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109 Cards in this Set
- Front
- Back
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Foot drop is a ____ motor sign whereas chorea is a ___ motor sign. (positive/negative)
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Foot drop is a negative motor sign whereas chorea is a positive motor sign.
Foot drop: anterior tibialis muscle not working, loss of movement. Chorea: basal ganglia problem, gain of abnormal movements. |
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What does NMS(neuro-motor system) do?
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Generates neural signals that activate selected muscles and set the level and timing of muscle activity.
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What is the hierarchical organization of neuromotor system?
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Higher levels (eg. cerebral cortex) direct voluntary movements.
Lower levels (eg. brainstem) coordinate muscle activity in a variety of movements. |
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Can cortical regions act directly on spinal cord?
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Yes. This is known as the parallel organization of NMS.
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T/F: Sensory input/feedback is sent to entire NMS before, during, and after movement.
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T.
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What are the four components of the neuromotor system(NMS)?
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Upper motor neurons
Lower motor neurons Cerebellum Basal ganglia |
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Are there direct motor projections from basal ganglia and cerebellum to the spinal cord?
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NO. Basal ganglia and cerebellum assist in formulating and modulating motor commands from cortex and brainstem.
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What is the only type of motor neuron that initiate muscle contraction?
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alpha motor neurons: also known as the lower motorneurons.
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Muscle fibers that are innervated by alpha motor neurons are called ____.
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Extrafusal muscle fibers.
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What are some lower motor neuron signs?
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paresis/paralysis
muscle denervation: fasciculation, fibrillation, atrophy. flaccidity: low or absent muscle tone. decreased or absent stretch reflex. |
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Paresis and paralysis are ___.
A. Lower motorneuron signs B. Upper motorneuron signs C. Sign of spinal cord injury. |
A.
Paralysis can also be spinal cord injury, but usually temporary. |
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Fascicularion, fibrillation, and atropy are ___.
A. Lower motorneuron signs B. Upper motorneuron signs C. Sign of spinal cord injury. |
A.(muscle denervation)
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Flaccidity is a ___.
A. Lower motorneuron sign B. Upper motorneuron sign C. Sign of spinal cord injury. |
A.
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Hyporeflexia is a ___.
A. Lower motorneuron sign B. Upper motorneuron sign C. Sign of spinal cord injury. |
A.
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What is the smallest functional unit in the motor system?
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motor unit
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What are the two mechanisms body uses to increase force of muscle contraction?
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1. increase firing rate
2. increase motor unit recruitment |
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What is the size principle?
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The orderly sequence of motor unit recuitment:
- units with smaller force before units with larger force - units with small fatigability before greater fatigability. |
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Motor units with what kind of property is ideal for maintaining posture?
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Fatigue resistant motor units: that's why they are usually recuited first.
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What are the two control over alpha motor neuron recruitment and firing rate?
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1. strength of synaptic input.
2. alpha motor neuron excitability. |
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NMS coordinates muscular acitvity by ___.
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- selecting which muscles are activated in a task.
- setting the level and timing of muscle activity. |
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T/F: Spinal cord injuries is usually limited to a small area.
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F. The initial damage is limited, but the affected area expands as various cellular processes damage axons, kill cells, and limit regeneration.
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What are some motor signs of spinal cord injury?
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- loss of voluntary movements
- temporary paraylsis - spasticity - clonus |
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Loss of voluntary movement is a ___.
A. Lower motorneuron sign B. Upper motorneuron sign C. Sign of spinal cord injury. |
C.
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Spasticity is a ___.
A. Lower motorneuron sign(s) B. Upper motorneuron sign(s) C. Sign(s) of spinal cord injury. |
C. or B (different causes)
C: caused by changes in excitability of motor neurons or changes in monoaminergic input to motor neurons. B: changes in descending synaptic drive to motor neurons. Spasticity: - hyperactive stretch reflexes. - increased resistance to rapid muscle stretch. |
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Clonus is a ___.
A. Lower motorneuron sign(s) B. Upper motorneuron sign(s) C. Sign(s) of spinal cord injury. |
B,C.
Clonus: uncontrolled oscillating limb movement initiated by muscle stretch. |
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Name some types of reflexes.
