M.A. (Psychology) / Please refer to full text to view abstract

D.Litt. et Phil. (Psychology) / The aim of this study was to investigate the effect that hypertension has on brain function. A neuropsychological test battery comprising of the following tests was employed as a multivariate measure of brain dysfunction in a quasiexperimental, matched group design: a) The Complex Figure Test of Rey (copy, immediate recall and delayed recall), b) the Logical Memory Test, c) the Digits Span Test, d) the Verbal Paired Associate Learning Subtest, e) the Controlled Oral Word Generation Test, fr the Trail Making Test, and the Digit Symbol Substitution Subtest, This permitted a comparison in brain functioning between a group of hypertensive and a group of normotensive participants that were matched according to age, handedness, level of education and sex. The matching of variables increased the sensitivity of the study by controlling extraneous variables and ensured that the groups were compatible on the paired variables. The results were statistically analyzed by employing the Mann-Whitney U statistic for small groups and the Chi-square statistic on the measured variables. Further, content analysis was employed to test for significant differences in strategies of coping, immediate recall and delayed recall of the Complex Figure of Rey. The results indicated that: 1. there were significant differences in attention and concentration, motor functioning, perceptual abilities, information processing, memory, and planning and organisation between the two groups, with the hypertensive group obtaininq significantly lower scores on test measuring these variables; and 2. there were no significant differences in the verbal abilities (word fluency) of the two groups. The results support previous research, finding indications of vocal lesions located across the brains of people suffering from hypertension. Practical implications of the results are discussed and recommendations for future research have been made...

The interactions between soil physical properties, particularly soil structure and bulk density, and the rooting of four herbaceous crops grown for biomass on three common Piedmont soil series were examined. The effect of these crops on soil properties over time was also studied. The rooting of the biomass crops studied seemed to be affected by soil physical factors on two of the three soils. Even though bulk density on all three soils (Appling, Cecil, and Davidson) appeared high enough to drastically limit rooting, such limitations were found only at the Appling sites and, to a much lesser extent, at the Cecil sites. Well-developed soil structure seemed to be instrumental in the success of the biomass crops on these dense Piedmont soils. All of the species studied had vigorous root systems in well-structured, high-density soils. Weeping lovegrass (<i>Erogrostis cuxvula</i>) was particularly insensitive to high bulk densities. The root systems of switchgrass (<i>Panicum virgatum</i>), birdsfoot trefoil (<i>Lotus corniculatus</i>), and sericea lespedeza (<i>Lespedeza cuneata</i>) were all heavily influenced by the high densities of the nearly structureless Appling soils; but lovegrass roots were quite prolific there. For this reason lovegrass should be considered first for biomass production on similar marginal soils. All soils had higher organic matter contents after four years of biomass production. Soil nutrient concentrations, particularly soil K, were also higher, especially under switchgrass. Soil Ca and Mg contents were higher under the two legumes than under the two grasses. / Master of Science

The purpose of this thesis was to investigate the influence of postural anxiety on the capacity for Flexible Resource Allocation (FRA) among younger (YA) and older adults (OA). Two experiments were conducted to explore (a) the influence of heightened postural anxiety on the flexible allocation of attention among OA and (b) the influence of concurrent postural challenge and postural anxiety on FRA among YA. Participants performed a postural task concurrently to a cognitive task according to three instructional sets directing task priority. Experiment one revealed that FRA was compromised among OA during circumstances of heightened anxiety. This capacity however, remained available among YA. Therefore, for the second experiment I varied the support surface to explore whether the capacity for FRA could be sustained when posture was challenged beyond static stance. Results indicated that YA altered cognitive task performance according to instructional set without compromising postural stability. These findings suggest that even when posture is challenged during heightened postural anxiety, YA maintain the capacity to automatically allocate attention to a postural task while performing a secondary task. Conversely, it seems that heightened postural anxiety strengthens the attentional bias to posture and subsequently compromises FRA among OA. Overall, results from this thesis suggest that the capacity for FRA is age and situation dependent. / xi, 107 leaves : ill. ; 29 cm

