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Query: faculty: "FNWI" and publication year: "2011"

AuthorAnne Marije Kaag
TitleMAPPING DOPAMINERGIC FUCNTION USING PHARMACOLOGICAL MRI
Supervisor-
Year2011
FacultyFaculty of Science
ProgrammeFNWI MSc Brain and Cognitive Sciences
AbstractSPECT and PET imaging are currently used to investigate dopaminergic (DA) function in humans. Unfortunately, these techniques are limited in their use due to radioactive exposure. Therefore, the objective of this paper was to provide evidence for the usefulness of pharmacological (ph) MRI in the investigation of in vivo DA function in humans. To achieve this, two different types of phMRI studies are discussed. In the first study, arterial spin labelling (ASL) was used to map the effects of intravenous dexamphetamine (AMPH) administration on CBF within the striatum, thalamus, prefrontal cortex and anterior cingulated gyrus. This study revealed that the AMPH-induced phMRI response resembled that of AMPH-induced increases in extracellular DA and phMRI responses, as has previously been reported in animal studies. Furthermore, the AMPH-induced changes in phMRI signal within the striatum, PFC and thalamus, were strongly correlated with age, what is suggested to reflect differences in D1 and D2 receptor availability. This study therefore provided important evidence that AMPH-induced changes in phMRI signal are related to DA functioning. In the second study, BOLD fMRI was used to investigate the effect of orally administered methylphenidate (MPH) on brain activity during the anticipation of monetary reward, in healthy controls and recreational AMPH users. This study revealed that MPH strongly reduced reward related activity in controls within important regions of the mesolimbic DA system, including the striatum. Interestingly, MPH did not affect reward related activity within any of these regions in AMPH users. These differential effects of MPH on reward processing, are suggested to reflect abnormalities within the DAergic system in recreational AMPH users. These abnormalities might be linked to reduced reward sensitivity which is suggested to underlie the development of addiction. More importantly, as MPH is the drug of choice in the treatment of attention deficit hyperactive disorder (ADHD), this study led to renewed inside in the possible treatment effects of MPH in ADHD. Although the exact relationship between DAergic function and the phMRI response following a DAergic challenge remains to be investigated, this paper provide important evidence for the usefulness of phMRI for mapping DAergic function. Therefore, phMRI will eventually form a reliable alternative to SPECT and PET imaging, creating new possibilities for investigating DAergic function in humans.
LanguageEngels
Document type scriptie master
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