recreational drugs (pack 1) Flashcards
what do drugs target?
reward pathways
What are reward pathways
circuit structures and nerves that are linked to activities of specific NT, especially dopamine
how are dopamine reward pathways activated
by doing natural rewarding behaviours such as sex or eating food
what happens when DP are activated?
behaviours stimulate release of dopamine in certain parts of the brain…messages are sent to frontal cortex and we feel pleasurable feelings, they are rewarding and make us likely to carry on doing it
How do recreational drugs work?
- target dopamine pathways
2.increase levels of dopamine so get reward
- prolong and intensify activity in reward pathway by ensuring the dopamine continually excites the Post SN so that they keep firing
what are the 3 ways in which drugs may affect synaptic transmission
- increasing amount of dopamine released into synaptic cleft
- blocking the Pre SN transporters so that reuptake is stopped and remains in synaptic cleft
- stopping action of enzymes that would normally break down the NT, so more dopamine left in synaptic cleft
what are the four steps of how cocaine effects synaptic transmission
- blocks receptors on pre SN in VTA in the mid-brain
- pre SN do not reuptake dopamine, therefore, it remains in synaptic cleft for longer
- prolongs and intensifies stimulation of post SN
- VTA activates another area of brain associated with euphoria, the user experiences it
what do drugs do to the plasticity of the brain?
allows it to adapt to changes imposed on it by the use of the drug BUT brain wont operate properly without
what are the 4 things that happen to the user when they begin to feel dysphoria
- motivation to self-administer becomes over powering
- leads to repeated use of drug, which causes brain to down-regulate production of dopamine
- tolerance is built up as natural baseline becomes so low
- causes person to be physically dependent to avoid experiencing withdrawal
3 strengths of how drugs effect brain functioning and synaptic transmission
- Great deal of well-controlled, scientific evidence using animals…ethics (Van den Oever)
- brain scanning have also provided data…scientifically credible (Li et al) FMRI heroin has changed functioning in brains
- applications- develop medicines to help drug addicts give up using
2 weaknesses of how drugs effect brain functioning and synaptic transmission
- scanning techniques not yet sophisticated enough to show everything, tiny changes in synapses
- evidence comes from ANIMALS- may not be generalised to humans