NEUROSCIENCE FINAL EXAM
MULTIPLE CHOICE QUESTIONS WITH
CORRECT ANSWERS
Why is there no sensation of light at the optic disk?
A) Because the optic disk is a theoretical construct
B) Because there are no photoreceptors in the optic disk
C) Because optic nerve fibers exit the retina at this point
D) Because of the presence of the vitreous humor - Answer-B) Because there are no
photoreceptors in the optic disk
Which cells in the retina have axons that leave the retina?
A) Photoreceptors
B) Bipolar cells
C) Ganglion cells
D) Photoreceptors, bipolar cells, and ganglion cells - Answer-C) Ganglion cells
Why does the fovea appear like a pit in the retinal cross-section?
A) Because of the lateral displacement of cells above the photoreceptors
B) Because of a low ratio of photoreceptors to ganglion cells
C) Because photoreceptors are smaller in the fovea
D) Because of the presence of other cells that might scatter light - Answer-A)
Because of the lateral displacement of cells above the photoreceptors
What is meant by the term duplex retina?
A) The cones are sensitive to two different wavelengths
B) The retina is capable of both scotopic and photopic vision
C) Cones, not rods, are wavelength sensitive
D) The transition from all-cone daytime to all-rod nighttime vision is instantaneous -
Answer-B) The retina is capable of both scotopic and photopic vision
Which of the following corresponds to the photoreceptor "dark current"?
A) At rest, the membrane potential of a rod outer segment is about -30mV
B) Some retinal current is light and some is dark because of photoreceptor
pigmentation
C) The resting membrane potential of a rod outer segment is -65mV
D) The movement of negative across the photoreceptor membrane in the dark -
Answer-A) At rest, the membrane potential of a rod outer segment is about -30mV
What is the difference between ON-center ganglion cells and OFF-center ganglion
cells?
A) ON-center ganglion cells constitute about 90% of the ganglion cell population
while OFF-center ganglion cells constitute about 5% of the ganglion population
B) ON-center ganglion cells respond to stimulation of their receptive field centers
with a transient burst of action potentials while OFF-center ganglion cells respond
with a sustained discharge
,C) ON-center ganglion cells receive input from ON bipolar cells while OFF-center
ganglion cells receive input from OFF bipolar cells
D) In an ON-center ganglion cell, the response to stimulation of the center is
cancelled by the response to stimulation of the surround and this response
cancellation does occur in an OFF-center ganglion cell. - Answer-C) ON-center
ganglion cells receive input from ON bipolar cells while OFF-center ganglion cells
receive input from OFF bipolar cells
Which of the following is an example of parallel processing in the central visual
system?
A) Simultaneous input from two eyes provides the central visual system with
information about depth and the distance of an object from the observer
B) Independent streams of information arise from the ON-center and OFF-center
ganglion cells in each retina
C) M-P type retinal ganglion cells have different receptive field properties and their
projections to the brain are segregated through the lateral geniculate and striate
cortex
D) All of the above - Answer-A) Simultaneous input from two eyes provides the
central visual system with information about depth and the distance of an object from
the observer
True or false: In the process of signal amplification, a single G-protein is activated by
each photopigment molecule and each PDE enzyme breaks down a single cGMP
molecule. - Answer-False
True or false: A center surround receptive field consists of concentric circles with
antagonistic responses to the presence or absence of light. - Answer-True
Which of the following is the function of direction-selective striate cortex neurons?
A) Analysis of object shape
B) Analysis of object motion
C) Analysis of object color
D) Analysis of object meaning - Answer-B) Analysis of object motion
Which of the following is the common characteristic in the receptive fields in the
ganglion cells of the retina, the LGN, and striate cortex neurons in layer IVC?
A) Center surround antagonism
B) Elongated bar of light moving across the receptive field
C) Optimal orientation of a bar of light
D) Radial column of cells from pia to white matter - Answer-A) Center surround
antagonism
How does myelin help increase conduction velocity?
A) It provides electrical insulation
B) It makes the membrane more excitable.
C) It contains voltage gated sodium channels.
D) It increases axonal diameter. - Answer-A) It provides electrical insulation.
True or False: The size of the giant axon of the squid indicates that the neural
pathways that are important for survival have unusually large ions. - Answer-A) True
, True or False: In myelinated axons, action potentials spread very slowly. This type of
action potential propagation is called saltatory conduction. - Answer-B) False
Why do action potentials travel in only one direction?
