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Numerous studies have investigated motor learning by examining the adaptation of reaching movements to visuomotor perturbations that alter the mapping between actual and visually perceived hand position. The picture of the visuomotor transformation from visual input to motor input that has developed consists of three broad phases: integration of hand and target locations in a common reference frame, calculation of a movement vector between hand and target, and transformation of this movement vector from the common reference frame into motor commands. The process of adapting to a visuomotor rotation is generally viewed as an alteration of the vectorial representation of reach planning. When visual feedback is rotated, the motor and visual directions no longer coincide and the motor command executed is remapped to the subsequent visual direction produced. In the current set of studies, we examined how learning a visuomotor rotation while reaching to a target with a curved hand path generalizes to straight path reaching and novel target directions. We found that there is very little to no generalization of learning between curved reaches and straight reaches when given only endpoint feedback. With continuous visual feedback, we found partial transfer. This suggests that in the absence of visual feedback, the vectorial adaptation hypothesis is insufficient and adaptation to a visuomotor rotation is mediated by the later stages of the visuomotor transformation, when the motor commands specific to the hand path used are being generated. / Thesis (Master, Psychology) -- Queen's University, 2009-04-16 15:42:40.872

The learning and retention adaptations of muscle activity were studied during a novel multi-joint task. Electromyographic (EMG) signals were recorded from the posterior deltoid, long and lateral heads of the triceps, pectoralis major, biceps and brachioradialis muscles. These data were assayed in a pattern recognition analysis (SVD) to ascertain the minimum number of 'common features' or waveforms (W's) required to describe the set of input EMG patterns (IP). / Fifteen participants performed targeted arm movements, which incorporated the shoulder and elbow articulations, as fast and as accurately as possible in the horizontal plane. Both experimental (E) and control (C) groups were employed. The E group was trained (Day 1 to Day 4) and tested both pre- and post-learning. They were further re-tested during a retention period (RET) consisting of 1, 2, 4, 6 and 8 week post-learning sessions. The C group was tested before and after learning and at the end of the RET period. (Abstract shortened by UMI.)

The present thesis investigated the process of gross motor skill acquisition in the context of how movement pattern characteristics are organized and modified as a result of learning. The process of multisegmental skill acquisition was studied using performance production measures as a window to explore stable and transient changes in the movement control process. Bernstein's principles of exploitation of motion dependent torques, and the minimization of the degree of freedom were tested. / Twenty male subjects performed a total of 240 trials, as fast and accurate as possible, over 4 sessions for two tasks with different level of complexity (10 subjects per task). Kinematic and EMG data were acquired for a two segment model of the arm using a lightweight, adjustable manipulandum, and surface EMG for the PDL, PEC, TRI, and BIC muscles. Movement organization characteristics were revealed by wave pattern analyses performed with a phase breakdown technique, CCCF on torque partitioning components, and the CFs on the muscle activation waveforms. / The experimental protocol allowed enough practice for the tasks to be learned resulting in PT decrease. Consistent adaptations in movement organization were revealed by all three levels of analysis. Improvement in the performance production measures were in the same direction for both learning conditions, and the rate of change within experimental sessions decreased over time. The significant adaptations in movement organization occurred at the critical phases of each task (i.e. the power absorption--phase simple task, and the reversal phase--complex task). The EMG and joint torque components demonstrated significant amplitude and profile changes particularly during the critical phases. The subjects learned to perform the tasks faster by compensating the motion dependent torques components with the muscle torques in time and amplitude. This finding was consistent with the principle of exploitation of motion dependent torques which was enhanced with learning. Significant task specific motor program adaptations were revealed by the SVD analysis. The minimization of the degree of freedom hypothesis is consistent with the increasing covariation observed over learning between the antagonists PEC and BIC in the simple task, and for both the agonists PDL and TRI and antagonists PEC and BIC in the complex task. In addition the results justified the use of waveform analysis on performance production measures, as a method that can reveal important adaptation details in the underlying control mechanisms for gross motor skill.

