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WorksheetsF25 NSC 4354 Exam 2 TA Review
Total questions: 100
Worksheet time: 50mins
Where are the cell bodies of lower motor neurons (α motor neurons) located?
Dorsal horn of the spinal cord
Ventral horn of the spinal cord
Lateral horn of the spinal cord
Brainstem nuclei
The group of all lower motor neurons that innervate a single muscle is called a:
Motor unit
Motor neuron pool
Reflex arc
Muscle spindle
Where are the LMNs that control a particular muscle located in the spinal cord?
Contralateral dorsal horn
Ipsilateral ventral horn
Bilateral dorsal columns
Medial gray matter of the brainstem
According to the topographical map of lower motor neuron pools, neurons controlling the fingers and toes are found:
In the most medial portion of the ventral horn
In the most lateral portion of the ventral horn
In the dorsal horn
Evenly distributed throughout the spinal cord
Interneurons in the medial spinal cord are characterized by:
Covering only one spinal segment and being ipsilateral
Extending across several segments and being bilateral
Being strictly local and unilateral
Projecting only to distal muscles
γ (gamma) motor neurons are responsible for:
Produce the main force of muscle contraction
Setting intrafusal muscle fibers to an appropriate length
Inhibit α motor neuron activity during movement
Control reflexes of antagonistic muscles
An α (alpha) motor neuron innervates multiple _______ muscle fibers?
Intrafusal muscle fibers
Smooth muscle fibers
Extrafusal, striated, force-producing muscle fibers
Cardiac muscle fibers
What is a big advantage of an α motor neuron innervating multiple muscle fibers?
It stabilizes muscle fatigue
It spreads force evenly and prevents total loss of function if one neuron is lost
It limits fine control of movement
It reduces muscle tone
What is the definition of a motor unit?
A. A single muscle fiber and its sensory input
B. An α motor neuron and the muscle fibers it innervates
C. A group of α and γ motor neurons controlling a muscle
D. A muscle and its tendon
Which type of α motor neuron is the largest, produces the greatest force, but fatigues the fastest?
Slow (S)
Fast fatigue-resistant (FR)
Fast fatigable (FF)
Gamma (γ)
Which of the following correctly contrasts Group Ia and Group II muscle spindle afferents?
Group Ia afferents fire tonically to sustained stretch, while Group II respond phasically to small, quick stretches.
Group Ia afferents are coiled around intrafusal fibers and respond phasically, whereas Group II afferents signal sustained stretch and fire tonically.
Group Ia innervates nuclear chain fibers, and Group II innervates only extrafusal fibers.
Both Group Ia and Group II afferents respond only to dynamic changes in muscle length.
A single sensory axon of which type innervates a Golgi tendon organ (GTO)?
Group Ia
Group II
Group Ib
Alpha motor neuron
What is the primary function of the Golgi tendon organ (GTO) reflex circuit?
Increase muscle contraction during postural adjustments
Provide a negative feedback system to regulate muscle tension and protect muscles from excessive force
Detect changes in muscle length during rapid stretches
Activate gamma motor neurons to adjust spindle sensitivity
Which statement best describes the difference between muscle spindle (MS) and Golgi tendon organ (GTO) activity during passive stretch vs. active contraction?
During passive stretch, MS activity decreases and GTO activity increases; during active contraction, both are equally active.
During passive stretch, only GTOs are active; during active contraction, only MS are active.
During passive stretch, MS activity is minimal; during active contraction, MS activity dominates over GTO activity.
During passive stretch, both MS and GTO are activated, with MS more strongly; during active contraction, MS activity decreases due to unloading, while GTO activity increases with muscle tension.
Which of the following best describes the overall purpose of the flexion–crossed extension reflex?
To generate fine motor movements in the fingers
To withdraw a limb from a painful stimulus while maintaining balance with the opposite limb
To coordinate voluntary movement of both arms
To reduce activation of muscle spindles
Which of the following statements about central pattern generators is correct?
They require continuous sensory input to generate rhythmic movements.
They are local spinal cord circuits that control timing and coordination of movement, independent of descending projections.
They are located exclusively in the brainstem.
They only function during voluntary, conscious movement.
Which of the following is a hallmark feature of lower motor neuron syndrome?
Hyperreflexia
Spasticity
Paralysis or weakness of the affected muscles
Increased muscle tone
Which of the following tracts primarily mediates voluntary, skilled movements of the distal limbs?
