
127
Harmonics
Pure-tone components of a complex tone that have frequencies that are multiples of the fundamental frequency.
128
Hert (Hz)
The unit for designating the frequency of a tone. One Hertz equals one cycle per second.
129
Incus
The second of the three ossicles of the middle ear. It transmits vibrations from the malleus to the stapes
130
Inner Ear
The innermost division of the ear, containing the cochlea and the receptors for hearing.
131
Malleus
The first of the ossicles of the middle ear. Receives vibration from the tympanic membrane and transmits these vibrations to the incus
132
Middle ear and muscles
Middle ear - the small air-filled space between the auditory canal and the cochlea that contains the ossiclesMiddle-ear muscles - muscles attached to the ossicles in the middle ear. The smallest skeletal muscles in the body, they contract in response to very intense sounds and dampen the vibration of the ossicles.
133
Missing fundamental
the phenomenon in which you can still recognize a tone when the fundamental wave is missing (?)
134
Noise-induced hearing loss
a form of sensorineural hearing loss that occurs when load noises cause degeneration of the hair cells
135
Octave
tones that have frequencies that are binary multiples of each other (2,4, etc.). For example, a 800-Hz tone is one octave above a 400-Hz tone
136
Organ of corti
the major structure of the cochlear partition, containing the basilar membrane, the tectorial membrane, and the receptors for hearing.
137
Outer ear
The pinna and the auditory canal.
138
Oval window
a small, membrane-covered hole in the cochlea that receives vibrations from the stapes
139
Parabelt area
Auditory area in the temporal love that receives signals from the belt area.
140
Phase locking
firing of auditory neurons in synchrony with the phase of an auditory stimulus.
141
Place theory of hearing
the proposal that the frequency of a sound is indicated by the place along the organ of Corti at which nerve firing is highest. Modern place theory is based on Bekesy's traveling wave theory of hearing.
142
Presbycusis
a form of sensorineural hearing loss that occurs as a function of age and is usually associated with a decrease in the ability to hear high frequencies. Since this loss also appears to be related to exposure to environmental sounds, it is also called sociocusis.
143
Pure Tone
a tone with pressure changes that can be described by a single sine wave.
144
Resonance
a mechanism that enhances the intensity of certain frequencies because of the reflection of sound waves in a closed tube. Resonance in the auditory canal enhances frequencies between about 2000 and 5000 Hz.
145
Resonant frequency
the frequency that is most strongly enhanced by resonance. The resonance frequency of a closed tune is determined by the length of the tube.
146
Scala tympani
273
147
Scala vestibule
273
148
Sound pressure level (SPL)
a designation used to indicate that the reference pressure used for calculating a tone's decibel rating is set to 20 micropascals, near the threshold in the most sensitive frequency range for hearing.
149
Sound wave
pattern of pressure changes in a medium. Most of the sounds we hear are due to pressure changes in the air although sounds can be transmitted through water and solids as well.
150
Stapes
the last of the three ossicles in the middle ear. It receives vibrations from the incus and transmits these vibrations to the oval window of the inner ear.
151
Tectorial membrane
a membrane that stretches the length of the cochlea and is located directly over the hair cells. Vibrations of the cochlear partition cause the tectorial membrane to bend the hair cells by rubbing against them.
152
Temporal coding
the connection between the frequency of a sound stimulus and the timing of the auditory nerve fiber firing.
153
Tonotopic map
an ordered map of frequencies created by the responding of neurons within structures in the auditory system. There is a tonotopic map of neurons along the length of the cochlea, with neurons at the apex responding best to low frequencies and neurons at the base responding best to high frequencies.
154
Traveling wave
in the auditory system, vibration of the basilar membrane in which the peak of the vibration travels from the base of the membrane to its apex.
155
Transduction
In the sense, the transformation of environmental energy into electrical energy. For example, the retinal receptors transduce light energy into electrical energy.
156
What are the 3 types of pain
inflammatory, neuropathic, nociceptive
157
Inflammatory pain
cause by damage to tissue or inflammation of joints or by tumor cells
158
Neuropathic pain
caused by lesions or other damage to the nervous system (ex. carpal tunnel, brain damage from stroke)
159
Nociceptive pain
pain caused by activation of receptors in the skin called nocicpetors
160
Nociceptors
specialized cell receptors that respond to tissue damage or potential damage
161
What is the direct pathway model of pain? What evidence led researchers to question this model of pain perception?
This model says that pain occurs when specific nociceptor receptors in the skin are stimulated and send their signals directly from the skin to the brain. Researchers started questioning this when pain was noted to be affected by factors in addition to stimulation of the skin.