Principles of motor learning (PMLs) refer to a set of concepts which are considered to facilitate the process of motor learning. PMLs can be broadly grouped into principles based on (1) the structure of practice/treatment, and (2) the nature of feedback provided during practice/treatment. Application of PMLs is most evident in studies involving non-speech- motor tasks (e.g., limb movement). However, only a few studies have investigated the application of PMLs in speech-motor tasks. Previous studies relating to speech-motor function have highlighted two primary limitations: (1) Failure to consider whether various PMLs contribute equally to learning in both non-speech and speech-motor tasks, (2) Failure to consider whether PMLs can be effective in a clinical cohort in comparison to a healthy group. The present research was designed to shed light on whether selected PMLs can indeed facilitate learning in both non-speech and speech-motor tasks and also to examine their efficacy in a clinical group with Parkinson’s disease (PD) in comparison to a healthy group. Eighty healthy subjects with no history of sensory, cognitive, or neurological abnormalities, ranging 40-80 years of age, and 16 patients with PD, ranging 58-78 years of age, were recruited as participants for the current study. Four practice conditions and one feedback condition were considered in the training of a speech-motor task and a non-speech- motor task. The four practice conditions were (1) constant practice, (2) variable practice, (3) blocked practice, and (4) random practice. The feedback was a combination of low-frequency, knowledge of results, knowledge of performance, and delayed feedback conditions, and was paired with each of the four practice conditions. The participants in the clinical and non-clinical groups were required to practise a speech and a non-speech-motor learning task. Each participant was randomly and equally assigned to one of the four practice groups. The speech-motor task involved production of a meaningless and temporally modified phrase, and the non-speech-motor task involved practising a 12-note musical sequence using a portable piano keyboard. Each participant was seen on three consecutive days: the first two days served as the acquisition phase and the third day was the retention phase. During the acquisition phase, the participants practised 50 trials of the speech phrase and another 50 trials of the musical tune each day, and each session lasted for 60-90 min. Performance on the speech and non-speech tasks was preceded by an orthographic model of the target phrase/musical sequence displayed on a computer monitor along with an auditory model. The participants were instructed to match their performance to the target phrase/musical sequence exactly. Feedback on performance was provided after every 10th trial. The nature of practice differed among the four practice groups. The participants returned on the third day for the retention phase and produced 10 trials of the target phrase and another 10 trials of the musical sequence. Feedback was not provided during or after the retention trials. These final trials were recorded for later acoustic analyses. The analyses focused on spatial and temporal parameters of the speech and non-speech tasks. Spatial analysis involved evaluating the production accuracy of target phrase/tune by calculating the percentage of phonemes/keystrokes correct (PPC/PKC). The temporal analysis involved calculating the temporal synchrony of the participant productions (speech phrase & tune) during the retention trials with the target phrase and tune, respectively, through the phi correlation. The PPC/PKC and phi correlation values were subjected to a series of mixed model ANOVAs. In the healthy subjects, the results of the spatial learning revealed that the participants learned the speech task better than the non-speech (keyboard) task. In terms of temporal learning, there was no difference in learning between the speech and non-speech tasks. On an overall note, the participants performed better on the spatial domain, rather than on the temporal domain, indicating a spatial-temporal trade-off. Across spatial as well as temporal learning, participants in the constant practice condition learned the speech and non-speech tasks better than participants in the other practice conditions. Another interesting finding was that there was an age effect, with the younger participants demonstrating superior spatial and temporal learning to that of the older participants, except for temporal learning on the keyboard task for which there was no difference. In contrast, the PD group showed no significant differences on spatial or temporal learning between any of the four practice conditions. Furthermore, although the PD patients had poorer performances than the healthy subjects on both the speech and keyboard tasks, they showed very similar pattern of learning across all four practice conditions to that of the healthy subjects. The findings in the current study tend to have potential applications in speech-language therapy, and are as follows: (1) a constant practice regime could be beneficial in developing speech therapy protocols to treat motor-based communication disorders (e.g., dysarthria), (2) speech therapists need to exercise caution in designing speech therapy goals incorporating similar PMLs for younger and older adults, as the application of similar PMLs in younger and older adults may bring about different learning outcomes, (3) and finally, it could be beneficial for patients to practise speech tasks which would require them to focus either on the spatial or temporal aspect, rather than focussing on both the aspects simultaneously.

The brain undergoes structural changes in response to new experiences like learning a new skill. Skilled motor movements depend greatly on the primary motor cortex for their execution. Recent studies describe rat strain differences in motor performance related to differential synaptic efficacy in the motor cortex of rats. Previous studies identified differences in motor performance related to differential dendritic morphology and strain related differences in synaptic function in the motor cortex. Strain differences are one way of investigating anatomical organization and behaviour of the motor system. The object of this research was to examine strain related differences in dendritic morphology in layer II / III pyramidal cells of the forelimb area of the sensory motor cortex in both Long-Evans and Fischer 344 rats after reach training. This research also examined whether changes in reaching behaviour could be attributed to changes in dendritic morphology. Rats were trained once a day for 30 days to reach for a food pellet through a slot in a reaching box. Pyramidal cells in the motor sensory forelimb (MSF) cortex were stained with the Golgi Cox method. Subsequent analysis of Sholl and branch order data of cell drawings determined that there were no significant differences in any measure of dendritic length or dendritic length at branch order 3, 4, 5 of pyramidal cells in layer II/III of the MSF cortex between the Long Evans and Fischer 344 rat strain. The only significant strain related difference was that the Fischer 344 strain exhibited fewer reaches for each food pellet obtained, demonstrating greater reaching proficiency than similarly trained Long-Evans rats. These findings suggest that further research examining strain comparisons is required to understand the neural mechanisms underlying the differences in motor behaviour observed in these rat strains.

