1
Q
repeated communication = inc in what
A
quantal content, quantal size
2
Q
increase in quantal content and quantal size known as what
A
long term potentiation
3
Q
associating a stimulus with a response requires what
A
homosynaptic plasticity, heterosynaptic plasticity
4
Q
what is homosynaptic plasticity
A
hange in synaptic strength that occurs only at the synapse that was directly activated.
5
Q
what is heterosynaptic plasticity
A
change in synaptic strength that occurs at synapses that were not directly activated, triggered by a modulatory signal (e.g., serotonin, dopamine, NE) or a third neuron.
6
Q
classical conditioning is what
A
associative learning
7
Q
example of classical conditioning
A
Pavlov’s dog
8
Q
Aplysia claifornica has what advantages
A
small number of identified neurons, experimentally robust, has simple behaviors
9
Q
for the aplysia California, what is the US
A
tail shock which elicits strong gill retraction
10
Q
for alyplasia california, what is the CS
A
mantle touch
11
Q
association of CS and US strengthens what
A
responses to the CS
12
Q
response to the CS is strengthen how
A
via prolonged conditioning
13
Q
describe massed trials
A
trials over a short period of time, short term changes in behavior
14
Q
describe spaced trials
A
trials spread over a long period, long term changes in behavior
15
Q
electrophysiology reflects what
A
behavioral output
16
Q
what do we need to see a response between sensory neuron and motor neuron
A
available vesicles which can decrease if there is a repetitive stimulus
17
Q
unpaired pathway describe it
A
only sensory neuron is activated, less response
18
Q
paired pathway describe it
A
US and CS together, interneuron involved with shock and a lot more neurotransmitters involved, harder contraction
19
Q
What molecular
mechanisms
underlie the CS-
US association?
A
short term sensitization, coincidence detectors
20
Q
describe a coincidence detector
A
protein that detects two separate events and elicits a secondary response
21
Q
what are the 2 coincidence detectors
A
neuron activation, synaptic activity
22
Q
for coincidence detectors, what is required
A
both events must temporally overlap
23
Q
for CS pathway, what is the first step
A
serotonin is released due to shock, activates Gs, this enhances adenylyl cyclase
24
Q
second step of the CS pathway
A
AP occurs due to touch, Ca2+ influx, activates calmodulin, and enhances adenylyl cyclase
25
in the CS pathway, who is the coincidence detector
adenylyl cyclase
26
cAMP activates what
PKA
27
PKA does what
closes K+ channels and increases readily releasable vesicle pool
28
closing K+ channels does what
increases excitability, increases Ca2+ influx
29
increasing readily releasable vesicle pool does what
increases quantal content
30
molecular basis for long term memory is what
protein synthesis
31
long term changes in behavior = long term changes in
synaptic efficiency, synaptic structure
32
synaptic efficiency and synaptic structure both require what
protein synthesis
33
PKA activates what
CREB
34
CREB does what
increases persistent PKA activity = long term sensitization
induces production of synaptic proteins = long term structural changes
35
associate a predictive stimulus with an innately
meaningful stimulus
classical conditioning
36
In Aplysia, adenylyl cyclase serves as a
molecular coincidence detector
37
Short term plasticity =
sensitization (short lived)
38
sensitization = what
transient changes in excitability and quantal content t
39
Long term plasticity =
long lived bc it requires protein synthesis
40
long term plasticity results in persistent changes in what
synapse structure and thus efficiency
41
membrane resistance symbol
RM
42
internal resistance symbol
Ri
43
capacitance symbol
C
44
conductance symbol
Gion
45
current symbol
Iion
46
membrane potential symbol
Vm
47
time constant symbol
Tau
48
length constant symbol
lambda
49
equilibrium potential symbol
E ion
50
An interneuron is typically responsible for?
Wrapping around axons to ensure saltatory conduction
Targeting invaders (bacteria, viruses) in the brain
Mediating communication between afferent sensory neurons and an efferent motor neurons
Ensure the action potential spike is as strong as possible
Mediating communication between afferent sensory neurons and an efferent motor neurons
51
Which of the following is true regarding afferents in the PNS?
