neuro final Flashcards
1
Q
What consists of the anatomy of the human eye?
A
sclera, iris, cornea, pupil
2
Q
What are the cornea and lens important for?
A
They are important for focus and they use refraction to bend light
3
Q
What is the retina used for?
A
Its used to transduce light(to detect light)
4
Q
What is the optic nerve used for?
A
Axons that carry visual to rest of brain
5
Q
Where is an object when more refraction is needed(more focus)?
A
Near the eye
6
Q
Where is an object when less refraction is needed(more focus)?
A
Further from the eye
7
Q
What are photoreceptors made of?
A
Rods + Cones
8
Q
What do photoreceptors do
A
Light is transduced into neural activity by the photoreceptors in the retina
9
Q
How does the cellular organization of the retina go?
A
It goes from photoreceptors(light sensitive) to horizontal cells, to bipolar cells, to amacrine cells, to ganglion cells
10
Q
What do ganglion cells do?
A
They fire action potentials and send output through the optic nerve
11
Q
What do photoreceptors do for rods and cones?
A
Photoreceptors outer segments absorb light & trigger changes in the rod/cone membrane potential
12
Q
What factors are important for rods?
A
high sensitivity for night vision, achromatic, not present in fovea(low acuity)
13
Q
What factors are important for cones?
A
Low sensitivity for day vision, chromatic(3 types of pigments), concentrated in fovea(high acuity)
14
Q
What are the similarities between cones and rods?
A
They both have mitochondria’s, nucleus, synaptic vesicles, cilium, plasma membrane
15
Q
What’s the correct flow of info about light, from peripheral sensory organ to the brain
A
Photoreceptors to bipolar cells to retinal ganglion cells to optic nerve to brain
16
Q
What is the fovea a region of?
A
High visual acuity and color vision
17
Q
What do horizontal cells interact with?
A
They interact with photoceptors and bipolar cells to modify responses to light and integrate across many cells
18
Q
What causes color blindness?
A
Mutations in any of the 3 cone photopigments/opsins
19
Q
What happens if light shines strongly in this receptive field?
A
Photoreceptors release less glutamate when light shines strongly in this receptive field
20
Q
Do photoreceptors depolarize in the dark?
A
Yes, and they hyperpolarize in the light
21
Q
What does the activation of a rhodopsin molecule set off a chain reaction that leads to the ?
A
Closing of a large number of sodium channels
22
Q
what does the phototransduction on rods and cones do?
A
Phototransduction is the process by which the absorbed light triggers an electrical response (the neural signal) in rods and cones
23
Q
.Why are our eyes good at detecting light/dark edges?
A
Because of the center-surround response of ganglia cells
24
Q
Where does direct input go through to reach bipolar cells?
A
Through the receptive field center
25
Where does indirect input go through to reach bipolar cells?
Through the field surround
26
What do horizontal cells provide photoreceptors and bipolar cells?
They provide them indirect inhibitory input
27
What happens to On-Center bipolar cells in response to light?
They depolarize
28
What happens to Off-Center retinal ganglion cells in response to light?
They don't fire action potentials
29
What order are photoreceptors, off ganglion cells and off bipolar cells put in when responding to light?
Photoreceptor hyperpolarizes in light(less glutamate release) then Na+ channels-Off-bipolar cells hyperpolarize in light, then Off-ganglion cell(no AP in light)
30
What order are photoreceptors, on ganglion cells and on bipolar cells put in when responding to light?
Photoreceptor hyperpolarizes in light(less glutamate release) then metabotropic glutamate receptors-On-bipolar cells depolarize in light, then On-ganglion cell(lots of AP in light)
31
When light enters the eye, what does it pass before reaching the photoreceptors at the rear end of the retina?
In passes the ganglion cells and bipolar cells
32
What influences the membrane potential of photoreceptors, then bipolar cells, then ganglion cells?
Light
33
What is the cornea?
