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Advances in implantable MEMS technology has made possible adaptive micro-robotic implants that can track and record from single neurons in the brain. Development of autonomous neural interfaces opens up exciting possibilities of micro-robots performing standard electrophysiological techniques that would previously take researchers several hundred hours to train and achieve the

Advances in implantable MEMS technology has made possible adaptive micro-robotic implants that can track and record from single neurons in the brain. Development of autonomous neural interfaces opens up exciting possibilities of micro-robots performing standard electrophysiological techniques that would previously take researchers several hundred hours to train and achieve the desired skill level. It would result in more reliable and adaptive neural interfaces that could record optimal neural activity 24/7 with high fidelity signals, high yield and increased throughput. The main contribution here is validating adaptive strategies to overcome challenges in autonomous navigation of microelectrodes inside the brain. The following issues pose significant challenges as brain tissue is both functionally and structurally dynamic: a) time varying mechanical properties of the brain tissue-microelectrode interface due to the hyperelastic, viscoelastic nature of brain tissue b) non-stationarities in the neural signal caused by mechanical and physiological events in the interface and c) the lack of visual feedback of microelectrode position in brain tissue. A closed loop control algorithm is proposed here for autonomous navigation of microelectrodes in brain tissue while optimizing the signal-to-noise ratio of multi-unit neural recordings. The algorithm incorporates a quantitative understanding of constitutive mechanical properties of soft viscoelastic tissue like the brain and is guided by models that predict stresses developed in brain tissue during movement of the microelectrode. An optimal movement strategy is developed that achieves precise positioning of microelectrodes in the brain by minimizing the stresses developed in the surrounding tissue during navigation and maximizing the speed of movement. Results of testing the closed-loop control paradigm in short-term rodent experiments validated that it was possible to achieve a consistently high quality SNR throughout the duration of the experiment. At the systems level, new generation of MEMS actuators for movable microelectrode array are characterized and the MEMS device operation parameters are optimized for improved performance and reliability. Further, recommendations for packaging to minimize the form factor of the implant; design of device mounting and implantation techniques of MEMS microelectrode array to enhance the longevity of the implant are also included in a top-down approach to achieve a reliable brain interface.
ContributorsAnand, Sindhu (Author) / Muthuswamy, Jitendran (Thesis advisor) / Tillery, Stephen H (Committee member) / Buneo, Christopher (Committee member) / Abbas, James (Committee member) / Tsakalis, Konstantinos (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Writing is an intricate cognitive and social process that involves the production of texts for the purpose of conveying meaning to others. The importance of lower level cognitive skills and language knowledge during this text production process has been well documented in the literature. However, the role of higher level

Writing is an intricate cognitive and social process that involves the production of texts for the purpose of conveying meaning to others. The importance of lower level cognitive skills and language knowledge during this text production process has been well documented in the literature. However, the role of higher level skills (e.g., metacognition, strategy use, etc.) has been less strongly emphasized. This thesis proposal examines higher level cognitive skills in the context of persuasive essay writing. Specifically, two published manuscripts are presented, which both examine the role of higher level skills in the context of writing. The first manuscript investigates the role of metacognition in the writing process by examining the accuracy and characteristics of students' self-assessments of their essays. The second manuscript takes an individual differences approach and examines whether the higher level cognitive skills commonly associated with reading comprehension are also related to performance on writing tasks. Taken together, these manuscripts point towards a strong role of higher level skills in the writing process and provide a strong foundation on which to develop future research and educational interventions.
ContributorsAllen, Laura K (Author) / McNamara, Danielle S. (Thesis advisor) / Connor, Carol (Committee member) / Glenberg, Arthur (Committee member) / Arizona State University (Publisher)
Created2014
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Description
Epilepsy is a group of disorders that cause seizures in approximately 2.2 million people in the United States. Over 30% of these patients have epilepsies that do not respond to treatment with anti-epileptic drugs. For this population, focal resection surgery could offer long-term seizure freedom. Surgery candidates undergo a myriad

Epilepsy is a group of disorders that cause seizures in approximately 2.2 million people in the United States. Over 30% of these patients have epilepsies that do not respond to treatment with anti-epileptic drugs. For this population, focal resection surgery could offer long-term seizure freedom. Surgery candidates undergo a myriad of tests and monitoring to determine where and when seizures occur. The “gold standard” method for focus identification involves the placement of electrocorticography (ECoG) grids in the sub-dural space, followed by continual monitoring and visual inspection of the patient’s cortical activity. This process, however, is highly subjective and uses dated technology. Multiple studies were performed to investigate how the evaluation process could benefit from an algorithmic adjust using current ECoG technology, and how the use of new microECoG technology could further improve the process.

