BioPsych Final

Question 1 of 160

1

Which of the following statements about neural and glial cells is false?

Select one of the following:

Mitochondria are concentrated at presynaptic terminals.
The endoplasmic reticulum is concentrated in axons.
Exocytosis and endocytosis are important for synaptic communication.
Glial cells rapidly transmit long-range electrical signals.
Both b and d

Explanation

Question 2 of 160

1

Which technique first produced unequivocal support for the neuron doctrine of the nervous system (as opposed to the reticular theory)?

Select one of the following:

Golgi stain (light microscopy)
Extracellular electrical recordings
EEG (electroencephalogram)
Acetylcholinesterase staining
Electron microscopy of nervous tissue

Explanation

Question 3 of 160

1

Which of the following is an advantage that intracellular recordings have over extracellular recordings?

Select one of the following:

They are technically easier to obtain.
They can be used in many more parts of the nervous system.
They can record synaptic and receptor potentials.
They can record from many neurons at once.
All of the Above

Explanation

Question 4 of 160

1

Which of the following is not part of the brain?

Select one of the following:

Diencephalon
Cerebellum
Cerebral Hemispheres
Spinal Cord
Brainstem

Explanation

Question 5 of 160

1

Antibody staining is used to

Select one of the following:

identify neurons expressing specific genes.
visualize the distribution of specific proteins in the nervous system.
trace anterograde pathways.
trace retrograde pathways
reveal structural changes associated with experimental lesions

Explanation

Question 6 of 160

1

Which of the following is not an established role for glial cells?

Select one of the following:

Integrating information to assist neural computation
Maintaining the ionic milieu surrounding nerve cells
Hastening the propagation of neural impulses
Assisting synaptic transmission via neurotransmitter uptake
Providing scaffolds that assist neural development

Explanation

Question 7 of 160

1

Which of the following is a feature that distinguishes the four model organisms from other animals that have been intensively studied by neuroscientists?

Select one of the following:

Ease of genetic analysis and manipulation
Nervous systems of substantial complexity
An extensive and interesting behavioral repertoire
Specific neural structures or behaviors of interest
All of the above

Explanation

Question 8 of 160

1

Which of the following type of glial cell myelinates peripheral axons?

Select one of the following:

Schwann Cells
Oligodendrocytes
Astrocytes
Microglia
All of the above

Explanation

Question 9 of 160

1

Representation of which of the following is best accomplished using a topographic map?

Select one of the following:

The visual world
Objects
Odors
Episodic Memory
Verbs and Nouns

Explanation

Question 10 of 160

1

Which of the following is not a true statement about a center-surround receptive field?

Select one of the following:

It can be mapped by electrophysiological recording techniques.
It is characterized by a circular center and a donut-shaped surround.
It can involve an excitatory response (e.g., to touch).
It can involve an inhibitory response (e.g., to touch).
It is found only in primary sensory cortex.

Explanation

Question 11 of 160

1

The type of nerve cell that synapses upon muscles is called a(n)

Select one of the following:

dorsal root neuron
cranial neuron
afferent neuron
motor neuron (or motorneuron)
spinal interneuron

Explanation

Question 12 of 160

1

Which of the following is not considered to be a “model” organism?

Select one of the following:

Zebrafish
Fruit fly
The nematode C. elegans
Mouse
The marine snail Aplysia

Explanation

Question 13 of 160

1

The set of neurons and small ganglia associated with the digestive tract is called the _______ nervous system.

Select one of the following:

Peripheral
autonomic
enteric
sympathetic
parasympathetic

Explanation

Question 14 of 160

1

The structural brain imaging technique that relies on atoms behaving as small magnets is called

Select one of the following:

MRI
fMRI
PET
SPECT
CT

Explanation

Question 15 of 160

1

Which of the following statements about the expression of genes in the nervous system is true?

Select one of the following:

Every gene in the human genome is expressed in the CNS.
There are tens of thousands of neuron-specific genes (i.e., genes that are not expressed outside the CNS).
Most of the genes in the human genome are expressed in the CNS.
Humans have 100 times more genes than invertebrate animals such as Drosophila.
Humans have three to four times more genes than mice have.

Explanation

Question 16 of 160

1

The scientist who shared the Nobel Prize with Camillo Golgi for his anatomical studies of the CNS was

Select one of the following:

Allesandro Volta
Luigi Galavani
Santiago Ramon y Cajal
Louis Pasteur
Thomas Hodgkin

Explanation

Question 17 of 160

1

Cognitive neuroscience is concerned with

Select one of the following:

mathematical ability
emotions
language
abstract thought
all of the above

Explanation

Question 18 of 160

1

The brain imaging technique that makes use of a narrow X-ray beam is called

Select one of the following:

MRI
fMRI
PET
SPECT
CT

Explanation

Question 19 of 160

1

A neuron that innervates (i.e., makes synaptic contact with) a large number of other neurons

Select one of the following:

represents convergent neural signaling.
represents divergent neural signaling.
represents massive neural integration.
must fire at very high frequencies to be useful.
can fire only at very low frequencies.

Explanation

Question 20 of 160

1

The technique that first revealed the tremendous diversity of neuronal cell types (numbering in the hundreds or thousands in vertebrate animals) is called

Select one of the following:

the Nissl stain
the Golgi stain
cresyl violet staining
fluorescence staining
electron microscopy

Explanation

Question 21 of 160

1

Which of the following best describes nerve cells?

Select one of the following:

Nerve cells are exceptionally good conductors of electricity (much better than copper wires).
Nerve cells are similar in their electrical conduction properties to copper wires.
In comparison to copper wires, nerve cells are relatively poor conductors of electricity.
Nerve cells are unable to conduct electricity under any circumstances.
Nerve cells are electron sinks: they absorb many electrons, but no electricity comes out of them.

Explanation

Question 22 of 160

1

The resting membrane potential is not exactly equal to the Nernst potential for potassium because

Select one of the following:

the Nernst equation is not able to predict potentials that precisely.
rapid fluctuations in membrane potential prevent accurate measurements.
the membrane has some resting permeability to species other than potassium.
potassium does not contribute to the resting membrane potential.
All of the above

Explanation

Question 23 of 160

1

Which of the following is not a cause of sensory receptor potentials?

Select one of the following:

Heat
Pressure
Sounds
Chemicals
Brain Waves

Explanation

Question 24 of 160

1

he equation used to calculate membrane potential when there are multiple permeant ions is called the _______ equation.

Select one of the following:

Nerst
ionic imbalance
Goldman
Finch and Augustine
atomic permeability

Explanation

Question 25 of 160

1

Which of the following statements about ionic distributions in nerve cells is false?

Select one of the following:

Potassium is higher inside cells than outside cells.
Sodium is higher outside cells than inside cells.
Chloride is higher outside cells than inside cells.
Calcium is higher outside cells than inside cells.
The total concentration of all ionic species is approximately the same for all nerve cells in all animals.

