Practice question:
Slow-twitch muscle fibers are innervated by
motoneurons with small somata and narrow diameter axons. Compared with large motoneurons, small
motoneurons
a) conduct more quickly and are activated first.
b) conduct more slowly but are activated first.
c) conduct more quickly but are less excitable.
d) conduct more slowly and are less excitable.
Answer: b
Practice question:
In the flexor/crossed-extensor reflex the sensory
neuron, which carries the pain response into the spinal cord on the ipsilateral
side, directly (that is, not through an interneuron)
a) activates the extensor motoneuron on the
ipsilateral side of the brainstem.
b) crosses over and activates the extensor
motoneuron on the contralateral side of the brainstem.
c) activates the flexor motoneuron on the
ipsilateral side of the brainstem.
d) crosses over to the contralateral side of the
brainstem and activates the flexor motoneuron.
Answer: c
Neurobiology
303
Practice question:
Which of the following statements is true concerning
central pattern generators (CPGs)?
a) CPGs are found only in
the invertebrate nervous system.
Oscillatory neural circuits are not found in vertebrates.
b) The frequency of oscillation of a CPG is
independent of sensory input.
c) Computational models of CPGs
are based on reciprocal inhibition between neural elements, but reciprocal
inhibitory connectivity patterns are not observed in real CPGs.
d) Real CPGs are composed
of several sub-oscillators that together produce oscillation at a frequency
that can be intermediate between the oscillations of the individual
sub-oscillators.
Answer: d
Neurobiology
303
Practice question:
Sensory input can
a) increase the frequency of a CPG.
b) reverse the response of a reflex.
c) decrease the frequency of a CPG.
d) all of the above.
Answer: d
Neurobiology
303
Practice question:
Neurons once thought to be command neurons
a) can greatly speed up a response.
b) are necessary for the responses they mediate.
c) are found only in invertebrates.
d) are giant sensory neurons.
Answer: a
Neurobiology
303
Practice question:
Purkinje cells are the principal
cells of the
a) globus pallidus
b) premotor cortex
c) cerebellar cortex
d) supplementary motor area
Answer: c
Neurobiology
303
Practice question:
The two acoustic neurons in noctuid moths are
designated as A1 and A2. In response to
a bat cry an individual noctuid moth performs a steep dive. Which of the following sensory response
configurations most likely gave rise to this evasive behavior.
a) A2 is active alone
b) A2 is more active than A1
c) A1 is active alone
d) A1 and A2 are equally active
Answer: d
Neurobiology
303
Practice question:
Giant interneurons were thought to mediate a fast, di-synaptic escape response pathway from cerci sensory
neurons to leg motoneurons in the cockroach.
Later evidence ruled out this hypothesis. Of the following pieces of evidence against
the hypotheses, which one is false?
a) The delay between cerci stimulation and
initiation of escape is longer than would be expected for a di-synaptic
pathway.
b) Sensory neurons don’t contact the giant
interneurons directly.
c) The giant interneurons don’t contact motoneurons
directly.
d) Cerci stimulation can still elicit escape even
after the giant interneurons are destroyed.
Answer: b
Neurobiology
303
Practice question:
In intact toads, visually responsive neurons that
respond to small, moving stimuli or to thin stimuli moving along their long
axis could be considered as “prey detectors”.
Neurons that exhibit these response properties are found in which region
of the intact toad brain?
a) retina
b) pretectum
c) tectum
d) visual cortex
Answer: c
Neurobiology
303
Practice question:
An image of a banana is flashed onto the left side
of the visual field of a human, split-brain patient. This patient is most likely
a) able to use her left hand to feel around and
retrieve a banana unseen from inside a box.
b) able to verbally identify the banana.
c) able to use her right hand to feel around and
retrieve a banana unseen from inside a box.
d) unable to recognize the image.
Answer: a
Neurobiology
303
Practice question:
In a hypothetical experiment, a researcher cuts the
optic nerve of a frog and rotates the eye upside-down. Then she places a blindfold over the eye and
removes it after the optic nerve has reinnervated the tectum. What would the researcher probably observe?
a) That the optic nerve connections to the tectum
have been reorganized so that the visual world again appears right-side-up to
the frog.
b) That the optic nerve fibers have become partially
reorganized so that an object moving from side-to-side now appears to move
up-and-down.
c) That the optic nerve fibers have reinnervated the
tectum in a random order due to lack of activity in the optic nerve fibers.
d) That the optic nerve fibers have grown back to
their original positions on the tectum, and the visual world appears
upside-down to the frog.
