3.1.2 Dopamine & addicton Flashcards
what is dopamine?
neurotransmitter involved in learning and pleasure
what are high levels of dopamine associated with?
addictions and positive symptoms of schizopohrenia
dopamine was associated with addiction through research on what animals?
rats
what is the prefrontal cortex part of?
frontal lobe
what is the prefrontal cortex involved in?
cognitive functions, memory, language, planning and decision making
what is the nucleus accumbens and what does it do?
small region at the front of the brain which helps regulate survival drives (food, thirst)
the nucleus accumbens is not only associated with survival drives but also…
motivation and rewards
what is the nucleus accumbens affected by?
drugs such as cocaine, cannabis and heroin
where is the ventral tegmental area (VTA) found?
the midbrain
what does the ventral tegmental area produce and form?
dopamine
one of major dopamine pathways in the brain
what is the VTA affected by?
drugs, nicotine, alcohol and heroin
when using an addictive substance what is activate in the VTA?
dopamine neurones
neurones then project to the nucleus accumbens via what?
the mesolimbic dopamine pathway
what does the activation of the nucleus accumbens cause?
increased dopamine levels
the mesolimbic dopamine system is also known as the pleasure centre what does it induce when activated?
feelings of euphoria
how could the mesolimbic dopamine pathway be explained in terms of evolutionary behaviours?
reward system acts as a source of positive reinforcement encouraging behaviours that help survival and reproduction
addictive behaviours and substances trigger the release of dopamine in the 1. _______ leading to a sense of pleasure in the 2._______
- VTA - ventral tegmental area
2. NA - nucleus accumbens
Volkow suggested the mesolimbic dopamine pathway is the starting point for what?
an addiction
but, what turns the behaviour into an addiction? (volkow)
the changes the mesolimbic dopamine pathway causes changes in the frontal cortex
what functions are associated with the frontal cortex?
decision making
memory
language
problem solving
we can se changes in the frontal lobes circuits which usually decide what?
what we pay attention to
due to the attention we pay to it the brain attaches what to the behaviour?
too much importance
so the dopamine system makes the individual want to do what?
engage in the addictive behaviour
overtime what can long term drug use do to the activity of the dopamine reward system?
reduce its activity
this decrease in activity is caused by D2 dopamine receptors doing what?
decreasing in number
becoming less sensitive to the effects of a substance/ behaviour
due to reduced activity more of what is needed?
activity to provide the same mood modification
due to changes in the brain if the individual stops the behaviour what will they experience?
withdrawal symptoms e.g. sweating, mood swings, cold shakes, vomiting, insomnia, depression
how does negative reinforcement apply to relapse?
by continuing the addiction you are removing something unpleasant (withdrawal symptoms)