Computational algorithms can quickly and objectively find signal characteristics that may not be detectable with visual inspection, but many assume the data are stationary and/or linear, which biological data are not. An empirical mode decomposition (EMD) based algorithm was developed to detect potential seizures and tested on data collected from eight patients undergoing monitoring for focal resection surgery. EMD does not require linearity or stationarity and is data driven. The results suggest that a biological data driven algorithm could serve as a useful tool to objectively identify changes in cortical activity associated with seizures.

Next, the use of microECoG technology was investigated. Though both ECoG and microECoG grids are composed of electrodes resting on the surface of the cortex, changing the diameter of the electrodes creates non-trivial changes in the physics of the electrode-tissue interface that need to be accounted for. Experimenting with different recording configurations showed that proper grounding, referencing, and amplification are critical to obtain high quality neural signals from microECoG grids.

Finally, the relationship between data collected from the cortical surface with micro and macro electrodes was studied. Simultaneous recordings of the two electrode types showed differences in power spectra that suggest the inclusion of activity, possibly from deep structures, by macroelectrodes that is not accessible by microelectrodes.
ContributorsAshmont, Kari Rich (Author) / Greger, Bradley (Thesis advisor) / Helms Tillery, Stephen (Committee member) / Buneo, Christopher (Committee member) / Adelson, P David (Committee member) / Dudek, F Edward (Committee member) / Arizona State University (Publisher)
Created2015
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Description
Simulation theory states that text comprehension is achieved by simulating (or imagining) text content using motor, perceptual, and emotional systems. Hence, motor skill should correlate with comprehension skill. In fact, previous research has linked fine motor skills (FMS) with word processing and mathematical skills. I predicted a positive relationship between

Simulation theory states that text comprehension is achieved by simulating (or imagining) text content using motor, perceptual, and emotional systems. Hence, motor skill should correlate with comprehension skill. In fact, previous research has linked fine motor skills (FMS) with word processing and mathematical skills. I predicted a positive relationship between FMS and reading comprehension. Children enrolled in a reading comprehension intervention were assessed on FMS using the Movement ABC-2. There was a significant correlation between FMS and comprehension of narrative texts, but contrary to the prediction, the correlation was negative. Also unexpected, the control condition performed better on comprehension questions than the intervention conditions. To try to understand these results, we examined the time each child took to answer the comprehension questions. Many children answered the questions quickly, and average time to answer the questions was strongly correlated with comprehension scores. Children may have been answering questions quickly (and randomly) in order to advance to the next story. Nonetheless, the data do not support a relationship between FMS and reading comprehension.
ContributorsWeiss, Julia (Author) / Glenberg, Arthur (Thesis director) / Gomez Franco, Ligia (Committee member) / Peter, Beate (Committee member) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
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Description
Do good readers embody more or less? The current investigation examined embodiment effects as a function of individual reading skill in the context of two cognitive theories of reading comprehension. The Construction-Integration model predicts that sensorimotor activity during reading will correlate negatively with reading skill, because good readers focus on

