Long-term motor skill learning has been consistently shown to result in functional as well as structural changes in the adult human brain. However, the effect of short learning periods on brain structure is not well understood. In the present study, subjects performed a sequential pinch force task (SPFT) for 20 min on 5 consecutive days. Changes in brain structure were evaluated with anatomical magnetic resonance imaging (MRI) scans acquired on the first and last day of motor skill learning. Behaviorally, the SPFT resulted in sequence-specific learning with the trained (right) hand. Structural gray matter (GM) alterations in left M1, right ventral premotor cortex (PMC) and right dorsolateral prefrontal cortex (DLPFC) correlated with performance improvements in the SPFT. More specifically we found that subjects with strong sequence-specific performance improvements in the SPFT also had larger increases in GM volume in the respective brain areas. On the other hand, subjects with small behavioral gains either showed no change or even a decrease in GM volume during the time course of learning. Furthermore, cerebellar GM volume before motor skill learning predicted (A) individual learning-related changes in the SPFT and (B) the amount of structural changes in left M1, right ventral PMC and DLPFC. In summary, we provide novel evidence that short-term motor skill learning is associated with learning-related structural brain alterations. Additionally, we showed that practicing a motor skill is not exclusively accompanied by increased GM volume. Instead, bidirectional structural alterations explained the variability of the individual learning success.

Chronic neck pain, including subclinical neck pain (SCNP), is a significant problem that places a burden on the healthcare system. Chiropractic manipulation has shown not only to be effective in treating symptoms of neck pain, but also in providing a neuromodulatory effect on the central nervous system. The motor cortex and cerebellum are thought to be important neural structures involved in motor learning and sensorimotor integration (SMI), and are therefore key structures to investigate how SMI is changed in a SCNP group following chiropractic care. Motor sequence learning (MSL) has also been shown to provide alterations in cerebellar projections to the motor cortex. Therefore, the studies in this thesis set out to determine if it was possible to induce both cortical and cerebellar learning, and if chiropractic care could alter motor output via transcranial magnetic stimulation measures to facilitate this learning. The study‟s results suggest that in a healthy group of subjects there is alteration in the intracortical inhibition of the motor cortex and no significant change in the cerebellum, following MSL. However, the results also suggest that in a SCNP group, there is a modulation of the cerebellar connections to the motor cortex but no effect specific to the motor cortex following both MSL and chiropractic manipulation. Therefore, these findings suggest that people with intermittent neck pain have concomitant changes in SMI and could manifest as clinical symptomology. / UOIT

This thesis reports on a multi-phased research project conducted to evaluate the use of the Cognitive Orientation to daily Occupational Performance (CO-OP) approach with adults with stroke. Current approaches to motor recovery, called systems approaches, suggest that movement arises from a dynamic interaction among several different systems, including perception, cognition, and action, all within the context of the individual and his or her environment. CO-OP is an established treatment approach for children with motor-based performance problems that takes into account interactions among several systems, as well as individual needs and environmental factors. CO-OP is a client-centred, problem solving approach based on the theoretical foundations of learning and motor learning theory. The objectives of this project were: to examine the efficacy of CO-OP to improve motor skill acquisition and performance in adults living with chronic stroke; to explore other benefits of the approach; and to identify adaptations for use with adults with stroke. Two series of single case experimental studies were conducted, with three participants completing each. In addition, semi-structured interviews were conducted. Findings from the single case experiments provide evidence that CO-OP is associated with performance improvements in both trained and untrained self-selected goals in adults more than one year post stroke. As well, pre-post measures suggest there may be changes in performance satisfaction, motor control, generalized use of the affected upper extremity, and self-efficacy. Interview findings provided valuable information about the experiences of participants with the approach; the interview respondents enjoyed the increased sense of responsibility that came with problem solving on their own, but expressed a desire to have ongoing professional support. Suggestions for modifications to CO-OP for use adults with stroke are made. CO-OP is a promising approach to improve functional independence in adults with stroke. Future research is warranted.

The vestibulo-ocular reflex (VOR) is a simple reflex that stabilizes gaze by moving the eyes in the opposite direction to the head. The gain of the VOR (ratio of head to eye velocity) can be increased or decreased during motor learning. It is thought that the memory for learned changes in the VOR gain is initially encoded within the cerebellar flocculus. Furthermore, these learned gain changes can be disrupted or consolidated into a long-term memory. In this thesis we describe novel results that show that consolidation of the VOR can take place rapidly, within 1 hour after learning has stopped. Furthermore, we demonstrated that unlike learning, which has been shown to have frequency selectivity, disruption and rapid consolidation generalize across the range of frequencies. We suggest that disruption and rapid consolidation in the VOR are local mechanisms within the cerebellar cortex, and do not require new learning. This thesis also provides additional evidence for the idea that learned gain increases and decreases are the result of separate mechanisms, most likely long-term depression and potentiation respectively, at the parallel fibre-Purkinje cell synapses. We demonstrate that learned gain increases, but not decreases, require the activation of type 1 metabotropic glutamate receptors (mGluR1) and B type γ-aminobutyric acid (GABAB) receptors. Blocking one or both of these receptors with an antagonist inverts gain-up learning, while the agonist augments gain-up learning. Furthermore, we provide novel evidence that these receptors are co-activated during gain-up learning.

