Medial pain system Flashcards
Nociception
Noxious or highly unpleasant stimulus within the PNS or CNS
Pain
Emotion
-conscious experience associated with noxious stimuli
Direct Anterior lateral pathway
Nociception
temperature
tactile sensations
Neospinothalamic tract
Part of the anterior lateral pathway
- Nucleus found in laminae IV of dorsal horn
- synapse on VPL in thalamic nucleus
- project to primary somatosensory cortex
Indirect anterior lateral pathways
Limbic/ autonomic/ endocrine and motor components of pain
Posterior medial pathways
Visceral nociceptive information arises in the gut to convey -tmeperature -pain -irritation -chemical changes -stretch from visceral organs Run with Vagus and sympathetic
Paleospinothalamic
Synapse in the reticular formation
-end up in ACC and insular cortex
Spinoreticular
Caudal RF - sends projections back to IML -regulates sympathetic NS Rostral RF and locus coeruleus (LC) - innervate paraventricular nucleus of hypothalamus and MITN
Spinomesencephalic
Axons from dorsal horn and intermediate gray
- Has PAG neurons that regulate ANS
- signals to the amygdala
- send descending projections to inhibit pain sensation
Referred Pain
Cross wiring in the dorsal horn with visceral nociceptive input- perceived as cutaneous pain from segmentally related dermatomes
-cause limbic activation
Posterior midline myelotomy
performed to get rid of the source of pain
Reticular formation
important for pain processing
- Raphe nucleus
- Locus ceruleus
- parabrachial area- referred pain
- nucleus gigantocellularis
Nucleus Ambiguus
breathing and HR
Gigantocellular RF
projects to sympathetic IML
Medial pain system activates
Limbic system
Locus coeruleus
Alert and print to significant events
primes neuroendocrine and limbic system
MITN (Midline and intralaminar nucleus of thalamus
engages cortical areas involved in pain perception and reactions to it
PAG
Direct control of ANS–> HR and BP as result of painful stimulus
Limbic/autonomic activation
Involves ACC/ PAG and MCC
- ACC/PAG- unpleasantness of pain
- MCC- location of stimulus
Rostral RF
Ascending info to forebrain centers
Caudal RF
Response- transmitted to lower motor and autonomic centers
PAG and RF
Regulate the ANS
-modify HR/BP and other sensory inputs in response to pain
Learning and anticipation
Depends on connects with amygdala and thalamus
- Medial motor areas– SMA and CMA
- ACC also involved
Nocifensive behavior
Pain avoidance - Medial motor areas- SMA and CMA -S1 stimulus -S2 motor response Anticipation of pain is a learning process
Noxious pain increase membrane excitability
-increases Ca++ removing Mg++ and creating a memory
Pain empathy
activation of lateral nociceptive and medial pain systems
-evokes sympathy pain
Pain inhibition
MCS
-provides pain relief by activating descending pain signaling pathways from ACC
Upper CBL changes in pain management
increase pain tolerance
Lower CBF changes in pain management
decreased unpleasantness