Explanation

Question 26 of 160

1

Which of the following statements about action potentials is false?

Select one of the following:

They can transmit signals over long distances.
They boost the spatial spread of electrical signals.
They are elicited by hyperpolarization.
They occur at threshold.
They are all-or-none.

Explanation

Question 27 of 160

1

A measured membrane potential of +58 mV would be consistent with _ inside the cell and _ outside the cell.

Select one of the following:

100 mM K+, 10 mM K+
10 mM Na+, 100 mM Na+
10 mM Cl-, 100 mM Cl-
100 mM K+, 100 mM Na+
All of the above

Explanation

Question 28 of 160

1

The different electrical signals occurring in nerve cells are caused by _______ the cell membrane.

Select one of the following:

positive charges bound to the inner and outer faces of
negative charges bound to the inner and outer faces of
movements of charged proteins within the plane of
fluxes of ions across
patterns of electrical eddy currents inside

Explanation

Question 29 of 160

1

Which of the following is not necessary for neurons to communicate electrically?

Select one of the following:

Consumption of metabolic energy
Use of active transporters to create ionic gradients
Separation of large amounts of electrical charge, with excess positive charges stored inside the cell
Selective permeability of the cell membrane via different kinds of ion channels
Changes in membrane potential caused by the movement of ions across the cell membrane

Explanation

Question 30 of 160

1

Hodgkin and Katz proposed that sodium was the predominant ion associated with the firing of an action potential because

Select one of the following:

the membrane potential approaches the Na+ Nernst potential during the rising phase.
the membrane potential approaches the Na+ Nernst potential during the falling phase.
sodium ions can move more quickly than other ionic species.
sodium ions are the only ions that can flow into the nerve cell body.
the sodium gradient explains the rising phase, falling phase, and overshoot of the action potential.

Explanation

Question 31 of 160

1

Which of the following is not a reason for the usefulness of the squid giant axon in neuronal studies?

Select one of the following:

The large size of the axon makes it easy to penetrate with recording electrodes.
The axoplasm can be extruded, thus allowing studies of its composition.
Large synapses between giant nerve cells make them easy to study.
Correct Giant ion channels allow for the insertion of recording electrodes into the channels.
Properties of the squid’s axons and synapses can be related to its behavior

Explanation

Question 32 of 160

1

Studies of the ionic basis of the action potential in squid giant axon found that

Select one of the following:

decreasing sodium outside the cell decreases the size of the action potential.
decreasing sodium outside the cell increases the size of the action potential.
decreasing potassium outside the cell decreases the size of the action potential.
decreasing potassium outside the cell increases the size of the action potential.
manipulating sodium has large effects on both the size of the action potential and the resting membrane potential.

Explanation

Question 33 of 160

1

The transmembrane potential is generated by

Select one of the following:

repulsion of positive and negative charges.
diffusion of ions down a concentration gradient.
the greater mobility of small ions.
the selectivity of the membrane to pass positive charges only.
All of the above

Explanation

Question 34 of 160

1

Which of the following statements about the ionic permeability of cell membranes is false?

Select one of the following:

The permeability of some ions can be very low.
The permeability of some ions can change over time.
In resting nerve cells, the membrane is quite permeable to potassium.
In resting nerve cells, the membrane is quite permeable to sodium.
All of the above statements are true.

Explanation

Question 35 of 160

1

Which of the following factors is important in determining the membrane potential when there are multiple permeant ions?

Select one of the following:

The concentration gradient of the individual ionic species
The permeability of the membrane to the individual ionic species
The sum total of all of the ions on both sides of the membrane
Both a and b
All of the above

Explanation

Question 36 of 160

1

The synaptic potential

Select one of the following:

makes communication between nerve cells possible.
occurs only in response to external stimuli.
propagates along axons.
determines the cell’s resting potential.
All of the above

Explanation

Question 37 of 160

1

Which of the following is not a usual kind of potential exhibited by nerve cells?

Select one of the following:

Resting membrane
Action
Reaction
Receptor
Synaptic

Explanation

Question 38 of 160

1

Which of the following statements about electrochemical equilibrium is false?

Select one of the following:

Electrochemical equilibrium involves the movement of a relatively small number of ions.
Ionic gradients are necessary for the generation of the membrane potential.
The size of the potential is proportional to the size of the ion gradient.
The direction of the ion gradient determines the polarity of the membrane potential.
For a given ion concentration gradient, the resulting potential is independent of the number of charges on the ion.

Explanation

Question 39 of 160

1

Typically, neurons firing action potentials encode a signal’s intensity by

Select one of the following:

changing the size of their action potentials.
Correct changing the frequency of their action potentials.
firing at precise moments so as to signal different sized signals.
sending signals of different sizes down different axonal branches.
All of the above

Explanation

Question 40 of 160

1

In their studies of the resting membrane potential of the squid giant axon, Hodgkin and Katz found that

Select one of the following:

increasing potassium outside the axon depolarized the axon’s potential.
increasing potassium outside the axon hyperpolarized the axon’s potential.
increasing sodium outside the axon depolarized the axon’s potential.
increasing sodium outside the axon hyperpolarized the axon’s potential.
changing external sodium and potassium had identical effects on the resting axon potential.

Explanation

Question 41 of 160

1

Which of the following is not an observation that helped to identify sodium as the early current of the action potential?

Select one of the following:

The current declined when there was decreased driving force on sodium fluxes.
The current disappeared near the Nernst potential for sodium.
The early current was blocked by tetrodotoxin.
The early current was unaffected by tetraethylammonium.
When the late current was blocked, the reversal potential of the inward current shifted to a negative membrane potential.

Explanation

Question 42 of 160

1

In an experiment using a series of voltage steps to study the two different ionic currents associated with the action potential (as shown in Figure 3.2), it was found that

Select one of the following:

both currents had the exact same voltage dependence.
both currents increased monotonically with increasingly large voltage steps.
both currents decreased with increasingly large voltage steps.
the early current increased initially, but then it decreased in size as the voltage step was increased.
the late current increased initially, but then it decreased in size as the voltage step was increased.

Explanation

Question 43 of 160

1

Which of the following statements about myelination is false?

Select one of the following:

Myelin sheaths are created by glial cells.
Myelin serves to sharply increase the time constant of the axon.
Multiple layers of closely opposed glial membranes wrap the axon and serve as an electrical insulator.
Myelin is absent at the nodes of Ranvier.
Sodium and potassium channels are clustered at the nodes of Ranvier.

Explanation

Question 44 of 160

1

The mode of action potential propagation along myelinated axons is called

Select one of the following:

salutatory
scleorid
oligodendroid
ranvierian.
hyperian

Explanation

Question 45 of 160

1

Which of the following was not seen in the voltage-clamp study of squid action potentials?

Select one of the following:

Capacitive currents in response to hyperpolarizing voltage steps
Capacitive currents in response to depolarizing voltage steps
A transient inward current as a result of depolarization
A sustained outward current as a result of hyperpolarization
All of the above were seen in squid giant axons.