They project towards the CNS
The project away from the CNS
They insulate the axons of neurons
They exist in the spinal cord
They project towards the CNS
52
Of the choices below, select ALL that represent the functions of glial cells in the brain.
- Guideposts during development
Initiation of the action potential
Electrical insulation for neurons
-Assisting with neurons' cellular metabolism (supplying resources/removing waste)
-Opening of voltage-gated Na+ channels
-Send sensory input into the CNS
-Recycling of neuronal signaling materials
guideposts during development, assisting with neurons cellular metabolism, electrical insulation for neurons, and recycling of neuronal signaling materials
53
When voltage-gated Na+ channels open, Na+ will __________the neuron. There is a __________ current which __________ the membrane.
enter; positive; depolarizes
enter; negative; depolarizes
leave; negative; hyperpolarizes
leave; positive; hyperpolarizes
enter; negative; depolarizes
54
You're conducting a voltage clamp experiment using a neuron which Vrest = -68mV, EK+ = -90mV and ENa+ = 35mV. You clamp Vm at 0mV. How do you expect the ionic current to respond and why?
K+ will have a strong drive to leave the cell because it's experiencing the strongest driving force.
55
You're recording from a neuron in which Vrest = -75mV, ECl- = -70mV, EK+ = -85mV and ENa+ = 40mV. You increase permeability to Na+. True or false: This will cause Vm to depolarize because more Na+ ions will enter the cell following their chemical gradient.
true
56
You're recording from a neuron in which Vrest = -75mV, ECl- = -70mV, EK+ = -85mV and ENa+ = 40mV. You increase the intracellular (internal) concentration of K+. True or false: This will cause Vm to hyperpolarize because the chemical drive for K+ to leave the cell has increased.
true
57
Resting membrane potential depends on the differential distribution of ions, however it is mostly dictated by:
K+ ions wanting to enter the cell following their chemical gradient.
Na+ ions wanting to leave the cell following their chemical gradient.
Ca2+ ions wanting to enter the cell following their chemical gradient.
K+ ions wanting to leave the cell following their chemical gradient.
K+ ions wanting to leave the cell following their chemical gradient
58
Neuron X has half the density of K+ leak channels relative to Neuron Y. If both neurons have the same axon diameter, graded potentials will travel farther in:
Neuron X because it has a higher Rm than Neuron Y.
Neuron Y because it has a higher Rm than Neuron X.
Neuron X because it has a lower Ri than Neuron Y.
It will travel the same distance because axon diameter is equal.
Neuron X because it has a higher Rm than Neuron Y.
59
A passive potential that slightly depolarizes a neuron without reaching threshold is called...
an excitatory post synaptic potential
60
During an IPSP, the membrane hyperpolarizes. This could be due to:
K+ ions leaving.
Cl- ions entering.
Na+ ions entering.
A and B are both possible.
A and B are both possible
61
Ion channels open and close stochastically, however they are more likely to open...
...as the membrane depolarizes (as Vm increases).
...when ion concentration inside/outside the cell increases.
...if the neuron is smaller.
...during the repolarization phase of the AP.
as the membrane depolarizes
62
Which statement about refractory periods is correct?
A second AP can never be generated during the relative refractory period.
A second AP can be generated during the absolute refractory period with enough current.
A second AP can be generated during the relative refractory period with enough current.
Both refractory periods are characterized by total inactivation of ion channels in the membrane.
A second AP can be generated during the relative refractory period with enough current.
63
Which of the following create the absolute refractory period?
The absolute refractory period occurs because voltage-gated Na+ channels inactivate, so there is no inward Na+ current to be evoked.
The absolute refractory period occurs because voltage-gated K+ channels inactivate, so there is no inward Na+ current to be evoked.
The absolute refractory period occurs because neurons require at least 10ms between APs.
