Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.

Thesis (Ph. D.)--University of Oregon, 2004. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 432-460). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 114-121).

Thesis (Ph. D.)--Rutgers University, 2008. / "Graduate Program in Biomedical Engineering." Includes bibliographical references (p. 139-144).

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2009. / Title from first page of PDF file (viewed August 11, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 36-39).

Thesis (Ph.D.)--Murdoch University, 2009. / Thesis submitted to the Faculty of Health Sciences. Includes bibliographical references (leaves 220-238)

Elevated levels of pro-inflammatory cytokines are implicated in the pathogenesis of major depression. Human and animal studies have shown that pro-inflammatory cytokines can induce a behavioural repertoire of symptoms collectively referred to as 'sickness behaviours', which include cognitive and mood symptoms, social withdrawal and sleep disturbance. When likened to clinical depression, these symptoms appear to be strikingly similar. Moreover, subsets of depressed patients have raised inflammatory markers, 30-50% of patients receiving cytokine treatment in the form of interferon-α (IFN-α) therapy develop depressive symptoms, and significantly higher rates of depression are associated with chronic inflammatory conditions, such as rheumatoid arthritis (RA). Converging evidence has led to the hypothesis that chronic, low-grade inflammation could lead to more persistent alterations in neuropsychological function that might be instrumental in the pathophysiology of depression. However, the mechanisms for this potential modulation of mood and cognitive function are unclear. The current thesis therefore aimed to enhance understanding of the neuropsychological underpinnings of the link between inflammation and depression. Negative emotional processing biases are well-recognised in the aetiology of depression; however potential inflammation-induced alterations in emotional processing remain unexplored. Thus, a series of studies were conducted using human models of immune system activation to examine neuropsychological function. The first study demonstrated that IFN-α treatment in patients with hepatitis C produced negative biases in emotional categorisation, attentional vigilance and a specific effect of enhanced recognition of disgust. The subsequent study found a specific effect of false discrimination of disgusted faces in a healthy volunteer model of inflammatory challenge with typhoid vaccination, however further effects on emotional processing were limited. Typhoid vaccination was also shown to disrupt sleep continuity in ways that may be relevant to depression in the third study. Negative biases were not evident, however, in patients with RA. The final study found that neuropsychological effects of the atypical antidepressant tianeptine were similar to effects following IFN-α, which may be of interest considering tianeptine's purported serotonergic re-uptake enhancing properties and the effects of cytokines on serotonin metabolism. This thesis provides intriguing, yet preliminary, evidence that inflammatory pathways may modulate emotional processing - a mechanism which, if supported, may have future implications for improved identification and treatment of subgroups of depressed patients.