A protective layer on the front of the eye
34
What structures or cells of the mammalian auditory system transduces pressure changes into electrical signals that are eventually relayed to the brain?
Hair cells
35
Traveling along the basilar membrane, away from the ossicles towards the apex, does what to the frequency?
It goes from high to low
36
what does auditory transduction depend on?
K+ influx into the cell, Mechanically-gated ion channels, and the stereocilia bending
37
Do photoreceptors and hair cells generate action potentials?
No
38
What is increased intensity encoded by?
Spikes/second
39
What is auditory information transduced through?
Mechano-electrical transduce(MET)transduction
40
What is visual information transduced by?
Photoreceptor transduction
41
What is the best intervention for deafness if it is caused by deletion or mutation rendering the mechano-electrical transduce non-functional?
Cochlear implant
42
What type of somatosensory neurons transduce proprioceptive signals about the body's position in space?
A-alpha fibers(la and ib fibers)
43
What type of sensory neurons detect pain?
A-delta and c-fibers
44
Of all the somatosensory neurons, what fibers conduct the fastest and why?
A-alpha fibers(la or ib fibers) bc they have the largest diameter and are myelinated
45
What is adaptation in somatosensory?
Its a change over time to a sustained stimulus
46
What does the gate control theory of pain help explain?
Why rubbing an injury can reduce pain
47
What is hyperalgesia?
It is enhanced pain
48
What is a process that contributes to hyperalgesia?
Inflammation and release of sensitizing molecules from the immune cells
49
What type of fibers are used for pain?
Unmyelinated fibers
50
What type of ending detects pain?
Free nerve endings
51
What type of channels can pain involve?
TRP channels
52
What are the ways your body encodes information about a sensory stimulus?
Phase locking, firing frequency, cortical maps which spatially represent some feature of sensory stimulus, and population or combinatorial coding
53
Which neurotransmitter is released across the neuromuscular junction?
Acetylcholine
54
What is the primary motor cortex responsible for?
execution of movement
55
What is the premotor cortex responsible for?
Planning movement
56
Writing a letter requires which motor regions?
The primary motor(M1), premotor cortex, and supplementary motor cortex
57
Which half of the brain controls voluntary movement in the right half of the body?
The left(vice versa)
58
What is the key neurotransmitter in long-term potentiation?
Glutamate
59
What process may be involved in long-term depression to output something out of the postsynaptic membrane?
LTD may involve endocytosis or recycling of AMPA receptors out of the postsynaptic membrane
60
Sensations are constrained to what?
To what can be detected by receptors and what can be interpreted by the brain
61
individual neurons are tuned(respond strongly) to what?
To particular features of complex stimuli
62
Stimulus qualities are represented in what manner?
In an orderly manner in relevant brain regions
63
What is the general organizational flow of the auditory system?
From the auditory cells in the cochlea(in the ear), to the brainstem neurons, to the MGM of thalamus, to the auditory cortex
64
What is the general organizational flow of the visual system?
From the Photoreceptors to the other retinal neurons to the LGN of the thalamus to the visual cortex
65
What maps are key features formed by the peripheral sensory organs and refined at all levels in the brain?
Tonotopic maps and retinotopic maps
66
What are the functional evidence for TMC as the MET?
Mutation causes deafness, expressed in organ of corti, TMC1 has multiple transmembrane domains, localized near stereocilia, deletion/mutation reduces single ion channels currents(in response to mechanical stimulus)
67
How do you identify thermoreceptors?
Expression profiling leads to identification of ion channels that confer heat/cold sensitivity
68
What is the process of identifying thermoreceptors?
Capsaicin-sensitive neurons to cDNA to transfect into non-responsive cells to identify cDNA that confers sensitivity
69
What does it mean when the indirect path is inhibitory(GABA) when outputting to bipolar cells?
The effect of the surround is the opposite to the center
70
What is the process of amplification of sound?
Sound vibrates the tympanic membrane, then the tympanic membrane moves ossicles, then the ossicles vibrate fluid in cochlea at oval window
71
What effect does sound have on the basilar membrane?
