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- Genre: Doctoral Dissertation
Description
The recent spotlight on concussion has illuminated deficits in the current standard of care with regard to addressing acute and persistent cognitive signs and symptoms of mild brain injury. This stems, in part, from the diffuse nature of the injury, which tends not to produce focal cognitive or behavioral deficits that are easily identified or tracked. Indeed it has been shown that patients with enduring symptoms have difficulty describing their problems; therefore, there is an urgent need for a sensitive measure of brain activity that corresponds with higher order cognitive processing. The development of a neurophysiological metric that maps to clinical resolution would inform decisions about diagnosis and prognosis, including the need for clinical intervention to address cognitive deficits. The literature suggests the need for assessment of concussion under cognitively demanding tasks. Here, a joint behavioral- high-density electroencephalography (EEG) paradigm was employed. This allows for the examination of cortical activity patterns during speech comprehension at various levels of degradation in a sentence verification task, imposing the need for higher-order cognitive processes. Eight participants with concussion listened to true-false sentences produced with either moderately to highly intelligible noise-vocoders. Behavioral data were simultaneously collected. The analysis of cortical activation patterns included 1) the examination of event-related potentials, including latency and source localization, and 2) measures of frequency spectra and associated power. Individual performance patterns were assessed during acute injury and a return visit several months following injury. Results demonstrate a combination of task-related electrophysiology measures correspond to changes in task performance during the course of recovery. Further, a discriminant function analysis suggests EEG measures are more sensitive than behavioral measures in distinguishing between individuals with concussion and healthy controls at both injury and recovery, suggesting the robustness of neurophysiological measures during a cognitively demanding task to both injury and persisting pathophysiology.
ContributorsUtianski, Rene (Author) / Liss, Julie M (Thesis advisor) / Berisha, Visar (Committee member) / Caviness, John N (Committee member) / Dorman, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
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.
ContributorsShibata, Daisuke (Author) / Santello, Marco (Thesis advisor) / Dounskaia, Natalia (Committee member) / Kleim, Jeffrey (Committee member) / Helms Tillery, Stephen (Committee member) / McBeath, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
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.
ContributorsThatte, Aparna (Author) / Ozel, Filiz (Thesis advisor) / Ahrentzen, Sherry (Thesis advisor) / Guhathakurta, Subhrajit (Committee member) / Arizona State University (Publisher)
Created2011
Description
Auditory scene analysis (ASA) is the process through which listeners parse and organize their acoustic environment into relevant auditory objects. ASA functions by exploiting natural regularities in the structure of auditory information. The current study investigates spectral envelope and its contribution to the perception of changes in pitch and loudness. Experiment 1 constructs a perceptual continuum of twelve f0- and intensity-matched vowel phonemes (i.e. a pure timbre manipulation) and reveals spectral envelope as a primary organizational dimension. The extremes of this dimension are i (as in “bee”) and Ʌ (“bun”). Experiment 2 measures the strength of the relationship between produced f0 and the previously observed phonetic-pitch continuum at three different levels of phonemic constraint. Scat performances and, to a lesser extent, recorded interviews were found to exhibit changes in accordance with the natural regularity; specifically, f0 changes were correlated with the phoneme pitch-height continuum. The more constrained case of lyrical singing did not exhibit the natural regularity. Experiment 3 investigates participant ratings of pitch and loudness as stimuli vary in f0, intensity, and the phonetic-pitch continuum. Psychophysical functions derived from the results reveal that moving from i to Ʌ is equivalent to a .38 semitone decrease in f0 and a .75 dB decrease in intensity. Experiment 4 examines the potentially functional aspect of the pitch, loudness, and spectral envelope relationship. Detection thresholds of stimuli in which all three dimensions change congruently (f0 increase, intensity increase, Ʌ to i) or incongruently (no f0 change, intensity increase, i to Ʌ) are compared using an objective version of the method of limits. Congruent changes did not provide a detection benefit over incongruent changes; however, when the contribution of phoneme change was removed, congruent changes did offer a slight detection benefit, as in previous research. While this relationship does not offer a detection benefit at threshold, there is a natural regularity for humans to produce phonemes at higher f0s according to their relative position on the pitch height continuum. Likewise, humans have a bias to detect pitch and loudness changes in phoneme sweeps in accordance with the natural regularity.
