Deck 1: Principles of Signaling and Organization

Question 1

Which scientist defined the neuron as the single cell unit of the nervous system?

A) Camillo Golgi
B) Otto Loewi
C) Ramón y Cajal
D) Alan Hodgkin
E) Rudolf Virchow

Answer 1

C

Question 2

The neuronal connections in the nervous system can be

A) convergent only.
B) divergent only.
C) convergent and divergent only.
D) recurrent only.
E) convergent, divergent, recurrent, or parallel.

Answer 2

E

Question 3

Rods and cones are present in the retina layer that is

A) closest to the lens.
B) furthest away from the lens.
C) exactly in the middle of the retina.
D) not present in the retina.
E) in different layers in the retina.

Answer 3

B

Question 4

In what order is visual information in the retina transmitted?

A) Bipolar cell $\rightarrow$ photoreceptor $\rightarrow$ retinal ganglion cell
B) Retinal ganglion cell $\rightarrow$ bipolar cell $\rightarrow$ photoreceptor
C) Photoreceptor $\rightarrow$ 0bipolar cell $\rightarrow$ retinal ganglion cell
D) Bipolar cell $\rightarrow$ retinal ganglion cell $\rightarrow$ photoreceptor
E) Photoreceptor $\rightarrow$ retinal ganglion cell $\rightarrow$ bipolar cell

Question 5

Which of the following cells is not a glial cell?

A) Schwann cell
B) Purkinje cell
C) Astrocyte
D) Oligodendrocyte
E) Müller cell

Question 6

Which of the features below distinguishes neurons from glial cells?

A) Ability of producing action potentials
B) Resting membrane potential
C) Ion channels
D) Receptors for neurotransmitters
E) Ion pumps

Question 7

The cell type that detects light in the retina is a(n)

A) photoreceptor cell.
B) bipolar cell.
C) amacrine cell.
D) Müller cell.
E) ganglion cell.

Question 8

Which cell connects the photoreceptor cell with the retinal ganglion cell in the retina?

A) Amacrine cell
B) Müller cell
C) Horizontal cell
D) Bipolar cell
E) Cone cell

Question 9

Which cell type has the most elaborate dendritic branching?

A) Dorsal root ganglion neuron
B) Motor neuron
C) Pyramidal cell of cortex
D) Retinal ganglion cell
E) Purkinje cell of cerebellum

Question 10

Most neurons receive synaptic input in the

A) cell body and dendrites.
B) cell body only.
C) axon.
D) dendrites only.
E) axon and dendrites.

Question 11

The signal intensity is encoded by which property of the action potential?

A) Amplitude
B) Duration
C) Delay time
D) Frequency
E) Number

Question 12

Local graded potentials encode the intensity of a signal by

A) delay time.
B) frequency.
C) size of the membrane potential change.
D) number of potentials.
E) duration.

Question 13

The resting membrane potential of neurons is typically at

A) -65 mV.
B) +65 mV.
C) -6 mV.
D) +6 mV.
E) -650 mV.

Question 14

The amplitude of the local graded potential is decreasing as the potential is spreading over the neuronal membrane because of the

A) phospholipid bilayer.
B) presence of myelin sheaths.
C) presence of ion pumps in the plasma membrane.
D) presence of ion channels in the plasma membrane.
E) net negative charge inside the cell.

Question 15

Which of the following cells can produce an action potential?

A) Retinal ganglion cell
B) Rod photoreceptor
C) Bipolar cell
D) Cone photoreceptor
E) Müller cell

Question 16

The maximal firing frequency of neurons is

A) 10,000 Hertz.
B) 1,000 Hertz.
C) 100 Hertz.
D) 10 Hertz.
E) 1 Hertz.

Question 17

What determines whether the threshold for the initiation of an action potential is reached?

A) Combined excitatory and inhibitory inputs
B) Excitatory inputs only
C) Inhibitory inputs only
D) Resting membrane potential
E) The number of synaptic inputs

Question 18

This technique allows measuring currents through single ion channels.

A) Tungsten wire
B) Intracellular recording
C) Patch recording
D) Multi-electrode recording
E) Extracellular recording.

Question 19

When using fluorescent probes to visualize neuronal activity, the probe typically detect which ion?

A) Na⁺
B) K⁺
C) Cl^-
D) Mg²⁺
E) Ca²⁺

Question 20

Which technique is used to measure activity in specific regions of a human brain while the subject is performing a task?

A) Multiphoton microscopy
B) Functional magnetic resonance imaging
C) Electroretinogram
D) Electroencephalogram
E) X-ray

Question 21

Excitatory postsynaptic potentials are caused by

A) light.
B) hyperpolarization.
C) depolarization.
D) no change in membrane potential.
E) potassium influx.

Question 22

The maximum number of synaptic inputs a CNS neuron can have is

A) 10,000.
B) over 100,000.
C) 1,000.
D) 100,000.
E) 5,000.

Question 23

Which of the following molecules cannot be transmitted from one neuron to the next through an electrical synapse?

A) Sodium ion
B) Chloride ion
C) cAMP
D) Glucose
E) Protein kinase A

Question 24

Which of these properties describes the electrical synapse best?

A) Ion-specific
B) Size-specific
C) Slow conduction
D) Only occurs between neurons
E) Only occurs between glial cells

Question 25

The amount of neurotransmitter per vesicle is

A) dependent on the amount of depolarization.
B) dependent on the age of the neuron.
C) dependent on the frequency of the action potential.
D) relatively constant for a specific neuron.
E) is highly variable.

Question 26

Which statement describes synaptic plasticity best?

