Dopamine & Conditioning

Dopamine & Conditioning

1. To what extent can arbitrary stimuli become conditioned to a drug in humans?

   • Discrete stimuli
     • Field & Duka (2002)
       • CS+ and CS- stimuli. Alcohol apricot / passionfruit. Euphoria and desire for alcohol became associated with CS+ stimulus after just 4 days. Evidence for acquired attentional component to CS+ stimuli
       • social drinkers
   • Environmental / Contextual stimuli
     • Foltin & Haney (2000)
       • crack cocaine addicts
       • Stimuli paired with cocaine increased heart rate and skin temperature after 4 days of training. No inittial bias to one or the other, but after training participants preferred stimuli previously pairedwith cocaine.
         • Acquired conditioning effects in CS+ stimuli

2. To what extent does Pavlovian conditioning lead to DA release in the NA of human participants?

   • Schott et al. (2008)
     • Widespread activation during reward vs neutral trials in ventral striatal and surrounding regions

3. To what extent can a drug of abuse such as amphetamine support conditioning in humans, and what might be the dopaminergic consequences of any conditioning?

   • Boileau et al (2007)
     • More dopamine released in both Placebo and Amphetamine conditions
       • Drugs can support conditioning in humans, to release dopamine

4. Summary

   • Mesoaccumbens dopamine activation is highly rewarding, but also occurs in response to aversive situation
   • This system responds particularly strongly to conditioned, rather than unconditioned stimuli
   • This suggests that the purpose of mesoaccumbens dopamine is to modulate the extent to which conditioned stimuli govern our behaviour
   • This also implies that mesoaccumbens dopamine activation may not be 'pleasurable' as such, despite its potent ability to control our behaviour