It causes its displacement
72
What is the basilar membrane?
It is the base below the haircells;flexible
73
What happens to the stereocilia in response to the sound waves deflecting the basilar membrane?
Stereocilia bends
74
What does the stereocilia bending do?
It converts sound to electrical signals
75
What happens when mechanical stimulus converts to electrochemical signals?
The mechanical stimulus stretches or shortens stereocilia's tip links
76
What does it mean when the mechanical stimulus stretch in a certain direction?
It opens MET, triggers k+ influx, depolarization, neurotransmitter release
77
What are hair cells?
They are not a neuron and they maintain in the receptor potentials
78
What do afferent neurons of the auditory nerve relay to?
They relay auditory info to CNS
79
What consists of an artificial cochlea?
Bypass typical auditory transduction pathway, sound processor with microphone, coil transmits electrical signal to implant, implant has array of electrodes, placed to stimulate the auditory-vestibular nerve
80
What makes a tonotopic map?
The location(depends on tone/pitch/freq) of activated neurons
81
What is the auditory pathway from ear to brain?
Signals sent form inferior colliculus(midbrain) to medial geniculate nucleus(MGN) of thalamus to auditory cortex(A1)
82
What is the somatosensory system?
Different sensations activate different nerves(labeled line theory), different sensations activate the same nerves with different intensities, and different sensations activate different subsets of nerves(pattern theory)
83
Nerve size dictates what?
It dictates type
84
What is Aα?
Largest diameter sensory afferents(muscles)
85
What is Aβ?
Slightly smaller diameter fibers(touch)
86
What is Aδ, C?
Smaller diameter fibers(pain, itch, temperature)
87
What do TRP channels mediate?
Pain, temperature, and itch
88
What does TRPA1 respond to?
Many chemicals like cinnamic aldehyde or allcin
89
What does TRPV1 respond to?
Capsaicin, heat, histamine
90
What does TRPM8 respond to?
Menthol and cold
91
What do sensitized pain neurons result from?
Intense, sustained activation
92
Aδ, Aβ, and Aα go through which sensory pathway?
The dorsal column-medial leminscal pathway
93
Aδ and C go through which sensory pathway?
The spinothalamic pathway
94
What is the gate control theory of pain?
Activation of touch neurons can inhibit pain due to interactions between touch and pain neurons in the spinal cord
95
What does a single motor unit consist of?
one ALPHA motor neuron and all of the muscle fibers it controls
96
each muscle fiber only has
one motor neuron
97
1 alpha motor neuron has
many fibers
98
What do organization of motor neurons represent?
groups of muscles in the spinal cord
99
What can the body do to increase muscle contraction?
Increase firing rate of motor neurons and recruit additional motor units
100
What is the process of excitation-contraction coupling?
Alpha motor neuron AP then acetylcholine is released at neurotransmitter junction, then acetylcholine binds receptors which depolarizes muscle cell then the muscle cell fires an and AP causes calcium release then calcium leads to contraction which requires ATP
101
What do lateral pathways specialize in?
Distal voluntary movements
102
What do ventromedial pathways specialize in?
Posture, balance, locomotion
103
What is the knee-jerk reflex process?
Stretching stimulates sensory receptor, then sensory neuron excited, then within spinal cord, then motor neuron is exited, then effector(quads contracts to relive stretching
104
What cortical areas are involved in voluntary movement?
Primary(initiation and execution) motor cortex and the premotor(Planning) and supplementary(initiation) motor cortex
105
What are mirror neurons and what do they do?
They respond in preparation for the execution of a particular movement but also when the same action is being preformed by another individual
106
What area are mirror neurons in?
In the ventrolateral area of the premotor cortex
107
What are prediction errors?
The discrepancy between predicted and actual information
108
What relays on prediction errors?
both motor and non-motor neurons
109
What is aplysia to humans?
It is changes in synaptic strength underlying learning and memory
110
What two parts consist of memory consolidation?
