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Sanes Chapter 8 Questions

[1] Which is the most accurate statement?

a. The components needed for neurotransmission are primarily generated by the postsynaptic neuron.

b. Most of the components needed for neurotransmission are generated immediately prior to the formation of functional contact.

c. Most of the components needed for neurotransmission are generated within the growth cone.

d. Many of the components needed for neurotransmission are generated in both the growth cone and the postsynaptic site well before the establishment of functional contact.*

[2] About _______ percent of the genes encoding post-synaptic proteins are homologous between mammals and yeast.

a. 25b. 20*c. 15d. 10

[3] Most synapses on the soma and dendrites of mammalian neurons, release:

a. GABAb. Glutamate and neuromodulatory transmittersc. GABA and neuromodulatory transmittersd. Glutamate and GABA*

[4] Functioning synapses evolved at about the time of the

a. Metazoans (1,237M years ago)b. Eumetazoans (1,036M years ago)*c. Bilaterians (910M years ago)d. Deuterostomes

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[5] The evolutionary appearance of functioning synapses occurred at about the same time as the evolutionary appearance of which of these synaptic proteins?

a. Calcineurinb. Neuroligins*c. synGAPd. stargazing

[6] In cerebral cortex, glutamatergic synapses tend to be located on the ___________ where as GAGAergic synapses tend to form on the ___________

a. cell body; proximal dendriteb. dendritic spine; cell body*c. proximal dendrite; dendritic spined. dendritic spines; axons

[7] A key difference between the older “reticular theory” (syncytium) and the modern “neuron theory” is

a. presence or absence of synapsesb. unidirectional vs bidirection flow of electrical activityc. both of these are correct*d. neither of these are correct

[8] Which of these most accurately describes the general features of synaptogenesis:

a. some of the building blocks of synaptogenesis are manufactured by neurons before they make contact with each other

b. differentiation of synapses begins upon first contact, induced by intercellularsignaling (glia, extracellular matrix, nearby neurons)

c. synapses do not mature immediately after being formedd. all of these are true*

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[9] Why does the resting membrane potential become more negative during development?

a. Decrease in extra-cellular K+ as regulated by glial cells*b. Increase in extra-cellular C+ as regulated by glial cellsc. Actually, the resting membrane potential becomes more positive during

developmentd. Actually, the resting membrane potential changes very little during

development

[10] Membrane input resistance and membrane time constant

a. Tend to decrease with age*b. Tend to increase with agec. Change very little during developmentd. Do not co-vary during development; as one increases the other decreases

[11] Which channel is the most common and fastest in the mature nervous system?

a. Calciumb. Sodium*c. Potassiumd. They are all about the same in the mature organism but differ in the

immature organism

[12] Changes in membrane potential during maturation is about the same (10 mV) for all species.

a. Trueb. False*

[13] There are different types of potassium channels, different types of sodium channels and different types of calcium channels.

a. True*b. False

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[14] The appearance of transient, resurgent and persistent sodium currents at different times during development is not correlated with changes in action potential properties.

a. Trueb. False*

[15] The acquisition of GABAergic phenotypes, and process outgrowths, is related to

a. The appearance of Low-voltage activated (LVA) or T currents early in synaptogenesis*

b. The appearance of Low-voltage activated (LVA) or T currents later in synaptogenesis

c. The appearance of High-voltage activated (HVA) or N and L currents early in synaptogenesis

d. The appearance of High-voltage activated (HVA) or N and L currents later in synaptogenesis

[16] Studies on dissociated spinal motor neurons from the chick embryo found that

a. T-type calcium channels decline with age*b. L-type calcium channels decline with agec. N-type calcium channels decline with aged. T-type calcium channels increase while N-type and L-type decrase with with

age

[17] Calcium-activated potassium current (|-K[Ca]) is affected by extrinsic signals from target or preganglionic afferents as follows:

a. Either target removal or deafferentation reduces (|-K[Ca]) by 90-100%*b. Only deafferentation reduces (|-K[Ca]) by 90-100%c. Only target removal reduces (|-K[Ca]) by 90-100%d. Either target removal or deafferentation increases (|-K[Ca]) by 90-100%

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[18] Accumulation of small vesicles at the presynaptic membrane is a characteristic of

a. Newly formed synapsesb. The point at which a synapse will formc. Later, more mature synapses*d. None of these are correct