Explanation

Question 46 of 160

1

Voltage clamp data, in which investigators analyzed membrane conductances during action potentials, showed all of the following except

Select one of the following:

the sodium current was rapidly activated by depolarization.
the potassium current activates on a comparatively slow time scale of a few ms.
at certain potentials, there can be zero current even with a large conductance.
depolarization leads to a time-dependent inactivation of the sodium current.
depolarization leads to a time-dependent inactivation of the potassium current.

Explanation

Question 47 of 160

1

For which of the following reasons was the development of the voltage clamp critical to investigations of the ionic basis of the action potential?

Select one of the following:

Voltage changes in the cell cannot be seen without voltage clamp.
Ionic conductances can be activated only in cells that have been voltage clamped.
Voltage clamping allows simultaneous control of membrane potential and measurement of permeability changes.
Sodium and potassium currents are activated in non-overlapping voltage regimes.
All of the above

Explanation

Question 48 of 160

1

The inventor of voltage clamp was

Select one of the following:

Kenneth Cole.
Alan Hodgkin.
Andrew Huxley.
Bernard Katz.
Alessandro Volta.

Explanation

Question 49 of 160

1

Which of the following statements on either the rising or overshoot phase of the action potential is false?

Select one of the following:

The time from threshold to maximum depolarization is essentially instantaneous (i.e., too fast to be measured accurately with current electronics).
A positive feedback loop leads to a regenerative depolarization that would increase continuously if unchecked.
The degree of depolarization is limited in part by the declining driving force on sodium entry.
The degree of depolarization is limited in part by the inactivation time course for the sodium current.
The degree of depolarization is limited in part by the activation time course of the potassium current.

Explanation

Question 50 of 160

1

Neurons exhibit a threshold above which an action potential is triggered because of

Select one of the following:

a positive feedback loop between sodium current activation and potassium inactivation.
a positive feedback loop between depolarization and sodium current activation.
a negative feedback loop between sodium current activation and inactivation.
the precise time constant of sodium channel activation (i.e., a threshold would not be observed if this were measurably changed).
pacemaker-like activity that is present in all nerve cells.

Explanation

Question 51 of 160

1

Which of the following is not integral to the action potential waveform?

Select one of the following:

A change in permeability of the membrane to sodium
A change in permeability of the membrane to potassium
A transient increase in the sodium current
An initial decrease in the potassium current
A “self-activating” aspect to the rise in the sodium current

Explanation

Question 52 of 160

1

Which of the following statements about multiple sclerosis (MS) is false?

Select one of the following:

MS is characterized by demyelination of axons along with some axon loss.
It was recently proven that all cases of MS are due to persistent infection by a tropical parasite.
Cases of MS vary considerably in terms of severity and progression of the illness.
Symptoms of MS may include weakness, paralysis, double vision, monocular blindness, and abnormal somatic sensations.
Magnetic resonance imaging can help diagnose some cases of MS.

Explanation

Question 53 of 160

1

Which of the following was shown to eliminate the early inward current in squid giant axons?

Select one of the following:

Removal of external sodium
Doubling of external sodium
Removal of external potassium
Doubling of external potassium
Removal of all external cations

Explanation

Question 54 of 160

1

Action potentials are generated

Select one of the following:

at most subthreshold voltages.
only when the cell reaches threshold.
only when the membrane potential exceeds threshold by 5 to 10 millivolts.
intermittently, but usually when the membrane potential exceeds threshold.
only after all of the sodium channels are open.

Explanation

Question 55 of 160

1

The _______ most directly affects the rate of information processing within the central nervous system.

Select one of the following:

number of sodium channels along an axon
number of potassium channels along an axon
propagation speed of action potentials
threshold voltage of neurons
ratio of sodium to potassium channels

Explanation

Question 56 of 160

1

Which of the following statements about the spread of electrical signals/currents along an axon is false?

Select one of the following:

The spread of a passive signal is limited by the leakage of current out of the axon.
The time course of passive signal spread slows with increasing leakiness of the axon.
The membrane length constant describes how far an action potential can propagate along an axon.
Action potentials can propagate for long distances without decrement.
Action potential propagation requires both current flow along the axon and ion fluxes across the axon membrane.

Explanation

Question 57 of 160

1

Which of the following explains the unidirectional propagation of action potentials?

Select one of the following:

The voltage dependence of the sodium channels
The voltage dependence of the potassium channels
The presence of a refractory period at a location where an action potential has just passed
Sufficient “leakiness” of the axons, such that backward propagation of action potentials is prevented
The polarized orientation of microtubules within the axon

Explanation

Question 58 of 160

1

When current is injected into an axon,

Select one of the following:

an action potential is evoked before the current has spread any distance from the point of injection.
the current will spread only in one direction.
the current will spread passively only if it is a depolarizing current.
the current will decay exponentially with increasing distance from the injection site (if no action potential is present).
the current will propagate as an oscillating wave independently of its polarity.

Explanation

Question 59 of 160

1

Which of the following does not stem from the application of Ohm’s law to ionic conductances?

Select one of the following:

The driving force on the ionic current is the difference between the membrane potential and the ion’s Nernst potential.
The conductance for an ion is inversely proportional to the resistance of the membrane to the passage of that ion.
All permeant ions experience an identical driving force at each time point during the course of an action potential.
The conductance for each ion can be calculated based on the measured ionic currents and the calculated driving force.
The calculations stemming from Ohm’s law can be used to derive a mathematical description of the action potential.

Explanation

Question 60 of 160

1

Which of the following was not one of the features of Hodgkin and Huxley’s mathematical model?

Select one of the following:

The action potential can be reconstructed based entirely upon the time course and amplitudes of the ionic conductances.
The fast-rising phase can be accounted for by selective sodium entry.
The model mimics the experimentally measured refractory period.
The falling phase can be at least partially accounted for by the activation time course of the potassium current.
The undershoot can be accounted for by the time course of sodium current reactivation.

Explanation

Question 61 of 160

1

Which of the following is the main reason that the opening of sodium channels causes a very rapid depolarization of most neurons?

Select one of the following:

The movement of a sodium ion produces a larger voltage change than the movement of other ions.
Sodium ion diffusion proceeds so quickly that whenever sodium channels are open, there is a rapid directional flux across the membrane.
The conjunction of the sodium gradient and the negative membrane potential produces a very large driving force on sodium ions.
All of the above
None of the above

Explanation

Question 62 of 160

1

In familial hemiplegic migraine, the underlying mutation in a calcium channel causes

Select one of the following:

abnormally functioning pain receptors in the peripheral nervous system.
enhanced synaptic excitation of second-order pain-sensitive neurons.
abnormal activation of thalamic pain centers.
abnormal activation of neocortical pain centers.
the syndrome by some unknown mechanism

Explanation

Question 63 of 160

1

In which of the following ways do potassium channels in the squid giant axon differ from sodium channels?