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- at single joint: stretch reflex.
- multiple joints: throughout a limb: flexor reflex. - joints on both sides of the body: crossed extension reflex. |
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Reflexes are generated in ___.
A. Spinal cord B. Brainstem C. Cortex D. A and B |
D.
Reflex in brainstem: sneezing, pupillary light reflex. |
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T/F: Reflexes are fixed.
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NO!
CNS can turn off or grade the reflexes (variation in excitability). |
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Stretch reflex is evoked by ____ whereas tonic stretch reflex is produced by ____.
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Stretch reflex is evoked by quick stretch whereas tonic stretch reflex is produced by slow or maintained stretch.
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T/F: Spinal cord function is limited to reflexes.
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F.
Spinal cord functions include: - voluntary ocntrol - reflexes |
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T/F: Spinal cord itself can alter muscle coordination based on sensory feedback in the absence of any descending information.
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T.
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T/F: Spinal circuits can change dramatically as a result of training or in response to injury.
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T.
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Stretch reflex normally maintains a steady level of tension in muscles called ____.
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muscle tone
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What is activated when one muscle is stretched?
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Myotatic unit:
- alpha motor neurons to the homonymous muscle are excited - alpha motor neurons to the synergistic muscles are excited - alpha neurons to the antagonistic muscles are inhibited |
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A stretch activates ____.
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- muscle spindle receptors
- afferents |
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What test is used to diagnose abnormalities in nerve conductions and reflexes?
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EMG (electroneurological examination)
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EMG test:
Which has a shorter time delay, M wave or H wave? |
M wave: direct electrical activation of alpha motor neurons.
H wave: signal has to go through the reflex pathway. |
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What are the two wave forms observed in a EMG test?
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M wave
H wave |
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When using tendon tap instead of electric signal, which wave form is elminated?
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M wave
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Hyperactive stretch reflex of extensor muscles in the lower extremity and tonic flexion are typical presentation of ____.
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Hemiparetic gait (spasticity).
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What are some outputs from cortical motor areas?
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1. corticobulbar tract: projects to brainstem nuceli and MNs.
2. corticospinal tract: projects to spinal premotor interneurons and MNs. 3. upper motorneurons |
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List the cortical motor areas.
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M1: Brodmanns area 4.
Premotor cortices: -supplementary motor area (SMA, medial area 6). - lateral premotor cortex (PM, lateral area 6). |
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Hemiparesis is a ___.
A. Lower motorneuron sign(s) B. Upper motorneuron sign(s) C. Sign(s) of spinal cord injury. |
B.
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Permanent loss of individual finger movement is a ___.
A. Lower motorneuron sign(s) B. Upper motorneuron sign(s) C. Sign(s) of spinal cord injury. |
B.
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Corticobulbar tract is the regulator of brainstem neurons. Loss of function is this will lead to what manifestation in upper and lower extremities?
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In upper extremity: loss of inhibitory regulation of red neuclei (flexion).
In lower extremity: extension |
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What are some inputs to primary motor cortex?
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- SMA(supplementary motor area)
- lateral premotor cortex - S-1 - posterior parietal |
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What is a typical activity progression of muscle contraction starting from lateral premotor cortex?
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Lateral premotor cortex
Primary motor cortex EMG (muscle contraction) body movement |
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T/F: Somatotopic organization of primary motor cortex is a one-to-one mapping of body parts, muscles, or movements.
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F.
Ex: neurons influencing movement of the thumb are distributed across multiple territories in M1 and these territories overlap with others. |
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What is cortical plasticity?
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Ability of cortical neurons and circuits to transform their responses.
Ex. Distribution of neuron territories changes after stroke and with behavioral recovery. |
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What gives muscle movement precision?
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Temporal firing of a populations of neurons. Single neuron firing has low precision.
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M1 neurons have encode different parameters of movements. What are the parameters?
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direction
force velocity |
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What do neuron in supplementary areas and lateral premotor areas specialize in?
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Plan for movements:
- sequencing movements - associate sensory cues with motor response - delay task execution - confirm handshape to object - using visual imagery to plan movement |
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Which area is more active in response to visual cues?
