abstract: Parkinson's disease (PD) is a neurodegenerative disorder that produces a characteristic set of neuromotor deficits that sometimes includes reduced amplitude and velocity of movement. Several studies have shown that people with PD improved their motor performance when presented with external cues. Other work has demonstrated that high velocity and large amplitude exercises can increase the amplitude and velocity of movement in simple carryover tasks in the upper and lower extremities. Although the cause for these effects is not known, improvements due to cueing suggest that part of the neuromotor deficit in PD is in the integration of sensory feedback to produce motor commands. Previous studies have documented some somatosensory deficits, but only limited information is available regarding the nature and magnitude of sensorimotor deficits in the shoulder of people with PD. The goals of this research were to characterize the sensorimotor impairment in the shoulder joint of people with PD and to investigate the use of visual feedback and large amplitude/high velocity exercises to target PD-related motor deficits. Two systems were designed and developed to use visual feedback to assess the ability of participants to accurately adjust limb placement or limb movement velocity and to encourage improvements in performance of these tasks. Each system was tested on participants with PD, age-matched control subjects and young control subjects to characterize and compare limb placement and velocity control capabilities. Results demonstrated that participants with PD were less accurate at placing their limbs than age-matched or young control subjects, but that their performance improved over the course of the test session such that by the end, the participants with PD performed as well as controls. For the limb velocity feedback task, participants with PD and age-matched control subjects were less accurate than young control subjects, but at the end of the session, participants with PD and age-matched control subjects were as accurate as the young control subjects. This study demonstrates that people with PD were able to improve their movement patterns based on visual feedback of performance and suggests that this feedback paradigm may be useful in exercise programs for people with PD. / Dissertation/Thesis / Doctoral Dissertation Bioengineering 2015

abstract: Dexterous manipulation is a representative task that involves sensorimotor integration underlying a fine control of movements. Over the past 30 years, research has provided significant insight, including the control mechanisms of force coordination during manipulation tasks. Successful dexterous manipulation is thought to rely on the ability to integrate the sense of digit position with motor commands responsible for generating digit forces and placement. However, the mechanisms underlying the phenomenon of digit position-force coordination are not well understood. This dissertation addresses this question through three experiments that are based on psychophysics and object lifting tasks. It was found in psychophysics tasks that sensed relative digit position was accurately reproduced when sensorimotor transformations occurred with larger vertical fingertip separations, within the same hand, and at the same hand posture. The results from a follow-up experiment conducted in the same digit position-matching task while generating forces in different directions reveal a biased relative digit position toward the direction of force production. Specifically, subjects reproduced the thumb CoP higher than the index finger CoP when vertical digit forces were directed upward and downward, respectively, and vice versa. It was also found in lifting tasks that the ability to discriminate the relative digit position prior to lifting an object and modulate digit forces to minimize object roll as a function of digit position are robust regardless of whether motor commands for positioning the digits on the object are involved. These results indicate that the erroneous sensorimotor transformations of relative digit position reported here must be compensated during dexterous manipulation by other mechanisms, e.g., visual feedback of fingertip position. Furthermore, predicted sensory consequences derived from the efference copy of voluntary motor commands to generate vertical digit forces may override haptic sensory feedback for the estimation of relative digit position. Lastly, the sensorimotor transformations from haptic feedback to digit force modulation to position appear to be facilitated by motor commands for active digit placement in manipulation. / Dissertation/Thesis / Doctoral Dissertation Kinesiology 2014

The present study determined how object-based alignment effects are influenced by the arrangement of the stimuli and response options. It is well established that the magnitude of these effects differ depending on the mode of responding. This finding has often been used to support claims that viewing photograph images of graspable objects can automatically trigger motor representations, regardless of the intentions of the observer. Our findings instead suggest that the distinction between response modes is primarily a difference in response discriminability. More importantly, it was found that this influence of response discriminability works in a completely opposite manner, dependent on the technique used to center the frying pan stimuli. Pixel-centered stimuli produced a handle-based alignment effect that was enhanced under conditions of high response discriminability. Object-centered stimuli produced a body-based alignment effect that was diminished under conditions of high-response discriminability. These findings provide overwhelming evidence that qualitatively different principles govern the alignment effect found with pixel-centered and object-centered stimuli. Crucially, these finding also provide strong evidence against the notion that motor representations are triggered by images of graspable objects in the absence of an intention to act. / Graduate

