ALS Pathway

Question 1

Nociception

Answer 1

physiological reception

Question 2

Pain

Answer 2

subjective perception or feeling

Question 3

ALS does what

Answer 3

conveys nociception, thermal, and non-discriminative touch sensation from body to higher brain centers

Question 4

What tracts are involved? Anatomically

Answer 4

1. Spinothalamic
2. Spinoreticular
3. Spinomesencephalic
4. Spinotectal
5. Spinohypothalamic

Question 5

Phylogenetic names for the tracts

Answer 5

Neospinothalamic system (direct) 
Paleospinothalamic System (indirect)

Question 6

Neospinothalamic System

Answer 6

Direct
Spinal cord --> thalamus --> sensory cortex
about 15% of nociceptive fibers 
(spinothalamic tract)
Conscious levels

Question 7

Paleospinothalamic System

Answer 7

indirect
Spinal cord –> RF –> thalamus –> hypothalamus –> limbic cortex
about 85% of nociceptive fibers
Unconscious levels

Question 8

Dermatome

Answer 8

a stripe or band of skin that is innervated by a pair of spinal nerves

Question 9

A lesion to a dorsal root or spinal nerve results in

Answer 9

sensory deficits in a degmental distribution

Question 10

Neo path

Answer 10

fast, sharp, well localized pain sensation

Question 11

Neo path consists of

receptors?

Answer 11

3 neuron pathway with receptors being free nerve endings

Question 12

Neuron 1 cell body Neo path

Answer 12

DRG

Question 13

Neuron 2 cell body Neo path

Answer 13

Dorsal horn of spinal cord

Question 14

Neuron 3 cell body Neo path

Answer 14

VPL of thalamus

Question 15

Neo pathway is __ organized

Answer 15

somatotopically

Question 16

Fibers of neuron one (neo path)

Answer 16

thinly myelinated A-delta fibers

Question 17

The peripheral process od neo path terminates

Answer 17

in a somatic or visceral structure as a free nerve ending

Question 18

The central process of neo path runs

Answer 18

in dorsal root of spinal nerve and enters the zone of Lissauer in the white matter
then bifurcates into short asc and desc that ascend or descend 1-3 segments and then enter gray matter to synapse

Question 19

Neo path - Second order neuron cell body is located in

Answer 19

dorsal horn of spinal cord

Question 20

Neo path - Second order neuron cell body then does what

Answer 20

decussates in anterior white commissure to opp side and ascends in anterior or lateral (most) spinothalamic tract to terminate in VPL of thalamus

Question 21

Neo path - third order neuron cell body in

Answer 21

VPL of thalamus

Question 22

Neo path - third order neuron axon does what

Answer 22

traverses the posterior limb of internal capsule and the corona radiata to ascend to prmary somatosensory cortex (Brod 3, 1, 2) in postcentral gryus –> consciousness

Question 23

Primary somatosensory cortex projects to

Answer 23

projects to the secondary somatosensory cortex where interpretation and storage of info takes place

Question 24

Paleo path consists of

Answer 24

multisynaptic neural sequence
relays slow, dull, poorly localized pain sensation to limbic cortex or hypothalamus
Like an alerting system (pain in night)

Question 25

LImbic cortex processes

Answer 25

learning, memory, emotions and drives

Question 26

Hypothalamus functions in

Answer 26

autonomic and reflex responses to pain | Sets off protective autonomic reflex responses to protect body

Question 27

Receptors for paleo path

Answer 27

free nerve endings of pseudounipolar neurons

Question 28

``` Paleo path - first order neuron Fibers Peripheral process Cell body Central process ```

Answer 28

Fibers are nonmyelinated C fiebrs Peripheral process teminates in a somatic or visceral structure as a free nerve ending Cell body is in DRG Central process terminates in dorsal horn

Question 29

Paleo path - second order neuron | Cell body

Answer 29

Dorsal horn of the spinal cord

Question 30

Paleo path - second order neuron...what does it do

Answer 30

Ascend ipsilaterally | The axons from the spinoreticular tract to terminate in retifular formation

Question 31

Reticular formation is involved in

Answer 31

arousal and wakefulness

Question 32

Reticular formation projects to the

Answer 32

intralaminar nuclei of the thalamus, hypothalamus, and limbic cortex

Question 33

Intralaminar nuclei are ___ organized

Answer 33

not somatotomically organized so nociception is poorly localized

Question 34

Spinomesencephalic tract terminates in the

Answer 34

terminates in the periaqueductal gray matter and midbrain raphe nuclei Fibers from the brainstem descend to the spinal cord where they modulat the transmission of nociception

Question 35

Spinotectal Tract terminates

Answer 35

terminates in the superior colliculus which is involved in the reflex turning of the head, and upper body toward a noxious stimulus

Question 36

Spinohypothalamic tract terminates

Answer 36

in the hypothalamus where it stimulates they hypothalamospinal tract which is involved in autonomic and reflex responses to noxous stimulus

Question 37

Anterolateral cordotomy or tractotomy of lateral spinothalamic tract is performed to

Answer 37

alleviate intractable pain

Question 38

The lateral spinothalamic tract is sectioned

Answer 38

contralateral to the side of pain and 2 or more segments below the level of the lesion

Question 39

If pain at L1 on left side where should lesion be made?

Answer 39

at T9 on the opposite side (right side) | fourth level above the origin of the pain

Question 40

A unilateral lesion of the spinothalamic tract will result in

Answer 40

loss of pain and temp sensaion on the contralateral side of the body, two or more segments below the level of the lesion

Question 41

A unilateral lesion involving the VPL or internal capsule or primary somatosensory cortex will result in

Answer 41

loss of pain anf temp sens from opposite side of the body

Question 42

If there is a lesion in the cingulate or insular cortexx patients are

Answer 42

consciously aware of the pain but they dont seem to experience the affective component of pain and dont have emotional response to it

Question 43

Anertior cerebral artery occlusion

Answer 43

sensory deficits in contralateral leg and foot

Question 44

Middle cerebral artery occlusion

Answer 44

sensory deficits in contralateral UL and face

Question 45

Lenticulostraite artery occlusion

Answer 45

sensory deficits on contraalteral side of body

Question 46

Posterior cerebral artery occlusion

Answer 46

deficitss in contralateral side fo body

Question 47

Caudal Pons -AICA and basilar

Answer 47

Spinothalamic tract

Question 48

Rostal Medulla - vertebral artery and PICA

Answer 48

Spinothalamic tract

Question 49

ALS is supplied by the

Answer 49

anerior spinal artery at spinal cord levels