162
What is the gate control model of pain?
In this model there are additional pathways that influence the signals sent from the spinal cord to the brain. Nociceptors, mechanoreceptors, and central control impact the transmission cell that "creates" pain.
163
How do nociceptors impact the gate control model of pain?
They send excitatory signals to the transmission cell (causing pain). Excitatory signals from the neurons in the dorsal horn "open the gate" and increase the firing of the transmission cells (more pain).
164
Mechanoreceptors
specialized cell receptors that respond to non-painful tactile stimulation
165
How do mechanoreceptors impact the gate control model of pain?
When activity in the mechanoreceptors reach the dorsal horn inhibitory signals "close the gate" and decrease the firing of the transmission cells (less/no pain).
166
Central control
information related to cognitive functions such as expectation, attention, and distraction
167
How does central control impact the gate control model of pain?
Similar to mechanoreceptors, activity coming down from the brain also closes the gate and decreases transmission cell activity, thus decreasing pain.
168
Give an example of when expectation influenced pain
the placebo effect makes a patient expect some sort of medical relief, thus creating relief completely or partially. An interesting fact about placebos is that they can attach themselves to particular parts of the body (meaning your hand can be in pain while your foot is impacted by a placebo)
169
Give an example of when shifting attention influenced pain
not feeling pain until you see the blood, or playing a video game while changing the bandages of burn victims.
170
Give an example of when emotional distraction influenced pain
showing pictures of positive actions (playing sports) vs. negative actions (breaking a leg) impact the way a person feels as they stick their hand in a bucket of cold water.
171
Pain matrix
subcortical structors (hypothalamus, amygdala, thalamus, and areas of the cortex: somatosensory cortex/S1, anterior cingulate cortex/ACC, the prefrontal cortex/PFC, and the insula)
172
Describe the multimodal nature of pain
Pain is made up of both sensory (throbbing, dull, prickly) and emotional/affective (torturing, annoying, sickening) experiences
173
Pain
an unpleasant sensory and emotional experience
174
Opiods
chemicals such as opium and heroin that impact pain perception and attach themselves to receptor sites. These receptor sites are the same receptors that are activated by endorphines
175
Endorphines
endogenous (naturally occurring) morphine
176
Explain how people are impacted by watching other people being touched/hurt/etc.
Empathetic people are more likely to experience more pain while watching someone else in pain than people who are not classified as highly empathetic
177
What is the relation between heat and cold receptors--do we use the same receptors to sense both heat and cold?
We use thermo-receptors to feel temperature. They do not respond to anything other than temp. And there a different receptors for each. These receptors can feel radiant and touched temp.
178
Where are thermo-receptors located?
embedded in the epidermis and dermis
179
Where do the heat receptors project to? Where do the cold receptors project to?
Heat is projected to S1 and cold is projected to SII.
180
As the temperature increases, what happens to the response of a heat receptors? As the temperature decreases, what happens to the response of a cold receptors?
1) increase firing rate as temperature rises or falls ( at least to a certain extent)2) continue to fire so long as high/low temperature remains3) decreases firing rate as temperature decreased/increased
181
What is naloxone? How is it used in relation to pain?
A medical drug that is often injected into a person who has overdosed on heroin. It can almost immediately reverse the effects because it attached to the receptor sites that are usually occupied by heroin and blocks the action of the drug.
182
Describe the phantom limb phenomenon in relation to pain
People who have had a limb amputated can often feel as though the limb is still there, as well as, continue experiencing pain in the limb. Removal of pain nerves and cells does not affect the pain, thus informing us that pain is also mental.
183
What is a T-cell (pain section)?
A transmission cell affects pain, as in the increase of activity of a t-cell will result in more pain while a decrease in activity reduces pain.
184
Explain the mirror box treatment associated with phantom limb pain
placing your hand in a box with a mirror that gives the illusion that your other hand is in the box too is know to impact the pain associated with a clenched fist that an amputee might be feeling from their phantom limb. Having a realistic and "perfect" set up is necessary in creating the illusion.
185
Medial lemniscal pathway to the brain
large, fast fibers that are associated with kinesthesis (limb position) and touch. This pathway projects to S1
186
Spinothalamic pathway to the brain
smaller, slower fibers that are associated with pain and temperature. This pathway projects to S1.