Do good readers embody more or less? The current investigation examined embodiment effects as a function of individual reading skill in the context of two cognitive theories of reading comprehension. The Construction-Integration model predicts that sensorimotor activity during reading will correlate negatively with reading skill, because good readers focus on relations among abstract ideas derived from the text. Supposedly those abstract ideas have little or no sensorimotor content, hence any sensorimotor activity while reading is wasted effort. In contrast, the simulation theory predicts that sensorimotor activity will correlate positively with reading skill, because good readers create a simulation of what is happening within the text to comprehend it. The simulation is based in neural and bodily systems of action, perception, and emotion. These opposing predictions were tested using the reading-by-rotation paradigm to measure embodiment effects. Those effects were then correlated with reading skill measured using the Gates-McGinite standardized reading test. Analyses revealed an unexpected interaction between condition and congruency, and a negative relationship between embodiment and reading skill. Several caveats to the results are discussed.
ContributorsRakestraw, Hannah Marie (Author) / Glenberg, Arthur (Thesis director) / McNamara, Danielle (Committee member) / Van Gelderen, Elly (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of Film, Dance and Theatre (Contributor) / Department of English (Contributor)
Created2013-12
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Description
Motor behavior is prone to variable conditions and deviates further in disorders affecting the nervous system. A combination of environmental and neural factors impacts the amount of uncertainty. Although the influence of these factors on estimating endpoint positions have been examined, the role of limb configuration on endpoint variability has

Motor behavior is prone to variable conditions and deviates further in disorders affecting the nervous system. A combination of environmental and neural factors impacts the amount of uncertainty. Although the influence of these factors on estimating endpoint positions have been examined, the role of limb configuration on endpoint variability has been mostly ignored. Characterizing the influence of arm configuration (i.e. intrinsic factors) would allow greater comprehension of sensorimotor integration and assist in interpreting exaggerated movement variability in patients. In this study, subjects were placed in a 3-D virtual reality environment and were asked to move from a starting position to one of three targets in the frontal plane with and without visual feedback of the moving limb. The alternating of visual feedback during trials increased uncertainty between the planning and execution phases. The starting limb configurations, adducted and abducted, were varied in separate blocks. Arm configurations were setup by rotating along the shoulder-hand axis to maintain endpoint position. The investigation hypothesized: 1) patterns of endpoint variability of movements would be dependent upon the starting arm configuration and 2) any differences observed would be more apparent in conditions that withheld visual feedback. The results indicated that there were differences in endpoint variability between arm configurations in both visual conditions, but differences in variability increased when visual feedback was withheld. Overall this suggests that in the presence of visual feedback, planning of movements in 3D space mostly uses coordinates that are arm configuration independent. On the other hand, without visual feedback, planning of movements in 3D space relies substantially on intrinsic coordinates.
ContributorsRahman, Qasim (Author) / Buneo, Christopher (Thesis director) / Helms Tillery, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
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Description
Motor behavior is prone to variable conditions and deviates further in disorders affecting the nervous system. A combination of environmental and neural factors impacts the amount of uncertainty. Although the influence of these factors on estimating endpoint positions have been examined, the role of limb configuration on endpoint variability has

Motor behavior is prone to variable conditions and deviates further in disorders affecting the nervous system. A combination of environmental and neural factors impacts the amount of uncertainty. Although the influence of these factors on estimating endpoint positions have been examined, the role of limb configuration on endpoint variability has been mostly ignored. Characterizing the influence of arm configuration (i.e. intrinsic factors) would allow greater comprehension of sensorimotor integration and assist in interpreting exaggerated movement variability in patients. In this study, subjects were placed in a 3-D virtual reality environment and were asked to move from a starting position to one of three targets in the frontal plane with and without visual feedback of the moving limb. The alternating of visual feedback during trials increased uncertainty between the planning and execution phases. The starting limb configurations, adducted and abducted, were varied in separate blocks. Arm configurations were setup by rotating along the shoulder-hand axis to maintain endpoint position. The investigation hypothesized: 1) patterns of endpoint variability of movements would be dependent upon the starting arm configuration and 2) any differences observed would be more apparent in conditions that withheld visual feedback. The results indicated that there were differences in endpoint variability between arm configurations in both visual conditions, but differences in variability increased when visual feedback was withheld. Overall this suggests that in the presence of visual feedback, planning of movements in 3D space mostly uses coordinates that are arm configuration independent. On the other hand, without visual feedback, planning of movements in 3D space relies substantially on intrinsic coordinates.
ContributorsRahman, Qasim (Author) / Buneo, Christopher (Thesis director) / Helms Tillery, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
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Description
The purposes of the study are to: 1) investigate how students' motivation towards reading is related to their reading comprehension skills, and 2) assess the impact of using an Intelligent Tutoring System to improve comprehension. Interactive Strategy Training for Active Reading and Thinking-3 (iSTART-3) is a game-based tutoring system designed