La mise en place d’un comportement semble en grande partie déterminée par la capacité du système cognitif à intégrer, au sein de représentations cohérentes, le flux continu d’informations provenant de l’environnement. Les travaux réalisés lors de cette thèse viennent modérer ce lien de causalité, et apportent des éléments en faveur d’une co-détermination de l’intégration des informations perceptives et de la mise en place d’un comportement moteur. En d’autres termes, cette thèse soutient l’idée que les actions effectuées par un individu ne sont pas seulement le produit d’une activité interne, mais sont aussi et surtout une condition de possibilité de la construction d’une représentation cohérente de nos interactions avec l’environnement.La première étude que nous avons réalisée a permis de mettre en évidence le rôle fonctionnel des réponses motrices dans le processus d’intégration. Dans une seconde étude, nous avons montré que les composants perceptifs et moteurs ne sont pas seulement co-activés lors de l’activité perceptive, mais bien intégrés les uns aux autres au sein d’une même représentation sensorimotrice. Enfin, notre dernière étude indique que la construction de telles représentations pourrait dépendre de l’intégration des conséquences sensorimotrices de nos actions. Pris dans une perspective plus large, l’ensemble de ces résultats souligne le rôle fondamental de l’action dans la cognition, et suggère finalement de reconsidérer la distinction stricte que nous opérons habituellement entre les éléments perceptifs et moteurs qui composent nos représentations. / The ability to integrate the vast amount of information coming from the environmentinto a coherent representation is usually considered a necessary conditionfor any behavior to take place. In this Ph.D. thesis, our proposal is to moderatethis apparent causality, and to bring new elements that support the idea of a codeterminationof the building of sensorimotor representations and the execution ofmotor behavior. In other words, we propose that actions are not only adapted toexternal constraints through an internal activity, but also contribute to the buildingof coherent representations of the world. Therefore, we made a series of experimentsto highlight the role of motor activity in the process of binding perceptiveinformation. The first study examined the functional role of motor responses inthe integration process, which were found to be a necessary condition for an integrationto take place. The second study investigated the link between perceptiveand motor components. The results showed that both are indeed integrated into acommon sensorimotor representation. Our final study shed light on the fact thatbuilding sensorimotor representations seems to rely on the integration of sensorimotoraction-effects. Taken together, our results point toward the critical role of motoractivity in cognitive processes, and question the relevance of distinguishing motorcomponents from perceptive ones.

Electrophysiology has produced a wealth of information concerning characteristic patterns of neural activity underlying movement control in non-human primates. Such patterns differentiate functional classes of neurons and illuminate neural computations underlying different stages of motor planning and execution. The scarcity of high-resolution electrophysiological recordings in humans has hindered such descriptions of brain activity during uniquely human acts such as speech production. The goal of this dissertation was to identify and quantitatively characterize canonical temporal profiles of neural activity measured using surface and depth electrocorticography electrodes while pre-surgical epilepsy patients read aloud monosyllabic utterances. An unsupervised iterative clustering procedure was combined with a novel Kalman filter-based trend analysis to identify characteristic activity time courses that occurred across multiple subjects. A nonlinear distance measure was used to emphasize similarity at key portions of the activity profiles, including signal peaks. Eight canonical activity patterns were identified. These activity profiles fell broadly into two classes: symmetric profiles in which activity rises and falls at approximately the same rate, and ramp profiles in which activity rises relatively quickly and falls off gradually. Distinct characteristic time courses were found during four different task stages: early processing of the orthographic stimulus, phonological-to-motor processing, motor execution, and auditory processing of self-produced speech, with activity offset ramps in earlier stages approximately matching activity onset rates in later stages. The addition of an anatomical constraint to the distance measure to encourage clusters to form within local brain regions did not significantly change results. The anatomically constrained results showed a further subdivision of the eight canonical activity patterns, with the subdivisions primarily stemming from sub-clusters that are anatomically distinct across different brain regions, but maintained the base activity pattern of their parent cluster from the analysis without the anatomically constrained distance measure. The analysis tools developed herein provide a powerful means for identifying and quantitatively characterizing the neural computations underlying human speech production and may apply to other cognitive and behavioral domains.

Performance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to alter behavior. Molecular layer interneurons (MLIs) inhibit Purkinje cells to modulate dendritic excitability and action potential output. How MLIs contribute to the regulation and encoding of climbing fiber-evoked adaptive movements remains poorly understood. In this dissertation, I used genetic tools to manipulate the activity of MLIs while monitoring Purkinje cell dendritic activity during a cerebellum-dependent motor learning task with different contexts to evaluate how MLIs are involved in this process. The results show that by suppressing dendritic Ca2+ signals in Purkinje cells, MLI activity coincident with climbing fiber-mediated excitation prevents the occurrence of learning when adaptation is not necessary. On the other hand, with error signals present, disinhibition onto Purkinje cells, mediated by MLI-MLI microcircuit, unlocked the ability of climbing fibers to induce plasticity and motor learning. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

