Unit 2_Ascending Neural Pathways

Question 1

What are two major sensory pathways conveying information from the body to the brain?

Answer 1

1. Dorsal Column Medial Lemniscal (DCML) for touch and conscious proprioception
2. Anterolateral System (ALS) for pain and temperature

Question 2

What major sensory pathway conveys touch and conscious proprioception from the body to the brain?

Answer 2

Dorsal Column Medial Lemniscal (DCML)

Question 3

What major sensory pathway conveys pain and temperature from the body to the brain?

Answer 3

Anterolateral System (ALS)

Question 4

How can we differentiate whether something might be a problem at the nerve root vs the peripheral nerve?

Answer 4

See if patients have sensory losses that follow specific patterns known as dermatomes

Question 5

If patients have a sensory loss in a dermatome area, where has the injury likely occurred?

Answer 5

In the CNS (nerve root, spinal cord, cortex)

Question 6

If patients have a sensory loss in a peripheral nerve pattern, where has the injury likely occurred?

Answer 6

Outside the CNS

Question 7

What dorsal root ganglia branch (peripheral nerve –> dorsal horn) organization deals with touch and proprioception, includes Group I and Group II nerve fibers from muscle spindle and GTO, and a beta from skin?

Answer 7

Medial Bundle Branches (DCML)

Question 8

What dorsal root ganglia branch (peripheral nerve –> dorsal horn) organization deals with pain and temperature, includes Group III and Group IV nerve fibers from muscle, and a delta and C from Skin?

Answer 8

Lateral Bundle Branches (ALS)

Question 9

Where do the peripheral nerve (somatosensory) pathways for DCML and ALS terminate?

Answer 9

Parietal Cortex

Question 10

What steps do the following describe?

1. First order neurons
   DRG-dorsal root ganglia
   (or cranial nerve nuclei or ganglia)
2. Second order neurons
   Spinal cord or brainstem
   Axons cross
3. Third order neurons
   Thalamus (VPL and VPM; Intralaminar nuclei)
4. Internal capsule
5. Termination in parietal cortex

Answer 10

General Organization of Primary Somatosensory Pathways

Question 11

Where is the sensory version of the homunculus located?

Answer 11

In the partietal cortex

Question 12

What structure is made up of white matter and include axon tracts that are going to travel up to the parietal cortex where cell bodies are found (gray matter)?

Answer 12

Internal Capsule

Question 13

What order of neurons include the DRG-dorsal root ganglia (or cranial nerve nuclei or ganglia)?

Answer 13

First order neurons

Question 14

What order of neurons pick up at the spinal cord or brainstem and where axons cross?

Answer 14

Second order neurons

Question 15

What order of neurons pick up at the thalamus and include VPL and VPM; Intralaminar nuclei?

Answer 15

Third order neurons

Question 16

What areas, where synapses take place, are not simply relay areas? These are the areas where our experience is being shaped including developing complex receptive fields.

Answer 16

In the medulla and cerebral cortex

Question 17

What nuclei take information from the face and body and related to somatic sensation and travel to the primary somatosensory cortex?

Answer 17

Ventral Posterior Medial (VPM)

Ventral Posterior Lateral (VPL)

Question 18

What system carries the following sensations:
1. Light touch/pressure
2. Tactile discrimination
Two-point discrimination
Stereognosis
3. Conscious Proprioception
Static position sense
Kinesthetic sense
Vibration

Answer 18

Dorsal Column/Medial Lemniscal System (DCML)

Question 19

What nuclei is responsible for all body sensations?

Answer 19

Ventral Posterior Lateral Nucleus (VPL)

Question 20

What nuclei is responsible for face sensation?

Answer 20

Ventral Posterior Medial Nucleus (VPM)

Question 21

What nuclei carries upper extremity sensation?

Answer 21

Cuneate

Question 22

What nuclei carries lower extremity sensation?

Answer 22

Gracile

Question 23

If an individual has an injury at the spinal cord level, what side will the injury affect?

