This thesis investigates the behavioural and anatomical correlates of recovery from motor cortex damage in rats. The effectiveness of behavioural, pharmacological, and regenerative treatments was investigated using models of focal stroke. Chronic bilateral motor deficits were found after motor cortex damage induced by various methods. These behavioural deficits were similar in severity and duration although they were correlated with different patterns of reorganization seen in Golgi-stained tissue. Animals with motor cortex injury benefited from postinjury olfactory stimulation, chronic administration of nicotine, and infusions of epidermal growth factor followed by erythroprotein. Different mechanisms of plasticity in remaining cortical circuits are discussed as possible candidates responsible for the behavioural improvement. The current thesis expands the current knowledge of the effects of adult cortical damage to ares critical to motor control. It may also stimulate research on therapies and possible mechanisms that might enhance recovery after stroke. / xviii, 299 leaves : ill. (some col.) ; 29 cm.

Diseases of the central and peripheral nervous systems affect one in five people in North America. Parkinson’s disease (PD) is the second most common neurodegenerative disease, after Alzheimer’s disease, and occurs in approximately 1% of the general North American population. PD is a progressive movement disorder that is characterized by resting tremor, rigidity, bradykinesia (slowness of movement) or akinesia (absence of spontaneous movement), as well as postural instability. Current treatment of PD is symptom-based, and no pharmacological treatment currently exists to slow the progression of bradykinesia and akinesia. In fact, pharmacological therapies produce motor side effects in advanced stages of the disease. Given the difficulty in initiating and controlling movement as PD advances, and the ineffectiveness of medical therapies after prolonged treatment, physical and music therapies can be used to supplement classical therapies. Listening to, and performing, music affects a number of neural regions, including those that mediate motor behaviour, arousal or activation, and emotion. Despite anatomical connections between the auditory and motor systems at the level of the spinal cord, brain stem, midbrain, and cortex, the neural and behavioural mechanisms for sound-induced activation remains unclear. It is known, however, that PD patients recruit external sensory stimuli to improve movement. The aim of the current research was to create an animal model of sound-induced activation and to test the effect of previous motoric experience on the potency of auditory stimuli. To investigate behavioural activation in the normal and haloperidol-treated rat, two tasks were used: 1) orienting responses were analyzed for movement components in saline and haloperidol treated rats v to find out if rats responded in the same to a variety of naturally produced and generated activating sounds, and 2) a grid climbing task allowed for the righting components of naïve and familiar cataleptic rats to be compared. Our findings revealed that familiar auditory cues could release parkinsonian rats from catalepsy. The current research supports the theory that auditory stimulation retains “special access” to motor regions otherwise impaired in PD and likely bypasses basal ganglia circuitry to normalize movement through alternative pathways. / xiv, 142 leaves : ill. (some col.) ; 29 cm

The purpose of this thesis is to describe the organization of the movements of skilled reaching. Our knowledge of reaching behaviour has been limited to an understanding of specific actions. Results from this thesis describe how reaching is the product of interactions of various parameters that assemble in an integrative way in ontogeny, yet can become dismantled on one level, or generally, throughout multiple levels of what constitutes the behaviour after stroke in adults. These findings demonstrate that skilled reaching constitutes motor parameters that may not be visible in a healthy adult, but that function through development, and by inhibitory systems in adults, to create a smooth and finely articulated action. An examination of the movement patterns of reaching within the full context of the behaviour can be applied to therapeutic strategies for motor disorders and, most importantly, deepen our understanding of the relations between reaching and cognition. / xiii, 254 leaves : ill. (some col.) ; 29 cm

Bimanual movement is integral to daily function. As such, it is important to understand factors that influence bimanual performance. Playing the piano was employed to examine bimanual movement. Additionally, the weather prediction task was administered as a measure of non-declarative learning. Sex influenced motor performance. Males tended to perform asymmetrical movements with less skill than females. Age affected motor performance. Older adults were less proficient, but improved similarly with practice as young adults. Further, older adults exhibited differential deterioration of bimanual movement. Feedback and music training affected motor performance. Females performed bimanual movement less proficiently with auditory feedback. Individuals with music training performed bimanual movements relative to unimanual movements better with feedback. Music training moderated age-related differential deterioration of bimanual movements. Older adults performed significantly worse than young adults on the weather prediction task. In addition, the weather prediction task correlated with motor measures in a sample including older adults. / xii, 159 leaves : ill. ; 29 cm