Event related potentials (ERPs) are obtained from noninvasive electroencephalograms (EEG) which measure neuronal activity of brain on the scalp. However, conventional ERPs derived by averaging of single EEG trials have strong latency variability and are smeared, resulting in blurred scalp topography, especially in late components of ERP. The smearing problem had been addressed by reconstructing ERPs after latency correction with a new EEG analysis method Residue Iteration Decompo¬sition (RIDE), which was demonstrated in a face priming paradigm to improve distinctness in scalp topography (Ouyang et al., 2011). This thesis aims to (1) extend the benefits of RIDE to neural source space by localizing the neural generators of ERPs, thereby developing an integrated RIDE framework for improvement in source localization and causal modeling of effective source networks, and (2) apply the framework to the face priming paradigm for famous faces, to explore the dynamics of face processing and priming. We localized sources through brain electrical source analysis for both conventional ERP and RIDE derived ERPs (RERPs). RERPs allowed localization of an additional motor execution source (Premotor Cortex, PMC), apart from 5 other common sources, of which 2 (Occipital Lobe, OL; Fusiform Gyrus, FG) were obtained from early activity (< 250 ms) and 3 (Mediotemporal lobe, MTL; Prefrontal Cortex, PFC; Anterior Temporal Lobe, ATL) from late activities (> 250 ms) of RERPs respectively. Priming effects, i.e., the difference between primed famous (PF) and unprimed famous (UF) face conditions in source waveforms (SWFs), were extended and enhanced in RERPs, especially for late sources. The priming effects revealed (1) the role of sources in each hemisphere that play in perception, memory and execution, (2) parallel processing of information in sources, (3) early processing in the right hemisphere, and (4) predominance of the right hemisphere in face recognition. Results confirmed SWFs of RERPs as better choice for the dynamic causal model (DCM). Two candidate DCM models, forward (F) and forward-backward (FB) were outlined on each hemisphere with SWFs from PF and UF conditions of RERP data. Priming has tendency to facilitate the FB model in the left hemisphere. On the other hand, independent of model preference, priming strengthened a bidirectional connection between FG and PFC in both hemispheres; this indicates a strong role of FG in structural representation and of PFCs in controlling decisions about face familiarity. Priming modulates the pathway FGMTLPFC differently in the two hemispheres, strengthening the involvement of MTL in the left hemisphere and weakening in the right hemisphere. This indicates proficiency of the left and right MTL in processing different aspects of facial information. Further, a backward connection ATLPFC in the left hemisphere was found to be functionally relevant for both conditions in speeding up response time in individual subjects, reinforcing the role of PFC in executive functioning and ATL in naming of famous faces. Thus, an integrated framework of source localization and DCM with RERPs allows a novel, comprehensive understanding of time resolved dynamics in face recognition and priming, thereby piloting prospects of its application to other experimental paradigms.

The development of fluent reading requires coordinated development of key fiber pathways. While several fiber pathways have been implicated in reading, including the recently re-identified vertical occipital fasciculus (VOF), inferior longitudinal fasciculus (ILF), arcuate fasciculus and its 3 components, and inferior fronto-occipital fasciculus (IFOF), whether these fiber pathways support reading in young children with little to no exposure to print remains poorly understood. Consequently, over the course of three studies, the current dissertation aimed to narrow this research gap by addressing the following research questions: 1) Which fiber pathways support early literacy skill in young children 5-10 years old? 2) Are microstructural properties of these tracts predictive of age-related changes in reading across an interval of two years? 3) Do different components of the recently identified VOF differentially support reading? To answer these questions, we used diffusion-weighted imaging to measure white-matter development and to relate the microstructural properties of each fiber pathway to early literacy and literacy development. We report several novel findings that contribute to our growing understanding of the white matter connections supporting early literacy and literacy. For the first time, these studies revealed that the re-identified VOF can be reliably tracked in young children, bilaterally and is composed of three main components, which project from occipital temporal sulcus to angular, and middle and superior occipital gyri. We also found that the left AF, bilateral ILF, and particular components of the VOF play a role in early literacy and literacy development. Implications for contemporary models of reading development are discussed.

Healthy aging is associated with a reduction in slow-wave sleep (SWS), crucial for declarative memory consolidation in young adults; consequently, previously observed benefits of sleep on declarative learning in older adults could reflect a passive role of sleep in protecting memories from waking interference, rather than an active, stabilizing effect. To dissociate the passive and active roles of sleep, a visuo-spatial task was administered; memory was probed after a 12 hr interval consisting of either daytime wake or overnight sleep and post-wake/post-sleep stability of the memories was tested following task-related interference. Ninety five older adults (mean=65.43 yrs; SD=7.6 yrs) and 137 young adults (mean= 21.22yrs; SD=2.62 yrs) were tested across either an “Interference” or a “No Interference” condition (without exposure to the interference). In both young and older adults, sleep significantly benefitted performance compared to wake, such that the memories were more resistant to subsequent interference. For young adults, post-sleep performance was correlated with time spent in SWS and delta power density during SWS early in the night. Additionally, the interaction between NREM and REM early in the night played an important role in stabilizing the memories. There were no significant correlations between sleep parameters and over-sleep performance changes in older adults; however, high performing older adults benefitted from greater amounts of REM sleep early in the night, and from the interaction between NREM and REM during this time period. These results suggest that the active role of sleep in declarative memory consolidation persists in an aging population.