The locus coeruleus (LC) is a nucleus within the brainstem associated with physiological arousal and attention performance, with altered structure and function previously identified in neurodegenerative disorders. Pathologies related to difficulties with attention have previously been understood within a cortical triple network model, abnormalities in which may be relate to dysfunction in either LC structure or function. To examine the possibility of LC alteration being associated with inattentive symptom report, a set of analyses have been performed. In the first analysis, LC neuromelanin contrast was regressed onto ADHD symptom report for 141 individuals across the lifespan, finding a significant negative relationship between neuromelanin in the right hemisphere of the LC and inattentive symptom report. A second analysis tested for possible mediation of the neuromelanin contrasts with structural volumes of regions associated with the salience network, which has also been previously associated with attention deficits and ADHD symptoms. These findings support the relationship between LC and attention-related behavior through both neuromelanin-sensitive and structural imaging, and observes multiple significant structural associations for cortical regions previously associated to inattention functionally. / Master of Science / Within the brainstem is a collection of neurons called the Locus Coeruleus (LC), associated with the production of neurotransmitters associated with attention. In Magnetic Resonance Imaging (MRI) networks of brain regions associated with attention have been previously observed, with both differences in region connections and abnormalities in region composition being observed. Given the small size of the LC general volume measurement is considered difficult, but use of multi-atlas techniques and neuromelanin contrasts allow for methods of LC structure and integrity to be compared. The present study attempts to integrate the LC into this larger concept of attention processing, called the triple network model, by testing associations between structural measures of the LC, regions associated with the three triple network model networks, and attention report in 140 participants. LC contrasts were found to be significantly associated with inattention, as were structural values for the regions connected to the previously identified networks. Mediation of neuromelanin by these regions failed to produce significant results, but neuromelanin was mediated by the volume of the LC itself. The findings here support continued use of these structural techniques with regard to the LC and other applicable neural structures, as well as further work to define the relationship between the LC and the triple network model.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/119045 |
| Date | 01 1900 |
| Creators | Neal, Joshua |
| Contributors | Psychology, Lee, Tae-Ho, Breaux, Rosanna, Richey, John A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | ETD, application/pdf, application/pdf |
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