The absolute refractory period occurs because voltage-gated Ca2+ channels inactivate, preventing an AP.
The absolute refractory period occurs because voltage-gated Na+ channels inactivate, so there is no inward Na+ current to be evoked.
64
Myelin has several biophysical consequences. Of the options below, select ALL that are a result of myelinating an axon.
Increases Rm
Decreases capacitance
Restricts voltage-gated Na+ channels to Nodes of Ranvier
Distributes voltage-gated Na+ channels evenly across the axon
Increases AP conduction velocity
Decreases Ri
increases RM, decreases capacitance, restricts voltage gated Na+ channels to Nodes of Ranvier, increases AP conduction velocity
65
Which statement accurately describes the difference between graded potentials and action potentials?
Graded potentials are the result of major changes in membrane permeability
Graded potentials are all-or-nothing, whereas action potentials are passive and occur frequently
Action potentials decay more rapidly than graded potentials
Unlike graded potentials, action potentials do not decay
Unlike graded potentials, action potentials do not decay
66
Which ion experiences the greatest driving force at the peak of the action potential?
K+ because the Vm at the AP peak is furthest from EK+.
K+ because the Vm at the AP peak is closest to EK+.
Na+ because the Vm at the AP peak is furthest from ENa+.
Na+ because voltage-gated Na+ channels remain open for the duration of the AP spike.
K+ because the Vm at the AP peak is furthest from EK+.
67
The concentration of K+ is always higher inside a neuron at rest. Based on chemical gradients, K+ would want to leave the cell. Additionally, there are many "leak channels" in a membrane which are always open for this kind of movement. What prevents all the K+ in a neuron from rushing out of the cell at rest?
At rest the inner membrane is negative, attracting the positive charge of K+
68
Which of the following best describes the relationship between the opening of Na+ channels and gNa?
As Vm increases, channels are more likely to open, decreasing gNa.
As Vm increases, so does Rm, which causes gNa to decrease.
As Vm increases, channels are more likely to open, increasing gNa.
As Vm increases, channels are more likely to open, however gNa always remains the same.
As Vm increases, channels are more likely to open, increasing gNa.
69
What is TRUE of the nature of action potentials in regards to permeability and ion current?
K+ permeability increases once threshold is reached and voltage-gated channels open
During an AP, Vm is pulled towards ENa+ and then to EK+
During an AP membrane permeability stays unchanged for K+
A and B are true
During an AP, Vm is pulled towards ENa+ and then to EK+
70
Think of the length constant, λ. What metrics does λ depend on?
Rm and Ri
71
What is true of ionic transmembrane proteins?
They contain 6 subunits that are repeated 4x.
They contain variable numbers of subunits depending on the ion they are specific to.
They contain hydrophilic amino acids within their transmembrane domains.
They require ATP to open and close.
They contain 6 subunits that are repeated 4x.
72
What is the molecular basis of how ion channels physically open?
The S4 helix undergoes a conformational change that opens the pore.
73
What determines the speed at which voltage-gated Na+ channels inactivate?
Affinity of the inactivation particle for its TM binding site.
74
Think about how ion channels close. Imagine you are measuring current of a Na+ channel. How would INa+ be affected if you DECREASED affinity of the inactivation particle for its binding site?
INa+ would increase because the channel would close more slowly.
75
Think about the ion specificity of ion channels. Imagine you're studying the ability for certain ions to pass through certain channels. If it were possible to increase the pore size of sodium channels to permit K+ movement, what would happen?
IK+ would increase and leave the cell. This would offset incoming Na+ and make it harder to depolarize the cell.
76
You're studying variations in EPSP responses from a single neuron that has two presynaptic partners, A and B. Neurons A and B never fire simultaneously, so the postsynaptic neuron always receives input from one at a time. You notice that when the neuron receives input from Neuron B only, the EPSP response is always higher than input from Neuron A alone. What can you conclude about Neurons A and B?
Neuron B might have more vesicles within the axon terminal.
