Quizzes part 2 Flashcards
The first motor units to be activated are:
Slow and fatigue-resistant
A spinal pre-motor neuron that projects medially, spans several segments, and crosses the midline is most likely to connect with:
Trunk motor neurons
When a limb bud is removed, the motor pools of motor neurons that would innervate the muscles in that limb are smaller because
Motor neurons without a target die
The first axon to follow a pathway is called a
Pioneer
The first axon to follow a pathway is called a
Pioneer
Dorsal Root Ganglion explants respond to multiple neurotrophic factors because
Different sensory neurons respond to different factor
Spinal interneurons that cross the midline in the flexion reflex:
Help you to stay upright when you lift the other foot.
The relative duration of stance and swing phases
- vary depending on the gait
- are most similar during trotting
-are determined by central pattern generators in the spinal cord
-all of these
A single motor neuron will innervate
many muscle fibers
A common feature of interneurons that control the timing of activity in a central pattern generator is
reciprocal inhibition
You are looking at fly embryos, and find one that lacks the longitudinal tracts that extend from the anterior to posterior ends of the nervous system. You suspect it is a mutant in the gene _____.
roundabout (robo)
A loss-of-function mutation in netrin will result in
fewer axons crossing the midline
When a limb bud is removed, the motor pools of motor neurons that would innervate the muscles in that limb is smaller because
motor neurons without a target die
A neuron in V1 which has an ocular dominance score of 4 receives input
from both eyes equally
During the stance phase of locomotion
extensor muscles are more active than flexor muscles
A motor unit:
-consists of one motoneuron and the muscle fibers it innervates
- is one of many hundred that control a given muscle
-consists of a single fiber type
-all of these
When a filopodium encounters a repulsive cue it
retracts
Adding an extra limb bud to a chick
prevents the death of neurons that would normally die
Dorsal root ganglion neurons
-are dervied from neural crest
-may require either NT-3, NGF, or BDNF
-encode sensory information
-all of these
At the midline
Netrin initially attracts axons, and then slit repels them
Strabismus
Increases the number of V1 neurons that respond to one eye or the other, but not both
In normal adult cats, most V1 neurons recieve input from
both eyes
Dorsal Root Ganglion explants respond to multiple neurotrophic factors because
different sensory neurons respond to different factors
During normal development in mammals, the numbers of pre- and postsynaptic cells are matched by
making too many and killing the extras
Golgi tendon organs
sense active tension
When an animal’s gait changes from walking to galloping, which of the following changes?
- the phasing of fore and hindlimb movment
- the duration of stance and swing phases
- the phasing of limb movement on the two side
- all of these
When Slit binds to Robo the axon is
repelled
Blindfolding one eye after the critical period is over
will have no effect on ocular dominance
Strabismus disrupts normal ocular dominance because
the image falls onto the wrong part of one retina, desynchonizing inputs to
the cortex
As a result of cerebellar long-term depression
inhibition of neurons in deep cerebellar nuclei by Purkinje neurons is reduced
Which of the following is a characteristic of Purkinje cells that allows for the high level of convergence from the granule cells?
An elaborate dendritic tree that extends perpendicularly to the parallel fibers
Fibers from structure(s) cross the midline prior to synapsing in the cerebellum?
Pontine nuclei
Synaptic depression of the gill-siphon withdrawal reflex in Aplysia
is homosynaptic
Which of the following does not involve the cAMP- PKA pathway?
long-term depression in the cerebellum
Long-term depression (LTP) is considered to be anti-Hebbian
because simultaneous activation of pre-and postsynaptic neurons causes weakening of a synapse
Long-term potentiation can activate “silent” synapses by
causing the addition of AMPA-type glutamate receptors
In classical conditioning, the subject will respond to unconditioned stimulus
always
Which of the following is not affected by blocking protein synthesis?
massed training
In order to disrupt a memory of that has already formed through fear conditioning anisomycin must be administered
at the time the memory is recalled
What cell type does not have direct contact with Purkinje cells?
Mossy fibers
Fibers from which structure(s) cross the midline prior to synapsing in the cerebellum
Pontine nuclei
Feedback information about motor errors is transmitted to the cerebellar cortex via
climbing fibers from neurons in the inferior olive
Synaptic plasticity can last as long as
the life of an organism
During sensitization of the gill withdrawal reflex in Aplysia, serotonin (5-HT) released is caused by
a noxious stimulus to the tail
Facilitation of the gill-siphon withdrawal reflex in Aplysia
all of these
-involves block of a K channel
- is heterosynaptic
-requires serotonin
Which of the following is evidence that hippocampal LTP is requires for spatial memory in the Morris water maze?
learning is blocked by APV
Compared to wild-type flies, dunce flies
do not learn to associate odor with foot shock
Long-term memory in flies requires
-activation of CREB
- synthesis of new proteins
- multiple training sessions with time in between
-all of these
During postnatal synaptic refinement, such as synapse elimination in the cerebellum or development of ocular dominance in the visual cortex, presynaptic neurons that lose synapses on one target cell
keep synapses on other target cells are generated
Closing one eye of an adult cat (> 1 year old) will
not affect ocular dominance at all
If the input from the contralateral eye was blocked during the first three months of a cat’s life, the ipsilateral eye will dominate the visual cortex for
the entire life of the cat
When synaptic connection would be most affected by the presence of a GABA antagonist in the cerebellum?
Purkinje cell input onto deep cerebellar nuclear cells
Protein synthesis is critical for
both late long-term potentiation and long-term memory
Which of the following is an example of heterosynaptic plasticity?
sensitization of the Aplysia gill withdrawal reflex
Consolidation refers to
the transfer of a memory from short-to long-term storage
Classical conditioning is a form of
implicit memory
The axon terminals of neurons projecting to the cerebellum from pontine nuclei, the spinal cord, and vestibular nuclei are called
mossy fibers
Axons from the cerebellum cortex that provide input to the cerebellum
must synapse in the pontine nuclei
Hippocampal long-term depression
requires a lower stimulation frequency than long-term potentiation
Long-term depression (LTP) is considered to be anti-Hebbian
because stimultaneous activation of pre-and postsynaptic neurons causes weakening of a synapse
Long-term fear conditioning
requires protein synthesis in the amygdala
Feed-forward information regarding intended movement is carried by
parallel fibers from granule cells
The two loops of the cerebellum are
deep excitatory and cortical inhibitory
In hippocampal LTP, the “coincidence detector” is
the NMDA receptor
Reconsolidation refers to
the need to restore a memory each time it is recalled
Loss of cerebellum
Block the ability to adjust the gain of the vestibulo-ocular reflex
