- Title
- Anatomical and physiological characterisation of central vestibular neuronal populations
- Creator
- Wellings, Thomas Peter
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2018
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Balance is a multimodal sense requiring integration of vestibular, visual, and proprioceptive signals to allow constant awareness of head and body position in space. The vestibular system is of particular importance to our sense of balance, with fast reflexes controlling eyes, neck, and body to stabilize vision and posture during locomotion. The vestibular nuclei receive constant inputs from the vestibular periphery, but are also widely interconnected with visual, proprioceptive, autonomic, and cerebellar networks. Importantly, the vestibular nuclei provide more than a simple signal relay role in balance. Rather, the vestibular nuclei are an important site for neuroplasticity, modulating these varied signals to ensure smooth movement through space. While the relay roles of the vestibular nuclei are well known, how vestibular signals are modulated within the brain is less well understood. A barrier to understanding how signals are modulated has to do with the organization of the vestibular nuclei. The nuclei have overlapping borders and with heterogeneous cellular morphology, there is little to distinguish subpopulations of neurons. I have used a combination of anatomical and physiological techniques to better characterize three groups of neurons within the vestibular nuclei. First, I characterized neurons in the parvocellular medial vestibular nucleus (MVNp) expressing the calcium-binding protein calretinin (CR). These neurons have a lower excitability than surrounding MVN neurons, with a predominantly excitatory neurotransmitter phenotype. A large proportion of these neurons is likely to represent vestibulo-sympathetic projection neurons. I also characterized an additional group of neurons in the rostral MVN that express another calcium binding protein, parvalbumin (PV). These small neurons have faster kinetics than surrounding neurons, and may represent commissural inhibitory neurons, potentially important for vestibular velocity storage. Finally, I investigated giant Deiters’ neurons of the lateral vestibular nucleus, critical for fast vestibulospinal reflexes to the trunk and limbs. These neurons have distinct electrophysiological characteristics. In particular, the response to inhibition, compared to MVN neurons was less excitable and required larger inputs, suggesting the physiology of neurons in vestibulospinal pathways is distinct from those in the vestibulo-ocular pathways. Using anatomical techniques developed during this work, I showed that these postural neurons are involved in neurodegeneration in Parkinson’s disease in human brain tissue.
- Subject
- vestibular; physiology; anatomy; thesis by publication
- Identifier
- http://hdl.handle.net/1959.13/1384927
- Identifier
- uon:32141
- Rights
- Copyright 2018 Thomas Peter Wellings
- Language
- eng
- Full Text
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| View Details Download | ATTACHMENT01 | Thesis | 8 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 110 KB | Adobe Acrobat PDF | View Details Download |