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dc.contributor.advisorBilkey, David
dc.contributor.authorElston, Thomas Ward
dc.date.available2018-03-20T03:03:08Z
dc.date.copyright2018
dc.identifier.citationElston, T. W. (2018). Adaptive motivational signals in the anterior cingulate cortex and ventral tegmental area (Thesis, Doctor of Philosophy). University of Otago. Retrieved from http://hdl.handle.net/10523/7934en
dc.identifier.urihttp://hdl.handle.net/10523/7934
dc.description.abstractThis thesis focused on the role of the anterior cingulate cortex’s (ACC) interactions with the dopaminergic neurons in the ventral tegmental area (VTA) during adaptive behaviour. The overall question guiding this work was: how does information gained during goal pursuit modify and motivate subsequent behaviour? This larger question was operationalized as two projects: (i) to determine whether cortical influence over the dopaminergic midbrain is a mechanism by which ACC signals are implemented as VTA motivation signals; and (ii) to determine the interplay between the ACC and VTA during the initiation and maintenance of behavioural change. In the first project, we monitored and modelled ACC and VTA local field potentials of rats running laps of varying physical difficulty for fixed rewards. The effortful condition required rats to climb over a 30-cm barrier, whereas no barrier was present under the non-effortful condition. The key finding was that ACCVTA 4-12 Hz signalling increased in trials when the lap was easier than expected. Importantly, this increase was significantly correlated with, but not confounded by, changes in motivation, as measured by running speed. The findings of this first project indicated that the ACC-VTA circuit is a plausible mechanism by which behaviour is modified. This led us to ask whether changes in the ACC-VTA circuit are related to the initiation and persistence of behavioural change. To assess the interplay between the ACC and VTA during the initiation and persistence of behavioural change, we monitored ACC single units and LFPs as well as LFPs in VTA of rats performing a cost-benefit foraging task with changing contingencies. Through a combination of behavioural, electrophysiological, and modelling analyses, we found that the initiation of exploratory behaviour and the persistence of behavioural change were associated with ACC  VTA signalling. Additionally, we characterized the content of ACC neuronal task models, and showed that ensembles of ACC neurons encode simple actions and values. This was important because, despite the longstanding assumption that the ACC encodes neuronal models of the task at hand, the content of those internal representations remained unclear. Furthermore, we demonstrated that value-coding elements of ACC neuronal task models are particularly influenced by the VTA. This is important because it suggests that mesocortical dopaminergic signalling is a means by which ACC models of the task at hand could be both initiated and modified. The thesis concludes by presenting a novel incentive-salience, task-model onset theory of ACC function.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectneuroscience
dc.subjectelectrophysiology
dc.subjectmotivation
dc.subjectadaptation
dc.subjectanterior cingulate
dc.subjectventral tegmental area
dc.titleAdaptive motivational signals in the anterior cingulate cortex and ventral tegmental area
dc.typeThesis
dc.date.updated2018-03-20T01:37:11Z
dc.language.rfc3066en
thesis.degree.disciplinePsychology; Brain Health Research Centre
thesis.degree.nameDoctor of Philosophy
thesis.degree.grantorUniversity of Otago
thesis.degree.levelDoctoral
otago.openaccessOpen
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