77
Think about the Poissonian distribution of neurotransmitter release and how this relates to a graph measuring mini-end plate potentials (MEPPs- see below). One distinguishing feature of the Poissonian distribution is that there is variability around mean PSP height. What is the reason for this variability (i.e. why aren't MEPPs consistently the same in amplitude)?
Because there is variability in the number of vesicles available to fuse for release
Because there is variability in the probability that a vesicle will fuse at the axon terminal membrane
78
How are reserve pool vesicles released from the pool so they can be used for neuronal communication?
Reserve pool vesicles are bound by synapsin+actin. Ca2+ activates calmodulin, which activates CaMKII, which phosphorylates synapsin to release it from actin.
79
Which change below affecting the GABA lifecycle would increase GABA signaling?
Increased glutamic acid decarboxylase activity.
Decreased glutamic acid decarboxylase activity.
Depletion of glutamate in the axon terminal.
Decreased GABA receptor sensitivity.
Increased glutamic acid decarboxylase activity.
80
Which of the following is a common (i.e. shared) feature of the biogenic amines?
They all rely on VMAT for packaging into vesicles.
81
Which of the following is NOT a catecholamine?
Serotonin
Dopamine
Norepinephrine
Epinephrine
serotonin
82
Neuropeptidergic vesicles differ from classical transmitter vesicles in that:
They have a lower binding affinity for Ca2+.
83
Which of the statements below about nitric oxide is TRUE?
It decays passively.
It is stored in specialized vesicles.
It targets nitridic receptors on presynaptic cells.
None of the above.
it decays passively
84
ionotropic or metabotropic fast synapses
ionotropic
85
ionotropic or metabotropic directly opened by a ligand for ion flow
ionotropic receptors
86
ionotropic or metabotropic slow synapses
metabotropic
87
ionotropic or metabotropic coupled with G protein that activates other ion channels
metabotropic
88
ionotropic or metabotropic AMPA and NMDA receptors
ionotropic
89
ionotropic or metabotropic can be inhibited by arrestin enzyme
metabotropic
90
ionotropic or metabotropic GABAa receptors
iontropic
91
Which of the following best describes reversal potentials?
The voltage at which current is equal and opposite in flow.
The voltage at which a neurotransmitter elicits no net current.
The voltage that Vm is drawn to when an ionotropic receptor is activated.
B and C are both correct
92
Which of the following is a potential consequence of metabotropic receptor activation?
Gene expression changes.
Changes in quantal content.
Direct or indirect ion channel opening.
all of the above
93
Which of the following is NOT a method by which metabotropic receptors are inactivated?
Inactivation particle with binding affinity for the pore
Inhibition by the arrestin protein
Degradation by lysosomes
Desensitization through GTP hydrolysis
inactivation particle with binding affinity for the pore
94
Thinking of G proteins, we talked about 4 major subtypes of the Ga subunit.
True or false? The Gs subtype functions to enhance activity of adenyl cyclase.
true
95
If neuromodulation causes a postsynaptic neuron to become less excitable, which of the following is a possible explanation?
Voltage-gated K+ channels are less likely to open.
Voltage-gated Ca2+ channels are more likely to open.
More transmembrane receptors have been placed in the membrane.
Voltage-gated Na+ channels are less likely to open.
voltage gated Na+ channels are less likely to open
96
If neuromodulation as a result of intracellular signaling causes a presynaptic neuron to have increased quantal content, which of the following is a possible explanation?
Serotonin has caused a cascade that results in decreased K+ conductance and increased Ca2+ conductance at the terminal.
Serotonin has caused a cascade that results in increased K+ conductance and decreased Ca2+ conductance at the terminal.
Serotonin has caused a cascade that results in more vesicles being bound by actin.
Serotonin has caused a cascade that results in less cAMP production.
Serotonin has caused a cascade that results in decreased K+ conductance and increased Ca2+ conductance at the terminal.
