Neuroscience Review

Question 1

Lower Motor Neuron

Answer 1

Alpha motor neuron
Located in AH of spinal cord or cranial nerve nuclei
Innervate skeletal muscle fibers

Question 2

LMN Lesion

Answer 2

Flaccid Paralysis
Hyporeflexia
Denervation Atrophy
Sensory Loss
Fasciculations 
Fibrillations

Question 3

LMN of face

Answer 3

Hemiplegia of ipsilateral face

Question 4

Upper Motor Neuron

Answer 4

Motor neurons originating in cerebral cortex/brainstem

Carry information to LMN

Question 5

UMN Lesion

Answer 5

Immediate - hypotonia/flaccid weakness (spinal shock)
Later - Spastic paralysis ** 
Hypertonia
Hyperreflexia (Clonus)
Abnormal reflexes ** 
Muscles affected in large groups
NO signs of muscle denervation

Question 6

UMN of face

Answer 6

Hemiplegia of contralateral lower face

Question 7

Lesion to Dorsal Column

Answer 7

Decussates in dorsal column nuclei

Loss of tactile discrimination, vibratory sense, proprioception IPSILATERAL

Question 8

Lesion to Somatosensory cortex, Thalamus, ML

Answer 8

CONTRALATERAL loss of tactile discrimination, vibratory sense, proprioception, stereogenesis, graphesthesia

Question 9

Lesion to Anterolateral system

Answer 9

Decussate in spinal cord
Midline - bilateral loss of pain/temp
One side - contralateral loss of pain/temp

Question 10

Lesion Lateral to Corticospinal tract

Answer 10

Muscle weakness/hypotonia (negative SX) CONTRALATERAL

Loss of fine control of digits

Question 11

Lesion of Large area of Motor Cortex, Internal Cortex, Descending tract

Answer 11

UMN Lesion SX Contralateral to lesion
Loss of fine tactile, temp/pain
Spasticity if multiple cortical areas damaged

Question 12

Lesion of Descending tract of spinal cord

Answer 12

UMN SX ipsilateral below lesion

Question 13

Peripheral Neuropathy

Answer 13

Stocking/glove pattern of sensory loss

Loss of fine tactile etc. pain/temp in hands/feet

Question 14

Paraplegia

Answer 14

transection of spinal cord between cervical/lumbar

Question 15

Quadriplegia

Answer 15

transection of spinal cord high cervical

Question 16

Brown-Sequard Syndrome

Answer 16

Hemisection of spinal cord
Loss of dorsal column ipsilateral
Loss of anterolateral contralateral

Question 17

Parietal Neglect Syndrome

Answer 17

Lesion to non-dominant hemisphere

Question 18

Ischemic stroke involving Anterior cerebral a.

Answer 18

Contralateral loss of lower limb

Question 19

Ischemic stroke involving Middle cerebral a.

Answer 19

Contralateral loss of upper limb

Question 20

Large fibers

Answer 20

fast, myelinated
fine tactile, 2pt, vibratory, proprioception
can attenuate pain
Group I - afferent spindle and Golgi tendon afferent
Group II - encapsulated endings
Affected first in nerve pressure palsy and peripheral neuropathy

Question 21

Group III (Ad)

Answer 21

Small, lightly myelinated

Sharp/fast pain

Question 22

Group IV (C)

Answer 22

Smallest, slowest, unmyelinated

Burning/slow pain

Question 23

Enkephalin interneurons

Answer 23

Excited by Raphe Nucleus of brainstem

Release enkephalin that binds to mu receptors of C/D axons carrying pain signals = inhibition

Question 24

ALS

Answer 24

Motor disease
Display both UMN/LMN symptoms - spasticity and fasciculations
Weakness in upper/lower limbs, bulbar muscles

Question 25

Parkinson's

Answer 25

Degeneration of DA neurons from substantia nigra to striatum | SX: rhythmic tremor at rest, hypertonicity, bradykinesia, postural reflex impairment, frozen gait

Question 26

Huntington's

Answer 26

Selective loss of GABA/enkephalin projection from striatum to GPe Followed by widespread degeneration of striatal neurons and cortical neurons SX: chorea, dementia, slow movements

Question 27

Sydenham Chorea

Answer 27

rapid, involuntary, purposeless movement of face, feet, hands Primarily in children - complication of GAS hemolytic infx, RF, polyarthritis AI: antigens of strep similar to basal ganglia

Question 28

Lesion to vestibulocerebellum

Answer 28

disturbance in equilibrium/eye control | Ataxia, nystagmus, smooth pursuit eye defects

Question 29

Lesion to Spinocerebellum

Answer 29

ipsilateral hypotonia, dysmetria, pendular reflex

Question 30

Lesion to cerebrocerebellum

Answer 30

disturbances initiating/terminating movements, multi-joint problems, time