The ability to process and respond to environmental cues requires the transformation of a sensory stimulus into an appropriate motor response, a process known as a sensorimotor transformation. The anti-saccade task can be used to investigate the ability of a subject to suppress a reflexive saccade towards a visual stimulus (pro-saccade) and generate a voluntary saccade 180° away from it. Additional steps are involved in the anti-saccade sensorimotor transformation that do not occur in the pro-saccade, which may produce performance differences between pro- and anti-saccade metrics. We were interested in exploring these differences to gain insight on the mechanism of the sensorimotor transformation of the anti-saccade and to uncover any directional biases in saccadic performance. Two experiments were performed, one in which stimuli were presented at 20 angular positions with a constant eccentricity of 12°, and another using 18 possible eccentricities along the horizontal. Pro-saccades had faster SRTs and velocities, larger amplitudes, higher accuracy and less variation in their trajectories than anti-saccades. Pro- and anti-saccade performance was shown to exhibit a similar dependence on both saccade goal direction and eccentricity. Differences manifested as a generalized reduction in anti-saccade performance that can be described as a scalar multiple of pro-saccade performance at all locations. Possible causes of this reduced performance were speculated to be i) the involvement of higher cortical structures, ii) errors in the internal representation of the stimulus, iii) sensorimotor coordinate transformation inaccuracy, and iv) online updating of the motor plan and the speed accuracy trade off inherent to saccades. The results of this study are comparable to previous monkey and human studies however certain differences were found that require further investigation. Further investigation is also required to determine the validity of the possible causes of performance reduction in the anti-saccade task and their specific contributions. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2011-09-08 16:31:18.398

Afferent somatosensory inputs ascend from the periphery to the cortex carrying information about touch that is critical for planning motor responses. At the cortical level, this information is subject to modulation from its earliest arrival in somatosensory cortex where factors such as task-relevance begin to shape how the sensory signals are processed. The goal of such modulation is largely to facilitate the extraction of relevant sensory information (and suppression of irrelevant signals) early in the processing stream, and these functions are in part carried out by top-down influences from cortical and sub-cortical structures. Efforts to understand the mechanisms contributing to modulation of sensory-specific cortex have revealed that crossmodal signals (i.e. simultaneously presented stimuli from a different modality) can also influence early sensory processing, but the precise nature of this modulation and what may drive it is largely unknown. It is the purpose of this thesis to investigate the modulation of somatosensory cortex, specifically how task-relevant modulation of somatosensory cortex might be influenced by crossmodal (visual) stimuli, and whether specific task requirements have any bearing on SI excitability. The studies comprising this thesis aim to address these gaps in our mechanistic understanding of the networks involved in modulating somatosensory cortex. Studies 1 and 2 employed functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) to investigate how task-relevant visual and vibrotactile stimuli modulate somatosensory cortex and to probe the role of a frontoparietal network in mediating this modulation. Studies 3 and 4 also used EEG to determine how manipulating the relevance of the stimuli affects the modulation of somatosensory event-related potentials (ERPs), and to probe how task-specific sensory-motor requirements mediate excitability in somatosensory cortex as well as frontal and parietal regions. The results of this thesis provide insight into the factors that modulate somatosensory cortex and the role of a fronto-parietal network in subserving these modulations.

Thesis (MAppSc in Physiotherapy) -- University of South Australia, 1993

Thesis (M.S. in mechanical engineering)--Washington State University, December 2008. / Title from PDF title page (viewed on Dec. 23, 2008). "School of Mechanical and Materials Engineering." Includes bibliographical references (p. 72-76).

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xii, 141 p.; also includes graphics (some col.). Includes bibliographical references (p. 128-141). Available online via OhioLINK's ETD Center

The focus of this thesis is how the body and its corporeal articulations can be used as a tool for composing for contemporary dance, with the aim of creating music with corporeal qualities that communicates on a physical level. For this purpose the author has collaborated with choreographers in a practice-based approach to examine how the body of the composer can be exploited in composition and performance, and how the voice can be exploited as a mediator between body movement and music. The body and its sensorimotor system is the foundation for our understanding of abstract concepts in music; the immaterial movement of music can serve as a foundation for a deep bodily-sensed understanding of complex concepts. By reversing this process of understanding, or rather by engaging in the action-perception loop of conceptual understanding, this understanding can help encapsulating abstract and complex concepts artistically in music. For this purpose the Feedback Instrument has been created, representing a direct way of engaging the sensorimotor system of the composer, where the intuitive body resonances are engaged in close connection with the sounding music.

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Yes / To enable effective interaction with the environment, the brain combines noisy sensory information with expectations based on prior experience. There is ample evidence showing that humans can learn statistical regularities in sensory input and exploit this knowledge to improve perceptual decisions and actions. However, fundamental questions remain regarding how priors are learned and how they generalize to different sensory and behavioral contexts. In principle, maintaining a large set of highly specific priors may be inefficient and restrict the speed at which expectations can be formed and updated in response to changes in the environment. However, priors formed by generalizing across varying contexts may not be accurate. Here, we exploit rapidly induced contextual biases in duration reproduction to reveal how these competing demands are resolved during the early stages of prior acquisition. We show that observers initially form a single prior by generalizing across duration distributions coupled with distinct sensory signals. In contrast, they form multiple priors if distributions are coupled with distinct motor outputs. Together, our findings suggest that rapid prior acquisition is facilitated by generalization across experiences of different sensory inputs but organized according to how that sensory information is acted on.

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