187
Large-diameter fibers (L-fibers)
are associated with high thresholds and sharp bursts of pain because they adapt more quickly than the slow fibers (meaning they slow back down after the pain starts). They respond to heat and pressure. Mechanoreceptors
188
Small-diameter fibers (S-fibers)
are associated with duller, throbbing, and long-lasting pain. They respond to heat, pressure, cold, and noxious chemicals. Nociceptors
189
What are some of the functions of the odor perception?
not in book
190
What is the difference between the detection threshold and the recognition threshold?
The odor detection threshold is the lowest concentration of a certain odor compound that is perceivable by the human sense of smell. Odor recognition threshold?
191
What are some factors that need to be taken into account when measuring the detection threshold and the difference threshold?
not in book
192
How well can people identify odors? What is the role of memory in odor recognition?
When we have trouble identifying odors, this trouble results not from deficiency in our olfactory system, but the inability to retrieve the odor's name from our memory
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Olfactory Receptor Neurons
There are 350 different types of ORNs in the mucosa in humans and there are about 10,000 of each type (aka millions of ORNs. They are responsible for "coding" each smell molecule that comes in.
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Glomeruli
small structures in the olfactory bulb that receive signals from similar olfactory receptor neurons. One function of each glomerulus is to collect information about a small group of odorants.
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Olfactory receptors
a protein string that responds to odor stimuli
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Olfactory bulb
the structure that receives signals directly from the olfactory receptors. The olfactory bulb contains glomeruli, which receive these signals from the receptors.
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What is calcium imaging in regards to odor recognition?
When an olfactory receptor responds, the concentration of calcium ions increases inside the ORN. Calcium images involves soaking olfactory neurons in a chemical that causes the ORN to fluoresce with a green glow when exposed to UV light. Increased calcium decreases the glow.
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Odorant's recognition profile
The pattern of activation for each odorant, indicating which ORNs are activated by the odorant
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What is optical imaging in regards to odor recognition?
can be used to measure the activity of large areas of the olfactory bulb by measuring how much red light is reflected from the olfactory bulb. The area of the brain that has been activated will produce less red light.
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Chemotopic map in olfactory
the pattern of activation in he olfactory system in which chemicals with different properties create a "map" of activation based on these properties. Also called Odor Map.
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How have optical imaging and the 2-deoxyglucose technique been used to determine a chemotopic map on the olfactory bulb?
These imaging techniques show that certain smells are associated with certain firings from specific groups ORN's thus allowing us to map particular areas associated with different smells.
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Perceptual map in olfactory
A map of different odor experiences arranged on the olfactory bulb. However, we are not to this point yet (and don't know if it is even possible)
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What are the main structures in the olfactory system past the olfactory bulb?
1) the piriform cortex, which is the primary olfactory area2) the orbitofrontal cortex, which is the secondary olfactory area
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How are odors represented in the piriform cortex and how is it different from the olfactory bulb?
orderly activation pattern in the olfactory bulb no longer exists in the piriform cortex. Activity associated with a single chemical is spread out over a large area, which large spaces between active neurons.
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What is it like when smelling something for the first time?
This can be compared to creating a new memory. You smell something and the ORNs are alerted, once you smell something again a connection between these ORNs may be present, and then after multiple encounters with the smell you may have the ability to recognize the odor.
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Retronasal route
The opening from the oral cavity, through the nasal pharynx, into the nasal cavity. This route is the basis for the way smell combines with taste to create flavor.
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Nasal pharynx
A passageway that connects the mouth cavity and the nasal cavity
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Flavor
the combination of taste and smell
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Give an example of when expectations about taste impacted taste judgements and brain response
Wine tasting based on the price of wine impacts your judgement of the taste; however, wine that has not been labeled with price is not
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Give an example of when satiety impacted flavor
Food appears to have a better taste when you are hungry vs when you are full
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What is the Proust effect?
the connection between taste and olfaction associated with the recall of a memory. There is a little hard evidence supporting this claim; however, we know it is true.
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Can newborns taste?
Yes, we know this because of facial expressions. We also know that during pregnancy and during breast-feeding, a baby is influenced by the health choices that the mother makes.
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Across-fiber patterns
the pattern of nerve firing that stimulus causes across a number if neurons. Also referred to as distributed coding.
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Amiloride
a substance that blocks the flow of sodium into taste receptors
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Amygdala
a subcortical structure that is involved in emotional responding and in processing olfactory signals
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Anosmia
loss of the ability to smell due to injury or infection
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Bimodal neuron
a neuron that responds to stimuli associated with more than one sense.
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Detection threshold in relation to olfactory
the lowest concentration at which an odorant can be detected. This is different from the recognition threshold, which requires a higher concentration of odorant.
