Question 1

Explain how channelrhodopsin works.

Accepted Answer

Channelrhodopsin is light-activated ion channel originally found in green algae. It has been adapted as optogenetic tools for neuroscience. By expressing channelrhodopsin in neurons and exciting it with blue light, one can depolarize the neuron with light control.

Question 2

Local graded potentials encode the intensity of a signal by

Accepted Answer

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

Question 3

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

Accepted Answer

Visual information like other sensory information is transmitted in a topographic fashion ensuring that spatial information is maintained by the arrangement of retinal ganglion cell axons within the optic nerve and then properly mapped to the visual centers in the brain.

Question 4

Which cell type has the most elaborate dendritic branching?

Accepted Answer

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

Question 5

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

Accepted Answer

After a neuron fires an action potential

Question 6

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?

Accepted Answer

Functional magnetic resonance (fMRI) ima

Question 7

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

Accepted Answer

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

Question 8

The main molecular signals that control cell differentiation are

Accepted Answer

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

Question 9

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.

Accepted Answer

Axons can be extremely long compared to

Question 10

Which of these properties describes the electrical synapse best?

Accepted Answer

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

Question 11

Different types of neurons can be distinguished by

Accepted Answer

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

Question 12

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?

Accepted Answer

Because the sharp electrode im

Question 13

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

Accepted Answer

A)  Combined excitatory and inhibitory inputs 
B)  Excitatory inputs only 
C)  Inhibitory inputs only 
D)  Resting membrane potential 
E)  The number of synaptic inputs 
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 14

Excitatory postsynaptic potentials are caused by

Accepted Answer

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

Question 15

Long-term synaptic plasticity typically involves changes in

Accepted Answer

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

Question 16

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

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

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

Accepted Answer

Electrical synapses allow fast electrica

Question 19

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

Accepted Answer

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

Question 20

Which of the following cells can produce an action potential?

Accepted Answer

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

Exam 1: Principles of Signaling and Organization

Explain how channelrhodopsin works.

Local graded potentials encode the intensity of a signal by

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

Which cell type has the most elaborate dendritic branching?

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

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?

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

The main molecular signals that control cell differentiation are

Which of these properties describes the electrical synapse best?

Different types of neurons can be distinguished by

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?

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

Excitatory postsynaptic potentials are caused by

Long-term synaptic plasticity typically involves changes in

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

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

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

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

Which of the following cells can produce an action potential?

Signaling in the Visual System

Functional Architecture of the Visual Cortex

Ion Channels and Signaling

Structure of Ion Channels

Ionic Basis of the Resting Potential

Ionic Basis of the Action Potential

Electrical Signaling in Neurons

Ion Transport Across Cell Membranes

Properties and Functions of Neuroglial Cells

Mechanisms of Direct Synaptic Transmission

Indirect Mechanisms of Synaptic Transmission

Release of Neurotransmitters

Neurotransmitters in the Central Nervous System

Transmitter Synthesis, Storage, Transport, and Inactivation

Synaptic Plasticity

The Molecular and Cellular Biology of Synaptic Plasticity

Mechanisms of Extrasynaptic Communication

Autonomic Nervous System

Walking, Flying, and Swimming: Cellular Mechanisms of Sensorimotor Behavior in Invertebrates

Sensory Transduction

Transduction and Transmission in the Retina

Touch, Pain, and Texture Sensation

Auditory and Vestibular Sensation

Constructing Perception

Initiation and Control of Coordinated Muscular Movements

Development of the Nervous System

Critical Periods in Sensory Systems

Regeneration and Repair of Synaptic Connections After Injury

Appendix

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