Wegener, Meredyth
(2017)
Impact of Learning and Diet on Two Distinct Populations of Midbrain Dopamine Neurons.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Dopamine is a crucial component of the neural mechanisms underlying motivation and reward learning, both of which are disrupted in psychiatric disorders. Much of the research in this field has focused on the role of ventral tegmental area (VTA) and its influence on the nucleus accumbens, but there is also evidence that the substantia nigra pars compacta (SNc), a separate dopaminergic region with its own efferent and afferent projections, contributes to guiding motivated behavior. Environmental insults, such as insufficient dietary nutrition, are thought to negatively impact the dopamine system and possibly promote the development of mental illness. These issues have not yet been investigated in the context of dopamine neuronal function during reward-mediated behavior. This dissertation sought to address this gap in our knowledge through two primary objectives. Using electrophysiology in awake-behaving animals, the first aim was to simultaneously record neuronal activity in the VTA and SNc during two reward-related associative learning paradigms to understand the role each region plays in motivated behavior. The second aim was to evaluate the impact of dietary deficiency on dopamine neuronal function and identify any region-specific effects in the VTA and SNc.
In our comparison of VTA and SNc, we employed an instrumental conditioning task, in which the animal executed a nose poke to earn a sugar pellet reward, and a Pavlovian conditioning task, which pairs a previously meaningless cue with a sugar pellet reward. We found that VTA and SNc may play similar roles in both forms of reward learning, possibly driven by common excitatory inputs between the two regions. We then measured correlations in activity of simultaneously recorded neurons within each region and found that how these correlations fluctuate in response to associative learning differed between regions. In our dietary manipulation experiment, we observed that event-evoked neuronal activity was reduced in animals lacking essential fatty acids, and this reduction is more pronounced in the SNc. Our findings suggest that the SNc may be more vulnerable to environmental insult and its role in reward learning and dysfunction in psychiatric disorders warrant further investigation.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
| Title | Member | Email Address | Pitt Username | ORCID |
|---|
| Committee Chair | Grace, Anthony | graceaa@pitt.edu | | | | Committee Member | Turner, Robert | | | | | Committee Member | Torregrossa, Mary | | | | | Committee Member | Cohen, Marlene | | | | | Committee Member | Napier, T Celeste | | | | | Committee Member | Moghaddam, Bita | | | |
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| Date: |
28 September 2017 |
| Date Type: |
Publication |
| Defense Date: |
25 July 2017 |
| Approval Date: |
28 September 2017 |
| Submission Date: |
11 August 2017 |
| Access Restriction: |
5 year -- Restrict access to University of Pittsburgh for a period of 5 years. |
| Number of Pages: |
153 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Neuroscience |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
electrophysiology n-3 PUFA Pavlovian Instrumental |
| Date Deposited: |
29 Sep 2017 01:14 |
| Last Modified: |
28 Sep 2022 05:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/33081 |
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