Lecture 27 - Neurochemistry: Pleasure and Pain 2 Flashcards Preview

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Flashcards in Lecture 27 - Neurochemistry: Pleasure and Pain 2 Deck (17):

Emotions are intimately linked with ...

physical expression


Define an emotion:

an internal, CNS state, which is triggered by specific stimuli (extrinsic or intrinsic to the organism)


what is used to measure pain in babies?

facial expression


what is the Serotonin system?

diffuse system in the brain

5HT neurons - associated with the raphe magnus


What is the catecholamines?

noradrenaline - another dffuse system in the bran

associated with locus coeruleus near the pons


What are the classification of opioid drugs?

Strong morphine, diamorphine (heroin), fentanyl

intermediate - partial agonsits, mixed agonsts-antagonists

weak - codeine


What are the major classes of centrally acting analgesic drugs?





SNRI (serotonin-noradrenaline reuptake inhibitors)


What is endorphin?

natural opioid peptide circulated in the CNS

There is much higher expression of other opioid peptides (dynorphin) which do specific opioid receptor activation


Where are the endorphin pepties found mostly

in the pain ascending modulatory pathways and

emotional modulating systems in the amygdala


What are the functions of the two specialised region of the amygdala?

cortical - Invovled in fear learning (think fear conditioning, rat hears sound and get shock. after a while on needs sounds to get fear response)

subcortical (central) - extensive outputs to regions in the brainstem which are responsible for coordinating the emotional outputs and responses to fear for instance (changes in BP, HR, resp, arousal, freezing, corticosteroids)


Describe the top-down modulation of psychological modulation of pain

cortical areas:

anterior cingulate
Prefrontal cortex

Midbrain (medulla) - can block pain information from the SC


What is the concept of reinforcers?

positive reinforcers (analgesics) increases the frequency of behaviour leading to their acquisition

negative reinforcer (pain) decrease the frequency of behaviour leading to their encounter and increase the frequency to behaviour leading to their avoidance


dopamine not only codes reward but...

the prediction of reward - if there is an unexpected reward the firing rate will be greater


expectations of pain also produce activity changes, but these correlate with _____ ____

nocebo hyperalgesia


There are substantial overlaps between regions that release opioids and regions that are activated during...

placebo analgesia - also correlaions with regions that release dopamine


Pain will reduce pleasure and...

pleasure will reduce pain

activated not only by chemicals (analgesics) but psychological ques


Summary - What is the psychobiological model of pain?

Cognition - attention, distractin, control

Mood - depression, anxiety, catastrophizing

Context - beliefs, expectations, placebo

Chemical and structural - atrophy and opioidergic/dopaminergic dysfunction

Injury: peripheral and central sensitisation

and of couse NOCICEPTION