Pathways

Question 1

Dorsal Column Medial Lemniscus conveys what info?

Answer 1

mechanical
conscious proprioception
from the body

Question 2

Dorsal Trigeminothalamic conveys what info?

Answer 2

mechanical
conscious proprioception
from the head/neck

Question 3

Dorsal Spinocerebellar conveys what info?

Answer 3

non-conscious proprioception
from LE & trunk below T1

Question 4

Cuneocerebellar conveys what info?

Answer 4

non-conscious proprioception
from UE & trunk T1 and above

Question 5

Spinolivary conveys what info?

Answer 5

non-conscious proprioception
from limbs
(just an additional pathway in addition to Dorsal Spinocerebellar & Cuneocerebellar)

Question 6

Dorsal Column Medial Lemniscus cell body locations

Answer 6

1. DRG
2. Caudal Medulla (Gracile or Cuneate nucleus)
3. VPL in thalamus

Question 7

Dorsal Column Medial Lemniscus (Lower Limb) pathway

Answer 7

N1 - enters spinal cord, ascends up Dorsal Column.
N1 synapse on N2 - Gracile Nucleus.
N2 - crosses over, ascends up Medial Lemniscus.
N2 synapse on N3 - VPL.
N3 - ascends up Internal Capsule to primary sensory cortex (medially).

Question 8

Dorsal Column Medial Lemniscus (Upper Limb) pathway

Answer 8

N1 - enters spinal cord, ascends up Dorsal Column.
N1 synapse on N2 - Cuneate Nucleus.
N2 - crosses over, ascends up Medial Lemniscus.
N2 synapse on N3 - VPL.
N3 - ascends up Internal Capsule to primary sensory cortex (more laterally).

Question 9

Dorsal Trigeminothalamic cell body locations

Answer 9

1. Trigeminal Ganglion
2. Main/Principle Trigeminal nucleus (in pons)
3. VPM of thalamus

Question 10

Dorsal Trigeminothalamic pathway

Answer 10

N1 - goes thru Trigeminal Ganglion, enters brainstem.
N1 synapse on N2 - Main/Principle Nucleus of Trigeminal.
N2 - crosses over, ascends up Dorsal Trigeminothalamic Tract.
N2 synapse on N3 - VPM.
N3 - ascends up Internal Capsule to primary sensory cortex.

Question 11

Dorsal Spinocerebellar pathway

Answer 11

N1 - afferent from muscle spindles, enters Clarke’s Nucleus (thoraco-lumbar dorsal horn of spinal cord).
N1 synapse on N2 - Clarke’s.
N2 - ascends ipsilaterally & passes thru Inferior Cerebral Peduncle to get to cerebellum.

Question 12

Cuneocerebellar pathway

Answer 12

N1 - afferent from muscle spindles, enters dorsal column, ascends ipsilaterally.
N1 synapse on N2 - Accessory (External) Cuneate Nucleus (just above Cuneate Nucleus in medulla).
N2 - passes thru Inferior Cerebral Peduncle to get to cerebellum.

Question 13

Spinolivary pathway

Answer 13

N1 - enters spinal cord, crosses over, ascends to Inferior Olive Nucleus (in medulla).
N1 synapse on N2 - Inferior Olive Nucleus.
N2 - crosses back over, passes thru Inferior Cerebral Peduncle to get to cerebellum.

Question 14

What is #1? What pathway(s) travel here?

Answer 14

Dorsal Column
Path: Dorsal Column Med Lemniscus from Lower Limb

Question 15

What is #2? What pathway(s) travel here?

Answer 15

Dorsal Column
Path: Dorsal Column Med Lemniscus from Upper Limb & Cuneocerebellar.

Question 16

What is #3?

Answer 16

Lissauer’s Tract

Question 17

What pathway travels through #4?

Answer 17

Dorsal Spinocerebellar

Question 18

What pathway travels through #5?

Answer 18

Spinothalamic

Question 19

What pathway travels through #6?

Answer 19

Spinolivary

Question 20

Spinothalamic Tract conveys what info?

Answer 20

Pain/temp from body

Question 21

Spinothalamic cell body locations

Answer 21

1. DRG
2. Dorsal horn of spinal cord
3. VPL of thalamus

Question 22

Spinothalamic pathway

Answer 22

N1 - enters spinal cord at dorsal horn.
N1 immediately synapses on N2.
N2 - crosses immediately (in spinal cord), ascends up Spinothalamic Tract.
N2 synapses on N3 - VPL.
N3 - passes thru Internal Capsule to primary sensory cortex (LE more medial, UE more lateral).

Question 23

Lissauer’s Tracts

Answer 23

Part of the Spinothalamic Pathway.
Once N1 hits dorsal horn, branches into collaterals.
Collaterals go up/down 1-2 segments.
Each collateral synapses on an N2 & follows the same remaining steps of the Spinothalamic Pathway.

Question 24

Affective-Motivational Pain Pathways convey what information?

Answer 24

Unpleasent quality of pain

Question 25

Affective-Motivational Pain Pathways originate from where?

Answer 25

Spinothalamic Pathway (branches off)

Question 26

Affective-Motivational Pain Pathways project where?

Answer 26

1. Reticular Formation (medulla) 2. Parabrachial Nucleus (pons) 3. Intralaminar Nuclei (thalamus)

Question 27

Affective-Motivational Pain Pathways: after reaching the Parabrachial Nucleus, where is their final destination?

Answer 27

Hypothalamus & Amygdala (emotion) Periaqueductal Gray Matter (monitors descending pathways)

Question 28

Affective-Motivational Pain Pathways: after reaching the Intralaminar Nuclei, where is their final destination?

Answer 28

Frontal Lobe Insula & Cingulate Cortex (emotion)

Question 29

Ventral Trigeminothalamic Tract conveys what info?

Answer 29

Pain/temp from face

Question 30

Ventral Trigeminothalamic Tract cell body locations

Answer 30

1. Trigeminal Ganglion 2. Spinal Nucleus of Trigeminal 3. VPM

Question 31

Ventral Trigeminothalamic Tract pathway

Answer 31

**N1** - goes thru Trigeminal Ganglion, enters pons, descends down to medulla. N1 synapse on N2 - **Spinal Nucleus of Trigeminal** (medulla). **N2** - crosses over, ascends up Ventral Trigeminothalamic Tract. N2 synapse on N3 - **VPM**. **N3** - ascends thru Internal Capsule to primary sensory cortex.

Question 32

Horizontal Gaze pathway (looking to the RIGHT in this case)

Answer 32

1. **LEFT** Frontal Eye Field & **LEFT** Superior Colliculus activate (receive info from retina). 2. Projects to **RIGHT** PPRF (in brainstem). 3. PPRF projects to **RIGHT** Abducens Nucleus. 4a. Abducens sends LMNs to **RIGHT** Lateral Rectus. 4b. Abducens sends Internuclear Neurons to **LEFT** Oculomotor Nucleus. 5. Oculomotor sends LMNs to **LEFT** Medial Rectus.