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Macrosmatic
having a keen sense of smell; usually important to an animal's survival
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Microsmatic
having a weak sense of smell; this usually occurs in animals like humans, in which the sense of smell is not crucial for survival
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Neurogenisis
the cycle of birth, development, and death of a neuron. This process occurs for the receptors of olfaction and taste.
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Nontaster
a person who cannot taste the compound phenylthiocarbamide
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Nucleus of the solitary tract
the nucleus in the brain stem that receives signals from the tongue, the moth and the larynx transmitted by the chorda tympani, glossopharyngeal, and vagus nerves
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Olfactory mucosa
the region inside the nose that contains the receptors for the sense of smell. There are 4 zones and a particular ORN type can be found in only one zone.
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Olfactory receptor neurons (ORNs)
sensory neurons located in the olfactory mucosa that contain the olfactory receptors
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Orbital frontal cortex (ORC)
an area in the frontal love, near the eyes, that receives signals originating in the olfactory receptors. Also known as the secondary olfactory cortex.
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Papillae
ridges and valleys on the tongues, some of which contain taste buds. There are four types of papillae: filiform, fungiform, foliate, and circumvallate
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Pheromone
chemical signal released by an individual that affects the physiology and behavior of other individuals
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Piriform cortex (PC)
an area under the temporal love that receives signals from glomeruli in the olfactory bulb. Also called the primary olfactory cortex.
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Supertaster
a person who is especially sensitive to 6-n-prophylthiouracil (PROP), a bitter substance. More prevalent in females.
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Taste bud
a structure located within papillae on the tongue that contains the taste cells
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Taste cell
cell located in taste buds hat causes the transduction of chemical to electrical energy when chemicals contact receptor sites or channels located at the top of this cell.
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Taste pore
an opening in the taste bud through which the tips of taste cells protrude. When chemicals enter a taste pore. they stimulate the taste cells and result in transduction
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Taster
a person who can taste the compound phenylthiocarbimide. They typically have a higher density of taste buds than non-tasters and have specialized receptors that non-tasters lack.
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Odetype
group of odorants with a specific chemical feature that determines firing rate
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What are the 5 taste receptors?
bitter, sweet, sour, salty, umami
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Describe the relation between signals from the mechanoreceptors, signals from the nociceptors, the medial lemniscal pathway, and the spinothalamic pathway
Signals from the mechanoreceptors are carried primarily on the medial lemniscal pathway and those from the nociceptors primarilybon the spinothalamic pathway
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In which brain structure do we find first find cells that are sensitive to input from both olfaction and taste?
The orbitofrontal cortex
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What is sound?
1) physical sound is pressure changes in the air or other medium2) perceptual sound is the experience we have when we hear
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Describe sound in terms of pressure changes in the air
a sound stimulus occurs when the movements or vibrations of an object cause pressure changes of condensations and rarefactions.
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Condensations in sound creation
the act of pushing the surrounding air molecules together as the diaphragm of the speaker moves out which causes a slight increase in the density of molecules near the diaphragm.
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Rarefactions in sound creation
when the speaker diaphragm moves back in causing air molecules that were spread out to fill in the increased space
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Pure tone
occurs when changes in air pressure occur in a pattern described by a mathematical function called a sine wave
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Sound frequency
the number of cycles per second that the pressure changes repeat which is measured in hertz (Hz)
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Sound amplitude
the size of the pressure change which is measured in decibels (dB) which are scaled down via Log because they grow exponentially. Amplitude and loudness is a perceptual sensation, not a physical one.
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Audibility curve
a curve that indicates the sound pressure level (SPL) at threshold for frequencies across the audible spectrum.
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Tone height
the perceptual experience of increasing pitch that accompanies increases in a tone's fundamental frequency
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Tone chroma
the perceptual similarity of notes separated by one or more octaves.
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Timbre
the quality that distinguishes between two tones that have the same loudness, pitch, and duration, but still sound different
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Describe the sensitivity of human hearing
People are least sensitive at low and high frequencies and most sensitive at middle frequencies
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Generally speaking, what is the psychological correlate of frequency of a pure tone?
Pitch
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Generally speaking, what is the psychological correlate of amplitude of a pure tone?
Loudness
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Pinna
The part of the ear that is visible on the outside of the head. It helps people localize sounds
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Auditory canal
The canal through which air vibrations travel from the environment to the tympanic membrane. It amplifies sounds at its resonance frequency, thus making them more audible
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Ossicles
Three small bones in the middle ear that transmit vibrations from the outer to the inner ear. One of the functions of these bones is to concentrate the sound pressure from a relatively large area on the tympanic membrane onto a much smaller area on the oval window.
