Neuro Practical 2.1.2

Question 1

what pathway carries discriminative touch ,proprioception, and vibration

Answer 1

dorsal column pathway

Question 2

what pathway carries pain, crude touch, and temperature?

Answer 2

spinothalamic

Question 3

what is the dorsal column pathway?

Answer 3

peripheral receptor -DRG - fasiculus cunateus/gracilis - nucelus cuneatus/ gracilis - internal arcuate fibres - medial lemniscus - VPL thalamus - internal capsule - corona radiata - post central gyrus

Question 4

what is the spinothalamic pathway?

Answer 4

peripheral receptor - DRG - dorsal horn - ventral white commisure - spintothalamic tract of spinal cord - spinal lemnisucs - VPL thalamus - internal capsule - corona radiata - post central gyrus

Question 5

• In which thalamic nucleus do neurons carrying sensory information for the head and neck synapse?

Answer 5

VPM

Question 6

• In which thalamic nucleus do neurons carrying sensory information from the rest of the body synapse?

Answer 6

VPL

Question 7

What areas of grey matter form the boundaries of the internal capsule on a horizontal section

Answer 7

caudate, lentiform, thalamus

Question 8

What is the functional arrangement of fibres within the internal capsule?

Answer 8

anterior, genu, posterior - Anterior limb contains fibres associated with higher functions (e.g. thalamo-frontal connections). Posterior limb contains major ascending somatosensory fibres (and descending motor fibres – you will see those next time!)

Question 9

Where is the primary somatosensory cortex?

Answer 9

The somatosensory cortex is located on the post central gyrus. This is the gyrus immediately posterior to the central sulcus, the only sulcus extending from the great longitudinal fissure to the lateral fissure.

Question 10

what is the sensory homunculus?

Answer 10

. The feet are located on the superior / medial surface, the face is located on the inferior / lateral surface of the gyrus (refer to your lecture slides to remind you of this topographical organisation as well as the distribution of cerebral arteries across the cerebral hemispheres).

Question 11

What is the principal arterial blood supply to the region of primary somatosensory cortex receiving information from the lower limb?

Answer 11

anterior cerebral

Question 12

• What is the principal arterial blood supply to the region of primary somatosensory cortex receiving information from the head?

Answer 12

middle cerebral artery

Question 13

where are DRGs located?

Answer 13

in the dural root sleeve, located in the intervertebral foramen

Question 14

what is a dorsal root ganglion?

Answer 14

A collection of sensory neuron cell bodies outside of the CNS

Question 15

C2 / C3 dermatome
C6 dermatome
T4 dermatome
T10 dermatome
L4 dermatome

Answer 15

c2/c3 = posterior scalp and neck
c6= anterior arm and thumb
t4 = nipple
t10 = bellybutton
l4 = knee (L3/L4)
s1 = ankle (s1/s2)

Question 16

what does the spinocerebellar pathway do?

Answer 16

process information about posture and motor coordination

Question 17

Where is general sensory information for the head and neck carried?

Answer 17

trigeminal nerve

Question 18

where will the cell bodies of the trigeminal nerve synapse?

Answer 18

the trigeminal ganglion which lies outwith the brainstem, the neurones will synapse in one of the following nuclei - in order of superior to inferior
mesencephalic
cheif sensory
nucleus of spinal tract of trigeminal

Question 19

What type of sensory information is associated with each of the trigeminal nerve
brainstem nuclei?

Answer 19

mesencephalic = proprioception
cheif sensory = touch and pressure
nucleus of the spinal trat = pain and temperature

Question 20

Trigeminothalamic fibres (second order neurons) will decussate in the brain stem and then travel to the thalamus. Where in the thalamus do these fibres synapse with third order neurons?

Answer 20

VPM of the thalamsu

Question 21

how many neurones are in the spinocerebellar pathway?

Answer 21

2

Question 22

where do the cell bodies of the spinocerebellar pathway lie

Answer 22

DRG (1) and dorsal grey horn of the spinal cord (2)

Question 23

what are the two principal tract relating to the spinocerebellar pathway?

Answer 23

dorsal spinocerebellar tract - axons do not deccussate
ventral spinocerebellar tract - axons do decussate

Question 24

on what side does the spinocerebellar tract rise

Answer 24

the dorsal spinocerebellar tract ascend ipsilaterally and enters the cerebellum through the inferior cerebellar peduncle from the medulla

the ventral spinocerebellar tract ascends contralaterally and decussate back in the brainstem before entering the cerebellum though the superior cerebellar peduncle from the midbrain

Question 25

what type of sensory information is carried in the spinocerebellar tract

Answer 25

• information about relative stretch in muscles from muscle spindles
• information about the stretch in tendons from tendon organs
• output from joint receptors
• information about pressure on skin and superficial fascia