Answer: d
Neurobiology
303
Practice question:
Imagine a person who, through some genetic defect,
did not produce nerve growth factor (NGF) during infancy and does not produce
it as an adult. Based on what we know
about NGF, what deficit might you imagine this person would have?
a) Inability to feel pain in his extremities.
b) Inability to increase his heart rate through
increased parasympathetic activity.
c) Inability to feel light touch and vibration in
his extremities.
d) Inability to decrease his heart rate through
increased parasympathetic activity.
Answer: a
Neurobiology
303
Practice question:
Suturing both eyes shut of a kitten from
birth until two months postpartum will prevent which of the following:
a) The development of a topographic projection from the retina to the superior colliculus.
b) The development of eye specific layers in the
lateral geniculate nucleus.
c) The development of ocular dominance columns in the primary visual cortex.
d) The development of normal response properties for
neurons in the visual cortex.
Answer: d
Practice question:
One eye of a kitten is sutured shut from birth until
two months postpartum. The drug amino
phosphonovaleric acid (APV) is infused into its cerebrospinal fluid during this
period. What effect will this combined
treatment have on the formation of ocular dominance columns?
a)
Ocular dominance columns will develop normally because APV will block NMDA
receptors and so remove the competitive advantage of inputs from the open eye.
b)
Ocular dominance columns will develop normally because APV will block NGF
receptors and so stabilize the connections from the sutured eye.
c)
Inputs from the open eye will take over most of the area of the primary visual
cortex because APV will block NMDA receptors and so enhance the competitive
advantage of inputs from the open eye.
d)
Inputs from the open eye will take over most of the area of the primary visual
cortex because APV will increase the rate of biosynthesis of NGF and so enhance
the competitive advantage of inputs from the open eye.
Answer: a
Neurobiology
303
Practice question:
Heterosynaptic facilitation of the Aplysia gill-withdrawal reflex is
brought about by secretion of serotonin onto the sensory neuron to motoneuron
synapse from an interneuron. Serotonin
acts through a protein cascade that culminates in the activation of protein
kinase A (PKA). PKA has two effects on
the synapse. Which are they?
a)
Blocking calcium channels and reducing the number of neurotransmitter vesicles.
b)
Blocking potassium channels and reducing the number of neurotransmitter
vesicles.
c)
Blocking calcium channels and increasing the number of neurotransmitter
vesicles.
d)
Blocking potassium channels and increasing the number of neurotransmitter
vesicles.
Answer: d
Neurobiology
303
Practice question:
Eye blinks can be conditioned to a tone in rabbits
because neural signals related to sensory inputs as different as corneal
stimulation and sound can be associated in the brain. At which two locations in the brain are these
neural signals first brought together?
a) red nucleus and inferior olive
b) cerebellar cortex and interpositus nucleus
c) cochlear and interpositus nuclei
d) cerebellar cortex and pontine nucleus
Answer: b
Neurobiology
303
Practice question:
In a children’s story, a farmer see a butterfly
struggling to emerge from its chrysalis, and he helps the beautiful insect by
peeling its pupal shell. Sadly, this
well-intentioned help prevents the butterfly from developing the ability to fly
and it dies. The moral of the story is
that butterflies, like children, sometimes need to struggle in order to
develop. While essentially true this
story misses a scientific detail. Which?
a)
A pharate butterfly will die immediately from exposure if it is removed from
its chrysalis.
b)
A pharate butterfly will be unable to develop the ability to fly if its
chrysalis is removed because it uses nutrients in the chrysalis to produce the
hormone ecdysone.
c)
A pharate butterfly uses chemical cues in the chrysalis to guide structural
changes in the dendritic morphology of certain abdominal motoneurons.
d)
A pharate butterfly will still produce eclosion behavior, even if it is removed
from its chrysalis, and by that behavior it will develop adult abilities
including the ability to fly.
Answer: d
Neurobiology
303
Practice question:
A male rat that during development lacked testosterone receptors in the medial preoptic area would probably show which one of the following deficits as an adult?
a) impaired copulatory behavior
b) lack of motor control of the penis
c) impaired lordotic behavior
d) lack of orienting response to receptive females
Answer: a