[19] The structural characteristics that identify a newly-formed synapse are

a. Few vesicles in the presynaptic membrane, no evidence of PSD in the postsynaptic membrane and a tight junction between the two membranes*

b. Vesicles in the presynaptic membrane, evidence of PSD in the postsynaptic membrane and a cleft between the two membranes

c. Few vesicles in the presynaptic membrane, evidence of PSD in the postsynaptic membrane and a cleft between the two membranes

d. Vesicles in the presynaptic membrane, no evidence of PSD in the postsynaptic membrane and a tight junction between the two membranes

[20] In vitro techniques for studying synaptogenesis enable researchers to

a. Find evidence for the onset of electrical activityb. Use evidence of the onset of electrical activity to study synapse

morphologyc. Use evidence of the onset of electrical activity to infer functionality of what

can’t be seen with electron microscopes*d. Independently examine the pre- and post-synaptic membranes

[21] Why do most inhibitory synapses form on dendritic spines?

a. So that their activity can be more easily summed togetherb. To more effectively halt the activity of the cellc. To enable the cell to separate the functional role of each inputd. They don’t; they typically cluster near the soma*

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[22] When a postsynaptic marker protein (PSD-95) is added to developing hippocampal slices or developing midbrain areas, the new postsynaptic sites appear first

a. On axonal growth cone filopodiab. On dendritic filopodia*c. On axosomatic filopodiad. In the extracellular matrix

[23] Evidence that glial processes may serve a gate-keeping function for where and when synapses may form is provided by the observation that

a. Inhibitory connections to cells of the medial superior olive at first form only on the cell body because the dendritic processes are surrounded by glia

b. Excitatory connections to cells of the medial superior olive at first form only on the dendrites because the cell bodies are surrounded by glia*

c. Glial processes invading a synaptic region because a cell adhesion molecule has been eliminated, facilitate synaptogenesis

d. All of these are correct

[24] Developing synaptic morphology on pre- and post-synaptic membranes always requires the presence of components on both sides of the synaptic cleft.

a. Trueb. False*

[25] The onset of synaptogenesis and the rate of synaptogensis varies by

a. Speciesb. Region of cortexc. Gestational aged. All of these are correct*

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[26] Some developing synapses can be identified by anatomy alone and some by physiology alone.

a. Trueb. False*

[27] Before a growth cone reaches its post-synaptic target, it has been equipped with an ACh transmitter-releasing mechanism.

a. True*b. False

[28] What experimental technique suggested that a mechanism for vesicular release from growth cone filopodia may be present prior to the formation of the synapse?

a. Optical, looking at a fluorescent dye released from vesicles when the neuron is depolarized*

b. Electrical, looking at changes in the presynaptic membrane at the point where the vesicles are located

c. Optical, looking at the tight junction with an electron microscoped. All of these are correct

[29] One of the techniques for studying the diverse electrical properties of neurons is to adjust the membrane potential to different holding voltages and then observe whether current flows across the membrane; this is called

a. Voltage-clamp*b. Ligand-gatec. Ionic compositiond. Batteries and switches

[30] The patch-clamp technique offers a rigorous biophysical means for measuring the movement of a single type of ion, e.g., potassium.

a. Trueb. False*

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[31] The patch-clamp technique uses electrodes to

a. Form low-resistance seals over a small piece of membrane that can be excised from the cell to study its electrical properties in vitro

b. Form high-resistance seals over a small piece of membrane that can be excised from the cell* to study its electrical properties in vitro

c. Form low-resistance seals over a large section of membrane making it easy to study its electrical properties in vitro

d. Form high-resistance seals over a large section of membrane making it easy to study its electrical properties in vitro

[32] An advantage of the patch-clamp technique is that the excised membrane being studied in vitro

a. Often contains a single channel*b. Makes it possible to expose the inner surface to various defined mediac. Makes it possible to expose the outer surface to various defined mediad. None of these are correct

[33] Studying the electrical properties of individual neurons using a gigaOhm-seal and a patch electrode allows experimenters to dynamically control

a. The intracellular composition*b. The size of ion channelsc. The neuron’s membrane potentiald. The flow of ions through the channels

[34] What is optogenetics?

a. Introducing ion-sensitive fluorescent dyes into neural tissueb. Introducing ion-sensitive fluorescent dyes into culture dishes containing

neural membranec. Manipulating “caged” compounds that only become activated when

exposed to light of specific wavelengthsd. Genetically introducing a substance which, when exposed to light, induces

the flow of ions across neural membranes*

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[35] Although recording the exact moment when a cell is first contacted by a growth cone in vivo has not been possible, in vitro studies of muscle cells put into contact with growing neuritis has shown spontaneous synaptic events

a. Within seconds of first contact*b. Within 10-20 minutes of first contactc. Within several hours of first contactd. Within a day of first contact