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In the middle ear, there are small muscles attached to the ossicles. What function does contraction of these muscles have?
It dampens very loud sounds, thus protecting the ear from potential damage
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What is the role of the envelope on the traveling wave?
It traces out the point of maximum displacement to a particular sound along the length of the basilar membrane
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What causes the de-polarization of a hair cell?
The bending of the cilia in one particular direction
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What are the two primary factors that influence our perception of the timbre of a sound, such as a musical note?
1) Harmonic structure2) Attack and decay
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What does the pitch we perceive corresponds to?
The rate at which the waveform repeats itself
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What does the main characteristic frequency of an auditory neuron refer to?
The frequency of sound to which the neuron is most sensitive
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Explain the periodicity theory of pitch perception
the pitch we perceive corresponds to the rate at which the waveform repeats itself
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Bandpass filter
has the role of passing all frequencies between two bounds, blocking frequencies below the lower bound and above the upper bound
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Phoneme
The smallest unit of sound that distinguishes the meaning of two words in a language
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What is the difference between the formation of vowels and consonants?
Vowels are made with an open vocal tract; consonants are made with at least a partially closed tract
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Fourier analysis
The idea that the basilar membrane breaks the sound down into its component frequenciesand that auditory neurons signal those individual frequencies to the brain
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Apex (of the cochlear)
the end of the cochlear furthest from middle ear
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Attack and Decay (in regards to sound)
Attack = the build up of sound at the beginning of the toneDecay = the decease in sound at the end of the tone.They are one of the two primary factors that influence perception of timbre.
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Auditory receiving area (A1)
The area of the cortex, located in the temporal lobe, that is the primary receiving area for hearing.
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Base (of the cochlea)
The part of the cochlea nearest the middle ear
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Basilar membrane
a membrane that stretches the length of the cochlea and controls the vibration of the cochlear partition
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Belt area
Auditory area in the temporal love that receives signals from the core area and sends signals to the parabelt area
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Cilia
fine hairs that protrude from the inner and outer hair cells of the auditory system. Bending the cilia of the inner hair cells leads to transduction.
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Cochlea
The snail-shaped, liquid-filled structure that contains the structures of the inner ear, the most important of which are the basilar membrane, the tectorial membrane, and the hair cells.
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Cochlear implant
a device in which electrodes are inserted into the cochlea to create hearing by electrically stimulating the auditory nerve fibers. This device is used to restore hearing in people who have lost their hearing because of damaged hair cells.
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Cochlear partition
A partition in the cochlea, extending almost its full length, that separates the scala tympani and the scala vestibuli. the organ of Corti, which contains the hair cells, is part of the cochlear partition.
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Decibel (dB)
A unit that indicates the pressure of a sound stimulus relative to a reference pressure: dB=20log(P/Psub0) whee P is the pressure of the tone and Psub0 is the reference pressure.
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Tympanic membrane/Eardrum
The membrane located at the end of the auditory canal that vibrates in response to pressure changes. This vibration is transmitted to the bones of the middle ear.
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Equal loudness curves
A curve that indicates the sound pressure levels that result in a perception of the same loudness at frequencies across the audible spectrum.
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First harmonic/Fundamental Frequency
The first harmonic of a complex tone; usually the lowest frequency in the frequency spectrum of a complex tone. The tone';s other components, called higher harmonics, have frequencies that are multiples of the fundamental frequency.
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Frequency spectrum
A plot that indicates the amplitude of the various harmonics that make up a complex tone. Each harmonic is indicated by a line that is positioned along the frequency axis, with the height of the line indicating the amplitude of the harmonic.
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Hair cells (ear)
Inner - auditory receptor cell in the inner ear that is primarily responsible for auditory transduction and the perception of pitchOuter - auditory receptor cells in the inner ear that amplify the response of inner hair cells by amplifying the vibrations of the basilar membrane.
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Harmonics
Pure-tone components of a complex tone that have frequencies that are multiples of the fundamental frequency.
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Hert (Hz)
The unit for designating the frequency of a tone. One Hertz equals one cycle per second.
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Incus
The second of the three ossicles of the middle ear. It transmits vibrations from the malleus to the stapes
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Inner Ear
The innermost division of the ear, containing the cochlea and the receptors for hearing.
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Malleus
The first of the ossicles of the middle ear. Receives vibration from the tympanic membrane and transmits these vibrations to the incus
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Middle ear and muscles
Middle ear - the small air-filled space between the auditory canal and the cochlea that contains the ossiclesMiddle-ear muscles - muscles attached to the ossicles in the middle ear. The smallest skeletal muscles in the body, they contract in response to very intense sounds and dampen the vibration of the ossicles.