Vestibulospinal tract
Reticulospinal tract
Lateral corticospinal tract
Ventral corticospinal tract
The ventral corticospinal tract differs from the lateral corticospinal tract in that it:
Decussates in the medulla
Controls contralateral distal musculature
Terminates bilaterally in the spinal cord
Arises mainly from the supplementary motor area
Damage to upper motor neurons in the facial region of the motor cortex typically results in:
Paralysis of the entire ipsilateral face
Paralysis of the contralateral lower face only
Paralysis of the contralateral upper face only
Bilateral paralysis of all facial muscles
The primary motor cortex (M1) is located in which cortical layer’s pyramidal cells?
Layer 2
Layer 3
Layer 4
Layer 5
Which statement best describes the motor homunculus?
Each region of M1 activates a single muscle only
It’s a rigid topographic map of individual muscles
It’s a flexible map where overlapping areas encode coordinated movements
It’s identical to the somatosensory homunculus
Which cortical region is most active during self-initiated or memorized motor sequences?
Premotor cortex
Supplementary motor area
Primary motor cortex
Somatosensory cortex
Which of the following best describes mirror neurons?
Neurons that fire during movement but not during observation
Neurons that fire during both performance and observation of similar actions
Neurons that fire only when tools are used to complete tasks
Neurons that fire exclusively during visual stimuli without motion
The premotor cortex contributes to motor behavior by:
Encoding self-generated movements
Selecting context-appropriate movements using multisensory input
Directly activating alpha motor neurons for precise hand control
Maintaining posture via vestibular feedback
The vestibulospinal tracts are primarily responsible for:
Initiation of voluntary distal limb movements
Feedforward postural adjustments
Reflexive feedback control of balance and head position
Control of fine finger movements
Which of the following is a function of the reticulospinal pathway?
Feedback correction to vestibular imbalance
Feedforward adjustments that stabilize posture
Control of extraocular muscles
Reflex eye and head coordination
The lateral vestibulospinal tract primarily activates:
Neck flexors
Distal wrist flexors
Limb extensor (antigravity) muscles
Contralateral trunk flexors
Which statement about directional tuning in M1 neurons is true?
Each neuron encodes one precise movement direction
Individual neurons are broadly tuned and direction is population-encoded
Neurons encode only velocity, not direction
Movement direction is determined by cerebellar output only
Which pathway involves indirect cortical control via brainstem nuclei?
Corticospinal
Corticobulbar
Cortico-reticulospinal
Rubrospinal
The initial flaccidity after UMN damage is called:
Clonus
Spasticity
Spinal shock
Babinski phase
The Babinski sign in adults is indicative of:
Lower motor neuron lesion
Upper motor neuron lesion
Peripheral neuropathy
Basal ganglia damage
The reticular formation contributes to motor control mainly by:
Coordinating rhythmic limb movements like locomotion
Mediating precision grip strength
Controlling distal muscles only
Transmitting sensory information to the thalamus
In upper motor neuron syndrome, which feature typically appears after spinal shock resolves?
Hypotonia
Loss of posture reflexes
Spasticity and hyperreflexia
Bilateral flaccid paralysis
Which non-motor loop regulates emotional behavior, anxiety, and drug addiction?
Limbic loop
Oculomotor loop
Body movement loop
Prefrontal loop
If the striatum is receiving no excitation from the cortex, what effect does this have on the globus pallidus?
The GP will be inhibited
The GP will continue firing tonic inhibition
The GP will stop firing completely
The GP will fire transient inhibition
What areas within the BG have high levels of spontaneous activity?
Substantia nigra
VA/VL complex of thalamus
Striatum
Globus pallidus
A and D
What part of the basal ganglia inhibits the superior colliculus for unwanted movement?
Substantia nigra pars compacta
Globus pallidus internal
VA/VL thalamus
Substantia nigra pars reticulata
Globus pallidus external
What neurons receive excitatory glutamatergic synapses from cortical neurons?
Dopaminergic neurons
Cortical pyramidal neurons
Medium spiny neuron
Globus pallidus neurons
Disinhibition of the thalamus in the direct pathway is caused by what?
Excitation of the globus pallidus
Inactivation of the striatum
Lack of cortical input
Activation of the striatum
What is the function of the direct pathway vs. the indirect pathway?
Direct pathway initiates movement; indirect inhibits movement
Direct inhibits movement; indirect inhibits movement
Direct pathway initiates movement; indirect initiates movement
Direct pathway initiates movement; indirect initiates movement
What effect does dopamine have on the BG circuitry?
