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Somatosensory Modulation during Speech Planning

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Previous studies have found that the detection of near-threshold stimuli is decreased immediately before movement and throughout movement production. This has been suggested to occur through the use of the internal forward model processing an efferent copy of the motor

Previous studies have found that the detection of near-threshold stimuli is decreased immediately before movement and throughout movement production. This has been suggested to occur through the use of the internal forward model processing an efferent copy of the motor command and creating a prediction that is used to cancel out the resulting sensory feedback. Currently, there are no published accounts of the perception of tactile signals for motor tasks and contexts related to the lips during both speech planning and production. In this study, we measured the responsiveness of the somatosensory system during speech planning using light electrical stimulation below the lower lip by comparing perception during mixed speaking and silent reading conditions. Participants were asked to judge whether a constant near-threshold electrical stimulation (subject-specific intensity, 85% detected at rest) was present during different time points relative to an initial visual cue. In the speaking condition, participants overtly produced target words shown on a computer monitor. In the reading condition, participants read the same target words silently to themselves without any movement or sound. We found that detection of the stimulus was attenuated during speaking conditions while remaining at a constant level close to the perceptual threshold throughout the silent reading condition. Perceptual modulation was most intense during speech production and showed some attenuation just prior to speech production during the planning period of speech. This demonstrates that there is a significant decrease in the responsiveness of the somatosensory system during speech production as well as milliseconds before speech is even produced which has implications for speech disorders such as stuttering and schizophrenia with pronounced deficits in the somatosensory system.

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2019-05

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Startle-evoked movement in multi-jointed, two-dimensional reaching tasks

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Previous research has shown that a loud acoustic stimulus can trigger an individual's prepared movement plan. This movement response is referred to as a startle-evoked movement (SEM). SEM has been observed in the stroke survivor population where results have shown

Previous research has shown that a loud acoustic stimulus can trigger an individual's prepared movement plan. This movement response is referred to as a startle-evoked movement (SEM). SEM has been observed in the stroke survivor population where results have shown that SEM enhances single joint movements that are usually performed with difficulty. While the presence of SEM in the stroke survivor population advances scientific understanding of movement capabilities following a stroke, published studies using the SEM phenomenon only examined one joint. The ability of SEM to generate multi-jointed movements is understudied and consequently limits SEM as a potential therapy tool. In order to apply SEM as a therapy tool however, the biomechanics of the arm in multi-jointed movement planning and execution must be better understood. Thus, the objective of our study was to evaluate if SEM could elicit multi-joint reaching movements that were accurate in an unrestrained, two-dimensional workspace. Data was collected from ten subjects with no previous neck, arm, or brain injury. Each subject performed a reaching task to five Targets that were equally spaced in a semi-circle to create a two-dimensional workspace. The subject reached to each Target following a sequence of two non-startling acoustic stimuli cues: "Get Ready" and "Go". A loud acoustic stimuli was randomly substituted for the "Go" cue. We hypothesized that SEM is accessible and accurate for unrestricted multi-jointed reaching tasks in a functional workspace and is therefore independent of movement direction. Our results found that SEM is possible in all five Target directions. The probability of evoking SEM and the movement kinematics (i.e. total movement time, linear deviation, average velocity) to each Target are not statistically different. Thus, we conclude that SEM is possible in a functional workspace and is not dependent on where arm stability is maximized. Moreover, coordinated preparation and storage of a multi-jointed movement is indeed possible.

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2016-12

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The impact of differences in ethnicity on women's perceptions of physical assets of a community

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This study is an initial step in exploring how urban design typologies can help inform community asset research to broaden the definition of physical assets. Asset based community development research identifies specific types of physical assets such as streets, structures,

This study is an initial step in exploring how urban design typologies can help inform community asset research to broaden the definition of physical assets. Asset based community development research identifies specific types of physical assets such as streets, structures, housing or vacant lots. This research argues that a comprehensive look at physical assets is needed, taking into consideration urban typologies such as paths, landmarks, views and districts as well as the spatial relationships that influence their significance. Community asset literature and conditions specific to the Sunnyslope community in Phoenix, Arizona suggest that differences in ethnicity such as spatial segregation, and socio-economic status exist. However, the literature does not address how these differences in ethnicity might influence residents' perceptions of physical assets. This study explores the questions - How do perceptions of physical assets vary among women of different ethnicities? What, if any, are the reasons behind these ethnic differences in perception? The research applied a survey instrument with open-ended and close-ended questions, and a map to mark frequently used routes. Assets identified by recoding open-ended responses were statistically analyzed for frequencies. The most frequently mentioned assets were analyzed by GIS for spatial relationships. Women of White and Latino ethnicities frequently chose individual buildings and locations as physical assets over paths, views, districts and landmarks. White women identified urban typologies as physical assets. In contrast, Latino women identified no significant urban typologies as assets. The inclusion of urban typologies confirmed and expanded upon physical assets previously identified by other asset-based studies on the community of Sunnyslope. Notable differences in ethnicity were found in the perception of physical assets of economic significance, assets for use and assets of visual appeal. Besides ethnicity, age and proximity to assets also influenced asset perception of White and Latino women. Community organizations need to take into consideration the ethnic differences in perception of physical assets, in the context of culture, spatial segregation and differing family structures. The inclusion of urban typologies helped highlight the differences in ethnicities for physical assets of visual appeal, and the use of leisure and recreation facilities.

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2011