A) Ability to release different amounts of neurotransmitters
B) Ability to switch between excitatory and inhibitory postsynaptic potentials
C) Temporary changes in synaptic efficacy
D) Ability to release different types of neurotransmitters
E) Temporary changes in number of synapses

Question 27

Long-term synaptic plasticity typically involves changes in

A) gene expression.
B) threshold for action potential.
C) chan membrane resistance.
D) resting membrane potential.
E) shape of the action potential.

Question 28

Neurotransmitters can be released from

A) presynaptic terminals only.
B) cell bodies only.
C) cell bodies, axons and dendrites.
D) dendrites only.
E) glial cells only.

Question 29

Different types of neurons can be distinguished by

A) sodium/potassium pumps.
B) neurotransmitters.
C) aquaporins.
D) voltage-gated sodium channels.
E) synaptotagmins.

Question 30

Which of these proteins is not regulated by calcium?

A) Calmodulin
B) Protein kinase C
C) Calpain
D) NCAM
E) Phospholipase C

Question 31

The intracellular calcium concentration in neurons is

A) 0.0001 mM.
B) 0.001 mM.
C) 0.01 mM.
D) 0.1 mM.
E) 1 mM.

Question 32

Which statement about axonal transport is true?

A) It only occurs in mature neurons.
B) It is unidirectional.
C) It is bidirectional.
D) It only transports neurotransmitter vesicles.
E) It only transports mitochondria.

Question 33

Neurons can get very old if they do not get damaged. How does the cell ensure that degraded proteins are replaced by new proteins everywhere in a neuron with many fine extended processes?

A) By regulation of ubiquitination
B) By axonal transport
C) By regulation of gene expression
D) By endocytosis
E) By posttranslational modifications

Question 34

Neural precursor cells have which property?

A) They can still divide.
B) They have the potential to give rise to neurons.
C) They have the potential to give rise to glial cells.
D) They derive from neuroectoderm.
E) All of the above

Question 35

Which molecular tools have been frequently used to analyze fate mapping in developing embryos?

A) Genetically encoded fluorescent proteins
B) Antibodies
C) In situ hybridization
D) Fluorescent microbeads
E) Optogenetics

Question 36

The typical order of events during nervous system development is

A) cell migration $\rightarrow$ cell differentiation $\rightarrow$ axon guidance $\rightarrow$ cell proliferation.
B) axon guidance $\rightarrow$ cell migration $\rightarrow$ cell proliferation $\rightarrow$ cell differentiation.
C) cell differentiation $\rightarrow$ cell proliferation $\rightarrow$ axon guidance $\rightarrow$ cell migration.
D) cell migration $\rightarrow$ cell differentiation $\rightarrow$ cell proliferation $\rightarrow$ axon guidance.
E) cell proliferation $\rightarrow$ cell differentiation $\rightarrow$ cell migration $\rightarrow$ axon guidance.

Question 37

Which model organism has been studied first to investigate how genes control development?

A) Mouse
B) Xenopus
C) Drosophila
D) Chicken
E) Rat

Question 38

Which pair of cell types has the same precursor cell?

A) Neuron and epithelial cell
B) Glial cell and fibroblast
C) Neuron and glial cell
D) Neuron and endothelial cell
E) Glial cell and leukocyte

Question 39

The main molecular signals that control cell differentiation are

A) cyclins.
B) transcription factors and morphogens.
C) morphogens.
D) hormones.
E) transcription factors.

Question 40

Which neuronal connection in an adult human has the highest regeneration potential following injury?

A) Optic nerve
B) Sciatic nerve
C) Dorsal column of spinal cord
D) Ventral column of spinal cord
E) Thalamo-cortical connection

Question 41

Which modern imaging technique can provide information about the area of the brain that is active when performing a specific task such as watching a video, and what are the limitations of this technique?

Question 42

Retina not only contains neurons but also glial cells. What are some key functions of glial cells and what is the name of the major glial cell type in the retina?

Question 43

How is the visual information maintained as signals are sent from the eye to the brain?

Question 44

Do all neurons strictly follow the cellular organization with cell body, axon and dendrites? If not, please provide an example for a neuron that does not follow this basic organization.

Question 45

What technique can you use to determine the connectivity of neurons in brain circuits?

Question 46

The fastest firing frequency of neurons is limited to 1000 Hz. Please explain why neurons cannot generate action potentials at higher frequency.

Question 47

Intracellular electrodes allow recording of resting membrane, local graded and action potentials; however, recordings are limited to a few minutes. Why can't you typically record for longer time with an intracellular electrode?

Question 48

Explain a benefit of chemical transmission between two neurons.

Question 49

Explain how channelrhodopsin works.

Question 50

Explain a main benefit of electrical synapse and provide examples where these synapses play a role.

Question 51

Calcium does not contribute much to the level of the resting membrane potential or action potential; however, it is a key signal for releasing neurotransmitter from the presynaptic terminal. Explain why.

Question 52

For a long time there was a dogma in the field that axons and their terminal cannot synthesize proteins. There is a lot of evidence that this is not correct and that local protein translation occurs in axon, growth cones and synapse. Explain why axonal transport is not always sufficient to deliver proteins to the sites where they are needed.

Question 53

The adult human brain contains in average 10¹¹ neurons making 10¹⁴ connections. The human genome has only about 24,000 genes. Even if 1000 genes would encode for axon guidance and synaptic targeting molecules, how is it possible to specify 10¹⁴ connections with only 10³ genes?

Question 54

The adult mammalian central nervous system has very limited regeneration capability. This is one of the major challenges in the field of neuronal repair and regeneration. Can you provide some possible explanations for this limited regeneration potential?