Select one of the following:

The potassium channels pass only a few ions per second.
The potassium channels show little voltage dependence.
The summing of the individual potassium channels does not reconstruct the macroscopic current.
Once the potassium channels open in response to a voltage step command, they tend to remain open.
All of the above

Explanation

Question 64 of 160

1

Which of the following ligand-gated ion channels is (are) not regulated primarily by an intracellular signal?

Select one of the following:

The IP3 receptor located on the endoplasmic reticulum
The potassium-activated calcium channel
The glutamate receptor
The cAMP- and cGMP-gated ion channels
The acid-sensing ion channels

Explanation

Question 65 of 160

1

Paddle-like, charged transmembrane domains of potassium channels may

Select one of the following:

serve as a plug or inactivation gate.
be the primary voltage sensors
confer ion selectivity to the channel.
enable the aggregation of channel subunits into functional channels.
All of the above

Explanation

Question 66 of 160

1

The proteins that establish ionic gradients are called

Select one of the following:

passive transporters.
active transporters.
voltage-gated ion channels.
ligand-gated ion channels.
permeability transition pores.

Explanation

Question 67 of 160

1

The calcium ATPase

Select one of the following:

is much simpler than the sodium–potassium pump because it has only three transmembrane regions.
pumps 15 calcium ions for each molecule of ATP consumed.
uses the same intracellular domain for both nucleotide binding and ion translocation.
pumps calcium in a cyclical process that utilizes energy from ATP.
is unique among transporters in that its pumping action involves no conformational changes.

Explanation

Question 68 of 160

1

Which of the following is a common, defining feature of membrane-bound active ion transporters?

Select one of the following:

All transporters are electrogenic.
All transporters transport two or more different ions.
All catalyze the conversion of ATP to ADP.
All are able to move at least one ion against its concentration gradient.
All of the above

Explanation

Question 69 of 160

1

In the operation of sodium–potassium ATPase,

Select one of the following:

there is an obligatory coupling of sodium efflux and potassium influx.
this transporter (or “pump”) is electrogenic.
phosphorylation and dephosphorylation are respectively associated with the sodium and potassium transport steps.
the pump transports two potassium ions for every three sodium ions.
All of the above

Explanation

Question 70 of 160

1

Individual ion channels

Select one of the following:

were visualized with the advent of the voltage clamp in 1956.
show the same time course as macroscopic ionic currents.
may pass thousands of ions per millisecond.
have a different voltage dependence than the macroscopic ionic current has.
have a different reversal potential than the macroscopic ionic current has.

Explanation

Question 71 of 160

1

Which of the following was not observed in studies measuring the efflux of radioactive sodium from the squid giant axon?

Select one of the following:

Dramatic increase of efflux during a brief train of action potentials
Sharp drop in efflux when extracellular potassium was removed
Dependence of efflux upon the presence of ATP
Decrease of efflux when mitochondrial ATP synthesis was inhibited
All of the above were observed.

Explanation

Question 72 of 160

1

A surprising result that emerged from the molecular analysis of ion channels was the

Select one of the following:

size of the individual ion channels.
voltage-dependence of the ion channels.
time-dependence of the ion channels.
discovery of differences in ionic selectivity.
sheer number of different ion channels.

Explanation

Question 73 of 160

1

Which of the following appears to contribute to the selectivity filter of the potassium channel?

Select one of the following:

The channel pore narrows to fit the size of a non-hydrated potassium ion.
Cations such as cesium are too large to pass through the pore.
Cations such as sodium are too small to be dehydrated at the pore filter.
All of the above
None of the above

Explanation

Question 74 of 160

1

Which of the following statements regarding the diversity of ion channels is false?

Select one of the following:

With only six different types, potassium channels are the least diverse channel type.
There are at least 10 different sodium channels in humans.
Sodium channels that do not inactivate have been found.
There are least 10 different types of calcium channels.
Calcium channels serve diverse functions such as influencing action potential shape and mediating the release of neurotransmitters.

Explanation

Question 75 of 160

1

Which of the following is not a variant of the patch clamp technique?

Select one of the following:

Cell attached
Intracellular
Whole cell
Inside–out patch
Outside–out patch

Explanation

Question 76 of 160

1

The TRP ion channel family includes channels responsive to

Select one of the following:

complex sequences of voltage commands.
heat and cold.
intracellular cyclic nucleotides.
hyperpolarization.
ultraviolet light.

Explanation

Question 77 of 160

1

The technique that provides the most direct information about the physical, three-dimensional structure of ion channels is

Select one of the following:

the sequencing of the channel’s amino acids.
physiological measurements of ion selectivity.
X -ray crystallography
fluorescence imaging of channel subunit dynamics.
All of the above provide similar information on the channel’s three-dimensional structure.

Explanation

Question 78 of 160

1

Which of the following is not a type of ion transporter that has been observed?

Select one of the following:

The sodium/calcium exchanger
The sodium/potassium/chloride co-transporter
The sodium/neurotransmitter co-transporter
The sodium/proton exchanger
All of the above transporters have been observed.

Explanation

Question 79 of 160

1

Which of the following is a major advantage to researchers of the Xenopus oocyte expression system?

Select one of the following:

Xenopus is the only lower vertebrate whose genome has been sequenced.
The unusually small size of the eggs makes patch-clamping relatively easy.
The oocytes have many endogenous ion channels to which exogenous channels can be compared.
The oocytes have quite thin membranes, which amplifies the ionic currents.
It facilitates physiological characterization of modified ion channel genes.

Explanation

Question 80 of 160

1

Animal toxins have been discovered that

Select one of the following:

block sodium channels.
prolong the open state of sodium channels.
alter the voltage-dependence of sodium channels.
block potassium channels.
All of the above

Explanation

Question 81 of 160

1

The two main families of neurotransmitter receptors are _ and _.

Select one of the following:

ligand-gated; ion-gated
ionotropic; metabotropic
voltage-gated; voltage-modulated
cationic; anionic
excitatory; inhibitory

Explanation

Question 82 of 160

1

Gap junctions (electrical synapses)

Select one of the following:

are found only in a few species of animals.
are far more numerous than chemical synapses.
have larger pores than voltage-gated ion channels.
are found only where there are large gaps between nerve cells.
are used to pass chemical neurotransmitters.

Explanation

Question 83 of 160

1

Listed below are the individual events that make up chemical synaptic transmission:

Diffusion of transmitter across the synaptic cleft
Depolarization of the presynaptic terminal
Vesicle fusion with plasma membrane
Opening of voltage-gated ion channels
Activation of presynaptic, calcium-sensitive proteins

Select one of the following:

a; b; c; d; e
b; d; e; c; a
b; e; d; c; a
e; d; b; c; a
a; b; d; e; c

Explanation

Question 84 of 160

1

Black widow spider venom is thought to disrupt the functioning of nerve terminals by

Select one of the following:

proteolytic cleavage of SNARE proteins.
circumventing the calcium-regulatory step of exocytosis to promote massive exocytosis.
binding to all molecules of synapsin, synaptotagmin, and synaptophysin and thereby preventing their normal functioning.
punching holes in vesicles and thereby causing release of their contents into the cytosol.
blocking calcium channels.