The purpose of the investigation was to determine the effect of variations in relative frequency of concurrent visual feedback (CVF) on the acquisition and retention of a serial skill. Subjects (n=24) were college-aged females with no gymnastics experience. Subjects viewed a demonstration tape of a skilled gymnast performing a series of seven gymnastics dance skills consisting of simple and complex movements. Following this, subjects performed the dance sequence in front of a floor to ceiling mirror for concurrent visual feedback on a certain percentage of acquisition trials. The percentage of trials a subject received CVF depended on the group to which a subject was assigned: 100% relative frequency of CVF, 50% CVF (given on alternating trials), 50% faded CVF, or a control group that received no CVF. All subjects participated in three, 12trial acquisition sessions on different days. A two-trialshort-term no-CVF retention test was administered after each acquisition session with one long-term retention test administered 72 hours after the last acquisition session.The results of this study indicated no significant differences in form rating scores between groups. Thus, variations in the relative frequency of CVF during acquisition did not seem to enhance or detract from acquisition or retention performance. In addition, the ability to reproduce the correct sequence was not dependent upon the variation in the frequency of CVF employed throughout acquisition trials.The presence of a significant session effect in both acquisition and retention form rating indicated that learning did occur regardless of the presence or absence of CVF. / School of Physical Education

Access to abstract permanently restricted to Ball State community only / Access to thesis permanently restricted to Ball State community only / Department of Communication Studies

The brain undergoes structural changes in response to new experiences like learning a new skill. Skilled motor movements depend greatly on the primary motor cortex for their execution. Recent studies describe rat strain differences in motor performance related to differential synaptic efficacy in the motor cortex of rats. Previous studies identified differences in motor performance related to differential dendritic morphology and strain related differences in synaptic function in the motor cortex. Strain differences are one way of investigating anatomical organization and behaviour of the motor system. The object of this research was to examine strain related differences in dendritic morphology in layer II / III pyramidal cells of the forelimb area of the sensory motor cortex in both Long-Evans and Fischer 344 rats after reach training. This research also examined whether changes in reaching behaviour could be attributed to changes in dendritic morphology. Rats were trained once a day for 30 days to reach for a food pellet through a slot in a reaching box. Pyramidal cells in the motor sensory forelimb (MSF) cortex were stained with the Golgi Cox method. Subsequent analysis of Sholl and branch order data of cell drawings determined that there were no significant differences in any measure of dendritic length or dendritic length at branch order 3, 4, 5 of pyramidal cells in layer II/III of the MSF cortex between the Long Evans and Fischer 344 rat strain. The only significant strain related difference was that the Fischer 344 strain exhibited fewer reaches for each food pellet obtained, demonstrating greater reaching proficiency than similarly trained Long-Evans rats. These findings suggest that further research examining strain comparisons is required to understand the neural mechanisms underlying the differences in motor behaviour observed in these rat strains.

This dissertation is comprised of three studies investigating the hypothesis that people who stutter (PWS) differ from people who do not stutter (PNS) in their motor skill learning abilities. The first study in this dissertation examined the ability to learn a novel sequential speech task following a 24-h retention period. Despite slower sequence durations compared to the PNS, PWS showed the ability to retain what they had learned for all measured variables on day one and following a 24-h consolidation period. The second study in this dissertation examined the ability to learn a sequential finger tapping task by observing the ability to produce the sequence under both tests of retention and interference. For tests of retention, PWS showed the ability to retain improvements in performance for all measured variables, albeit at slower speeds compared to PNS. For tests of interference, a significant interaction for reaction time and sequence duration revealed that PNS’ performance reached a relative plateau while PWS’ performance continued to show improvement. The third study in this dissertation investigated the extent to which individual differences in motor learning are associated with differences in stuttering treatment outcome. PWS participating in an intensive fluency treatment program were assessed for their working memory ability and their motor iii learning performance on a syllable reading and finger tapping task. Treatment success was measured at pre-treatment, post-treatment and six months follow-up using percent syllables stuttered, introspective clinical characteristics (OASES; Yaruss, 2010) and fluency effort. The relationship between motor learning and treatment outcome was examined using multiple regression analyses. Results did not support the hypothesis that the ability to learn a simple speech and nonspeech motor task is predictive of treatment outcome. Although treatment proved successful as evidenced by percent syllables stuttered and OASES scores, scores of fluency effort indicated that participants had not automated their newly learned fluency skills when speaking in everyday conversations. Together, these studies do not support the hypothesis of a motor learning deficit in PWS but rather support the assumption of limited motor abilities. Limited motor abilities are discussed as having implications to stuttering treatment outcome.