Electronic Theses and Dissertations

Date

2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Psychology

Committee Chair

Helen Sable

Committee Member

Deranda Lester

Committee Member

David Freeman

Committee Member

Frank Andrasik

Abstract

Elucidating how dopamine neurons operate regularly in aspects of neurochemical release and in pathological systems is essential for understanding their role in behavior, drug treatment, and disease. Fixed-potential amperometry (FPA) combined with carbon fiber microelectrodes has proven to be effective at probing these dynamic microsystems and precisely describing the regulatory mechanisms that govern dopamine neurotransmission. To date, we have utilized FPA to: a) observe and quantify differences in the neurochemical profile of phasic dopamine release in major dopaminergic afferents including the striatum, nucleus accumbens (NAc), amygdala, and prefrontal cortex through stimulation of the medial forebrain bundle (MFB), b) provide evidence that differing behavioral processes in the brain emerge from spatial and temporal variations in the phasic response, and c) identify a pathway originating in the cerebellar dentate that projects to nigrostriatal and mesolimbic systems, solidifying the role of the cerebellum in higher cognitive functions and neuropathology related to dopamine dysfunction. These findings provide evidence that the cerebellum regulates dopamine release in the cerebrum, and previous literature has shown that dopaminergic systems in the bilateral cerebral hemispheres contribute asymmetrically to behavior, structure, and function. To determine whether asymmetrical lateralization in the dopaminergic system occurs at the level of the cerebellum, cerebrum, or both, FPA was used to examine asymmetry of dopamine release in the dentate nucleus (DN)-NAc and MFB-NAc pathways. We found significant differences in the amplitude of phasic dopamine release in the DN-NAc systems, but not the MFB-NAc pathways. Results from this study support the notion that reward processes in the brain may be lateralized between cerebrocerebellar networks, with greater phasic release occurring in projections from the left cerebellar DN to the right NAc. These studies may provide more detailed information about the relationship between the cerebrocerebellar networks and lateralization of the dopaminergic system as well as potentially reveal novel targets for pharmacological interventions in neuropathology of the cerebellum.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to ProQuest

Notes

Open Access

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