Bio exp - Dopamine

• Dopamine is a neurotransmitter, a chemical that moves is the gaps between neuron's to Transmit messages
• Initiation

  Addictive behaviours and substances activate the Mesolimbic pathway in the brain, also know as the reward pathway, the addictive behaviour triggers the release of dopamine in the ventral tegmental area (VTA) of the brain witch lead to a sense of pleasure in the nucleus accumbens (NAc)
• We have evolved to feel a sense of pleasure when we take part in activities like eating and sex so we keep doing it as it is important for human survival and reproduction. This is known as an adaptive behaviour (part of initiation)
• Addiction is seen as a non-adaptive behaviour that releases a huge amount of dopamine, making an individual want to engage in the behaviour again. This leads to a maladaptive pathway reward system. (Part of initiation)
• Tolerance

  This is the repeated exposure to the addictive behaviour or substance that causes a reduced sensitivity to the dopamine release process.
• Repeated exposure - reduced sensitivity, the dopamine receptors become less sensitive the the effect of the addictive behaviour

  Volcov et al eveudence shows that more of the behaviour is needed to[ cause the same pleasure effect in the Mesolithic pathway ( tolerance )
• maintenance

  volcow et al found a decrease in D2 receptors and a decrease in dopamine in those who have a cocaine addiction
• The brain attaches too much attention/importance to the addictive behaviour and the cues associated with it. Therefore the dopamine makes the individual want to engage with the addictive behaviour rather than just liking it (maintenance)
• Relapse occurs when the individual returns to the addictive behaviour despite wanting to stop. This could be due to the fact that the dopamine levels are low and the individual wants to increase them.
• Relase ?


  brain changes lead to lasting memories of the addictive behaviour. When the individual has given up the addiction, they are often exposed to environmental reminders, like being in a pub, which leads to a small amount of dopamine being released. This causes the individual to desire a greater dopamine Reward, so they often return back to their addiction.