The prevalence of children with autism is increasing each year and so should services that can be rendered. One type of therapy that is utilized by a large portion of children with autism is Sensory Integration Therapy. Sensory integration is an essential part of normal functioning. Our nervous system takes in, filters, organizes, and makes use of motor and sensory information. This is the neurological process of sensory integration (Sensory Integration International, 1986). Sensory Integration Therapy takes that premise and provides sensory stimulating activities that will enhance the child's performance in certain areas of life. Its use on children with autism has grown tremendously in the last several years. The support for Sensory Integration Therapy has primarily been in the form of testimonials. Though empirical evidence supporting the use of Sensory Integration is lacking, it continues to be used by many parents. In an effort to better understand parents, this study investigated their perceptions of Sensory Integration Therapy and its negative and positive impact on their child with autism.

Despite a rise in the use of “learning by doing” pedagogical methods in praxis, little is known as to how the brain benefits from these methods. Learning by doing strategies that utilize complementary information (“enrichment”) such as gestures have been shown to optimize learning outcomes in several domains including foreign language (L2) training. Here we tested the hypothesis that behavioral benefits of gesture-based enrichment are critically supported by integrity of the biological motion visual cortices (bmSTS). Prior functional neuroimaging work has implicated the visual motion cortices in L2 translation following sensorimotor-enriched training; the current study is the first to investigate the causal relevance of these structures in learning by doing contexts. Using neuronavigated transcranial magnetic stimulation and a gesture-enriched L2 vocabulary learning paradigm, we found that the bmSTS causally contributed to behavioral benefits of gesture-enriched learning. Visual motion cortex integrity benefitted both short- and long-term learning outcomes, as well as the learning of concrete and abstract words. These results adjudicate between opposing predictions of two neuroscientific learning theories: While reactivation-based theories predict no functional role of specialized sensory cortices in vocabulary learning outcomes, the current study supports the predictive coding theory view that these cortices precipitate sensorimotor-based learning benefits.:I. Abkürzungsverzeichnis II. Abbildungsverzeichnis III. Einleitung 1. Fremdsprachenlernen 1.1 Sensorische Modalitätsvergleiche 1.2 Sensomotorisches Lernen 2. Lerntheorien 2.1 Theorie des prädiktiven Kodierens 2.2 Theorie des prädiktiven Kodierens für multisensorisches Lernen 3. Sulcus temporalis superior für biologische Bewegung 4. Transkranielle Magnetstimulation 4.1 Passagere Funktionsinhibition mittels transkranieller Magnetstimulation IV. Ableitung der Rationale V. Publikationsmanuskript VI. Zusammenfassung VII. Literaturverzeichnis VIII. Appendix A. Abbildungen B. Ergänzendes Material der Publikation C. Darstellung des eigenen Beitrags D. Erklärung über die eigenständige Abfassung der Arbeit E. Lebenslauf F. Publikationen G. Danksagung

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Sensorimotor integration refers to the process of combining incoming sensory information with outgoing motor commands to control movement. Short-Latency Afferent Inhibition (SAI), Long-Latency Afferent Inhibition (LAI) and Afferent Facilitation (AF) are three neurophysiological measures collected using Transcranial Magnetic Stimulation (TMS) to assess sensorimotor integration in humans. No studies to date have investigated the influence of tactile discrimination training on these measures. This study aimed to determine whether SAI, LAI, and AF are modulated following training on a custom-designed sensorimotor task which required participants to use their sense of touch to successfully navigate 3D printed maze with interchangeable paths. The maze training was separated into “high difficulty” and “low difficult” conditions which reflected the tactile challenge embedded within the maze. On an additional visit, no maze training was performed to serve as a control condition. Despite evidence of performance improvements during training, there were no significant changes in SAI, LAI or AF following training in either condition. Further, there was no correlation between the % change in SAI/LAI and improvements in total dwell time on the maze. As the functional significance of these measures is still unclear, these findings suggest that changes in SAI, LAI or AF may not be a valid metric to measure meaningful or functional changes related to skills or performance improvements induced by training. / Thesis / Master of Science in Kinesiology / Sensorimotor integration refers to the combination of incoming sensory information with outgoing motor commands in the nervous system to control movement. Short- Latency Afferent Inhibition, Long-Latency Afferent Inhibition and Afferent Facilitation are three measures that probe sensorimotor integration in humans using Transcranial Magnetic Stimulation. Although these measures have been well studied in both healthy and clinical populations in a variety of contexts, the influence of sensorimotor training on these measures remains unclear. This thesis aimed to determine if SAI, LAI and AF change following training on a novel tactile discrimination maze task. Further, the relationship between changes in sensorimotor integration and improvements in maze performance was explored. SAI, LAI and AF were not shown to be influenced by training, and there was no association between the changes in these measures and improvements in maze performance.