neuro lecture exam 3

what is pain?

A conscious, emotional experience associated with actual or potential tissue damage

what is nociception

Neural process of detecting harmful stimuli via sensory pathways (not conscious)

key difference between pain vs nociception

pain= perception (brain)

nociception= signal detection (nervous system)

what fibers carry fast pain?

Aδ fibers

characteristics of fast pain

sharp, well-localized, immediate

what pathway carries fast pain

spinothalamic tract

what fibers carry slow pain

c fibers

characteristic of slow pain

dull, aching, poorly localized

pathways for slow pain

spinoreticular + spinolimbic

superficial pain

localized, from skin

deep pain diffuse from

muscles/joints

what is pain felt in a different location than the source called

referred pain

nociceptive pain comes from

actual tissue damage

neuropathic pain

from abnormal nerve signaling (no stimulus needed)

what is gate control theory

pain signals can be modulated (increased or decreased) at spinal cord level by competing inputs

an example of gate control theory

hitting your hand, it hurts, you rub your hand which reduces pain

what is the pain matrix

brain network that processes pain

structures to know

thalamus → sensory relay

limbic system → emotional response

cortex → perception

PAG → pain modulation

what causes neuropathic pain

demyelination

ectopic firing

ephaptic transmission

what do UMNs do

send movement commands from brain

what do LMNs do

directly activate skeletal muscles

Lateral activating system (LAS)

controls voluntary, precise movement

LAS tracts

lateral corticospinal

corticobulbar

rubrospinal

Medial activating system (MAS)

controls posture, balance, trunk

MAS tracts

reticulospinal

vestibulospinal

tectospinal

anterior corticospinal

where does the corticospinal tract cross

medulla (pyramidal decussation)

damage above decussation?

opposite side weakness

damage below decussation

same side weakness

stretch reflex

resists muscle stretch

withdrawal reflex

pull away from pain

crossed extensor reflex

opposite limb stabilizes body

ventral horn organize

medial= proximal muscles

lateral= distal muscles

maybe a little hack if its

face problem → corticobulbar (LAS

fine movements → lateral corticospinal (LAS)

Balance/posture → MAS

vestibulocerebellum

balance + eye movements

vestibulocerebellum nucleus

fastigial

spinocerebellum

posture and gait

spinocerebellum nuclei

interposed

cerebrocerebellum

motor planning and precision

cerebrocerebellum nucleus

dantate

superior peduncles

output

middle peduncle

input from cortex

inferior peduncles

input from body

purkinje cells neurotransmitter?

GABA (inhibitory)

some clinical clues

wide based gait → spinocerebellum

dysmetria → cerebrocerebellum

nystagmus→ vestibulocerebellum

basal ganglia core structures

Caudate

putamen

globus pallidus

subthalamic nucleus

substantia nigra

direct pathway effect

increases movement

indirect pathway effects

decreases movements

dopamine effect on D1 receptors

excites and increases movements

dopamine effect on D2 receptors

inhibit indirect movements

parkisons

low dopamine, movement is slow and rigid

huntingtons

low indirect pathways, excessive movement

acute pain

short term, protective (injury just happened). immediate and temporary

chronic pain

long lasting, persists even after healing.

you step on a nail, receptors in your foot detect damage is

nociception

example: you touch a hot stove

fisrt feeling of OUCH is fast pain= Aδ fibers

second feeling throbbing burn is after the first pain which is c fibers

what happens when u feel pain

injury happens, signal enter spinal cord, crosses to opposite side, goes up to the thalamus, then to cortex THEN you feel pain

example of referred pain

heart attack where you feel pain in your left arm even though it has something to do with your heart

nociceptive=real tissue damage

neuropathic= nerve problem no actual injury needed

nociceptive example

broken bone or arthritis

neuropathic example

burning, shooting pain, tingling

if there is a scenario that talks about diabetic burning feet including clues about burning,shooting, tingling, chronic

pathway: spinothalmic

fiber: c fibers

pain type: deep

duration: chronic

type: neuropathic

why? diabetes damages nerves

which term refers to the neural process of detecting potential harm without conscious awareness?

nociception

the lateral corticospinal tract primarily controls

voluntary movements of limbs

which structure produces dopamine in the basal ganglia circuit

substantia nigra pars compacta

the cerebellar peduncle carrying mostly efferent signals to the midbrain and thalamus is the

superior cerebellar peduncle

which pain fiber type transmits ‘slow’, dull, aching pain

c fibers

the corticobulbar tract primarily controls muscles of the

face and head

damage to the substantia nigra pars compacta would most directly lead to

decreased dopamine release

which cerebella module regulates balance and eye movements

vestibulocerebellum

the spinothalamic tract is most responsible for transmitting

pain and temperature

lower motor neurons are located in the

ventral horn of the spinal cord

which basal ganglia pathway facilitates movement (“go” signals)

direct pathway

the only inhibitory output neurons of the cerebellar cortex are

purkinje cells

which theory of pain proposed that both timing and pathway type regulate pain transmission?

