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Modern functional imaging methods, such as positron emission tomography (PET) and single photon emission computed tomography (SPECT), provide non-invasive, quantitative tools for the direct measurement of neurotransmitter function in the living human brain. The dopamine system has been of key interest; first, because it has a prominant role in several(More)
BACKGROUND Brain dopamine neurons code rewarding environmental stimuli by releasing endogenous dopamine, a transmission signal that is important for reinforcement learning. Human reward-seeking gambling behavior, and especially pathological gambling, has been presumed to be modulated by brain dopamine. METHODS Striatal dopamine release was studied with(More)
BACKGROUND Early stage patients with Parkinson's disease (PD) show cognitive impairment in frontal lobe functions and memory tests. Hippocampal atrophy is seen in medicated patients with advanced PD. OBJECTIVES To examine whether prefrontal or hippocampal atrophy are already present in early stage PD, and whether such atrophy is associated with cognitive(More)
Previous imaging studies in Parkinson's disease have focused mainly on the striatum, a region with very high dopaminergic activity. Using modern high-sensitivity 3D [(18)F]fluorodopa (Fdopa)-PET, mesocortical monoamine projections can be studied. To study the frontal monoaminergic system in unmedicated early Parkinson's disease in vivo, we examined 20 early(More)
A distinctive personality type, characterized by introversion, inflexibility, and low novelty seeking, has been suggested to be associated with Parkinson's disease. To test the hypothesis that Parkinson's disease is associated with a specific dopamine-related personality type, the personality structures of 61 unmedicated Parkinson's disease patients and 45(More)
Dopamine is known to regulate food intake by modulating food reward via the mesolimbic circuitry of the brain. The objective of this study was to compare the effects of high energy input (i.v. glucose) on striatal and thalamic dopamine release in overweight and lean individuals. We hypothesized that glucose would induce dopamine release and positive ratings(More)
Donepezil and rivastigmine are acetylcholinesterase (AChE) inhibitors used to improve cholinergic neurotransmission and cognitive function in Alzheimer's disease (AD). This study examined direct effects of these drugs on AChE activity in the frontal, temporal, and parietal cortices in AD. Six AD patients were scanned with positron emission tomography before(More)
Recent neuroimaging studies indicate that placebo treatments can induce clinically relevant neurobiological responses in patients with Parkinson's disease, depression and pain. The present study aimed to investigate neurotransmitter function in psychostimulant expectation, with the focus on dopaminergic effects of placebo caffeine in healthy human subjects.(More)
Several magnetic resonance imaging (MRI) studies in substance use disorders have shown brain white matter integrity abnormalities, but there are no studies in pathological gambling, a form of behavioral addiction. Our objective was to investigate possible changes in regional brain gray and white matter volumes, and axonal white matter integrity in(More)
Brain activation was measured in professional interpreters during simultaneous interpreting (SI) vs. repetition (shadowing) of auditorily presented text by positron emission tomography (PET). SI into the native language (Finnish) elicited left frontal activation increases. SI into the non-native language (English) elicited much more extensive left-sided(More)