Conventional cylinder test measures have limited sensitivity in determining hemiparkinson rat forelimb use asymmetry and approximating substantia nigra (SN) dopaminergic neuron loss. This thesis investigates which cylinder test measures of hemiparkinson rat forelimb use asymmetry best predict methamphetamine-induced rotation and extent of dopaminergic neuron loss. Long-Evans rats were cylinder-tested after unilateral 1-methyl-4-phenylpyridinium (MPP+)-induced SN dopamine depletion. Time and count of numerous forepaw wall contact patterns were documented for MPP+ hemiparkinson rats and sham-operated controls using frame-by-frame video analysis, then regressed against methamphetamine-induced rotation and tyrosine hydroxylase-positive neuron depletion. Severely dopamine-asymmetric rats initiated movements slower and less often with the contralateral-to-lesion forepaw, indicating that the cylinder test may be used to assess Parkinson Disease motor impairments of bradykinesia and akinesia. Several new time and count asymmetry measures may improve cylinder test sensitivity to hemiparkinson-specific forelimb use asymmetries. / xi, 103 leaves : ill. ; 29 cm.

Stress is one of the most critical influences on behavior, performance and disease. Recent findings from our laboratory have shown that stress represents a major modulator of motor function in the intact and damaged brain. The mechanisms by which stress and stress hormones affect motor system function, however, have not yet been determined. The objective of this thesis was to determine the route of action of stress and stress hormones on the motor system in a rat model. The first experiment investigates whether corticosterone is involved in mediating stress-induced motor impairments. The second experiment compares the role of glucocorticoid and mineralocorticoid receptors in regard to modulating the motor response to stress. The third experiment determines the differential effects of stress on motor function in males and females. The final experiment systematically describes changes in neuronal cell signaling that affect normal function of motor areas. The results indicate that disturbance of fine motor control by stress is not associated with stress hormone increases. Furthermore, it is modulated through the glucocorticoid and mineralocorticoid receptors. Stress differentially impairs motor function in males and females. These changes in motor behaviour could possibly be the result of changes in neuronal cell signaling within the motor system. This research provides new insights into physiological influences in motor system function and disorders of the motor system. / ix, 128 leaves : ill. (some col.) ; 29 cm.

The reach-to-eat movement, in which a hand is advanced towards a food item, shapes to grasp the food item, and withdrawals to place the food item into the mouth for eating, is a behaviour that is performed daily. The movement is controlled by two sensory systems, vision to guide hand advance and grasping, and somatosensation to guide hand withdrawal and mouth placement. The purpose of the present thesis was to examine how the sensory control of reaching-to-eat develops in infancy and degenerates following neurodegenerative disorder. The tight coupling of vision to hand advance and somatosensation to hand withdrawal has a developmental profile from six months to one year of age. That is, six-month-old infants rely on vision to advance their hand, grasp the target, and withdrawal the target to the mouth. By twelve months of age, infants display the adult pattern of coupling vision to hand advance and grasping. The tight coupling of vision to hand advance degenerates with basal ganglia disease, such that subjects with Parkinson’s disease and Huntington’s disease show an overreliance on vision to guide hand advance for grasping and hand withdrawal for mouth placement. The results of the thesis demonstrate that efficient use of sensory control to guide motor behaviour is an important aspect of development that is disrupted by neurodegenerative disease. / xiv, 286 leaves : ill. ; 29 cm

