NEUROSCIENCE EXAM C QUESTIONS
AND ANSWERS
As motor unit size increases, which property of the α motor neuron decreases? -
Answer-excitability
asynchronous firing of motor neurons - Answer-provides a means by which a
population of motor neurons can maintain constant force over a finite time interval.
why does the H-wave disappear in H-reflex response at high stimulation current
amplitudes - Answer-the antidromic M-wave and H-wave collide and cancel each
other out
During the flexion-crossed extension reflex, stimulation would lead to _______ of
ipsilateral extensor muscles and _______ contralateral extensor muscles. - Answer-
inhibition; excitation of
which situation does correspond to a decreased H-reflex gain? - Answer-Warm up
before exercise
___ innervate striated muscle fibers, and _____ innervate specialized fibers called
___ - Answer-α motor neurons; γ motor neurons; muscle spindles
The local circuits in the spinal cord that are fully capable of controlling the timing and
coordination of complex locomotion are called - Answer-central pattern generators
which choice is not one of the pathophysiological mechanisms in ALS? - Answer-
lower motor neuron demyelination
____ prevents muscles from generating excessive tension and helps maintain a
steady level of tone during muscle fatigue - Answer-the Ib afterward from tendon
organs contacting Ib inhibitory inter neurons, decreasing the activity of a motor
neurons innervating the same muscle
Although the phenomenon is not well understood, the increased muscle tone and
spasticity that develop after an upper motor neuron injury appears to be due, at least
in part, to - Answer-increased responsiveness of motor neurons to Ia afferent inputs.
a person with damage to the direct motor pathway but an intact indirect motor
pathway, would have the most difficulty - Answer-writing
Corticospinal axons mostly - Answer-synapse onto spinal local circuit neurons
in an anticipatory postural response of a standing person about to tug on a handle,
the early response of leg muscles that precedes the actual tug is an example of -
Answer-feedforward motor control via reticulospinal tract
AND ANSWERS
As motor unit size increases, which property of the α motor neuron decreases? -
Answer-excitability
asynchronous firing of motor neurons - Answer-provides a means by which a
population of motor neurons can maintain constant force over a finite time interval.
why does the H-wave disappear in H-reflex response at high stimulation current
amplitudes - Answer-the antidromic M-wave and H-wave collide and cancel each
other out
During the flexion-crossed extension reflex, stimulation would lead to _______ of
ipsilateral extensor muscles and _______ contralateral extensor muscles. - Answer-
inhibition; excitation of
which situation does correspond to a decreased H-reflex gain? - Answer-Warm up
before exercise
___ innervate striated muscle fibers, and _____ innervate specialized fibers called
___ - Answer-α motor neurons; γ motor neurons; muscle spindles
The local circuits in the spinal cord that are fully capable of controlling the timing and
coordination of complex locomotion are called - Answer-central pattern generators
which choice is not one of the pathophysiological mechanisms in ALS? - Answer-
lower motor neuron demyelination
____ prevents muscles from generating excessive tension and helps maintain a
steady level of tone during muscle fatigue - Answer-the Ib afterward from tendon
organs contacting Ib inhibitory inter neurons, decreasing the activity of a motor
neurons innervating the same muscle
Although the phenomenon is not well understood, the increased muscle tone and
spasticity that develop after an upper motor neuron injury appears to be due, at least
in part, to - Answer-increased responsiveness of motor neurons to Ia afferent inputs.
a person with damage to the direct motor pathway but an intact indirect motor
pathway, would have the most difficulty - Answer-writing
Corticospinal axons mostly - Answer-synapse onto spinal local circuit neurons
in an anticipatory postural response of a standing person about to tug on a handle,
the early response of leg muscles that precedes the actual tug is an example of -
Answer-feedforward motor control via reticulospinal tract