A) The membrane just behind the action potential is refractory due to inactivated
potassium channels.
B) The membrane just behind the action potential is in refractory due to inactivated
sodium channels.
C) The membrane proteins are destroyed when an action potential fires and it takes
time to replace them.
D) There is not enough sodium in the extracellular space after an action potential
has just fired. - Answer-B) The membrane just behind the action potential is in
refractory due to inactivated sodium channels.
What is the meaning of the term animal model? - Answer-An animal model is an
animal whose evolutionary descent is close enough to humans' to use it for study
and comparative purposes -- systems and mechanisms work pretty similarly across
ancestral lineages
What are brain ventricles and what functions have been ascribed to them over the
ages? - Answer-The ventricles are sacs of cerebrospinal fluid in the brain that
a) help with naming, anatomical location description, and give a reference point
b) were thought to control movement and coordination
c) at one time, were thought to be empty space
Which of the following structures are unique to neurons?
Nucleus, mitochondria, rough ER, synaptic vesicle - Answer-Synaptic vesicle
What are two physical characteristics that distinguish axons from dendrites? -
Answer-Axon has significantly less branches and surface area reach than dendrites;
dendrites have ribosomes and lack heavy concentration of mitochondria; axons lack
ribosomes and have concentrated mitochondria in terminals.
What two functions do proteins in the neuronal membrane perform to establish and
maintain the resting membrane potential? - Answer-Proteins form ion pumps and
channels that use energy to ensure that the concentration of K+ inside the cell>Na+
inside; K+ inside >K+ outside. They also create the channels that open and close
during an AP to allow diffusion necessary for depolarization and repolarization.
When membrane is at potassium equilibrium potential, in which direction (in or out) is
there a net movment of potassium ions? Why? - Answer-There is no net movment at
equilibrium, but to maintain equilibrium, diffusion occurs in and out at the same rate.
Why is the action potential referred to as "all-or-none"? - Answer-If the AP does not
lead to depolarization (if the threshold is not exceeded), no AP will occur; if
depolarized, an AP is likely.
MULTIPLE CHOICE QUESTIONS WITH
CORRECT ANSWERS
Why is there no sensation of light at the optic disk?
A) Because the optic disk is a theoretical construct
B) Because there are no photoreceptors in the optic disk
C) Because optic nerve fibers exit the retina at this point
D) Because of the presence of the vitreous humor - Answer-B) Because there are no
photoreceptors in the optic disk
Which cells in the retina have axons that leave the retina?
A) Photoreceptors
B) Bipolar cells
C) Ganglion cells
D) Photoreceptors, bipolar cells, and ganglion cells - Answer-C) Ganglion cells
Why does the fovea appear like a pit in the retinal cross-section?
A) Because of the lateral displacement of cells above the photoreceptors
B) Because of a low ratio of photoreceptors to ganglion cells
C) Because photoreceptors are smaller in the fovea
D) Because of the presence of other cells that might scatter light - Answer-A)
Because of the lateral displacement of cells above the photoreceptors
What is meant by the term duplex retina?
A) The cones are sensitive to two different wavelengths
B) The retina is capable of both scotopic and photopic vision
C) Cones, not rods, are wavelength sensitive
D) The transition from all-cone daytime to all-rod nighttime vision is instantaneous -
Answer-B) The retina is capable of both scotopic and photopic vision
Which of the following corresponds to the photoreceptor "dark current"?
A) At rest, the membrane potential of a rod outer segment is about -30mV
B) Some retinal current is light and some is dark because of photoreceptor
pigmentation
C) The resting membrane potential of a rod outer segment is -65mV
D) The movement of negative across the photoreceptor membrane in the dark -
Answer-A) At rest, the membrane potential of a rod outer segment is about -30mV
What is the difference between ON-center ganglion cells and OFF-center ganglion
cells?