The purposes of the study are to: 1) investigate how students' motivation towards reading is related to their reading comprehension skills, and 2) assess the impact of using an Intelligent Tutoring System to improve comprehension. Interactive Strategy Training for Active Reading and Thinking-3 (iSTART-3) is a game-based tutoring system designed to improve students' reading comprehension skills. The current study was conducted in South Africa with 8th and 9th graders between the ages of 14 and 18. These students are multilingual and they learn English as a First Additional Language (English-FAL). Firstly, we predict that students who are highly motivated to read will have high comprehension scores than those who are slightly or not at all motivated to read. Secondly, we predict that the use of iSTART-3 will improve students' reading comprehension, regardless of their level of reading motivation, with better results for those who are more motivated to read. Counter to our predictions, the results did not reveal a relation between reading motivation and reading comprehension. Furthermore, an effect of iSTART-3 on reading comprehension was not found. These results were likely influenced by the small sample size and the length of the intervention.
ContributorsSeerane, Thato (Author) / McNamara, Danielle (Thesis director) / Glenberg, Arthur (Committee member) / Lynch, Christa (Committee member) / Department of Psychology (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
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Description
This study investigates whether children who are Dual Language Learners (DLLs) and who have poor reading comprehension will benefit from participating in the EMBRACE intervention. The reading comprehension program is based on the Theory of Embodied Cognition, which focuses on the embodied nature of language comprehension. Our understanding of language

This study investigates whether children who are Dual Language Learners (DLLs) and who have poor reading comprehension will benefit from participating in the EMBRACE intervention. The reading comprehension program is based on the Theory of Embodied Cognition, which focuses on the embodied nature of language comprehension. Our understanding of language is based on mental representations that we create through experiences and are integrated with according sensorimotor information. Therefore, by engaging the motor and language system through reading stories on an iPad that prompt the children to manipulate images on-screen, we might improve children's reading strategies and comprehension scores. Fifty-six children participated in reading three stories and answering related questions over a period of two weeks. Results showed that the intervention was successful in increasing reading comprehension scores in the physical manipulation condition but not in the imaginary manipulation condition. Although lower motor skill scores positively correlated with lower comprehension skills, the children's motor deficits did not moderate their performance on the intervention.
ContributorsValentin, Andrea Cristina (Author) / Glenberg, Arthur (Thesis director) / Restrepo, Maria Adelaida (Committee member) / Adams, Ashley M. (Committee member) / Department of Speech and Hearing Science (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
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Description
Recent work in free-recall tasks suggest that human memory foraging may follow a Lévy flight distribution – a random walk procedure that is common in other activities of cognitive agents, such as animal and human food foraging. This study attempts to draw parallels between memory search and physical search, with

Recent work in free-recall tasks suggest that human memory foraging may follow a Lévy flight distribution – a random walk procedure that is common in other activities of cognitive agents, such as animal and human food foraging. This study attempts to draw parallels between memory search and physical search, with the assumption that humans follow similar search patterns in both. To date, research merely equates the two processes (foraging in memory and the physical world) based on a similarity in statistical structure. This study starts with demonstrating a relationship between physical distance traveled and IRIs by having participants list countries. An IRI, inter-retrieval interval, is the time interval between items recalled. The next experiment uses multidimensional scaling (MDS) to derive a Euclidean perceptual space from similarity ratings of freely-recalled items and then maps the trajectory of human thought through this perceptual space. This trajectory can offer a much more compelling comparison to physical foraging behavior. Finally, a possible correlate of Lévy flight foraging is explored called critical slowing down. Statistically significant evidence was found in all three experiments. The discussion connects all three experiments and what their results mean for human memory foraging.
ContributorsGreer, Katharine Marie (Author) / Amazeen, Eric L. (Thesis director) / Glenberg, Arthur (Committee member) / Amazeen, Polemnia (Committee member) / Department of Psychology (Contributor) / School of Criminology and Criminal Justice (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12