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Missing fundamental
the phenomenon in which you can still recognize a tone when the fundamental wave is missing (?)
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Noise-induced hearing loss
a form of sensorineural hearing loss that occurs when load noises cause degeneration of the hair cells
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Octave
tones that have frequencies that are binary multiples of each other (2,4, etc.). For example, a 800-Hz tone is one octave above a 400-Hz tone
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Organ of corti
the major structure of the cochlear partition, containing the basilar membrane, the tectorial membrane, and the receptors for hearing.
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Outer ear
The pinna and the auditory canal.
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Oval window
a small, membrane-covered hole in the cochlea that receives vibrations from the stapes
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Parabelt area
Auditory area in the temporal love that receives signals from the belt area.
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Phase locking
firing of auditory neurons in synchrony with the phase of an auditory stimulus.
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Place theory of hearing
the proposal that the frequency of a sound is indicated by the place along the organ of Corti at which nerve firing is highest. Modern place theory is based on Bekesy's traveling wave theory of hearing.
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Presbycusis
a form of sensorineural hearing loss that occurs as a function of age and is usually associated with a decrease in the ability to hear high frequencies. Since this loss also appears to be related to exposure to environmental sounds, it is also called sociocusis.
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Pure Tone
a tone with pressure changes that can be described by a single sine wave.
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Resonance
a mechanism that enhances the intensity of certain frequencies because of the reflection of sound waves in a closed tube. Resonance in the auditory canal enhances frequencies between about 2000 and 5000 Hz.
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Resonant frequency
the frequency that is most strongly enhanced by resonance. The resonance frequency of a closed tune is determined by the length of the tube.
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Scala tympani
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Scala vestibule
273
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Sound pressure level (SPL)
a designation used to indicate that the reference pressure used for calculating a tone's decibel rating is set to 20 micropascals, near the threshold in the most sensitive frequency range for hearing.
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Sound wave
pattern of pressure changes in a medium. Most of the sounds we hear are due to pressure changes in the air although sounds can be transmitted through water and solids as well.
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Stapes
the last of the three ossicles in the middle ear. It receives vibrations from the incus and transmits these vibrations to the oval window of the inner ear.
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Tectorial membrane
a membrane that stretches the length of the cochlea and is located directly over the hair cells. Vibrations of the cochlear partition cause the tectorial membrane to bend the hair cells by rubbing against them.
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Temporal coding
the connection between the frequency of a sound stimulus and the timing of the auditory nerve fiber firing.
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Tonotopic map
an ordered map of frequencies created by the responding of neurons within structures in the auditory system. There is a tonotopic map of neurons along the length of the cochlea, with neurons at the apex responding best to low frequencies and neurons at the base responding best to high frequencies.
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Traveling wave
in the auditory system, vibration of the basilar membrane in which the peak of the vibration travels from the base of the membrane to its apex.
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Transduction
In the sense, the transformation of environmental energy into electrical energy. For example, the retinal receptors transduce light energy into electrical energy.
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wavelength*
the distance between the peaks of the electromagnetic waves
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visible light *
the energy within the electromagnetic spectrum that humans can perceive. It has wavelength between 400 and 700 nanometers.
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eye
the eyeball and its contents, which include focusing elements, the retina, and supporting structures.
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Electromagnetic Spectrum
continuum of electromagnetic energy that extends from the very-short-wavelength gamma rays to long-wavelength radio waves. Visible light is a arrow band within this spectrum.
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Wavelength
for light energy, the distance between one peak of lightwave to the next peak.
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Visibal light
the band of electromagnetic energy that activates the visual system and that, therefore, can be perceived. Fo humans, visible light has wavelengths between 400 and 700 nanometers.
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What color do short/long wavelengths appear?
short wavelengths appear blue, middle wavelengths green, and long wavelengths yellow, orange, and red.
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Accomodation
(focus) in vision, bringing objects located at different distance into focus by changing the shape of the lens.
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Near Point
the distance at which the lens can no longer accommodate enough to bring close objects into focus. Objects nearer than the near point can be brought into focus only by corrective lenses.
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Presbyopia
the inability of the eye to accommodate due to hardening of the lens and a weakening of the ciliary muscles. It occurs at people get old.
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Myopia
nearsightedness-- an inability to see distant objects clearly
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Far Point
as light is moved toward the eye the distance at which the light becomes focused on the retina.
