Ascending Spinal Cord

Question 1

Agraphesthesia

Answer 1

The inability to recognize letters and numbers drawn on the palm of the hand

Question 2

Three tracts in the anterolateral pathway

Answer 2

1) Spinothalamic
2) Spinoreticular
3) Spinomesencephalic

Question 3

Two ways Rostral Ventral Medulla (RVM) modulates pain

Answer 3

1) Inhibits pain by signaling to dorsal horn of spinal cord

2) Promotes Locus Ceruleus (Rostral Pons) which sends noradrenergic projections to regulate spinal cord

Question 4

Origin of Posterior Spinocerebellar Tract

Answer 4

Clarke’s Nucleus (medial part of Vamina VII). Axons run to the lateral funiculus of that same side to form the posterior spinocerebellar tract

Note: Both the tract and Clarke’s Nucleus do not exist caudal to L2

Question 5

Function(s) of Spinothalamic Tract

Answer 5

Believe to interact with spinoreticular in the emotional and arousal aspects of pain

Question 6

Bare nerve endings use which sensory neuron fiber type(s)? [Involve Pain, temperature, and itch]

Answer 6

A-delta and C

Question 7

Two types of non-conscious sensation. They’re not not perceived but routed to the cerebellum

Answer 7

1) Proprioception - afferent information reaching the cerebellum though the spinocerebellar pathways, essential for smooth motor coordination
2) Interoception - References unconscious afferent signals involved in visceral reflexes

Question 8

Subacute Combined Degeneration

Answer 8

Chronic demyelination and loss of axons in the dorsal and dorsolateral columns; more posterior columns than lateral corticospinal tract. May also involve deep white matter of hemispheres (dementia).

Patient shows loss of proprioception, discriminative touch, vibration, ataxia, and spastic weakness/paralysis

Question 9

Location of decussation for Anterolateral Pathway

Answer 9

Spinal Cord Anterior Commissure

Question 10

Laminae from which Spinomesencephalic Tract arises from

Answer 10

Laminae I & V of dorsal horn

Question 11

Two major major pathways involved in somatic sensory perception (therefore ascending)

Answer 11

1) Posterior (Dorsal) Column-Medial Lemniscal Pathway

2) Spinothalamic (Anterolateral) Pathway

Question 12

Location of the somatosensory cortex

Answer 12

post central gyrus

Question 13

SNRIs, TCAs (Tricyclic Antidepressants), and SSRIs – which are analgesic

Answer 13

SNRIs and TCAs. SSRIs are not

Question 14

Contralateral Neglect is a sign of what?

Answer 14

Cortical sign (occurs only from cortex lesion)

Question 15

Function of Posterior Spinocerebellar Tract

Answer 15

Conveys tactile, pressure, and proprioceptive information about the ipsilateral leg

Question 16

Function of Cuneocerebellar Tract

Answer 16

Sensory from ipsilateral upper thorax and arm

Question 17

Difference in function between Posterior/Anterior Spinocerebellar Tracts – which both deal with the leg

Answer 17

Anterior S.C Tract not only has Group I fibers (from mainly Golgi tendon organs) but also wide variety of cutaneous receptors like spinal interneurons and fibers of descending tracts. Activity is related more to attempted movement than simply to sensory signals!

Question 18

Termination of Cuneocerebellar Tract

Answer 18

Vermis

Question 19

Function(s) of Spinomesecephalic Tract

Answer 19

Involved in central regulation of pain

Question 20

The Spinocerebellar pathways enter the cerebellum from either the inferior or superior peduncles. Which is which?

Answer 20

Posterior Spinocerebellar Tract - Inferior
Anterior Spinocerebellar Tract - Superior
Cuneocerebellar Tract - Inferior

Question 21

Two types of conscious sensation perceived at the level of the cerebral cortex

Answer 21

1) Exteroceptive - sensations from the external world

2) Proprioceptive - arise within the body

Question 22

Function(s) of Spinoreticular Tract

Answer 22

Involved with pain and emotions.

• Arouses cerebral cortex to induce/maintain waking state
• Reports to the limbic cortex of anterior cingulate gyrus about nature of a stimulus
• emotional response may be pleasurable (stroking) or aversive (pinprick)

Question 23

Ascending pathway which carries touch, joint sensation, two-point discrimination, and vibratory sense from receptors to the cortex

Answer 23

Posterior Column-Medial Lemniscal Pathway

Question 24

Cause of Subacute Combined Degeneration

Answer 24

Deficiency in Vitamin B12 intake or metabolism

Question 25

Medial Medullary Lesion

Answer 25

Lesion involves the medial lemniscus. Causes contralateral loss of vibration and joint position sense

Question 26

Areas most noticeably affected (somatosensory) with a lesion in the thalamic region

Answer 26

Contralateral deficit most noticeable in face, hands, and foot

Question 27

Termination of Anterior Spinocerebellar Tract

Answer 27

Vermis

Question 28

Paresthias

Answer 28

Abnormal tingling/prickling sensation * Lesions in the anterolateral system more likely to produce painful paresthesias * Lesions in the dorsal column/medial lemniscal system are more likely to produce numbness or tingling

Question 29

What region does the Periaqueductal Gray Matter (Midbrain), itself controlled by higher brain regions and spinal cord, send signals to regulate pain?