Answer 23

The same side of the injury

Question 24

If an individual has an injury at the brainstem level, what side of the body will the injury affect?

Answer 24

The opposite side of the injury

Question 25

What sensory pathway conveys Unconcious Proprioception, Static position sense, Kinesthetic sense and Vibration?

It provides sensory information to the cerebellum to allow it to coordinate movement and balance.

Structures include nucleus dorsalis and spinocerebellar tracts.

Tracts exit the brainstem and the level of pons and medulla to go to cerebellum.
No synapses in thalamus, no termination in cortex.

Answer 25

Spinocerebellar Pathways

Question 26

What sensory pathway conveys Coarse touch, Pain, Temperature, Itch and Tickle?

Answer 26

Anterolateral System (ALS)

Question 27

What sensory pathways make up the Anterolateral System?

Answer 27

Lateral spinothalamic & Ventral/anterior Spinothalamic
Spinoreticular
Spinomesencephalic

Question 28

What Anterolateral System sensory pathway receives signals from lateral bundle of the dorsal root?

Follows the same course as Lateral Spinothalamic to brainstem.

Terminates in reticular nuclei in brainstem.
Connects to:
Intralaminar nuclei of thalamus
Hypothalamus
Limbic system

Function: Autonomic, affective responses to pain.

Answer 28

Spinoreticular

Question 29

What Anterolateral System sensory pathway receives signals from lateral bundle of the dorsal root?

Follows the same course as Lateral Spinothalamic to brainstem.

Terminates in periaqueductal gray matter
Function; endogenous pain modulation.

Answer 29

Spinomesencephalic

Question 30

What ascending pathway system does referred pain use, and will show up as a referred pain pattern (general region of pain)?

Answer 30

Anterolateral System

Question 31

What ascending pathway system causes loss of the following:

1. Light touch/pressure
2. Tactile discrimination
   Two-point discrimination
   Stereognosis
3. Conscious AND Unconscious Proprioception (spinalcerebellar)
   Static position sense
   Kinesthetic sense
   Vibration

Answer 31

Lesions in the Dorsal Column/Medial Lemniscal System

Question 32

What ascending pathway pattern causes patients to have difficulty with balance, coordination, and skin integrity?

*Spinocerebellar degeneration – Friedrich’s ataxia

Answer 32

Lesions in the Dorsal Column/Medial Lemniscal System

Question 33

What ascending pathway pattern causes loss of the following:

Coarse touch
Pain
Temperature
Itch
Tickle

Answer 33

Lesions in the Anterolateral system
System

Question 34

What ascending pathway pattern causes patients to have difficulty with risk of injury as they can not feel pain?

Answer 34

Lesions in the Anterolateral system
System

Question 35

What are deficits on the opposite side of the lesion?

Answer 35

Contralesional

Question 36

What are deficits on the same side of the lesion?

Answer 36

Ipsilesional

Question 37

Because projection axons of the ALS ascend as they cross, a spinal hemisection produces a loss of pain, temperature, and itch one to two segments caudal to the lesion. In contrast, loss of mechanical sensations (DCML) begins at the level of the lesion. What syndrome is this known as?

Answer 37

Brown-Sequard

Question 38

What does heat information from the leg and spinothalamic pathway travel in the thalamus?

Answer 38

Ventro posteriolateral (VPL)

*Where sensory info from the body travels

Question 39

Which of the following neurotransmitters is primarily excitatory?

GABA
Glutamate
Seratonin
Dopamine

Answer 39

Glutamate

Question 40

What is an example of a second messenger involved in long-term synaptic changes?

Answer 40

cAMP (cyclic AMP)

Question 41

Which of the following best describes the impact of glucocorticoids (cortisol) on long-term synaptic changes?

It binds to Ca2+ receptors
It is inhibitory
It interacts with glutamate’s synaptic functions
It causes neuronal death

Answer 41

It interacts with glutamate’s synaptic