Lauri Tuominen

Dr. Tuominen will present two studies on schizophrenia he and his team have conducted at the Royal’s Brain Imaging Centre in Ottawa. In the first study, his team used [11C]raclopride and simultaneous fMRI to investigate dopamine function and how it relates to psychotic disorders. They tested the hypothesis that in psychosis, adequate dopamine release in response to events that typically elicit dopamine response may be diminished. They first demonstrate that fear conditioning, a paradigm that elicits dopamine response in animals, can also be used to study dopamine release in humans. Using this paradigm, they then show that as predicted, dopamine release is reduced in first-degree relatives of schizophrenia. Moreover, the magnitude of that reduction was associated with paranoia. This study provides evidence that schizophrenia, in addition to chaotically increased dopamine tone, may involve a lack of adequate dopamine response. In the second study, he and his team studied the cholinergic system in patients with schizophrenia. Acetylcholine receptors are decreased in schizophrenia but less is known about the presynaptic cholinergic system and cholinergic innervation. In this study, using [18F]FEOBV PET, they show that presynaptic vesicular acetylcholine transporter levels, a proxy for cholinergic innervation, are lower in the prefrontal cortex and substantia nigra in schizophrenia and the decrease correlates with worse cognitive symptoms. This study provides further evidence for the disrupted cholinergic system in schizophrenia and first in vivo evidence for presynaptic cholinergic disruption. In the second study, he and his team studied the cholinergic system in patients with schizophrenia. Acetylcholine receptors are decreased in schizophrenia but less is known about the presynaptic cholinergic system and cholinergic innervation. In this study, using [18F]FEOBV PET, they show that presynaptic vesicular acetylcholine transporter levels, a proxy for cholinergic innervation, are lower in the prefrontal cortex and substantia nigra in schizophrenia and the decrease correlates with worse cognitive symptoms. This study provides further evidence for the disrupted cholinergic system in schizophrenia and first in vivo evidence for presynaptic cholinergic disruption.

Lauri Tuominen, MD PhD is a neuroscientist at the Institute of Mental Health Research at the Royal in Ottawa and an assistant professor at the department of psychiatry at the University of Ottawa.

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