Author's previously published articles appended. / Bibliography: leaves 292-341. / xviii, 388 leaves ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Psychology, 2005

published_or_final_version / Anatomy / Master / Master of Philosophy

abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

As compared with other imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI) provides distinctive advantages with better contrast and resolution in imaging brain anatomy and function in vivo. As compared with electrophysiological and histological tracing techniques, MRI enables longitudinal investigation with higher efficiency, lower labor cost and less possibility of sampling error. The major objective of this doctoral work is to utilize cellular and molecular MRI to investigate normal brain functions and injuries in vivo. The results successfully demonstrated MRI as an efficient and sensitive tool for providing comprehensive assessment of brain injuries for promoting accurate prognosis and timely intervention, and for studying fundamental questions with regard to cortical adaptations to challenges in the young adulthood. Firstly, diffusion tensor imaging (DTI) and T2-weighted imaging were employed to characterize longitudinal neuronal and axonal changes of pyramidal tract (PY), a critical part of corticospinal tract, following experimental intracerebral hemorrhage (ICH). Combining DTI with T2-weighted imaging results, ipsilateral PY injuries following ICH were diagnosed as four stages. Quantitative analysis revealed transient diffusivity decreases in PY both contralateral and ipsilateral to the primary hemorrhagic site. Evolution of the ipsilateral DTI parameters correlated with histological findings and indicated evolving and complex pathological processes underlying monotonic FA decrease. These results demonstrated multi-parametric DTI as a valuable imaging tool for non-invasive and longitudinal monitoring of secondary PY injuries. Secondly, DTI and manganese-enhanced MRI (MEMRI) were utilized to detect neuronal changes of substantia nigra (SN) following experimental ICH in rodents. DTI revealed early changes in SN both contralateral and ipsilateral to the primary hemorrhagic site. Evolution of the ipsilateral parameters correlated with the histological results. MEMRI provided insights into the cellular phenotype changes at the late stage. DTI can serve as a valuable imaging tool for non-invasive early detection and longitudinal monitoring of secondary SN injuries, while MEMRI could complementally provide information regarding the late stage inflammation process. Multi-parametric MRI could facilitate clinical and preclinical investigations of SN injuries for exploring disease mechanisms and developing new therapeutic strategies. Thirdly, MEMRI was performed to characterize the interhemispheric interactions in normal and monocularly deprived rodent visual brain. Characteristic transcallosal manganese labeling was observed in the normal group in a manner consistent with previous histological findings. Significant decrease of such labeling was observed in rats with left or right eyelid suturing, or with left eye enucleation, but not in rats with right eye enucleation. These results demonstrated MEMRI as an efficient tool for investigating interhemispheric interactions both anatomically and functionally. These results also indicated that the adult brain recruits different mechanisms for its adaptations to eyelid suturing and enucleation, thus shedding light on our understanding of the transcallosal interhemispheric excitation and inhibition. Lastly, new paradigms other than pressure injection for intracortical manganese administration in MEMRI were introduced to minimize the neuro-toxicity of manganese and maximize the sensitivity of MEMRI for studying cortical functional changes. Transmeningeal diffusion, osmotic pump-based infusion, and intranasal instillation were demonstrated to be successful in tracing interhemispheric connections and detecting stress-related cortical and subcortical changes. / published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / toc / Paediatrics / Master / Master of Philosophy

No description available.

A differential diagnosis between head injury and depression is critical to ensure proper treatment and appropriate interventions. Knowledge about this can only aid counseling psychologists' work with this population and, identifying a measure that can assist in this process is essential. The purpose of this study is to measure the utility of the Dean — Woodcock Neuropsychological Assessment System (D-WNAS) in distinguishing individuals with head injury from those who have a primary diagnosis of depression, and general neurological impairment. Participants included 433 adults (222 males, 211 females) between the ages 20-55 years of age (mean = 35.3 years, SD = 10.97 years) from the Midwestern United States. During the individual's treatment in the neuropsychological laboratory, each person was administered the following: the Dean-Woodcock Structured Interview (Dean & Woodcock, 1999), mental status exam, the Woodcock Johnson — Revised Tests of Cognitive Ability (WJ-R COG; Woodcock & Johnson, 1989b), the Woodcock Johnson — Revised Tests of Achievement (WJ-R ACH; Woodcock & Johnson, 1989a), and the Dean-Woodcock Sensory Motor Battery (DWSMB; Dean & Woodcock, 1999). This study indicates that responses to D-WNAS can be used to reliably classify adults into groups of depression, head injury, and general neuropsychological impairment. In particular, responses to the D-WSMB portion of the D-WNAS can be used to reliably classify adults into groups of depression, head injury, and general neuropsychological impairment. Classification results revealed that the original grouped cases were classified with 62.6 % (p < .001) accuracy and with 73.2% overall accuracy when the head injury and general neurological impairment groups were combined and compared to depression and normative groups. The WJ-R COG and WJ-R ACH were not as reliable as the D-WSMB at predicting group membership. / Department of Counseling Psychology and Guidance Services

The main purpose of the present study was to identify sensory-motor deficits caused by closed head injury (CHI) when individuals with CHI are compared to a normal sample. The study also investigated lower-level sensory-motor functioning, such as gait, balance, and coordination and its relation to neurological impairment related to CHI. Additionally, the study determined if age significantly influenced sensory-motor functioning.Archival data was utilized to complete the study. Data was collected from a large, Midwestern neurology clinic (CHI) as well as from a normative sample of individuals with no reported history of neurological impairment. Preliminary analyses were completed to identify outliers. Samples were then randomly selected from the impaired group (CHI) and matched with randomly selected subjects from the normative sample based upon age.Three separate analyses were completed. The first analysis focused on age and if age significantly influences sensory motor functioning. The second analysis was completed using an adult's only sample based upon the results that age significantly influenced sensory-motor performance. Finally, the third analysis utilized all age groups to determine how dramatically age had an impact on distinguishing between individuals with CHI versus a normative sample.Results demonstrated that age had a significant influence on sensory-motor performance. Measures of subcortical and cortical motor function, motor speed, motor coordination and tactile examination were able to accurately classify individuals with head injury from a normative sample to a clinically significant degree (78%). The study argues that the D-WSMB is a reliable and valid measure to utilize when evaluating individuals with CHI. / Department of Educational Psychology

Clinical neuropsychologists who assess patients following mild closed head injury (CHI) are often asked to offer an opinion whether there is evidence of malingering. Factors that impact the ability of a person to intentionally portray impairment are quite important since mis-diagnosis of malingering can result in delayed treatment. In this study knowledge of the sequelae of mild CHI was provided to normal college students in an effort to change reporting of symptoms and influence the type of malingering strategy used when completing the Neuropsychological Symptom Inventory (NSI). Subjects were randomly assigned to either a prior knowledge malingering group (PK;N=57), no prior knowledge malingering group (NPK;N=58), or control group (CON;N=61). The results showed that PK subjects endorsed more general and attention/concentration symptoms than NPK or CON subjects. The results also showed PK subjects were as likely to be detected by the NSI lie scale as NPK subjects. Thus, the NSI lie scale demonstrated sensitivity to malingering despite subjects having brief instruction about mild CHI. Also, having prior knowledge did not result in significantly different strategies when completing the NSI. Instead, both malingering groups reportedly used exaggeration and attempted to be consistent as frequent strategies. / Department of Educational Psychology

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / Department of Educational Psychology