97
True or false? Ionic current increases as Vm gets further from ERev due to increase driving force.
true
98
What is true of ionotropic nicotinic ACh receptors?
When opened, they bias Vm to somewhere in between ENa+ and EK+.
They are ligand gated.
They are specific to Na+ and K+.
When opened, they bias Vm to somewhere in between ENa+ and EK+.
all of the above
99
True or false? Ionotropic AMPA receptors elicit slower, more sustained responses than NMDA receptors.
false
100
What are some ways a postsynaptic cell displays plasticity at the synapse?
can inc/dec postsyn receptors, can change type of receptors
101
long term potentiation lasts how long
days to weeks
102
long term potentiaition trains
very short, high frequency stimulus trains
103
Homosynaptic LTP = what
input from one neuron
104
Heterosynaptic LTP =
input from one neuron enhances PSPs from other neurons
105
heterosynaptic LTP is what kind of partnership
associative partnership
106
LTP best studied where
hippocampus
107
features of hippocampal PW
highly subject to LTP, uses glutamate
108
2 glutamate receptors
AMPA and NMDA
109
AMPA has what channels
direct Na+/K+ channels
110
AMPA requires what ligand
glutamate ligand
111
AMPA is what gated
only ligand
112
NMDA is what kind of channels
Na+/K+/Ca2+ channels
113
NMDA requires what
glutamate, glycine, plus removal of Mg2+ from pore
114
NMDA is gated how
ligand and voltage gated
115
sender neurons in the hippcampus
Ca3
116
receiver neurons in the hippocampus
CA1
117
before LTP, what has a high failure rate
CA3 -> CA1
118
CA3->CA1 is what
associative
119
what is singular connection and when does this occur
singular vesicle release or failure altogether, occurs before long term potentiation
120
as long term potentiation occurs, what decreases
failure
121
as LTP occurs, what happens to quantal size distribution
it shifts to produce unitary responses
122
main event of early LTP
Ca2+ influx which activates calmodulin
123
activated calmodulin leads to what
increase in AMPA receptor conductance after phosphorylation
124
in early LTP, more ampa receptors added where
to post synapse
125
what enhances presynaptic quantal content
retrograde NO
126
which receptors are silent
only NMDA
127
what allows NMDA receptors to open
activation of other receptors plus depolarization of VM
128
what is coincidence detector for LTP
NMDA receptor
129
what are inserted at the previously silent synapse
AMPA receptors
130
AMPA receptors cause what in membrane
increase in AMPAR
131
What does LONG-TERM changes in behavior require?
protein synthesis, cAMP
132
list the events of late LTP
Ca2+ activates calmodulin, cAMP activates CREB
133
for late LTP, calmodulin activates what
adenylyl cyclase
134
CREB does what in LTP
makes new receptors and other post synaptic components
135
difference between episodic and semantic memory
episodic - self referenced, requires a context and place, kinda your own memory
semantic - facts, like a table is furnature
136
2 kinds of memory
episodic and semantic
137
for memory, how is context established
through NMDA activity
138
3 things you need to construct a cognitive map
direction, speed of movement, landmarks
139
what is responsible for your direction
head direction (HD) cells
140
what is responsible for speed of movement
grid cells
141
what is responsible for for landmarks
place cells
142
when do HD cells fire
when head is pointed in a given direction with relation to the environment
143
grid cells fire...
in specific locations forming a grid of equilateral triangles
144
place cells fire in response to what
landmarks that can dictate behavior
145
Episodic memory established thru
NMDA activity in HD, grid, and place cells
146
late LTP requires what
protein synthesis
147
new synapses form in LTP why
due to cAMP + CREB, protein production
148
what induces LTP, why
NMDA receptors, due to prolonged activation
149
in early LTP, Ca2+ leads to what
increase in postsyn AMPAR conductance due to phosphorylation and inc # of AMPARs in membrane
150
what increases quantal content in presynaptic cells
retrograde NO activity
151
retrograde NO activity inc what in what
quantal content in presynaptic cells
152