A. Premotor cortex B. Primary motor cortex C. Supplementary motor area |
A. cues from occipital cortex.
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Which area is more active in response to memory cues?
A. Premotor cortex B. Primary motor cortex C. Supplementary motor area |
C.
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Which area is equally active in response to visual cues?
A. Premotor cortex B. Primary motor cortex C. Supplementary motor area |
B.
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What is the hallmark of cerebellar disorders?
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Ataxia: difficulty with coordinating movements, manifested by inaccuracies of limb placement(dysmetria) and by defects in timing of muscle activity.
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What are some signs of lateral cerebellar syndrome?
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- hypotonia, pendular reflexes, dysarthria, slurred speech.
- dysmetria - decomposition of movements - fast pointing - impaired check |
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What are some signs of medial cerebellar syndrome?
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1. Anterior medial cerebellar syndrom:
- chronic alcoholic degeneration: disturbed gait and reflexes, wide-based stance, and reeling gait. 2. Posterior medial cerebellar syndrome: - truncal ataxia, axia disequilibrium - head rotation - nystagmus |
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If a patient shows disturbed reflexes, reeling gait, wide-based stance, what is the cause?
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Chronic alcoholic degeneration of cerebellum (anterior medial cerebellum syndrome).
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What part of the brain does finger-to-nose and heal-to-shin exam test?
If the result is abnormal, what is the symptom called? |
1. The exam tests cerebellum, specifically the lateral hemisphere.
2. If the result is abnormal, it's called dysmetria. |
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A patient has truncal ataxia, axial disequilibrium, head rotation, and some nystagmus, where is the lesion?
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Cerebellum, especially the posterior medial part (nodular lobe).
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Which part of the cerebellum is involved in motor planning, skilled and learned movements?
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cerebrocerebellum: involves red nucleus->inferior olivary nucleus->lateral hemisphere and dentate nucleus.
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Which part of the cerebellum is involved in ongoing execution of ongoing voluntary movements and limb muscle tone?
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Spinocerebrum:
- intermediate zone: involves lateral corticospinal tract and rubrospinal tract-> distal, flexor muscles. - vermis: involes both reticulospinal tract and lateral vestibulospinal tract-> proximal muscles, balance. |
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Which part of the cerebellum is involved in balance and eye movement?
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Vestibulocerebrum: MLF, medial and lateral vestibulospinal tracts.
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A patient has ataxic gait and nystagmus to the left side, where is the lesion? Be specific.
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Left vestibulocerebrum.
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What are the three deep cerebellar nuclei?
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- dentate
- fastigial - interposed nuclei |
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If a lesion is in the left cerebellum, muscles of which side of the body are affected?
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Ipsilateral: "double cross".
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Which of the following is involved in motor planning?
A. Primary motor cortex B. Premotor cortex C. Cerebellum D. Both B and C |
D.
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Which of the following contains all output tracts from cerebellum to the cortex?
A. Superior cerebellar peduncle B. Middle cerebellar peduncle C. Inferior cerebellar peduncle |
A.
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List two most severe lesions of the cerebellum.
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1. DCN: most output nuclei
2. Superior cerebellar peduncle: contains most output tracts from cerebellum. |
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Action(intension) tremor is a ____ problem where as resting tremor is a ____ problem.
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Action tremor is a cerebellum problem(dysmetria) where as resting tremor is a basal ganglia problem(hypokinesia).
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Inability to perform repetitive tasks is called ___.
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Disdiadochokinesia: a problem with spino- and cerebro- cerebellum.
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What is the general term of the following?
- dysmetria - disdiadochokinesia - asynergia: decomposition of movements |
Ataxia: hallmark of cerebellum problems.
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What are some general motor signs of spino- and cerebro- cerebellum deficits?
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- ataxia
- hypotonia - pendular reflexes - dysarthria: slurring, scanning speech. |
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What is the mechanism of dysmetria?
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Delay in braking due to delay in onset of antagonist muscle activity. As a result, limb overshoots target position.
*no change in velocity of movements. |
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A patient has an ataxic gait and tends to fall on his left side. Where is the lesion? Be specific.
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Left vestibulocerebellum.
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A patient demonstrates difficulty in walking in a balanced fashion. When you try to stablized his trunk, he has no problem walking straight. What can you do to localize the lesion?