This study compared the effects of two conditions on the motor development of preschool children and investigated the relationship between preschool children's motor development and perceived competence. Specifically, it provided information for discerning: a) the relative effects of a sensory-motor condition and an unstructured activities condition on the motor development of preschool children immediately following the 20-week intervention; and b) whether perceived competence was related to motor development in the preschool children following termination of the treatment. Additionally, a teacher survey which addressed the teacher-consultant relationship was developed and piloted within the context of the study for use in future research. Subjects were 31 children enrolled in two preschool programs including: a) the curriculum group (N=16), and b) the non-curriculum group (N=l5). The Peabody Motor Developmental Scales and the Pictorial Scale of Perceived Competence and Social Acceptance were used to assess the children's motor development and perceived competence, respectively. All subjects were tested prior to the 20- week intervention period and immediately following the intervention. A series of 2 (group) X 2 (testing time) repeated measures analyses of variance were used to analyze the impact of the two conditions. Results revealed that the motor development of subjects in both groups changed significantly over time; however, there were no differences between groups. Product-moment correlations and linear regression analyses were used to assess the relationship between preschool children's motor development and perceived competence. Results revealed that perceived competence relative to motor development did not change over time; however a reciprocal relationship between motor development and perceived competence in preschool children was found. The piloted teacher survey showed potential for evaluation of service delivery models and as a tool for teacher-consultant communication in future studies. / Graduation date: 1991

The vestibulo-ocular reflex (VOR) is a simple reflex that stabilizes gaze by moving the eyes in the opposite direction to the head. The gain of the VOR (ratio of head to eye velocity) can be increased or decreased during motor learning. It is thought that the memory for learned changes in the VOR gain is initially encoded within the cerebellar flocculus. Furthermore, these learned gain changes can be disrupted or consolidated into a long-term memory. In this thesis we describe novel results that show that consolidation of the VOR can take place rapidly, within 1 hour after learning has stopped. Furthermore, we demonstrated that unlike learning, which has been shown to have frequency selectivity, disruption and rapid consolidation generalize across the range of frequencies. We suggest that disruption and rapid consolidation in the VOR are local mechanisms within the cerebellar cortex, and do not require new learning. This thesis also provides additional evidence for the idea that learned gain increases and decreases are the result of separate mechanisms, most likely long-term depression and potentiation respectively, at the parallel fibre-Purkinje cell synapses. We demonstrate that learned gain increases, but not decreases, require the activation of type 1 metabotropic glutamate receptors (mGluR1) and B type γ-aminobutyric acid (GABAB) receptors. Blocking one or both of these receptors with an antagonist inverts gain-up learning, while the agonist augments gain-up learning. Furthermore, we provide novel evidence that these receptors are co-activated during gain-up learning.

This thesis reports on a multi-phased research project conducted to evaluate the use of the Cognitive Orientation to daily Occupational Performance (CO-OP) approach with adults with stroke. Current approaches to motor recovery, called systems approaches, suggest that movement arises from a dynamic interaction among several different systems, including perception, cognition, and action, all within the context of the individual and his or her environment. CO-OP is an established treatment approach for children with motor-based performance problems that takes into account interactions among several systems, as well as individual needs and environmental factors. CO-OP is a client-centred, problem solving approach based on the theoretical foundations of learning and motor learning theory. The objectives of this project were: to examine the efficacy of CO-OP to improve motor skill acquisition and performance in adults living with chronic stroke; to explore other benefits of the approach; and to identify adaptations for use with adults with stroke. Two series of single case experimental studies were conducted, with three participants completing each. In addition, semi-structured interviews were conducted. Findings from the single case experiments provide evidence that CO-OP is associated with performance improvements in both trained and untrained self-selected goals in adults more than one year post stroke. As well, pre-post measures suggest there may be changes in performance satisfaction, motor control, generalized use of the affected upper extremity, and self-efficacy. Interview findings provided valuable information about the experiences of participants with the approach; the interview respondents enjoyed the increased sense of responsibility that came with problem solving on their own, but expressed a desire to have ongoing professional support. Suggestions for modifications to CO-OP for use adults with stroke are made. CO-OP is a promising approach to improve functional independence in adults with stroke. Future research is warranted.

Two experiments were designed to examine the influence of the strength of perceptionaction coupling on the control and learning of a visuomotor tracking pattern. Participants produced rhythmic elbow flexion-extension motions to learn a visually defined 90° relative phase tracking pattern with an external sinusoidal signal which was set at 0.8 Hz with 8 cycles in a trial. Day 1 and Day 2 practice sessions consisted of a total of 72 practice trials. There were two visuomotor congruency groups, a congruent group with visual feedback representing the elbow’s rotation and an incongruent group with feedback representing the elbow’s rotation transformed by 180°. Before Day 1 practice (pre-practice) and 24 hours after Day 2 practice (post-practice), participants produced 0°, 45°, 90°, 135°, and 180° relative phase tracking patterns either with or without tracking feedback. The external signal and the limb’s feedback were provided in the same workspace in Experiment 1, while both signals were provided in a separate workspace in Experiment 2. The pre-practice results demonstrated that the 0° relative phase pattern was the most accurate and stable pattern, whereas the 90° and 135° relative phase patterns were less accurate and more variable. The incongruent group produced a more accurate and less variable 180° relative phase pattern compared to the congruent group. Practice led to a decrease in phase error and variability toward the required 90° relative phase pattern in both experiments. The congruent group produced more accurate tracking and less variable elbow amplitude compared to the incongruent group in the separate workspace, whereas no such congruency effects were found in the same workspace during practice. The post-practice results showed overall improvements in phase accuracy and stability in most relative phase patterns with practice. Overall deterioration in tracking performance was found when tracking without feedback in the pre- and post-practice sessions. These findings demonstrated that the perception-action coupling strength was modified by feedback, visuomotor mapping, perceptual pattern, and workspace framework. The differential strength of perception-action impacted the learning of the required visuomotor tracking pattern as well as the production of tracking accuracy and stability differentially among the other tracking patterns.

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2008. / Title from first page of PDF file (viewed July 10, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 332-356).

Thesis (M.Communication Pathology) -- University pf Pretoria, 2000. / Summary in English and Afrikaans.