[36] In typical synaptogenesis, structural maturation of the synapse __________ functional maturation of the synapse.

a. Precedesb. Lags behind*c. Occurs at about the same timed. Precedes or lags depending on the species being studied

[37] An in vitro study of newborn mouse basilar pontine nuclei cultured with their target neurons, the granule cells of the cerebellum, showed that __________ slowed down the speed of growth cones.

a. Only direct contact with granule cells in the culture medium*b. Only direct contact with glial cells in the culture mediumc. Presence or contact with granule cells suspended in the culture mediumd. Presence or contact with glial cells suspended in the culture medium

[38] Growth cones exhibit changes in membrane potential in response to guidance factors; the chemoattractant Netrin-1 ____________ the membrane and the chemorepellant Sema3A _______________ the membrane; contact with the target causes a flow of _________ ions into the growth cone filopodia.

a. Depolarized; hyperpolarized; Ca+*b. Hyperpolarized; depolarized; Na+c. Depolarized; hyperpolarized; Na+d. Hyperpolarized; depolarized; Ca+

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[39] Synaptic differentiation and maturation after a growth cone makes contact with a target cell, includes these steps, in this sequence:

a. Rapid influx of Ca+ ions, increase in actin polymerization, extension of microtubules toward the contact site*

b. Neurosecretory granules invade the lamellapodia, growth cone slows down and becomes stationary, rapid influx of Ca+ ions

c. Extension of microtubules toward the contact site, appearance of new calcium channels at growth cone edge,rapid influx of Ca+ ions

d. Accumulation of secretory vesicles and ion channels at contact site, growth cone slows down and becomes rounded, neurosecretory granules invade the lamellapodia

[40] The extrinsic synapse-inducing activity of astrocytes is due to the soluble factor

a. Cholesterol*b. Calciumc. Protein kinase Cd. The ionophore A23187

[41] Syn-CAMs (synaptic cell adhesion molecules) are the ____________ mammalian homolog of FasII (in Drosophila)

a. Brain-specific*b. Nerve-muscle junction specificc. Spinal cordd. Retinal

[42] What happens when non-neuronal cells are transfected with with SynCAM1 and placed in culture with hippocampal neurons?

a. They induce presynaptic differentiation*b. They induce postsynaptic differentiationc. They inhibit presynaptic differentiationd. They inhibit postsynaptic differentiation

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[43] What’s a myoball?

a. A single muscle cell*b. A single lamellopodiumc. A single nerve-muscle synapsed. None of these are correct

[44] Calcium-dependent cell adhesion molecules are known as

a. Catenins b. Cadherins*c. synCAMsd. puncta aherens

[45] In the developing nervous system, the large family of cadherins are primarily located

a. on growth conesb. at developing synapses*c. on post-synaptic membranesd. all of these are correct

[46] Cadherins bring pre- and post-synaptic membranes in close apposition and bind glutamate receptors to the synapse.

a. True*b. False

[47] Synaptogenesis seems to require interaction between two superfamilies of adhesion molecules

a. Ig and Cadherin*b. Nectin and Afadinc. Catenin and Afadind. Nectin and Cadherin

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[48] What is the adherens junction?

a. Site where nectin-afadin and cadherin-caenin proteins are colocalizedb. A close apposition of membranes of the growth cone and postsynaptic

neuronc. An earlier structure which later becomes the puncta adherensd. All of these are correct*

[49] The transmembrane proteins Neurexins (NRSN) are expressed in __________ and their binding partner neurolignins (NLGN) are expressed in __________. NLGN and NRXN are located in _____________

a. Growth cones; postsynaptic membranes; transport packets*b. Postsynaptic membranes; growth cones; extracellular spacesc. Postsynaptic membranes; growth cones; transport packetsd. Growth cones; postsynaptic membranes; extracellular spaces

[50] NLGN-NRXN signaling is absolutely required for the generation of anatomical synaptic contacts.

a. Trueb. False*

[51] In synaptogenesis, the Wnt-7a protein and its receptor, Frizzled, support

a. Presynaptic differentiation by inducing the accumulation of synapsin*b. Postsynaptic differentiation by inducing the accumulation of synapsinc. Presynaptic differentiation by inducing the accumulation of Bassoond. Postsynaptic differentiation by inducing the accumulation of Bassoon

[52] Which is the accurate observation?

a. Presynaptic transport packets tend to stabilize at a stationary postsynaptic site*

b. Postsynaptic transport packets tend to stabilize at a stationary presynaptic site