Explanation

Question 85 of 160

1

Compared with normals, the decrease in quantal size observed in familial infantile myasthenia would be most consistent with

Select one of the following:

fewer calcium channels in the presynaptic terminals.
a greater rate of spontaneous exocytosis depleting the size of the vesicle pool.
smaller synaptic vesicles.
a change in the sensitivity of the calcium release mechanism.
a loss of all ACh receptors at the neuromuscular junction.

Explanation

Question 86 of 160

1

In tracking recycling of synaptic vesicles, using HRP as a vesicle marker, the observed sequence of movements of HRP was

Select one of the following:

Endosome, coated vesicle, vesicle reserve pool
Vesicle reserve pool, coated vesicle, endosome
Endosome, vesicle reserve pool, coated vesicle
Coated vesicle, vesicle reserve pool, endosome
Coated vesicle, endosome, vesicle reserve pool

Explanation

Question 87 of 160

1

Which of the following statements about postsynaptic currents at the neuromuscular end plate is false?

Select one of the following:

Depolarizing currents can be recorded from outside–out patches of postsynaptic membrane.
Individual channels tend to stay open for no more than a few msec.
Acetylcholine can induce openings of ligand-gated ion channels.
The end plate potential is due to the opening of thousands or millions of channels.
The end plate channels show a regenerative opening pattern that propagates an action potential along the length of the muscle fiber.

Explanation

Question 88 of 160

1

Miniature end-plate potentials, or MEPPs, are produced

Select one of the following:

at miniature end-plates.
by the smallest axons.
in response to weak stimuli.
by the smallest neurotransmitters.
by spontaneous release of neurotransmitter.

Explanation

Question 89 of 160

1

To date, which of the following is not part of the experimental evidence favoring the vesicular release hypothesis of neurotransmission?

Select one of the following:

Fixed size of MEPPs
Quantized distribution of events occurring at the neuromuscular junction
Visualization of synaptic vesicles using electron microscopy
Correspondence between a vesicle’s acetylcholine content and MEPP size
Visualization of acetylcholine molecules diffusing out of the neck of the membrane-fused vesicle

Explanation

Question 90 of 160

1

The most important factor determining whether a receptor-operated ion channel is inhibitory or excitatory is

Select one of the following:

the ligand-binding properties of the receptor.
whether the permeant ion is positively or negatively charged.
whether the permeant ion’s reversal potential is positive or negative.
whether the permeant ion’s reversal potential is positive or negative to threshold
None of the above

Explanation

Question 91 of 160

1

Which of the following statements about EPSPs in the central nervous system is false?

Select one of the following:

They are much larger than end plate potentials.
EPSPs occurring close together in time can summate and help bring a neuron to threshold.
Multiple EPSPs arriving together at different locations on the dendritic tree can summate and help bring a neuron to threshold.
Their effect in the central nervous system can be nullified by IPSPs.
All of the above are false; none is true.

Explanation

Question 92 of 160

1

Activating end plate acetylcholine receptor channels produces 0 current at 0 mV, but is still able to elicit action potentials in muscle fibers because

Select one of the following:

the depolarization occurs so quickly that the membrane potential goes far positive to 0 mV and produces an overshooting action potential.
there are enough acetylcholine receptors to propagate the action potential along the length of the muscle fiber.
the receptor is also permeable to calcium, which binds to other channels to elicit action potentials.
depolarization of the membrane to 0 mV is sufficient to bring nearby membrane regions, which contain voltage-gated sodium channels, to threshold.
None of the above; acetylcholine does not elicit muscle action potentials

Explanation

Question 93 of 160

1

Gap junctions may exhibit all of the following features except for the ability to

Select one of the following:

pass small metabolites, including some second messengers.
pass electrical current bidirectionally.
pass electrical current unidirectionally.
amplify small incoming electrical signals into large regenerative potentials.
synchronize the activity of populations of nerve cells.

Explanation

Question 94 of 160

1

When a muscle fiber is held at a voltage of 0 mV at the neuromuscular end plate, acetylcholine no longer produces a current because

Select one of the following:

the acetylcholine receptor channels all close instantly at 0 mV.
an influx of sodium is balanced by an equal efflux of potassium.
the membrane conductance for each permeant ion is 0 at 0 mV.
at 0 mV, the potassium ions lodge in the receptor channel and block the influx of sodium.
the Nernst potentials for both sodium and potassium are 0 mV in muscle fibers.

Explanation

Question 95 of 160

1

The differential release of small, clear vesicles, versus large, dense-core vesicles, is best explained by

Select one of the following:

biophysical differences in the vesicles’ lipids that allow for easier fusion of small vesicles.
a more sensitive calcium-release mechanism on the dense-core vesicles.
a more delocalized calcium signal generated by intense neural stimulation.
the presence of novel fusion proteins on the dense core vesicles that bind neuropeptides.
All of the above

Explanation

Question 96 of 160

1

SNARE proteins participate in vesicle exocytosis by

Select one of the following:

forming a protein coat that maintains the vesicle’s integrity.
binding calcium and then forming a pore into the vesicle.
forming a protein complex that pulls the vesicle membrane against the plasma membrane.
linking calcium channels to exocytotic fusion sites.
pushing vesicles from the reserve pool into the docked pool.

Explanation

Question 97 of 160

1

The protein that is thought to cross-link vesicles to actin to form a reserve vesicle pool is called

Select one of the following:

synapsin.
synaptotagmin.
synaptobrevin.
synaptophysin.
snap 25.

Explanation

Question 98 of 160

1

Which of the following is an accepted criterion for defining a molecule to be a neurotransmitter?

Select one of the following:

It must be present in the presynaptic terminal.
It must be released in response to presynaptic electrical activity.
It must exert an effect on the postsynaptic cell.
All of the above
None of the above

Explanation

Question 99 of 160

1

The capability of a nerve terminal to rapidly and dramatically produce very large changes in calcium levels is most dependent on the

Select one of the following:

presence of calcium-selective ion channels.
enormous gradient of calcium across the membrane
fact that calcium is a positively charged ion.
fact that calcium is a divalent cation.
All of the above are essential for producing large, rapid concentration changes.

Explanation

Question 100 of 160

1

Which of the following experiments would indicate a role for calcium in transmitter secretion?

