Lecture 27 - Neurochemistry: Pleasure and Pain 2 Flashcards
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?
opioids
NSAIDS
cannabinoids
TCAs
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