Decreases inhibitory outflow, which increases movement
Decreases inhibitory outflow, which decreases movement
Increases inhibitory outflow, which increases movement
Increases inhibitory outflow, which decreases movement.
Which of the following is true?
D1 receptors excite the direct pathway, while D2 receptors inhibit the indirect pathway.
D1 receptors inhibit the direct pathway, while D2 receptors inhibit the indirect pathway.
D1 receptors excite the direct pathway, while D2 receptors excite the indirect pathway.
D1 receptors inhibit the direct pathway, while D2 receptors excite the indirect pathway.
Dopaminergic input from the ___ decreases Parkinson's disease.
Substantial nigra pars compacta
Internal globus pallidus
Striatum
VA/VL of the thalamus
Subthalamic nucleus
The primary motor cortex processes information for muscles on the ___ side of the body; the cerebellum processes information for muscles on ___ side(s) of the body.
Contralateral; the ipsilateral
Both; the ipsilateral
Contralateral; both
Ipsilateral; the ipsilateral
Both; both
What cell type does NOT have direct contact with Purkinje cells?
(a)
A patient with right cerebellar damage would most likely exhibit which symptoms?
Jerky, imprecise movements on the right side of the body
The inability to stop movement (hyperkinetic) on the left side of the body
Jerky, imprecise movements on the left side of the body
The inability to stop movement (hyperkinetic) on the right side of the body
Jerky, imprecise movements on both sides of the body
Fibers from this structure cross the midline prior to synapsing in the cerebellum?
Pontine nuclei
Vestibular nuclei
External cuneate nucleus
Red nucleus
Deep cerebellar cortex nuclei
The inferior olive crosses the midline via _____, whereas the pontine nuclei crosses the midline via the _____
Inferior cerebellar peduncle; middle cerebellar peduncle
Superior cerebellar peduncle; Inferior cerebellar peduncle
Middle cerebellar peduncle; inferior cerebellar peduncle
When the left cerebellum is damaged, which cortical region loses input (either directly or indirectly)?
Right motor cortex
Left motor cortex
Right somatosensory cortex
Left somatosensory cortex
Both Somatosensory and motor cortex
Movement of the distal muscles is associated with which region?
Lateral spinocerebellum
Medial cerebrocerebellum
List the order of cells starting from the deepest cerebellar layer, to the Purkinje cell.
Mossy fiber, granule cell, parallel fibers
Parallel fiber, granule cell, mossy fiber
Granule cell, parallel fiber, mossy fiber
Climbing fiber, granule cell, parallel fibers
How does the cerebellum reduce a detected error in movement?
By influencing upper motor neurons
By influencing lower motor neurons
By influencing the basal ganglia
None of the above
B and C
What two main gray matter structures are involved with motor error correction?
Laminated cerebral cortex and deep cerebral nuclei
Laminated cerebellar cortex and deep cerebellar nuclei
Laminated cerebral cortex and deep cerebral nuclei
Laminated cerebellar cortex and deep cerebellar nuclei
Which of the following directly sends GABAergic input to the deep cerebellar nuclei?
Mossy fiber
Purkinje cell
Basket cell
Climbing fiber
What is the function of the vestibulo-ocular reflex?
Dilation of the eye with light
Maintains gaze on a moving object without head movement
Sharp movement of the eye for glancing
What about the autonomic nervous system is true?
It controls involuntary bodily functions
It consists of sympathetic and parasympathetic divisions
It regulates heart rate and digestion
All of the above
What neurotransmitter is primarily released by sympathetic postganglionic cells neurons?
Acetylcholine
Norepinephrine
Serotonin
Dopamine
Where are the cell bodies of parasympathetic preganglionic neurons located?
Thoracic and lumbar spinal cord
Brainstem and sacral spinal cord
Sympathetic chain ganglia
Adrenal medulla
Which of the following is a function of the parasympathetic nervous system?
Increasing blood flow to muscles
Dilating bronchi
Stimulating salivation
Accelerating heart rate
What is the primary neurotransmitter used by both preganglionic sympathetic and parasympathetic neurons?
Norepinephrine
Acetylcholine
GABA
Glutamate
In the autonomic regulation of bladder function, which division causes the smooth muscle of the bladder to contract?
Sympathetic
Parasympathetic
Somatic
Enteric
Which structure plays a key role in integrating visceral sensory information with emotional processing?