ContributorsPatten, K. Jakob (Author) / Mcbeath, Michael K (Thesis advisor) / Amazeen, Eric L (Committee member) / Glenberg, Arthur W (Committee member) / Zhou, Yi (Committee member) / Arizona State University (Publisher)
Created2017
Description
Previous research from Rajsic et al. (2015, 2017) suggests that a visual form of confirmation bias arises during visual search for simple stimuli, under certain conditions, wherein people are biased to seek stimuli matching an initial cue color even when this strategy is not optimal. Furthermore, recent research from our lab suggests that varying the prevalence of cue-colored targets does not attenuate the visual confirmation bias, although people still fail to detect rare targets regardless of whether they match the initial cue (Walenchok et al. under review). The present investigation examines the boundary conditions of the visual confirmation bias under conditions of equal, low, and high cued-target frequency. Across experiments, I found that: (1) People are strongly susceptible to the low-prevalence effect, often failing to detect rare targets regardless of whether they match the cue (Wolfe et al., 2005). (2) However, they are still biased to seek cue-colored stimuli, even when such targets are rare. (3) Regardless of target prevalence, people employ strategies when search is made sufficiently burdensome with distributed items and large search sets. These results further support previous findings that the low-prevalence effect arises from a failure to perceive rare items (Hout et al., 2015), while visual confirmation bias is a bias of attentional guidance (Rajsic et al., 2015, 2017).
ContributorsWalenchok, Stephen Charles (Author) / Goldinger, Stephen D (Thesis advisor) / Azuma, Tamiko (Committee member) / Homa, Donald (Committee member) / Hout, Michael C (Committee member) / McClure, Samuel M. (Committee member) / Arizona State University (Publisher)
Created2018
Description
There is ample evidence from psychology and cognitive science that a person's beliefs, memories, expectations, concepts, and desires can influence how that person perceives the world. In other words, the way an object looks (the color, size, shape, etc.) to a person can vary according to his or her beliefs, memories, desires, and so on. But a person is principally justified in his or her beliefs about the world by how things look to that person. So, if how things look to a person justifies that person's beliefs about the world, and that person's prior beliefs, memories, and desires influence how things look, then his or her prior beliefs, memories, and desires influence the justification for his or her beliefs about the world. This influence creates several significant philosophical problems. In this dissertation, I introduce and attempt to solve these problems by constructing a theory of justification in which a person's beliefs about the world are justified if and only if his or her prior beliefs, memories, and desires constitute a coherent worldview.
ContributorsCrutchfield, Parker (Author) / Reynolds, Steven (Thesis advisor) / Cohen, Stewart (Committee member) / Kobes, Bernard (Committee member) / Kriegel, Uriah (Committee member) / Arizona State University (Publisher)
Created2011
Description
Learning to accomplish complex tasks may require a tight coupling among different levels of cognitive functions or components, like perception, acting, planning, and self-explaining. One may need a coupling between perception and acting components to make decisions automatically especially in emergent situations. One may need collaboration between perception and planning components to go with optimal plans in the long run while also drives task-oriented perception. One may also need self-explaining components to monitor and improve the overall learning. In my research, I explore how different cognitive functions or components at different levels, modeled by Deep Neural Networks, can learn and adapt simultaneously. The first question that I address is: Can an intelligent agent leverage recognized plans or human demonstrations to improve its perception that may allow better acting? To answer this question, I explore novel ways to learn to couple perception-acting or perception-planning. As a cornerstone, I will explore how to learn shallow domain models for planning. Apart from these, more advanced cognitive learning agents may also be reflective of what they have experienced so far, either from themselves or from observing others. Likewise, humans may also frequently monitor their learning and draw lessons from failures and others' successes. To this end, I explore the possibility of motivating cognitive agents to learn how to self-explain experiences, accomplishments, and failures, to gain useful insights. By internally making sense of the past experiences, an agent could have its learning of other cognitive functions guided and improved.