A) ON-center ganglion cells constitute about 90% of the ganglion cell population
while OFF-center ganglion cells constitute about 5% of the ganglion population
B) ON-center ganglion cells respond to stimulation of their receptive field centers
with a transient burst of action potentials while OFF-center ganglion cells respond
with a sustained discharge
,C) ON-center ganglion cells receive input from ON bipolar cells while OFF-center
ganglion cells receive input from OFF bipolar cells
D) In an ON-center ganglion cell, the response to stimulation of the center is
cancelled by the response to stimulation of the surround and this response
cancellation does occur in an OFF-center ganglion cell. - Answer-C) ON-center
ganglion cells receive input from ON bipolar cells while OFF-center ganglion cells
receive input from OFF bipolar cells
Which of the following is an example of parallel processing in the central visual
system?
A) Simultaneous input from two eyes provides the central visual system with
information about depth and the distance of an object from the observer
B) Independent streams of information arise from the ON-center and OFF-center
ganglion cells in each retina
C) M-P type retinal ganglion cells have different receptive field properties and their
projections to the brain are segregated through the lateral geniculate and striate
cortex
D) All of the above - Answer-A) Simultaneous input from two eyes provides the
central visual system with information about depth and the distance of an object from
the observer
True or false: In the process of signal amplification, a single G-protein is activated by
each photopigment molecule and each PDE enzyme breaks down a single cGMP
molecule. - Answer-False
True or false: A center surround receptive field consists of concentric circles with
antagonistic responses to the presence or absence of light. - Answer-True
Which of the following is the function of direction-selective striate cortex neurons?
A) Analysis of object shape
B) Analysis of object motion
C) Analysis of object color
D) Analysis of object meaning - Answer-B) Analysis of object motion
Which of the following is the common characteristic in the receptive fields in the
ganglion cells of the retina, the LGN, and striate cortex neurons in layer IVC?
A) Center surround antagonism
B) Elongated bar of light moving across the receptive field
C) Optimal orientation of a bar of light
D) Radial column of cells from pia to white matter - Answer-A) Center surround
antagonism
How does myelin help increase conduction velocity?
A) It provides electrical insulation
B) It makes the membrane more excitable.
C) It contains voltage gated sodium channels.
D) It increases axonal diameter. - Answer-A) It provides electrical insulation.
True or False: The size of the giant axon of the squid indicates that the neural
pathways that are important for survival have unusually large ions. - Answer-A) True
, True or False: In myelinated axons, action potentials spread very slowly. This type of
action potential propagation is called saltatory conduction. - Answer-B) False
Why do action potentials travel in only one direction?
A) The membrane just behind the action potential is refractory due to inactivated
potassium channels.
B) The membrane just behind the action potential is in refractory due to inactivated
sodium channels.
C) The membrane proteins are destroyed when an action potential fires and it takes
time to replace them.
D) There is not enough sodium in the extracellular space after an action potential
has just fired. - Answer-B) The membrane just behind the action potential is in
refractory due to inactivated sodium channels.
What is the meaning of the term animal model? - Answer-An animal model is an
animal whose evolutionary descent is close enough to humans' to use it for study
and comparative purposes -- systems and mechanisms work pretty similarly across
ancestral lineages
What are brain ventricles and what functions have been ascribed to them over the
ages? - Answer-The ventricles are sacs of cerebrospinal fluid in the brain that
a) help with naming, anatomical location description, and give a reference point
b) were thought to control movement and coordination
c) at one time, were thought to be empty space
Which of the following structures are unique to neurons?
Nucleus, mitochondria, rough ER, synaptic vesicle - Answer-Synaptic vesicle
What are two physical characteristics that distinguish axons from dendrites? -
Answer-Axon has significantly less branches and surface area reach than dendrites;
dendrites have ribosomes and lack heavy concentration of mitochondria; axons lack
ribosomes and have concentrated mitochondria in terminals.
What two functions do proteins in the neuronal membrane perform to establish and
maintain the resting membrane potential? - Answer-Proteins form ion pumps and
channels that use energy to ensure that the concentration of K+ inside the cell>Na+
inside; K+ inside >K+ outside. They also create the channels that open and close
during an AP to allow diffusion necessary for depolarization and repolarization.
When membrane is at potassium equilibrium potential, in which direction (in or out) is
there a net movment of potassium ions? Why? - Answer-There is no net movment at
equilibrium, but to maintain equilibrium, diffusion occurs in and out at the same rate.
Why is the action potential referred to as "all-or-none"? - Answer-If the AP does not
lead to depolarization (if the threshold is not exceeded), no AP will occur; if
depolarized, an AP is likely.