Synaptic consolidation(plasticity) and system consolidation
111
What are LTP mechanisms?
Strong depolarization is needed for calcium influx through NMDA receptors
112
What is the process of LTP mechanisms?
Glutamate binds to AMPA receptors causing Na+ influx and depolarization then NMDA receptors open upon glutamate binding and cell strongly depolarized to remove Mg2+ block then Ca2+ flows through the NMDA receptors pore into the cell
113
What are the key properties to LTP?
Persistence, input specificity, cooperativity, and associativity
114
What's the goal of immunofluorescence and immunohistochemistry(IHC)?
To visualize specific proteins in tissues
115
What approach is taken on immunofluorescence and immunohistochemistry(IHC)?
With specific antibodies and stains/dyes
116
What is the process of immunofluorescence?
It goes from adding a primary antibody, to adding a secondary antibody conjugated to fluorophore then a UV light is put on it then you visualize using a fluorescence microscopy
117
What is the process of immunohistochemistry?
Add primary antibody then add secondary antibody conjugated to HRP then add chromogen HRP catalyzes reaction to produce colored precipitate then colored precipitate accumulates around location of antigen, then visualize using brightfield microscopy
118
What does IHC identify?
Different subsets of taste receptor cells
119
What is immunohistochemistry?
Stain for taste receptor proteins in a taste bud(use antibodies against ENaC and TrpM5)
120
What is the expression analysis for immunofluorescence and immunohistochemistry?
Goal: use sequencing to quantify gene expression(at RNA transcript level) and Approach: microarray and RNAseq
121
What does RNAseq do?
Counts mRNA transcripts to quantify gene expression
122
What does TTX do?
Block voltage gated sodium channels, inhibits APs firing, can cause death by respiratory failure and are present in pufferfish
123
What does APV do?
Blocks glutamate receptors(NMDA) and provides info about neurotransmitters used by cells of interest
124
What does curare do?
Blocks acetylcholine receptors(nAChR specifically) and provides info about neurotransmitters used by cells of interest
125
What is calcium imaging?
It is used to measure neural activity, you add a chemical dye or genetically encoded indicator that can change its fluorescence in response to Ca2+ then image the brain with a microscope, this results in effectively measuring activity in individual neuros since increases in Ca2+ are associated with neurotransmission
126
What is GCaMP?
Calcium indicator
127
What does calcium imaging reveal?
Properties of taste responsive cells in the brain
128
What neurons relay the signal of GCaMP?
Voltage-sensitive dyes, fluorescence of dye changes to reflect changes in membrane potential directly
129
What is current-clamp electrophysiology used for?
To learn about the type of neurons and its ion channels
130
How is current-clamp electrophysiology done?
You apply/inject a known current to mimic the current that would be produced if the cell received inputs from other neurons to measure resulting change in membrane potential
131
What is electrophysiology: patch clamp?
For small cells, patch onto outside cell rather than piercing cell, enable recording from single channel
132
What is optogenetics?
It allows selective activation of neuron with blue light causing neurons expressing Channelrhodopsin2 to spike
133
What functional brain imaging techniques exist?
Temporal resolution, Spatial resolution, and invasiveness
134
What functional imaging measures neural activity leading to changes in blood flow?
fMRI, etc
135
What functional imaging neural activity generates electrical signals?
EEG, etc
136
what is fMRI (functional magnetic resonance imaging)?
Measurement of blood oxygenation: BOLD response, poor temporal resolution(6-8sec), relatively good spatial resolution
137
What does fMRI do?
Compare relative differences in brain activity between two or more conditions(rest vs preforming)
138
What is EEG (Electroencephalogram)?
Recordings of neural activity at scalp, good temporal resolution, poor spatial resolution: space distorted by scalp, non invasive
139
What does the averaging EEG signal provide?
Event-related potential(ERP): can be measures of reaction time or response to a stimulus
140
What is GWAS?
A genome-wide association study