Select one of the following:

Observation of presynaptic depolarizing currents after blockade of sodium channels
Voltage clamp experiments showing voltage-gated calcium channels in the presynaptic terminal
Induction of transmitter release by injection of calcium into the presynaptic terminal
Blockade of transmitter release by injection of calcium buffer into the presynaptic terminal
All of the above

Explanation

Question 101 of 160

1

Acetylcholine is used as a neurotransmitter at

Select one of the following:

the neuromuscular junction.
preganglionic synapses of the autonomic (visceral motor) nervous system.
postganglionic synapses of the parasympathetic nervous system.
widely distributed synapses in the central nervous system.
All of the above

Explanation

Question 102 of 160

1

Excitotoxicity

Select one of the following:

can result from very brief (sub-millisecond) increases in glutamate levels.
can be prevented by administration of glutamate receptor antagonists after a stroke has been diagnosed.
has not been correlated with the potency of compounds at glutamatergic receptors.
can occur in some forms of epilepsy and head trauma.
has been linked to a specific intracellular signaling pathway that activates a family of excitotoxicity genes.

Explanation

Question 103 of 160

1

Glutamate is

Select one of the following:

the most commonly used neurotransmitter in the brain.
neurotoxic at high concentrations.
a nonessential amino acid.
often synthesized from glial-synthesized glutamine.
all of the above

Explanation

Question 104 of 160

1

Serotonin reuptake blockers such as fluoxetine (Prozac) are used clinically

Select one of the following:

to treat hypertension.
to treat panic disorders.
as antidepressants.
as antipsychotics.
to treat generalized anxiety.

Explanation

Question 105 of 160

1

Peptide neurotransmitters are often released

Select one of the following:

shortly after their synthesis in presynaptic terminals.
as pre-propeptides.
as propeptides.
more readily and quickly than nonpeptide transmitters.
together with nonpeptide transmitters.

Explanation

Question 106 of 160

1

The presence of which of the following compounds or proteins in a cell makes it quite likely that the cell is a GABAergic neuron?

Select one of the following:

Pyridoxal phosphate
Glutamic acid decarboxylase
GABA transaminase
γ-hydroxybutyrate
Glutamine

Explanation

Question 107 of 160

1

One typically finds _______ subunits in the nicotinic acetylcholine receptors.

Select one of the following:

two
three
five
seven
nine

Explanation

Question 108 of 160

1

Listed below are the five steps in a nitric oxide (NO)-mediated signaling event.

1. Calcium binds to calmodulin
2. Activation of nitric oxide synthase
3. NO diffusion for tens of micrometers
4. Activation of guanylyl cyclase
5. Inactivation by reaction with oxygen

Select one of the following:

1; 2; 3; 4; 5
5; 4; 3; 2; 1
4; 2; 3; 1; 5
2; 3; 4; 1; 5
1; 5; 2; 3; 4

Explanation

Question 109 of 160

1

In terms of size, which of the following are the largest neurotransmitters?

Select one of the following:

Biogenic amines
Amino acid transmitters
Neuropeptide transmitters
Purinergic transmitters
Gaseous transmitters

Explanation

Question 110 of 160

1

Based upon the distribution of endocannabinoid receptors in the brain, it can be surmised that these compounds have a likely influence on

Select one of the following:

neocortex.
the hippocampus.
basal ganglia.
the hypothalamus.
All of the above

Explanation

Question 111 of 160

1

Which of the following is not a catecholamine?

Select one of the following:

Dopamine
Histamine
Norepinephrine
Epinephrine
All of the above are catecholamines.

Explanation

Question 112 of 160

1

Which of the following is not a class of opioid peptides?

Select one of the following:

Dynorphins
Endorphins
Enkephalins
Endocannabinoids
All of the above are opioid peptides.

Explanation

Question 113 of 160

1

Which of the following receptor types can be modulated by both barbiturates and benzodiazepines?

Select one of the following:

GABAA
GABAB
GABAC
Glycine
Muscarinc ACh receptor

Explanation

Question 114 of 160

1

The banded krait uses the neurotoxin _______ to paralyze its prey.

Select one of the following:

nicotine
muscarine
conotoxin
α-bungarotoxin
δ-tubocurarine

Explanation

Question 115 of 160

1

Cocaine acts

Select one of the following:

on GABAA receptors.
as an MAO inhibitor.
by blocking serotonin reuptake.
by blocking dopamine reuptake.
by blocking biogenic amine vesicular transporters.

Explanation

Question 116 of 160

1

Which of the following is not a feature of glutamate signaling systems?

Select one of the following:

The presence of multiple glutamate receptor families with different ionic selectivities
Voltage-dependent gating of certain types of glutamate receptor
the passage of large amounts of magnesium and calcium by NMDA receptors
The use of specialized proteins for loading glutamate into vesicles
The use of specialized proteins for removing glutamate from the synaptic cleft

Explanation

Question 117 of 160

1

Myasthenia gravis is characterized by

Select one of the following:

degeneration of lower motoneurons.
degeneration of upper motoneurons.
mutations affecting the synthesis of acetylcholine.
mutations affecting acetylcholine receptors.
an autoimmune attack on acetylcholine receptors.

Explanation

Question 118 of 160

1

The transmitter GABA excites immature cortical neurons because

Select one of the following:

immature GABA receptors pass more sodium than chloride.
immature GABA-receptive neurons have a more negative firing threshold than mature neurons.
immature GABA-receptive neurons express many Na+/K+/Cl– co-transporters.
immature GABA-receptive neurons express many K+/Cl– co-transporters.
the opening of GABA receptor channels tends to excite immature cortical networks because of the networks’ wiring.

Explanation

Question 119 of 160

1

While the nature of adenosine’s actions on central circuits is not well understood, adenosine is thought to have an inhibitory or relaxing effect because of which of the following observations?

Select one of the following:

Its presence in many inhibitory neurons
Its ability to block the reuptake of inhibitory transmitters
Its actions as a cofactor at glycine receptors
The consequences of xanthine (e.g., caffeine) blockade of adenosine receptors
The co-localization of adenosine with GABA in GABAergic synaptic vesicles

Explanation

Question 120 of 160

1

Listed below are the enzymes needed to synthesize epinephrine (adrenaline):

1. Dopamine beta-hydroxylase
2. Tyrosine hydroxylase
3. Phenylethanolamine-N-methyl transferase
4. DOPA decarboxylase

Select one of the following:

2; 4; 1; 3
3; 1; 4; 2
2; 1; 3; 4
1; 2; 4; 3
2; 4; 3; 1

Explanation

Question 121 of 160

1

Which of the following is an “effector” of G-protein-initiated signaling mechanisms?

Select one of the following:

Adenylyl cyclase
Guanylyl cyclase
Phospholipase C
All of the above
None of the above

Explanation

Question 122 of 160

1

Which of the following is not involved in the activation of CREB?

Select one of the following:

PKA
CaM kinase II
MAP kinase
ras
All of the above contribute to CREB activation

Explanation

Question 123 of 160

1

Which of the following is the slowest chemical signaling process?