Thalamus
Nucleus of the solitary tract
Basal ganglia
Cerebellum
Which of the following regulated the visceral motor system?
the myenteric (Auerbach’s) plexus
The sympathetic system
The parasympathetic system
Which nucleus receives inputs from most other nuclei of hypothalamus, regulates release of hormones from pituitary gland, projects to brainstem and preganglionic neurons to regulate ANS?
Paraventricular nucleus
Periventricular nucleus
If we get input from baroreceptors that blood pressure has risen, what information is processed?
Information is sent to the nucleus of the solitary tract, then inhibition of the sympathetic division and increase in parasympathetic division
Information is sent to the nucleus of the solitary tract, then inhibition of the parasympathetic division and increase in sympathetic division
Information is sent to the hypothalamus then inhibition of the parasympathetic division and increase in sympathetic division
Information is sent to the hypothalamus, then inhibition of the sympathetic division and increase in parasympathetic division
A child born with a unilateral cataract will experience less dramatic visual deficits than a child born with bilateral cataracts.
True
False
If a rat experiences monocular deprivation and then undergoes dark exposure, what is likely to happen in terms of visual function?
Dark exposure improves visual function in the deprived eye by increasing the detection thresholds of that eye.
Dark exposure causes no change in visual function for either eye.
Dark exposure permanently destroys ocular dominance columns in the visual cortex, leading to irreversible loss of binocular vision.
Dark exposure improves visual function of the non-deprived eye while further impairing the deprived eye.
In humans ______ matter increases and then decreases, whereas ______ matter increases throughout early childhood + adolescence.
White, Gray
Gray, White
Which disorder causes a lower increase in gray matter volume?
Parkinson’s
ALS
ADHD
Alzheimer’s
What is the fundamental summary of Hebb's postulate regarding synaptic strengthening?
Prune fast, stabilize slow
Use it or lose it
Fire together, wire together
Sprout together, grow together.
Postnatal brain development involves a "Construction phase" (post-natal growth of dendrites, axons, and synapses) followed by which phase?
Construction phase 2.0.
Pruning phase
Elimination phase
Reorganization phase.
A critical period is defined as the time when experience and the neural activity that reflects that experience have the:
Minimal effect on the structure of the cerebral cortex
Maximal effect on the acquisition or skilled execution of a particular behavior.
Only effect on the Elimination phase of synapse development.
Maximal effect on gray matter volume decrease.
What type of activity occurs before eye opening and is essential for shaping rudimentary circuit networks in the retinogeniculocortical pathway?
Random, low-frequency firing.
Experience-driven activity from light exposure.
Local oscillations, or “waves” of subthreshold activity.
Correlated activity between the two eyes
Ocular Dominance Columns (ODCs) are alternating series of eye-specific domains located in which specific cortical layer of V1?
Layer 1
Layers 2 and 3
Layer 4
Layer 6
In animals like monkeys, when is the functional segregation pattern that defines Ocular Dominance Columns already present?
Immediately following the end of the critical period
After 3–4 days of visual experience
Only after experience aligns orientation tuning
Already present at birth
In a normal adult cat, how do most visual cortical neurons respond to input from the two eyes?
Driven only by the contralateral eye
Driven entirely by the ipsilateral eye
Activated to some degree by both the ipsilateral and contralateral eyes
Driven equally well by either eye (Group 4) and no others
If one eye is sutured closed early in life (during the critical period), what is the resulting permanent condition in the deprived eye?
The deprived eye is restored to normal function upon reopening
The animal develops strabismus
Amblyopia, or “cortical blindness”
The eye develops bilateral cataracts
At the height of the critical period, how little time of eye closure is sufficient to profoundly alter the V1 ocular dominance profile?
2.5 months
1 year
As little as 3–4 days
10 days
In humans, amblyopia is most often the result of strabismus (misaligned eyes). This condition leads to the suppressed eye having very low acuity because:
The critical period never closes
The total amount of activity in both eyes is dramatically reduced
The visual input is completely eliminated
Inputs to the LGN from the optimally aligned eye are competitively advantaged, taking more V1 territory
When one eye is deprived, the open eye's stripes widen while the deprived eye's stripes diminish. This outcome demonstrates:
The Elimination phase occurring in reverse
Competitive interaction for post-synaptic space
A failure of orientation tuning alignment
The restoration of functional capacity
Which visual condition is considered much more deleterious to normal vision during the critical period?
Bilateral cataracts (complete disruption of visual input)
Unequal competition (monocular deprivation or strabismus)
Dark exposure paired with repeated training.