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Hyperopia
farsightedness-- a condition causing poor vision in which people can see objects that are far away but do not see near objects clearly.
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Transduction
In the senses, the transformation of environmental energy into electrical energy. For example, the retina receptors transduce light energy into electrical energy.
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Outer Segment
part of the rod and cone visual receptors that contain the light-sensitive visual pigment molecule.
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Isomerization
change in the shape of the retinal part of the visual pigment molecule that occurs hen the molecule absorbs a quantum of light. Isomerization triggers the enzyme cascade that results in transduction from light energy to electrical energy in the retinal receptors.
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Dark adaptation
visual adaptation that occurs in the dark, in which the sensitivity to light increases. This increase in sensitivity is associated with regeneration of the rod and cone visual pigments.
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Dark-adapted sensativity
the sensitivity of the eye after it has completely adapted to the dark.
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Peripheral retinal
the area of the retina outside the fovea
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About how many rods and cones are there?
120 million rods and only 6 million cones. The fovea contains only cones.
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Macular degeneration
a clinical condition that causes degeneration of the macula, an area of the retina that includes the fovea and a small surrounding area (common in older people)
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Retinitis Pigmentosa
a hereditary retinal degeneration disease that causes a gradual loss of vision, beginning in the peripheral retina creating tunnel vision and often causing complete blindness.
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Visual pigment
a light-sensitive molecule contained in the rode and cone outer segments. The reaction of the molecule to light results in the generation of electrical response in the receptors.
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Visual pigment bleaching
the change in the color of a visual pigment that occurs when visual pigment molecules are isomerized by exposure to light.
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Visual pigment regeneration
occurs after the visual pigment's two components--opsin and retinal--have become separated due to the action of light. Regeneration, which occurs in the dark, involves a rejoining of these two components to reform the visual pigment molecule. This process depends on enzymes located in the pigment epithelium.
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Rod-cone break
the point on the dark adaptation curve at which vision shifts from cone vision to rod vision.
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Monochromatic light
light that contains only a single wavelength
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Purkinje Shift
the shift from cone spectral sensitivity to rod spectral sensitivity that takes place during dark adaptation.
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Spectral sensitivity (curve)
the sensitivity if visual receptors to different parts of the visible spectrum. The Spectral sensitivity curve is the function relating a subject's sensitivity to light to the wavelength of the light. The spectral sensitivity curves for rod and cone vision indicate that the rods and cones are maximally sensitive at 500 nm and 560 nm, respectively.
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Absorbtion spectrum
a plot of the amount of light absorbed by a visual pigment versus the wavelength of light
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Cone spectral sensitivity curve
a plot of visual sensitivity versus wavelength for cone vision. Often measured by presenting a small spot of light to the fovea, which contains only cones. Can also be measured when the eye is light adapted, so cones are the most sensitive receptors.
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Rod spectral sensitivity curve
the curve plotting visual sensitivity versus wavelength, for rod vision. This function is typically measure when the eye is dark adapted by a test light presented to the peripheral retina.
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Bipolar cells
a retinal neuron that receives inputs from the visual receptors and sends signals to the retinal ganglion cells.
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Blind spot
the small area where the optic nerve leaves the back of the eye. There are no visual receptors in this area, so mall images falling directly on the blind spot cannot be seen.
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Cone
cone-shaped receptors in the retina that are primarily responsible for vision in high levels of illumination and for color vision and detail vision.
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Cone spectral sensitivity curve
a plot of visual sensitivity versus wavelength for con vision Often measure by presenting a small spot of light to the fovea, which contains cones. Can also be measure when the eye is light adapted, so cones are the most sensitive receptors.
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Convergence
When many neurons synapse onto a single neuron
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Cornea
the transparent focusing element of the eye that is the first structure through which light passes as it enters the eye. The cornea is the eye's major focusing element.
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Fovea ganglion cells
a neuron in the retina that receives inputs from bipolar and amacrine cells. The axons of the ganglion cells are the nerve fibers that travel out of the eye in the optic nerve.
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Lens
the transparent focusing element of the eye through which light passes after passing through the cornea and the aqueous humor. The lens's change in shape to focus at different distances is called accommodation.
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Light-adapted sensitivity
The sensitivity of the eye when in the light-adapted state. Usually taken at the starting point for the dark adaption curve because it is the sensitivity of the eye just before the lights are turned off.
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Optic Nerve
bundle of nerve fibers that carry impulses from the retina to the lateral geniculate nucleus and other structures. Each optic nerve contains about 1 million ganglion cell fibers.