Select one of the following:

Ion channel-mediated depolarization
G-protein-mediated modulation of ion channels
Phosphorylation of effector molecules by protein kinases
Synthesis of proteins after CREB activation
None of the above; all have similar time courses

Explanation

Question 124 of 160

1

Dendritic spines

Select one of the following:

were discovered with the invention of electron microscopy in the 1950s.
serve as “electrical compartments” to ensure localized depolarization.
serve as “chemical compartments” to concentrate biochemical mechanisms.
collectively form a set of hard-wired permanent neural connections.
are the sites of all excitatory and inhibitory synaptic transmission in the mammalian CNS.

Explanation

Question 125 of 160

1

Which of the following does not contribute to maintaining low levels of calcium in resting nerve cells?

Select one of the following:

Voltage-gated calcium channels
The plasma membrane calcium ATPase
The smooth endoplasmic reticulum calcium ATPase
The sodium–calcium exchanger
Mitochondria

Explanation

Question 126 of 160

1

Which of the following statements about dendritic spines is false?

Select one of the following:

They enable localized, transient increases in calcium.
They slow the diffusion of IP3, but do not prevent it from leaving the spine.
They are the sites of excitatory synapses in various parts of the CNS.
They have a bulbous head connected to a dendritic shaft by a narrow neck.
They usually contain just three proteins: NMDA receptors, mGluR receptors, and CaM kinase II.

Explanation

Question 127 of 160

1

Which of the following kinases is activated (in part) by a lipid?

Select one of the following:

Protein kinase A
Protein kinase C
Protein kinase G
CaM kinase II
CaM kinase IV

Explanation

Question 128 of 160

1

Which of the following statements about cell signaling pathways is true?

Select one of the following:

Cellular responses are always short-lived.
Cellular responses are always long-lived.
Signaling is always initiated by membrane-bound receptors.
Signaling is always initiated by intracellular receptors.
None of the above is true; all are false.

Explanation

Question 129 of 160

1

Which of the following is not integral to the functioning of protein kinases?

Select one of the following:

Hydrolysis of GTP prior to association of the regulatory and catalytic domains
Reliance on functionally distinct roles of the different domains
Binding of one or more messengers to a regulatory domain
Inhibition of a catalytic domain by a regulatory domain
Activation of a catalytic domain via a protein conformational change

Explanation

Question 130 of 160

1

Listed below are the events that make up NGF-mediated growth of sensory neurons:

1. TrkA receptor self-phosphorylation
2. Translocation of activated kinases to the nucleus
3. NGF-induced dimerization of membrane receptors
4. TrkA induction of the ras signaling pathway

Select one of the following:

1; 4; 3; 2
4; 1; 3; 2
3; 4; 1; 2
3; 1; 4; 2
1; 3; 4; 2

Explanation

Question 131 of 160

1

Which of the following is a second messenger whose activity is terminated by a phosphatase?

Select one of the following:

Calcium
CAMP
cGMP
Inositol trisphosphate
Diacylglycerol

Explanation

Question 132 of 160

1

The acetylcholine receptor at the neuromuscular junction would best be described as a(n)

Select one of the following:

channel-linked receptor.
enzyme-linked receptor.
G-protein-coupled receptor.
nuclear receptor.
gap junction.

Explanation

Question 133 of 160

1

Which of the following statements about protein kinase-based signaling is false?

Select one of the following:

Serine and threonine kinases are typically activated by second messengers.
Tyrosine kinases are typically activated by extracellular signals.
Each protein kinase has just one specific target protein that it phosphorylates.
The effects of protein kinases can be balanced by protein phosphatases.
Thousands of protein kinases are expressed in the brain.

Explanation

Question 134 of 160

1

Which of the following signaling pathways does not directly involve calcium?

Select one of the following:

Ryanodine receptor
IP3 receptor
cGMP
Phospholipase C
Calmodulin

Explanation

Question 135 of 160

1

Which of the following types of chemical signaling acts over a small neural region encompassing a cluster of nerve cells?

Select one of the following:

Endocrine
Exocrine
Paracrine
Synaptic
Ephaptic

Explanation

Question 136 of 160

1

Which of the following was an invention (by Roger Tsien) that enabled the first precise spatial and temporal measurements of intracellular calcium dynamics?

Select one of the following:

Voltage clamp
Fura-2
Calcium green
GFP
Channel rhodopsin

Explanation

Question 137 of 160

1

Tyrosine hydroxylase is a substrate for which of the following protein kinases?

Select one of the following:

PKA
PKC
CaM kinase II
MAP kinase
All of the above

Explanation

Question 138 of 160

1

Which of the following statements about the LTD mechanism in cerebellar Purkinje cells is false?

Select one of the following:

Alternating activation of climbing fibers and parallel fibers is required to induce LTD.
The firing of parallel fibers activates mGluR receptors and generates IP3.
Climbing fibers generate a large calcium signal in Purkinje cell dendrites.
Both IP3 and calcium are required to activate the IP3 receptors and depress AMPA receptor activity.
The strength of the parallel fiber synapses can be depressed for a long period of time.

Explanation

Question 139 of 160

1

The protein ras

Select one of the following:

regulates cell differentiation.
is a monomeric, or small, G-protein.
is named after the rat sarcoma tumor virus.
All of the above
None of the above

Explanation

Question 140 of 160

1

In a signal transduction cascade using G-proteins and cAMP, which of the following is not a signal amplification step?

Select one of the following:

Activation of G-proteins by an activated receptor
Activation of adenylyl cyclase molecules by G-proteins
Creation of cAMP molecules by adenylyl cyclase
Phosphorylation of target proteins by protein kinase A
All of the above are steps in which amplification occurs.

Explanation

Question 141 of 160

1

In the context of neuropathological activity, the phenomenon of kindling refers to

Select one of the following:

small burns made in cortex by an electrical stimulating electrode.
the ability to induce LTP in the amygdala and other brain regions in live animals.
the ability of daily administration of a weak, low-amplitude train of electrical pulses to gradually evoke larger and larger behavioral responses.
the phenomenon whereby a single, strong electrical pulse can evoke a full-blown seizure.
chaotic patterns of neural activity resembling the flame of a candle.

Explanation

Question 142 of 160

1

Which of the following was not an important factor in the discoveries made from the genetic analysis of learning and memory in fruit flies?

Select one of the following:

The ability to behaviorally assay large numbers of animals
Development of an assay that was sensitive to learning and memory deficits
The ability to discriminate learning deficits from sensory and motor deficits
Development of novel apparatus to perform the behavioral assays
All of the above were important.

Explanation

Question 143 of 160

1

Which of the following mechanisms contributes to the long-term enhancement of the gill withdrawal reflex in Aplysia but is not involved in the short-term enhancement of the reflex?

Select one of the following:

Activation of G-protein-coupled receptors by serotonin
Phosphorylation of CREB
Activation of adenylyl cyclase
Activation of protein kinase A
Decreased opening of potassium channels during presynaptic action potentials

Explanation

Question 144 of 160

1

Cerebellar LTD depends upon

Select one of the following:

synergistic actions of calcium and IP3 on internal calcium release channels.
synergistic actions of sodium and IP3 on internal calcium release channels.
activation of AMPA receptors by voltage-gated ion channels.
binding of IP3 to clathrin to activate endocytosis.
calcium-dependent insertion of GABA receptors into the postsynaptic membrane.