gate control theory

the rubrospinal tract assists primarily in

flexion of upper limbs

dopamine acting on D2 receptors of the basal ganglia tends to

excite movement

the cerebellar structure that provides the sole output from the cortex is the

purkinje cellss

which type of pain arises without nociceptors activation

neuropathic pain

the medial activating system (MAS) mainly influences

balance and posture

huntingtons disease results damage to which region

striatum

the cerebellar deep nucleus associated with limb coordination is the

dentate nucleus

which fibers produce sharp localized pain sensation

A (weird symbol) fibers

the reflex that maintains balance by extending the opposite leg during withdrawl is the

crossed-extensor reflex

parkinsons disease is classified as a

hypokinetic disorder

the cerebellar region that coordinates gait and trunk stability is the

spinocerebellum

the phenomenon where pain is percieved in a different location from its source is called

referred pain

upper motor neurons primarily originate in the

primary motor cortex

which basal ganglia structure inhibits unwanted movements

globus pallidus externa

purkinje cells release which neurotransmitter

GABA

which pain theory first identified nociceptors as direct sensory receptors

gate control theory

the vestibulospinal tract functions primarily to

maintain balance and head position

the direct and indirect basal ganglia pathways together regulate

motor activity

the middle cerebellar peduncle primarily carries input from the

spinal cord

chronic activation of nociceptors resulting in persistent pain is known as

central sensitization

the anterior corticospinal tract controls

voluntary trunk movements

the cerebellar lobe responsible for eye movement coordination is the

flocculondular lobe

case study 1: Patient Background: Sarah. a 60-year-old retiree, presents to the orthopedic clinic with complaints of chronic knee pain that has persisted for several years. She describes the pain as an internal throbbing sensation deep within both knees, exacerbated by weight-bearing activities such as walking and standing for prolonged periods Sarah reports stiffness and swelline in her knees. limiting her mobility and impacting her ability to perform daily activities. Additionally, she expresses feclines of frustration. anxiety, and helplessness due to the ongoing nature of her pain.

Clinical Assessment: Upon examination, Sarah demonstrates decreased range of motion in both knees and tenderness upon palpation of the knee joints. X-rays reveal evidence of osteoarthritis, with joint space narrowing, ostcophyte formation, and subchondral sclerosis consistent with degenerative changes.

36. Sarah describes her knee pain as a deep, internal throbbing sensation associated with osteoarthritis. Analyze which types of nociceptors and pain fibers are likely contributing to her symptoms. How does the location and duration of her pain support your reasoning about the underlying pain pathway and fiber type involved? (3pts)

c fibers are primarily responsible because of the long-term chronic pain she is experiencing

case study 1: Patient Background: Sarah. a 60-year-old retiree, presents to the orthopedic clinic with complaints of chronic knee pain that has persisted for several years. She describes the pain as an internal throbbing sensation deep within both knees, exacerbated by weight-bearing activities such as walking and standing for prolonged periods Sarah reports stiffness and swelline in her knees. limiting her mobility and impacting her ability to perform daily activities. Additionally, she expresses feclines of frustration. anxiety, and helplessness due to the ongoing nature of her pain.

Clinical Assessment: Upon examination, Sarah demonstrates decreased range of motion in both knees and tenderness upon palpation of the knee joints. X-rays reveal evidence of osteoarthritis, with joint space narrowing, ostcophyte formation, and subchondral sclerosis consistent with degenerative changes.

37. Despite treatment, Sarah continues to experience pain long after the initial joint degeneration began. Evaluate how peripheral sensitization and central sensitization may have contributed to the chronic nature of her pain. What cellular or synaptic changes in the spinal cord or brain could explain her persistent discomfort? (3 pts).

ps: occurs when inflammation mediators are activated, they lower nociceptor thresholds, which increases firing of pain receptors

cs: increased excitability of dorsal horn neurons due to increased glutamate and reduced inhibitory signaling leads to hyperalgesia and allodynia

case study 1: Patient Background: Sarah. a 60-year-old retiree, presents to the orthopedic clinic with complaints of chronic knee pain that has persisted for several years. She describes the pain as an internal throbbing sensation deep within both knees, exacerbated by weight-bearing activities such as walking and standing for prolonged periods Sarah reports stiffness and swelline in her knees. limiting her mobility and impacting her ability to perform daily activities. Additionally, she expresses feclines of frustration. anxiety, and helplessness due to the ongoing nature of her pain.

Clinical Assessment: Upon examination, Sarah demonstrates decreased range of motion in both knees and tenderness upon palpation of the knee joints. X-rays reveal evidence of osteoarthritis, with joint space narrowing, ostcophyte formation, and subchondral sclerosis consistent with degenerative changes.

38. Sarah expresses feelings of frustration, anxiety, and helplessness in response to her chronic pain. Describe how the pain matrix and descending modulatory systems might influence her pain perception. How could her emotional state amplify or dampen the transmission of pain signals in the central nervous system?

the pain matrix processes both sensory and emotional aspects of pain.

descending pathways can inhibt pain or facilitate pain when influenced by anxiety and stress

her anxiety in this case amplify pain perception by enhancing descending facilitation

CASE STUDY 2:

Patient Background

Dr. Green, a 47-year-old lecturer, complained that he could no longer accurately reach for or grasp objects. He described his arm movements as clumsy and poorly judged, making simple tasks such as picking up a pen or steering his car increasingly difficult.

Clinical Observations

On physical examination, Dr: Green demonstrated inaccurate reaching movements, with his hand overshooting or undershooting objects. Fine control of the distal upper limb was reduced, though proximal strength remained normal. Imaging revealed a small lesion in the midbrain region corresponding with impaired coordination of arm movements.

39. FILL IN THE BLANKS.

The rubrospinal tract originates in the____of the midbrain and primarily facilitates movement of the _______muscles of the____limbs.

red nucleus, flexor, upper