ContributorsZha, Yantian (Author) / Kambhampati, Subbarao SK (Thesis advisor) / Li, Baoxin BL (Committee member) / Srivastava, Siddharth SS (Committee member) / Wang, Jianjun JW (Committee member) / Arizona State University (Publisher)
Created2022
Description
This qualitative study begins with the supposition that all schools have cultural biases and that even within the same school culture, people see things differently. Internal biases can negatively affect the approach to school improvement. To disrupt these culture bound realities, parent perspectives were sought out to provide an alternate view into Zaharis Elementary School. Two critical assumptions were built into this study. One, that the vast reservoir of cultural knowledge among parents could be tapped, and two, once that cultural knowledge was uncovered, they the schoolpeople (1986) of Zaharis Elementary could do something with it to make a difference in the lives of children. A focus group framework was employed over a series of parent group interviews to explore the following research question: What are the multiple realities expressed by parents and what similarities and differences exist across these realities? Focus group discussions were transcribed, participant responses were coded, and a thorough and comprehensive analysis revealed that the majority of parent perceptions expressed fell within three emergent parent realities that were defined and presented. One, parents perceived that teaching and learning were social processes that support the development of student voice and nurture rich relationships. Two, parents perceived that learning through inquiry elevated class work to purposeful student learning, activates critical thinking, and fosters authentic real-world experience. And the third parent perception was teaching is teamwork and all members of the classroom community were teachers and learners.
ContributorsOliver, Michael (Author) / Marsh, Josephine P (Thesis advisor) / Serafini, Frank (Committee member) / Moses, Lindsey (Committee member) / Arizona State University (Publisher)
Created2021
Description
Color perception has been widely studied and well modeled with respect to combining visible electromagnetic frequencies, yet new technology provides the means to better explore and test novel temporal frequency characteristics of color perception. Experiment 1 tests how reliably participants categorize static spectral rainbow colors, which can be a useful tool for efficiently identifying those with functional dichromacy, trichromacy, and tetrachromacy. The findings confirm that all individuals discern the four principal opponent process colors, red, yellow, green, and blue, with normal and potential tetrachromats seeing more distinct colors than color blind individuals. Experiment 2 tests the moving flicker fusion rate of the central electromagnetic frequencies within each color category found in Experiment 1 as a test of the Where system. It then compares this to the maximum temporal processing rate for discriminating direction of hue change with colors displayed serially as a test of the What system. The findings confirm respective processing thresholds of about 20 Hz for Where and 2-7 Hz for What processing systems. Experiment 3 tests conditions that optimize false colors based on the spinning Benham’s Top illusion. Findings indicate the same four principal colors emerge as in Experiment 1, but at low saturation levels for trichromats that diminish further for dichromats. Taken together, the three experiments provide an overview of the common categorical boundaries and temporal processing limits of human color vision.
ContributorsKrynen, Richard Chandler (Author) / Mcbeath, Michael K (Thesis advisor) / Homa, Donald (Committee member) / Newman, Nathan (Committee member) / Stone, Greg (Committee member) / Arizona State University (Publisher)
Created2021
Description
Our ability to estimate the position of our body parts in space, a fundamentally proprioceptive process, is crucial for interacting with the environment and movement control. For proprioception to support these actions, the Central Nervous System has to rely on a stored internal representation of the body parts in space. However, relatively little is known about this internal representation of arm position. To this end, I developed a method to map proprioceptive estimates of hand location across a 2-d workspace. In this task, I moved each subject's hand to a target location while the subject's eyes were closed. After returning the hand, subjects opened their eyes to verbally report the location of where their fingertip had been. Then, I reconstructed and analyzed the spatial structure of the pattern of estimation errors. In the first couple of experiments I probed the structure and stability of the pattern of errors by manipulating the hand used and tactile feedback provided when the hand was at each target location. I found that the resulting pattern of errors was systematically stable across conditions for each subject, subject-specific, and not uniform across the workspace. These findings suggest that the observed structure of pattern of errors has been constructed through experience, which has resulted in a systematically stable internal representation of arm location. Moreover, this representation is continuously being calibrated across the workspace. In the next two experiments, I aimed to probe the calibration of this structure. To this end, I used two different perturbation paradigms: 1) a virtual reality visuomotor adaptation to induce a local perturbation, 2) and a standard prism adaptation paradigm to induce a global perturbation. I found that the magnitude of the errors significantly increased to a similar extent after each perturbation. This small effect indicates that proprioception is recalibrated to a similar extent regardless of how the perturbation is introduced, suggesting that sensory and motor changes may be two independent processes arising from the perturbation. Moreover, I propose that the internal representation of arm location might be constructed with a global solution and not capable of local changes.
ContributorsRincon Gonzalez, Liliana (Author) / Helms Tillery, Stephen I (Thesis advisor) / Buneo, Christopher A (Thesis advisor) / Santello, Marco (Committee member) / Santos, Veronica (Committee member) / Kleim, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2012