Differential roles of dopamine and acetylcholine in mesolimbic novelty processing
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1
University Medical Center Hamburg-Eppendorf, Germany
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2
Institute of Cognitive Neuroscience, University College London, United Kingdom
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3
Wellcome Trust Centre for Neuroimaging at UCL, United Kingdom
We used fMRI in combination with either dopaminergic or cholinergic neuropharmacology to investigate the role of both neurotransmitters in novelty encoding. As a main finding, we can show that, in contrast to placebo, both levodopa (dopamine precursor) and galantamine (acetylcholinesterase inhibitor) differentially modulate neural novelty signals in the mesolimbic system (including substantia nigra / ventral tegmental area [SN/VTA] and medial temporal lobe regions). Levodopa enhanced hippocampal responses to visually presented images independently of their novelty status and, possibly via feedback mechanisms, it attenuated novelty signals within the SN/VTA. Galantamine, on the other hand, reversed novelty signals (i.e. lead to repetition enhancement) within the medial temporal lobe and dopaminergic SN/VTA. Therefore, our results show that dopamine and acetylcholine play differential roles in mesolimbic novelty processing and they suggest that acetylcholine may lead to enhanced dopamine release as a function of stimulus repetition. As such, our results have significant implications for our understanding of the pharmacodynamics of both drugs which might help to develop new strategies for their clinical application.
Keywords:
Dopamine,
Memory
Conference:
XI International Conference on Cognitive Neuroscience (ICON XI), Palma, Mallorca, Spain, 25 Sep - 29 Sep, 2011.
Presentation Type:
Poster Presentation
Topic:
Poster Sessions: Neural Bases of Memory and Learning
Citation:
Bunzeck
N,
Guitart-Masip
M,
Dolan
RJ and
Duzel
E
(2011). Differential roles of dopamine and acetylcholine in mesolimbic novelty processing.
Conference Abstract:
XI International Conference on Cognitive Neuroscience (ICON XI).
doi: 10.3389/conf.fnhum.2011.207.00422
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Received:
24 Nov 2011;
Published Online:
28 Nov 2011.
*
Correspondence:
Dr. Nico Bunzeck, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, nico.bunzeck@gmail.com