Sensory Pathways 2

Question 1

Which type of fibres does the neo-spinothalamic tract transmit?

Answer 1

A delta

Question 2

Which type of fibres does the paleo-spinothalamic tract transmit?

Answer 2

C fibres

Question 3

Where do second order neurones of the neospinothalamic tract synapse?

Answer 3

Ventral posterolateral nucleus (VPL) of the thalamus

Question 4

Where do second order neurones of the paleospinothalamic tract synapse?

Answer 4

Intralaminar and dorsomedial nuclei of the thalamus

Question 5

What type of information does the neospinothalamic pathway carry?

Answer 5

Fast, sharp pain

Question 6

What type of information does the paleospinothalamic pathway carry?

Answer 6

Slow, dull pain

Question 7

Why is the neo pathways referred to as discriminating and the paleo referred to as undiscriminating?

Answer 7

VPL has somatotopic map so gives locational discrimination

DM and intralaminar areas only provide generalised location for pain

Question 8

What is the role of the spinoreticular pathway?

Answer 8

Motor response and ascending arousal

Question 9

What is the role of the spinomesencephalic pathway?

Answer 9

Descending pain modulation

Question 10

Which rexed laminae do the spinothalamic and spinomesencephalic tracts originate from?

Answer 10

1 and 5

Question 11

Which rexed laminae does the spinoreticular tract originate from?

Answer 11

6-8 (intermediate zone)

Question 12

What is the overall function of the spinothalamic tracts?

Answer 12

Pain basis for avoidance behaviours that protect us from harm

Question 13

What is said to be one of the hardest pains to bear?

Answer 13

Prolonged stimulation of the paleo-spinothalamic pathway

Question 14

Why does pain prevent sleep?

Answer 14

Spinothalamic tracts synapse with brainstem nuclei to increase arousal

Question 15

Why does pain make you sweat and feel nauseous?

Answer 15

Spinothalamic tracts indirectly stimulate autonomic circuitry

Question 16

Why is there an emotional component of pain?

Answer 16

Spinothalamic tracts positively associated with the limbic system

Question 17

How would a lesion to the neospinothalamic pathway present?

Answer 17

Decreased perception of pain and temperature on the contralateral side of the body, always one or two dermatomes below the level of the lesion (Lissauers tract)

Question 18

What is a cordotomy?

Answer 18

Surgical procedure where anterolateral portion of cord is lesioned using electrical current used in terminal disease pain

Question 19

How are paraesthesias associated with the spinothalamic tract felt?

Answer 19

Searing, shooting or burning pain

Question 20

What is the function of the mesencephalic nucleus?

Answer 20

Proprioception from mouth/jaw

Question 21

What is the function of the sensory nucleus?

Answer 21

Discriminating tough, vibration and conscious proprioception from the face

Question 22

What is the function of the spinal nucleus?

Answer 22

Pain and temperature sensation from face, back of tongue, pharynx, larynx and ear

Question 23

Where do neurones from the sensory nucleus project to?

Answer 23

VPM of thalamus

Question 24

What information is carried in the trigeminal lemniscus from the sensory nucleus?

Answer 24

Touch and sensation from the face

Question 25

What information is carried in the posterior trigeminothalamic tract from the sensory nucleus?

Answer 25

Touch and vibration from the mouth

Question 26

Where does the trigeminal lemniscus project to from the VPM?

Answer 26

Somatosensory cortex

Question 27

Which side of the spinal cord do the trigeminal lemniscus and posterior trigeminothalamic tracts travel from the sensory nucleus?

Answer 27

Posterior trigeminothalamic - ipsilateral | Trigeminal lemniscus - contralateral

Question 28

Where do C and A delta fibres enter the spinal cord from the spinal nucleus?

Answer 28

Mid pontine level

Question 29

Where is the spinal trigeminal nucleus?

Answer 29

C1

Question 30

Where do C and A delta fibres travel when they enter the spinal cord?

Answer 30

Down the cord to spinal nucleus in spinal trigeminal tract

Question 31

What is the path taken by 2nd order neurons from the spinal nucleus?

Answer 31

Cross midline and ascend contralaterally in trigeminal lemniscus Give off trigeminoreticular and trigeminomesencephalic tracts

Question 32

Where do 2nd order neurons from the spinal nucleus synapse?

Answer 32

VPM of thalamus

Question 33

What are the symptoms of trigeminal neuralgia?

Answer 33

Intense shotting sharp pain in areas innervated by the trigeminal nerve often in response to light tough

Question 34

What is thought to cause trigeminal neuralgia?

Answer 34

quasi-ectopic firing of nerve induced by normally low frequency APs

Question 35

What disease is trigeminal neuralgia associated with?

Answer 35

Demyelinating disorders such as MS

Question 36

What is trigeminal neuralgia treated with?

Answer 36

Voltage sensitive sodium channel blockers e.g. phenytoin

Question 37

What information enters the posterior spinocerebellar pathway?

Answer 37

LL proprioception

Question 38

What information enters the cuneocerebellar pathway?

Answer 38

UL proprioception

Question 39

Where do axons carrying proprioception from the lower limb synapse?

Answer 39

Clarke's nucleus

Question 40

Where do axons carrying proprioception from the upper limb synapse?

Answer 40

Accessory cuneate nucleus

Question 41

Where do the posterior spinocerebellar and cuneocerebellar pathways enter the cerebellum?

Answer 41

Inferior peduncle

Question 42

Where do axons from the limbs in the integrated pathway synapse?

Answer 42

Spinal border cells

Question 43

What 3 pathways synapse on spinal border cells?

Answer 43

Descending modulation Reflex arcs Limb proprioception

Question 44

Describe the path taken by neurons in the anterior spinocerebellar from the spinal border cells

Answer 44

Cross midline and ascend contralaterally Enter cerebellum at contralateral superior peduncle then recross ==> ipsilateral

Question 45

Describe the path taken by neurons in the rostral spinocerebellar from the spinal border cells

Answer 45

Ascend ipsilaterally | Enter cerebellum via the superior and inferior peduncles

Question 46

What information is carried in the rostral spinocerebellar pathway?

Answer 46

Integrated UL proprioception

Question 47

What information is carried in the anterior spinocerebellar pathway?

Answer 47

Integrated LL proprioception

Question 48

Name the 2 integrated cerebellar pathways

Answer 48

Anterior and rostrals spinocerebellar

Question 49

Name the 2 unintegrated cerebellar pathways

Answer 49

Cuneocerebellar | Posterior spinocerebellar

Question 50

Which protein is affected in Friedreich's ataxia?

Answer 50

Frataxin (multiple repeats of gene)

Question 51

What are the clinical features of Friedreich's ataxia?

Answer 51

Progressively uncoordinated limbs Wide based 'reeling' gait Intention tremor