Answer 29

Rostral Ventral Medulla (RVM) in the Medulla

Question 30

Distal Symmetrical Polyneuropathies

Answer 30

Cause bilateral sensory loss in a "glove and stocking" distribution (longest nerves affected) of all modalities

Question 31

Location of decussation for Posterior Column-Medial Lemniscal Pathway

Answer 31

Caudal medulla

Question 32

Lhermitte's Sign

Answer 32

Electric-like shock that occurs when there is damage to the dorsal columns in cervical areas of the spinal cord; it can be elicited by asking the patient to bend their neck forward

Question 33

Most affected senses in a Somatosensory Cortex lesion

Answer 33

Discriminative touch and joint position sense

Question 34

Where do Posterior Columns terminate

Answer 34

Posterior column nuclei in the medulla oblongata

Question 35

Spinal segments where fasciculus cuneatus is found

Answer 35

Only found in the cervical segments

Question 36

All afferent tertiary (neuron order) input ends up where

Answer 36

somatosensory cortex

Question 37

Spinocerebellar Pathways

Answer 37

Sensory fiber tracts running from spinal cord to cerebellum. 1) Posterior Spinocerebellar Tract 2) Anterior Spinocerebellar Tract 3) Cuneocerebellar Tract

Question 38

Termination of Spinoreticular Tract

Answer 38

Medullary-Pontine Reticular Formation

Question 39

Termination of Posterior Spinocerebellar Tract

Answer 39

Inferior Cerebellar Peduncle

Question 40

Origin of Anterior Spinocerebellar Tract

Answer 40

Spinal Border Cells (T12-L5)

Question 41

What might you see if cervical areas of the spinal cord are affected by Multiple Sclerosis?

Answer 41

Lhermitte's Sign

Question 42

Tabes Dorsalis

Answer 42

* Caused by tertiary syphilis; inflammatory involvement of the dorsal roots results in degeneration of dorsal columns * Patient presents with bilateral loss of fine touch, vibration and conscious proprioception * Romberg and/or Lhermitte Signs may be present

Question 43

Disturbance of posterior column function is most often associated with what group of pathologies

Answer 43

Demyelinating diseases such as multiple sclerosis

Question 44

Another mechanism in MS besides just the demyelination

Answer 44

Primary loss of neurons (neurodegeneration)

Question 45

Common manner in which Posterior Column-Medial Lemniscal and Spinothalamic Pathways ascend CNS

Answer 45

* First-order neurons occupy posterior root ganglia * Second-order somas on same side as original first-order neurons * Second-order neurons decussate (cross the midline) and ascend to terminate in thalamus * third-order neurons project form thalamus to somatic sensory cortex

Question 46

Laminae from which Spinoreticular Tract arises from

Answer 46

Laminae VI-VII of dorsal horn

Question 47

Romberg's Sign

Answer 47

Swaying when the patient stands with feet together and eyes closed (can be seen in demyelinating diseases and vestibular disorders)

Question 48

Two-Point Discrimination test

Answer 48

Measures tactile perception. Posterior (Dorsal) Column-Medial Lemniscal Pathway

Question 49

Synapse in the Ventral Posterior Medial (VPM) nuclei of the thalamus

Answer 49

Cranial nerves

Question 50

Among A-alpha, A-beta, A-delta, and C sensory neuron fiber types -- which is/are myelinated?

Answer 50

All but C are myelinated

Question 51

Lesions of the Postcentral Gyrus

Answer 51

Large lesion results in sensory loss involving fine touch, proprioception, vibration in the part of the body represented in that somatotopic projection. Paresthesias may present

Question 52

Sensory Ataxia

Answer 52

Patients with severe sensory ataxia can stand unsupported only with feel well apart and with gaze directed downward to include the feet. Gait broad-based with stamping action that maximizes any conscious proprioceptive function that remains

Question 53

Internal Arcuate Fibers

Answer 53

Axons of second order sensory neurons from the nucleus gracilis/cuneatus

Question 54

Manner in which sensory fibers add to the posterior columns

Answer 54

They add laterally. Medial portion of gracile fasciculus starts with information from legs and lower trunk. Cuneate fasciculus adds information from upper trunk, arm, neck and then finally the occiput

Question 55

Termination of Spinothalamic Tract

Answer 55

Some neurons of the spinothalamic terminate in the intralaminar and mediodorsal nuclei of the thalamus

Question 56

Origin of Cuneocerebellar Tract

Answer 56

Lateral Cuneate Nucleus

Question 57

Receptors involved with proprioceptive sensation (both conscious and non-conscious)

Answer 57

Receptors of the locomotor system (muscles, joints, bones) and of the vestibular labyrinth (ears and balance remember)

Question 58

Structures carrying the Posterior Column-Medial Lemniscal Pathway

Answer 58

Fasciculus Gracilis and Fasciculus Cuneatus

Question 59

Function of Anterior Spinocerebellar Tract

Answer 59

Sensory from ipsilateral leg

Question 60

Receptors involved with conscious exteroceptive sensation

Answer 60

Somatic: Touch, pressure, heat, cold and pain Telereceptors: Vision and hearing

Question 61

Synapse in the Ventral Posterior Lateral (VPL) nucleus of the thalamus

Answer 61

Medial lemniscus

Question 62

Lateral Pontine or Medullary Lesion

Answer 62

* Affects contralateral anterolateral and ipsilateral trigeminal pathway. * Loss of pain and temperature sensation in the body opposite the lesion * Loss of pain and temperature sensation in the face on the side of the lesion

Question 63

Asterogenesis

Answer 63

Loss of size/shape/texture discrimination

Question 64

Other names for spinothalamic pathway

Answer 64

Anterolateral or ventrolateral

Question 65

Termination of Spinomesencephalic Tract

Answer 65

Deviates from the anterolateral pathway in the midbrain to project to the midbrain periaqueductal gray and superior colliculus

Question 66

The Spinocerebellar pathways differ from Posterior Column-Medial Lemniscal and Anterolateral pathways by being ipsilateral. What's odd, though, about the Anterior Spinocerebellar Tract?

Answer 66

It's ipsilateral but crosses midline twice; once in spinal cord and again in cerebellum.