HC 5 - Food & Drugs Flashcards
4 things that can happen with neurotransmitters
- Blocked release, nothing gets released (Botox, muscle relaxation)
- Reuptake by axon terminals OR gliacells for reuse
(speed/cocaine slow reuptake norepinephrine down) - Deactivation by enzymes
- enzymes inactivate neurotransmitters
- Nerve gas destroyes AchE - Diffusion via blood
- transmitters gone of synaptic cleft
Dopamine
- associated with 3 things
- substance for?
- reward, goal proximity, motivation
- pleasure substance!
What happens with Dopamine in ADHD?
- Too much elimination of dopamine! High transport density
- increased cravings/impulses -> to dopamine!
- reduced inhibition
What is the matter with dopamine in Schizofrenia?
- overactive dopamine!
- DA-antagonists/blockers reduce hallucinations
3 executive functions in cognitive control
- working memory -> updating/monitoring
- switching/shifting -> ruis onderdrukken/engagement/disengagement task
- inhibition -> suppressing irrelevant dominant actions
executive function is not a unitair concept!
Cognitive control dilemma
Will versus Habit -> hard to not follow a habit
Flexibility versus Stability
Keep in mind: individual differences!
Cognitive consequence HIGH prefrontal DA
Cognitive STABILITY
- goal maintenance, focussing, suppress distraction, not flexible
Cogntive consequences LOW prefrontal DA
Cognitive FLEXIBILITY
- flexibility, inhibition/switching, sensitive for distraction
3 dopamine pathways
- Nigrostratial Pathway -> motor control, FLEXIBILITY, LOW PF DA
- Tubero Infundibular Pathway -> hormonal regulation, sensory processes
- Mesolimbic and Mesocortical Pathway -> memory, motivation, addiction, STABILITY, HIGH PF DA
high & low levels op dopamine associated with performance
LOW cognitive performance (reversed U-shape!)
- low dopamine = ADHD/Parkinson
- high dopamine = schizo & drug overdose
using stimulants & depressants to reach optimal base
Effects of drugs depends on 5 things
- task type & difficulty
- genetic predisposition
- age/gender/disease/infection/immunity
- type of drugs (depressant/stimulant)
- dosage + history
younger = more cognitive effects on behavior
What does COMT-gene polymorphism?
- 2 alleles
- enzymes INACTIVATE released dopamine
-> regulating flux in PFC - VAL-VAL allel
- MET-MET allel
VAL-VAL
- valine amino acid
- FAST DA loss -> LOW PFC DA
- warriors, resilient to stress
- need dopamine, use it, get rid of it -> no excess
- worse in sustained attention
FLEXIBILITY
VAL + Amphetamine = better performance WCST
N-back test: better efficiency with AMP, all levels
MET-MET
- methionine
- SLOW DA loss -> HIGH PFC DA
- worriers: neurotic, less resilient to stress
- extra dopamine: more agressive/neurotic (higher IQ)
- better in sustained attention
STABILITY
MET + Amphetamine = worse performance WCST
N-back test: high level = low accuracy & efficiency with Amp
effects of cocaine (dopamine) on chronic users
- placebo = deprived (no drugs, but used to)
- only improvement with intermediate dosage (100-200mg) -> better performance
- 300mg same performance as placebo, less able to inhibit