Explanation

Question 145 of 160

1

Which of the following statements about the plasticity of synapses in the mammalian CNS is false?

Select one of the following:

The hallmark of both short-term and long-term synaptic plasticity is that they always increase the strength of synaptic connections.
The efficacy of synapses can be adjusted by modulating the amount of neurotransmitter that is released.
Calcium ions play a central role in at least some forms of synaptic plasticity.
Changes in synaptic efficacy can occur over time scales ranging from milliseconds to years.
A variety of molecular mechanisms are involved in the different forms of synaptic plasticity.

Explanation

Question 146 of 160

1

Learning and memory processes in the fruit fly Drosophila show striking molecular overlap with analogous processes in Aplysia, in terms of their using all of the following except

Select one of the following:

phosphodiesterase.
adenylyl cyclase.
adenylyl cyclase activating pathways.
allosteric modulation of GABA receptors.
CREB gene regulation.

Explanation

Question 147 of 160

1

Which of the following mechanisms used in hippocampal LTD is not part of the hippocampal LTP mechanism?

Select one of the following:

History-dependent modification of synaptic efficacy
NMDA receptor activation
Calcium influx
Calcium-dependent activation of protein phosphatases
All of the above are used in both LTD and LTP.

Explanation

Question 148 of 160

1

Which of the following observations would demonstrate the spike timing-dependent plasticity of synapses?

Select one of the following:

Whether or not LTP occurs depends on the specific temporal pattern of action potentials.
LTP occurs whenever an action potential precedes an EPSP.
LTD occurs whenever an action potential follows an EPSP.
Switching the relative timing of action potential and EPSP by as little as 20 ms can switch the response from LTD to LTP, or vice-versa.
A rhythmic pattern of spike–EPSP–spike–EPSP, at 40 ms intervals, produces maximal LTP.

Explanation

Question 149 of 160

1

Which of the following is not part of the hippocampus?

Select one of the following:

Area CA1
Area CA3
Area MT
Dentate gyrus
None of the above; all are part of the hippocampus

Explanation

Question 150 of 160

1

After firing a short burst of action potentials in an axon, researchers observe a larger EPSP in the postsynaptic cell, and this effect seems to last a few tens of milliseconds. This is most likely due to the presynaptic terminal having

Select one of the following:

extra calcium.
lowered calcium.
extra sodium.
reduced sodium.
extra magnesium.

Explanation

Question 151 of 160

1

Which of the following statements about LTP is false?

Select one of the following:

LTP involves an enhancement in synaptic efficacy that can last for hours, days, weeks or even longer.
If one synapse (A) is very strongly stimulated (sufficient to cause LTP), and another nearby synapse (B) on the same dendrite is weakly stimulated at the same time, then the second synapse (B) will also show LTP.
If one synapse (A) is very strongly stimulated (sufficient to cause LTP), and a nearby synapse (B) on the same cell is weakly stimulated a few seconds later, then the second synapse (B) will also show LTP.
The requirement for coincident pre- and post-synaptic activity was predicted by Donald Hebb in 1949.
Hippocampal LTP was first reported by Bliss and Lomo about 1970.

Explanation

Question 152 of 160

1

Which statement about the mechanisms underlying hippocampal LTP induction is false?

Select one of the following:

An influx of calcium triggers two or more intracellular processes in the postsynaptic dendritic spine.
Calcium may trigger the release of a retrograde messenger that enhances transmitter release from the presynaptic terminal.
Calcium may activate CaM kinase II in such a way that it switches to a long-term “on” state.
Calcium may activate a signaling cascade that causes the insertion of glutamate receptors into the postsynaptic membrane.
Calcium decreases a resting leak current of sodium so that the postsynaptic cell is closer to threshold and therefore fires more easily.

Explanation

Question 153 of 160

1

Which of the following would not be a plausible mechanism explaining synaptic depression?

Select one of the following:

Inhibition of presynaptic calcium channels
Activation of presynaptic potassium channels
Depletion of docked synaptic vesicles in the presynaptic terminal
Delayed replenishment of vesicles to the reserve pool
Enhancement of presynaptic sodium currents

Explanation

Question 154 of 160

1

The key aspect of receptor gating in the associative induction of hippocampal LTP is that

Select one of the following:

all glutamate receptors open automatically whenever glutamate is in the synaptic cleft.
the NMDA receptor acts as a molecular coincidence detector
the AMPA receptor allows calcium into the cell only after the NMDA receptor is activated.
both the NMDA and AMPA channels must be open in order for the cell to depolarize.
All of the above are key aspects of LTP induction.

Explanation

Question 155 of 160

1

Firing an action potential in an axon initially causes a 10 mV depolarization (EPSP) in a postsynaptic neuron, but after giving a certain stimulus to the axon, firing it causes an 8 mV depolarization, after each action potential. This phenomenon is called

Select one of the following:

enhancement.
depression
facilitation.
augmentation
potentiation.

Explanation

Question 156 of 160

1

The targets of the phosphatases activated during hippocampal LTD are

Select one of the following:

voltage-gated ion channels.
ligand-gated ion channels.
synaptic vesicle regulatory proteins.
postsynaptic signaling pathways.
unknown

Explanation

Question 157 of 160

1

Which of the following is the band of hippocampal dendrites that receives inputs from the Schaeffer collaterals?

Select one of the following:

Mossy fibers
Perforant path
Stratum radiatum
CA1 region
CA3 region

Explanation

Question 158 of 160

1

Which of the following statements about long-term synaptic plasticity in Aplysia is false?

Select one of the following:

The efficacy of transmission at many synapses depends upon their history of synaptic activity.
The tracking of long-term changes in synaptic efficacy is difficult in mammalian systems because of the complexity of mammalian brains.
The gill withdrawal reflex in Aplysia can be enhanced by pairing a noxious stimulus with a mild touch.
Associative learning in the Aplysia gill withdrawal reflex is relatively independent of the timing or the order in which different stimuli are applied.
Gill withdrawal behavior in Aplysia can be altered for days or weeks by means of repeated pairings of shocks and touches.

Explanation

Question 159 of 160

1

The type of receptor that is critical for the induction of hippocampal LTP, by virtue of its admitting calcium into a dendritic spine, is called a(n)

Select one of the following:

AMPA receptor.
NMDA receptor
glycine receptor.
cholinergic GPCR.
noradrenergic GPCR.

Explanation

Question 160 of 160

1

Silent synapses are “silent” because they

Select one of the following:

have no presynaptic terminal.
have AMPA receptors but no NMDA receptors.
have NMDA receptors but no AMPA receptors.
lack voltage-gated sodium channels.
are continuously inhibited and so cannot be activated.

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