Monocular deprivation performed after 7 years of age
Until roughly what age can children usually learn a second language with fluent grammar and without an accent?
Age 14–15
Age 25
Age 7–8
Age 1
When patients recover deficits immediately after a stroke or injury, this recovery usually reflects what process?
Regrowth and replacement of damaged neurons
Successful long-distance axon growth
Reorganization of intact circuits
The elimination phase of synaptic development
Why does restoration of CNS neurons normally fail?
Local overgrowth of glial cells
Production of signals that inhibit neuron growth
Mechanisms that cause necrotic + apoptotic cell death of nearby neurons
All of the Above
What did Henry Head’s experiment show?
An example of CNS nerve regeneration
After severing a nerve in his arm, sensitivity to touch gradually returned after ~6 weeks and was not well localized
After severing a nerve in his arm, perception of light touch, temperature discrimination, and 2-point discrimination returned after ~6 weeks
Severing your nerves is always a good idea
Temoc has suffered an injury to one of his nerves and now has difficulty with leg movement. Which method should he pair with motor rehabilitation to improve recovery?
Vagus Nerve Stimulation
Visual cortex stimulation
Hippocampal stimulation
Cochlear stimulation
Successful Peripheral nerve regeneration requires the nerve to reactivate which biological process?
Neurogenesis in the ganglia
The developmental processes for axon growth, guidance, and synapse formation
Necrotic and apoptotic cell death mechanisms
Glial cell inhibition mechanisms
Which cell type is identified as the essential cellular mediator of peripheral axon regrowth?
Astrocytes
Macrophages
Schwann cells
Oligodendrocytes
What is the primary role of macrophages during peripheral nerve regeneration?
To myelinate the regrowing axon
To secrete growth-promoting signaling molecules
To inhibit glial cell proliferation
To clear the degenerating debris of severed axons
Restoration of damaged central nerve cells requires the growth of new processes from an existing cell body, a process known as:
Neurogenesis
Synaptogenesis
Sprouting
Myelination
Long-distance repair of central nerve cells generally fails primarily due to:
Necrotic and apoptotic cell death occurring too far from the injury site
The absence of multipotent neural stem cells
The lack of blood vessels in the CNS
Local overgrowth of glial cells and their production of signals that inhibit neuron growth
Glial scarring, which inhibits CNS growth, involves the local proliferation and extensive growth of processes from which two primary cell types?
Schwann cells and macrophages
Astrocytes and oligodendrocytes
Neurons and microglial cells
Sensory and motor neurons
What must nervous tissue retain in a distinct region to support successful neurogenesis?
Multipotent neural stem cells
A fully formed glial scar
High concentrations of inhibitory signaling molecules
Long-distance white matter tracts
In adult humans, new nerve cells are generated reliably in which two specific regions?
The primary visual cortex and the spinal cord
The olfactory bulb and the hippocampus
The cerebellum and the brainstem
The thalamus and the lateral geniculate nucleus (LGN)
The new neurons generated reliably in the adult human brain are primarily:
Projection neurons
Motor neurons
GABAergic interneurons
Bipolar sensory neurons
Neural stem cells are often found near blood vessels, suggesting they may be regulated by:
Only local inflammatory responses
Glial scarring solely
Circulating as well as local signaling molecules
Genetic factors established only during development
Due to nuclear weapons testing, atmospheric Carbon-14 was dramatically altered between the mid-1950s and 1960s. What difference in Carbon-14 concentration would be observed in relevant neurons when comparing an individual born in 1952 (pre-peak exposure) to one born in 1968 (post-alteration peak)?
The levels would be identical because the isotope only incorporates into glial cells
The 1952-born person would have higher levels
Higher concentrations of Carbon-14 in neurons of the 1968-born individual
The concentration difference would only be measurable in the Peripheral Nervous System (PNS)
Compared to the limited neurogenesis seen in adult mammals, what capacity is noted in several non-mammalian vertebrates, such as fish and songbirds?
They have superior capacity for peripheral nerve regeneration only
They can repair the damage primarily through the Elimination phase
They have the capacity for neurogenesis in response to brain injury
They exhibit a low level of glial cell proliferation that continues throughout life
Which of the following is NOT listed in the source material as a way damage to the Central Nervous System (CNS) can occur?
Physical trauma
Hypoxia
Genetic mutation resulting in uncontrolled cell growth
Neurodegenerative diseases