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[53] One of the principal characteristics of synaptogenesis is the accumulation of neurotransmitter receptors at the puncta adherens.

a. True*b. False

[54] AChRs cluster on muscle cells before motor neuron growth cones arrive in patterns that define the sites where NMJ synapses will locate.

a. Trueb. False*

[55] Four or more cytoplasmic proteins are required to mediate successful AChR clustering on the postsynaptic membrane.

a. True*b. False

[56] An in vitro experiment involving muscle cells and growth cones of frog spinal neurons showed that adhesion molecules were well established (grades 1-3 degrees of attachment) after

a. 1.5 minutesb. 15 minutes*c. Several hoursd. A day or longer

[57] Activity-dependent receptor clustering (e.g. release of glutamate)

a. Is a developmental mechanismb. Is used to adjust synaptic strength throughout the lifetime of the synapsec. Might be a developmental mechanism or might be a synaptic strength

adjusting mechanism*d. Is neither a developmental nor a synaptic strength adjusting mechanism

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[58] At the neuromuscular junction, a signal that is secreted from nerve terminals, induces receptor clustering; this proteoglycan is

a. Agrin*b. Neurexinc. Neuroligind. Netrin-g ligand

[59] Most neurotransmitter receptors are expressed before innervations occurs.

a. True*b. False

[60] What is the primary function of the MuSK protein?

a. Required for early pre-patterning of AChRsb. Required for nerve-induced clustering in muscle cellsc. Both of these are correct*d. Neither of these is correct

[61] In order for the Agrin-MuSK interaction to lead to clustering of AChRs, __________ must be present.

a. Dok-7 and Rapsyn*b. Rapsyn and Netrin-G ligandc. Neurexin and neuroligind. FGFR2

[62] The EphrinB-EphB signaling pathway is necessary to cluster

a. Ach Receptorsb. Glutamate receptors*c. GABAtergic receptorsd. NMDA receptors

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[63] Scaffolding proteins hold particular receptors together near the cytoplasmic surface; different scaffolding proteins may cluster different excitatory or inhibitory receptors.

a. True*b. False

[64] At the NMJ, the presence of a motor neuron has the effect of _________ the number of ___________ receptors in newly formed synapses.

a. Increasing; AChR*b. Increasing; GABAc. Decreasing; AChRd. Decreasing; GABA

[65] Glutamate receptors may be synthesized within a neuron’s dendrites, as well as in the soma.

a. True*b. False

[66] At the NMJ, receptor clustering can be described as a competition between

a. Agrin-MuSK signaling that facilitates clustering and Ach-AChR signaling that acts to deplete existing receptor clusters*

b. Agrin-MuSK signaling that inhibits clustering and Ach-AChR signaling that acts to facilitate the synthesis and clustering of AChRs

c. EphrinB-EphB signaling that inhibits clustering and TGFβ1 - β−Neuregulin-1 signaling that acts to facilitate the synthesis and clustering of AChRs

d. EphrinB-EphB signaling that facilitates clustering and TGFβ1 - β−Neuregulin-1 signaling that acts to deplete existing receptor clusters

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[67] In maturing rat neocortex, the duration of EPSPs __________ during the first two postnatal weeks from ________ to ________ ms.

a. Decreases; 400; 100;*b. Increases; 100; 400;c. Decreases; 6; 1;d. Increases; 1; 6;

[68] The maturation of receptor subunits for most transmitter systems in the CNS can be characterized as undergoing a developmental switch.

a. True*b. False

[69] GABA receptor subunits α1 and α5 are differentially expressed in the nervous system of P6 rats and adult rats:

a. In P6 rats α5 is heavily expressed in hippocampus and cortex whereas α1 is hardly present; in adult rat, α1 is heavily expressed and α5 is restricted*

b. In adult rats α5 is heavily expressed in hippocampus and cortex whereas α1 is hardly present; in P6 rats, α1 is heavily expressed and α5 is restricted

c. In P6 rats α5 is restricted in hippocampus and cortex whereas α1 is hardly present; in adult rat, α1 is heavily expressed and α5 is also heavily expressed

d. In P6 rats α5 is heavily expressed in hippocampus and cortex and α1 is also heavily expressed; in adult rat, α1 is restricted as is α5

[70] A few current studies suggest that the maturation of amino acid transporters has little effect on the kinetics of synaptic transmission.

a. Trueb. False*

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[71] Since neurons fire many times per second under normal conditions, their synaptic responses may become facilitated or depressed over time. This is referred to as:

a. Short-term plasticity*b. Scaffoldingc. Developmental switchd. IPSPs and EPSPs

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