Nociception and pain (Alice Whitney lecture 3)

which are more numerous within the skin; the C or Aδ fibers?

C

do smaller afferens terminate in the laminae close to the outside or inside of the sinal cord?

outside

do larger afferents terminate in the laminae close to the outside or inside of the spinal cord?

inside

which is the most critical lamina for the modulation of pain in the spinal cord?

substantia gelatinosa (II)

the larger the fiber diameter in afferent nerve fibers, the … (faster/slower) the conduction velocity

faster

types of nerve fibers which innervate muscles are shown below. give the corresponding classification for cutaneous nerves

1. Ia

2. Ib

3. II

4. III

5. IV

α, β, δ, γ

1. Aα

2. Aα

3. Aβ

4. Aδ

5. C

most nerves will include axons of different types, including both ... and …

afferents and efferents

peripheral nervous system works with the … system to protect the body

immune

free nerve endings are the first line of defence against … and … (the latter by working together with the immune system)

injury and infection

… … … receptors are specialised molecular sensors including … and … channels expressed by sensory neurons to detect … and …, the detection of which triggers … interactions, … and … in response to injury and infection

neural danger signal, TLR, TRP, DAMPs, PAMPs, neuroimmune, pain and inflammation

TRP channels are molecular mediators of …

nociception

C fibers primarily terminate in which two laminae (use numbers)

I and II

Aδ fibers primarily terminate in which two laminae

I and V

name the four ascending pathways (tracts) for transmission of pain

1. spinothalamic

2. spinoparabrachial

3. spinoreticular

4. spinomesencephalic

the different ascending pathways (tracts) for transmission of pain differ based on where they pass through the … on their was to the … …

brainstem, sensory cortex

in the gate control theory which fibers are the large diameter fibers? (answer with word instead of character)

A beta

in the gate control theory which fibers are the small diameter fibers? (answer with word instead of character)

A delta and C

in the gate control theory, the descending … pathways (the central control) additionally … the transmission of … stimuli from C and Aδ fibers

modulatory, inhibit, noxious

do the C and Aδ fibers excite or inhibit the inhibitory interneurons in the substantia gelatinosa?

inhibit

do Aβ fibers excite or inhibit the inhibitory interneurons in substantia gelatinosa?

excite

do C and Aδ fibers excite or inhibit the transmission cells in the spinal cord?

excite

when transmission cells are excited in gate control theory, they transmit … signals from the … … to the …, leading to the perception of pain

noxious, spinal cord, brain

… … of pain is the process by which mental states (attention, expectation, emotion, belief etc) alter the perception of pain

cognitive modulation

cognitive modulation of pain occurs via the … … … system

descending pain modulatory system

which region in the brain is involved in the nocebo response?

hippocampus

there are multiple brain areas that are known to underlie pain making up the pain …

neuromatrix

two important areas involved in generating the pain experience

sensory cortex and thalamus

two important areas in cognitive modulation of pain

PAG and RVM

direct electrical stimulation of the PAG produces … as it blocks the … response

analgesia, nociceptive

what do PAG and RVM stand for

periaqueductal grey and rostroventral medulla

the PAG coordinates the … response to …

defensive, threat

if … is injected into PAG this will trigger the descending pain modulation pathway

morphine

PAG is dependent on … and there is also an involvement of … in terms of triggering the descending pain modulation pathway

serotonin, opioids

offset analgesia is a phenomenon where a small decrease in a … heat stimulus results in a disproportionately large reduction in perceived …, acting as a form of … pain inhibition.

noxious, pain, endogenous

fMRI studies indicate activation of the … during offset analgesia

PAG

a deficit in the … … response has been observed in chronic pain patients

offset analgesia

four different types of interventional treatments for neuropathic pain

1. spinal cord stimulation

2. cortical stimulation of the primary motor cortex

3. deep brain stimulation of the thalamus and PAG

4. intrathecal drug delivery

phantom limb pain is largely driven by … plasticity, where the … cortex and sometimes the whole … cortex reorganizes after amputation, with neighboring brain regions … the area formerly representing the missing limb

cortical, somatosensory, sensorimotor, invading

phantom limb pain involved central as well as … mechanisms

peripheral

pain is defined as an unpleasant … and … experience associated with actual or poential tissue …, or described in terms of such …

sensory, emotional, damage, damage

chronic pain is defined as pain that lasts for how long after initial injury?

3-6 months

whch type of pain is no longer beneficial for survival?

chronic