The main objective of this work is to address the growing concern of balance loss and falls in the aging population. The initial aspect looks at balance control in a dynamic environment. Observation of age and gender influence on motor control will be made related to a new dynamic balance testing platform (DBTP). The topic of focus in the second portion relates to reaction time in an unstable environment. Research has found that balance improves when physical activity is a part of daily life for seniors. Physical activity influence on reaction time will be investigated with a new approach to exercise classes for seniors. Finally, an understanding of motor control and balance may be acquired and physical activity incorporated into the life of an elderly individual, however this will never fully prevent falls from taking place. A novel approach to injury prevention due to falls is explored in the final portion of this thesis. Study One - Using a newly constructed dynamic balance testing platform (DBTP), balance ability of three age groups was observed in two visual conditions and in relation to gender. Center of Gravity excursion (COGex) was observed to determine the differences between age groups and gender. Platform response patterns were also observed to asses the functionality of the DBTP as a new tool for balance testing. Three things were found: 1) Age differencesrelated to platform movement suggested that balance decreased with age in both visual conditions. 2) Gender differences between COGex found that males covered the most distance in both visual conditions when compared to females. 3) Gender differences between platform characteristics showed that females balanced longer and had lower platform movement rate than males, in both visual conditions. In order to consider the DBTP as a new tool for determination of balance ability, more refined tests are necessary. Study Two - Using pre- and post-training tests, the effects of a Fitball® exercise program on performance in eight subjects was documented. The exercise program focused on improving dynamic balance and postural stability of seniors. To evaluate progress-related changes, pre and post-tests in a dynamic environment were applied. Center of gravity (COG) excursion, catch success rate, and balance success rate were quantified, and synchronized data collection of 3D motion capture (VICON v8i) and ground reaction force (2 KISTLER platforms) was analyzed. During pre- and post-tests, participants stood in a walk-like stance and were asked to catch a weighted ball, which dropped unexpectedly. Results showed no significant changes in balance success rate. Significant improvements were found, however, in both COG control and catch success rate following training (p 0.05). Study Three - Falls in the elderly are inevitable so it is necessary to take precautions. This study looks at falls in relation to velocity characteristics of various locations on the trunk, and contrasts them to activities of daily living (ADL) in 13 individuals. A threshold level was established to be 2.0m/s, a value that exceeded all maximum resultant velocities for ADL, but was superseded by all fall activity resultant velocities. This suggests that a life vest, which responds similar to a vehicle airbag, may be created and worn that will deploy past a threshold of 2.0m/s with the incidence of a fall. / xiii, 91 leaves : ill. ; 29 cm. --

Stroke remains a leading cause of disability in the western world, with symptoms ranging in severity from mild congnitive or motor impairments, to severe impairments in both cognitive and motor domains. Despite ongoing research aimed at helping stroke patients the disease cannot be prevented or cured, therefore a large body of research has been aimed at identifying effective rehabilitative strategies. Based on our understanding of normal brain function, and the meachanisms mediating the limited spontaneous recovery that is observed following injury, factors that promote brain plasticity are likely to be effective treatments for stroke symptoms. The current thesis investigated three novel treatments (COX-2 inhibitor drug, vitamin supplement diet, and social experience) in a rat model of focal ischemia in the motor cortex. All three treatments have been previously shown to alter plasticity in the normal brain, however the current experiments show that the treatments have differential effects following stroke. The COX-2 inhibitors provided limited improvement in functional performance, whereas the vitamin supplement treatment had no effect. Social experience on the other hand was found to block the usually observed spontaneous improvements following the stroke. These results suggest that factors that alter dendritic plasticity may in fact serve as effective stroke treatments depending on the site and the mechanisms whereby the plastic changes are induced. / ix, 149 leaves : ill. ; 29 cm.

Middle cerebral artery (MCA) stroke can produce chronic incapacitating motor impairments. Understanding the neural basis of the motor syndromes is complicated by the diversity of neural structures damaged but the problem can be addressed in laboratory rats by inducing selective infarcts. Nevertheless, the motor syndromes that ensue from stroke in rats remain poorly understood and undermine its potential as a model for clinical stroke. The objective of the present thesis was to document the skilled reaching impairments from neocortical and subcortical MCA infarcts in rats. In addition, the integrity of the motor system components spared by the infarct was assessed neurophysiologically and neuroanatomically. Characteristic reaching impairments emerged from each infarct but there were also some overlapping features that might be explained by neural dysfunction extending beyond the boundaries of the infarct. The present studies showed that the laboratory rat is an ideal animal model for studying stroke, which should be of interest to both clinical and research scientists studying stroke. / xiii, 345 leaves : ill. ; 29 cm. + 1 CD-ROM