Neurobiological correlates of biased cognitive processing in smoking addiction

Addictive behaviours, such as smoking, are associated with biases in the
processing of drug-related stimuli. These processing biases are hypothesized to
have a causal effect on substance use and relapse in addiction. However, little
is known about the neural mechanisms behind these biases. Current studies
provide preliminary indications that addiction-related stimuli yield
differential neural activation in addicts as compared to other stimuli,
suggesting enhanced processing of these stimuli. However, more detailed
knowledge about the neurobiology of these biases is needed in order to design
better treatments for this chronic and invalidating condition. We will
investigate the neurobiology of attentional biases in two complementary
projects.

Project 1: To investigate the neuroanatoimical correlates of attentional
processing bias in nicotine addicts, using fMRI.
Project 2: To examine whether attentional biases are dependent on dopaminergic
transmission in the mesolimbic system using pharmaco-fMRI with a dopamine
challenge.

In the first project, participants will perform two attention tasks in the fMRI
scanner to examine the neural correlates of attentional bias. In the second
project a double-blind placebo controlled cross-over design will be used. In
both sessions participants will get either a single dose 2mg haloperidol of
placebo and perform the the attention tasks in the fMRI scanner. In both
projects 20 smokers will be compared with 20 non-smokers. Participants need to
abstain from alcohol use for 24 hours before scanning and 3 hours from smoking.

fMRI is a save and non-invasive method for measuring brain activity. Since
participants have to lie still in the scanner and are exposed to scanner noise,
effort will be made to make it as comfortable as possible. Previous studies
have shown that a challenge with a single dose 2mg haloperdiol can be used
safely without complications in these kind of study designs.