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Preference looking technique
a technique used to measure perception in infants. Two stimuli are presented, and the infant's looking behavior is monitored for the amount of time that infant spends viewing each stimulus.
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Pupil
the opening through which light reflected from objects in the environment enters the eye.
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Retina
a complex network of cells that covers the inside back of the eye. These cells include the receptors, which generate an electrical signal in response to lights, as ell as the horizontal, bipolar, amacrine, and ganglion cells.
357
Rod
a cylinder-shaped receptor i the retina that is responsible for vision at low levels of illumination.
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Rod monochromat
a person who has a retina in which the only functioning receptors are rods.
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Spectral sensitivity curve
the function relating a subject's sensitivity to light to the wavelength of the light The spectral sensitivity curves for rod and cone vision indicate that the rods and cones are maximally sensitive at 500nm and 560 nm, respectively.
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Visual acuity
the ability to resolve small details
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Which structures are responsible for focusing light?
Lens and cornea
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Where is the light focused? Where is it focused for objects we are looking directly at?
The retina. The fovea.
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Belongingness
the hypothesis that an area's appearance is influenced by the part of the surroundings that the area appears to belong to. This principle has been used to explain the perception of lightness in the Benary cross and White's illusion.
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Benary's Cross
A black cross with two triangles--one on the white space in the top right corner and one in a black part of the cross at the bottom. Both have the same amount of lateral inhibition, but one appears to be brighter than the other. This is thought to be because of the theory of belongingness
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Center-surround receptive fields
a receptive field that has a center-surround organization--arrangement of a neuron's receptive fields in which one area s surrounded by another area, like the hole in a donut. Stimulation of the center and surround causes opposite responses.
366
Complex cells
a neuron in the visual cortex that responds best ti moving bars with particular orientation
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Contrast threshold
the intensity difference that can just barely be seen between two areas For vision this is often measure using gratings with alternating light and dark bars.
368
Elaborate cells
?
369
End-stopped cells
a cortical neuron that responds best to lines of a specific length that are moving in a particular direction.
370
Feature detectors
a neuron that responds selectively to a specific feature of the stimulus such as orientation or direction of motion.
371
Grating stimuli
?
372
Hermann Grid
a display that results in the illusion of dark areas at the intersection of two white "corridors." This perception can be explained by lateral inhibition.
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Lateral Inhibition
Inhibition that is transmitted laterally across a nerve circuit. In the retina, lateral inhibition is transmitted by the horizontal and amacrine cells
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Mach Bands
illusory light and dark bands near a light-dark border than can be explained by lateral inhibition.
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Primary cells
?
376
Selective adaptation
a procedure in which a person or animal is selectively exposed to one stimulus, and then the effect of this exposure is assessed by testing with a wide range of stimuli. Typically, sensitivity to the exposed stimulus is decrease.
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Simple cortical cells
a neuron in the visual cortex that responds best ti bars of a particular orientation.
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Simultaneous contrast
the effect that occurs hen surrounding one color wth another changes the appearance of the surrounded color. Occurs for chromatic and achromatic stimuli.
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White's Illusion
a display in which two rectangles are perceived as differing in lightness even though they both reflect the same amount of light and even though the rectangle that is perceived as lighter received more lateral inhibition than the one perceived as darker,
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Rhodopsin
is the light-absorbing pigment in rods. Absorption of light by rhodopsin triggers a cascade of reactions involving over 12 chemicals
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What kind of damage would "artificial eyes" offer little hope for?
People born with cataracts or blind since birth
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What is the problem with using rhodopsin for these artificial eyes?
Sensitive only to blue light and people would see the world in shades of grey (aka no color vision). It likely would require a “boost” when used with humans--something like glasses to tune the lightwaves.
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What are the advantages and disadvantages of inserting the replacement pigment into ganglion cells? Into bipolar cells?
Ganglion cells are easily accessible and have more staying power. They also are the last to die-off in degenerative diseases. However, they may differ on the effects on vision and there is no binding package that can discriminate the types (20). Bipolar cells are difficult to access and injection risks detaching the retina from its support surface.
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What have been the results with mice using the replacement pigments?
We have used both bipolar and ganglion cells--in cases the cells do become light sensitive and fire an action potential in response to light. Mice are able to “pass” some simple behavioral tests like navigating a water maze, but their acuity measures ½ the acuity of normal mice.
385
How Do We Get Channelrhodopsin into Bipolar/Ganglion Cells?
Gene therapy: The protein gene is inserted into a virus and the virus is injected into the eye. The binding package of the gene is modified so that it will bind with only certain cells.