Previous findings showed that mild chronic restraint stress causes motor impairments in rats. These behavioural impairments might be related to molecular changes in brain areas that regulate motor functions, such as the cerebellum. Little is known about the role of the cerebellum in stress-induced behavioural alteration. We hypothesized that alteration in animal behaviour after chronic restraint stress is due to brain-specific changes in miRNA and proteins encoding gene expression. Our results revealed that expression of three miRNAs and 39 mRNAs was changed significantly after two weeks of stress. Furthermore, we verified one putative target for one of the changed miRNAs and expression of four randomly selected genes. Changes in gene expression disappeared after two weeks of recovery from stress. These findings provide a novel insight into stress-related mechanisms of gene expression underlying altered behavioural performance. The observations bear implications for the prevention and treatment of stress-related disorders and disease. / xii, 109 leaves. : ill. ; 29 cm

The thesis examines the ability of animals to construct a home base. The home base is a point in space where animals rear, groom, and circle and is a primary element in organized spatial behaviour (Eilam and Golani 1989). Once animals establish a home base, they make outward trips and stops, and after a series of trips and stops they return again to the home base. The home base behaviour of animals acts as a platform for asking questions about the cognitive organization of an environment. The thesis describes five main findings. Control and hippocampectomized animals use (1) proximal and (2) distal cues to form a home base and organize their behaviour. (3) Control and olfactory bulbectomized animals form home bases in the dark where as hippocampectomized animals are impaired suggesting self-movement but not olfactory cues play a role in home base behaviour. A final set of experiments demonstrated that control and hippocampectomized animals learn the position of (4) proximal and (5) distal cues so that in the cue's absence, animals still form a home base at that position. The demonstration that a central feature of exploratory behaviour, establishing a home base, is preserved in hippocampectomized rats in relation to proximal, distal, and conditioned visual cues - reveals that exploratory behaviour remains organized after hippocampal lesions. The inability of hippocampectomized rats to form a virtual home base in the absence of visual cues is discussed in relation to the idea that the hippocampus contributes to inertial behaviour that may be dependent upon self-movement cues. / xv, 232 leaves : ill. ; 29 cm.

The effect of anxiety on motor learning during a balance relevant task was investigated. Twenty participants (mean age 22.0 ± 2.7 years) were randomly divided into groups that completed the task whilst standing directly on the platform or on 9cm high pedestals, thus constructing Non-Anxious (NA) or Anxious (A) environments. Participants trained for 36 trials in a continuous, pseudo-random oscillating balance task consisting of pseudo-random amplitude translation at 0.5Hz for 45 seconds each on Day 1 and returned for Retention and Transfer tests on Day 2. Motor performance was impaired by training in an anxious environment and this effect persisted across retesting in both non-anxious and anxious environments. Anxiety also tended to further impair transfer of motor performance improvements to a non-anxious environment. These findings have implications for the success of balance training programs in patients who are anxious or afraid of falling. / ix, 103 leaves : ill. ; 29 cm

Stress has been shown to exacerbate cell death and cognitive deficits after ischemic injury in rodents, however, little is known of the effects of stress on motor recovery. The objective of this present thesis is to examine the effects of chronic stress on skilled motor recovery after devascularization lesion in rats. It was found that pre-lesion stress induced the most behavioural impairments, while post-lesion stress exacerbated infarct volume. The effects of chronic multiple stress on skilled motor recovery after lesion was also examined. Chronic multiple stress did not modulate skilled motor recovery nor did it have any influence on infarct volume. Additionally, stress had effect on edema after devascularization lesion. The present thesis suggests that the time of exposure to chronic stress in respect to the ischemic lesion, in addition to the type of stress, will differentially affect recovery and compensation in rats. / xii, 122 leaves : ill. ; 29 cm.

M.A. / Die doel van hierdie studie was tweeledig van aard. Die eerste doelstelling was om 'n behoeftebepaling te doen ten einde vas te stel wat die pasiente se algemene behoeftes is ten opsigte van narkose. Die tweede doelstelling was om 'n streshanteringsprogram te ontwikkel, toe te pas op toepaslike proefpersone, en te evalueer aan die hand van vier afhanklike veranderlikes, naamlik angsvlak, pynvlak, irrasionele kognisies en lokus van kontrole. Hierdie streshanteringsprogram is ontwikkel om prakties uitvoerbaar en pasi ntvriendelik gerig te wees sodat die effektiwiteit. vir toekomstige volgehoue gebruik getoets kon word.

The purpose of this project is to review literature on creatine monohydrate (simply known as creatine/Cr) supplementation and its effects on exercise, human performance, and health. Included in this project is basic information relating to the biochemical and physiological effects of Cr, including possible side effects.