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Ask the patient to lie down and do cycling motion of the legs.
If no problem doing it: vestibulocerebellum lesion. If trouble doing it: spinocerebellum lesion. |
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If a patient is unable to combine thumb and index finger flexion in a precise pinching motion, and also has trouble initiating movements. Where is the lesion?
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Cerebellum
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If a patient can not do rapid finger tapping and altrnating movements, where is the lesion?
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Intermediate zone of cerebellum.
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Rapid alternating movement tests which part of the cerebellum?
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Intermediate zone
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Appendicular ataxia is usually caused by lesions of ____ whereas truncal ataxia is often caused by damage to ____.
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Appendicular ataxia is usually caused by lesions of cerebellar hemispheres whereas truncal ataxia is often caused by damage to cerebellar vermis.
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List some symptoms of hyperkinetic disorderes.
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- Ballism: violent, large-amplitude movements of proximal limb.
- Chorea: jerky, random movements of limbs and orofacial structures. - athetosis: continual uncontrolled writhing of the extremities. - dystonia: sustained abnormal postures and slow movements. |
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What is this?
violent, large-amplitude movements of proximal limb. What type of symptom is this? |
Ballism: hyperkinesia
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What is this?
jerky, random movements of limbs and orofacial structures. What type of symptom is this? |
chorea: hyperkinesia
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What is this?
continual uncontrolled writhing of the extremities. What type of symptom is this? |
athetosis: hyperkinesia
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What is this?
sustained abnormal postures and slow movements. What type of symptom is this? |
dystonia: hyperkinesia
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Where is the lesion in hemiballism? Be specific.
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Subthalamic nucleus of basal ganglia.
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What is this?
impaired initiation of voluntary movements. What type of symptom is this? |
akinesia: hypokinesia
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What is this?
reduced amplitude and velocity of voluntary movements. What type of symptom is this? |
bradykinesia: hypokinesia
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What is this?
increased resistance to passive movements. What type of symptom is this? |
muscle regidity: hypokinesia
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What are the four hallmark symptoms of Parkinson's disease?
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- akinesia
- bradykinesia - muscle rigidity - resting tremor |
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T/F: In Parkinson's disease, the movement velocity is constant.
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T. That't why it takes longer for them to move over a longer distance.
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What are the input nuclei of basal ganglia?
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striatum: caudate and putamen.
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What are the output nuclei of basal ganglia? Which neclei has dompaminergic neurons?
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GPi and SNr
SNc contains dopaminergic neurons. |
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Corticostrial neurons are ___.
A. excitatory B. inhibitory |
A.
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GPi and SNr are ___.
A. excitatory B. inhibitory |
B.
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Where do the output tracts from basal ganglia go? (3)
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- thalamus: major route
- superior colliculus: eye movement (saccadic) - reticular formation in the brainstem: movements. |
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T/F: Basal ganglia is also involved in cognition and emotion.
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T.
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What are the effects of dopamine on D1 and D2 receptors?
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Dopamine stimulates D1, inhibits D2.
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What happpens when dopamine is low in the body?
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- less stimulation of D1: D1 usually excite movements, so less stimulation of D1 will result in hypokinesia.
- less inhibition of D2: D2 normally inhibit movements, so less inhibition of D2 will result in hypokinesia. |
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What are the effects of stimulated D1 and D2 on output nuclei of basal ganglia?
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Stimulated D1: inhibit GPi and SNr.
Stimulated D2: stimulate GPi and SNr. |
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Which is missing in Huntington's disease? D1 or D2?
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D2
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What are some available treatments for Parkinson's disease?
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- L-dopa
- pallidotomy: cut out GPi and SNr - deep brain stimulation: patterning the basal ganglia activity. |
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Romberg is test which part of the brain?
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Basal ganglia
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Postural reflex is testing which part of the brain?
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Basal ganglia
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Observing patient arising from a chair is testing which part of the brain?
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Basal ganglia
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Walking on heel is testing which part of the brain?
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Basal ganglia
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Hopping on one leg is testing which part of the brain?
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Basal ganglia
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Tandem walking is testing which part of the brain?
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Basal ganglia
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