Matching Items (9)

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A Functional and Structural MRI Investigation of the Neural Signatures of Dyslexia in Adults

Description

The International Dyslexia Association defines dyslexia as a learning disorder that is characterized by poor spelling, decoding, and word recognition abilities. There is still no known cause of dyslexia, although

The International Dyslexia Association defines dyslexia as a learning disorder that is characterized by poor spelling, decoding, and word recognition abilities. There is still no known cause of dyslexia, although it is a very common disability that affects 1 in 10 people. Previous fMRI and MRI research in dyslexia has explored the neural correlations of hemispheric lateralization and phonemic awareness in dyslexia. The present study investigated the underlying neurobiology of five adults with dyslexia compared to age- and sex-matched control subjects using structural and functional magnetic resonance imaging. All subjects completed a large battery of behavioral tasks as part of a larger study and underwent functional and structural MRI acquisition. This data was collected and preprocessed at the University of Washington. Analyses focused on examining the neural correlates of hemispheric lateralization, letter reversal mistakes, reduced processing speed, and phonemic awareness. There were no significant findings of hemispheric differences between subjects with dyslexia and controls. The subject making the largest amount of letter reversal errors had deactivation in their cerebellum during the fMRI language task. Cerebellar white matter volume and surface area of the premotor cortex was the largest in the individual with the slowest reaction time to tapping. Phonemic decoding efficiency had a high correlation with neural activation in the primary motor cortex during the fMRI motor task (r=0.6). Findings from the present study suggest that brain regions utilized during motor control, such as the cerebellum, premotor cortex, and primary motor cortex, may have a larger role in dyslexia then previously considered. Future studies are needed to further distinguish the role of the cerebellum and other motor regions in relation to motor control and language processing deficits related to dyslexia.

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  • 2016-12

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The Role of the Biogenic Amine Tyramine in Latent Inhibition Learning in the Honey Bee, Apis mellifera

Description

Animals must learn to ignore stimuli that are irrelevant to survival, a process referred to as latent inhibition. The Amtyr1 gene has been shown through quantitative trait loci mapping to

Animals must learn to ignore stimuli that are irrelevant to survival, a process referred to as latent inhibition. The Amtyr1 gene has been shown through quantitative trait loci mapping to be linked to strong latent inhibition in honey bees. Here we implicate this G-protein coupled receptor for the biogenic amine tyramine as an important factor underlying this form of learning in honey bees. We show that dsRNA targeted to disrupt the tyramine receptors, specifically affects latent inhibition but not excitatory associative conditioning. Our results therefore identify a distinct reinforcement pathway for latent inhibition in insects.

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  • 2016-12

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The Trajectory of Thought: Lévy Flight Patterns and Dynamical Systems in Human Memory Foraging

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,

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.

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  • 2016-12

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Analysis of Brain Activity in Elite Golfers

Description

It is unknown which regions of the brain are most or least active for golfers during a peak performance state (Flow State or "The Zone") on the putting green. To

It is unknown which regions of the brain are most or least active for golfers during a peak performance state (Flow State or "The Zone") on the putting green. To address this issue, electroencephalographic (EEG) recordings were taken on 10 elite golfers while they performed a putting drill consisting of hitting nine putts spaced uniformly around a hole each five feet away. Data was collected at three time periods, before, during and after the putt. Galvanic Skin Response (GSR) measurements were also recorded on each subject. Three of the subjects performed a visualization of the same putting drill and their brain waves and GSR were recorded and then compared with their actual performance of the drill. EEG data in the Theta (4 \u2014 7 Hz) bandwidth and Alpha (7 \u2014 13 Hz) bandwidth in 11 different locations across the head were analyzed. Relative power spectrum was used to quantify the data. From the results, it was found that there is a higher magnitude of power in both the theta and alpha bandwidths for a missed putt in comparison to a made putt (p<0.05). It was also found that there is a higher average power in the right hemisphere for made putts. There was not a higher power in the occipital region of the brain nor was there a lower power level in the frontal cortical region during made putts. The hypothesis that there would be a difference between the means of the power level in performance compared to visualization techniques was also supported.

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  • 2016-05

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Characterizing the Role of Arm Configuration on Patterns of Movement Variability in 3D Space

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

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.

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Date Created
  • 2014-05

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Cognitive Impact of Dietary Phytoestrogens

Description

There is preclinical evidence that the detrimental cognitive effects of hormone loss can be ameliorated by estrogen therapy (Bimonte, Acosta, & Talboom, 2010), however, one of the primary concerns with

There is preclinical evidence that the detrimental cognitive effects of hormone loss can be ameliorated by estrogen therapy (Bimonte, Acosta, & Talboom, 2010), however, one of the primary concerns with current hormone therapies is that they are nonselective, leading to increased risk of breast and endometrial cancers as well as heart disease. Thus, in order to achieve a successful and clinically relevant long-term hormone therapy option, it is optimal to find an estrogen therapy regimen that is selective to its target tissue. Recently, phytoestrogens have been found to exert selective, beneficial effects on cognition and brain. For example, genistein and diadzein produce neuroprotective effects in cognitive brain regions (Zhao, Chen, & Diaz Brinton, 2002). The purpose of this study was threefold: 1) to examine the cognitive impact of phytoestrogens in young ovariectomized rats, 2) to replicate the dose effects found in the Luine study (Luine et al., 2006), while controlling for manufacturer differences, and 3) to assess if the rodent diet used in our laboratory has an estrogenic-like cognitive impact.The current findings suggest that, at least for object memory, diets containing varying amounts of phytoestrogens can alter cognition, with diets containing high amounts of phytoestrogens showing potential benefits to this type of memory.

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Date Created
  • 2013-05

Biofeedback Music: A Junction of Music and Neurosignals

Description

Biofeedback music is the integration of physiological signals with audible sound for aesthetic considerations, which an individual’s mental status corresponds to musical output. This project looks into how sounds can

Biofeedback music is the integration of physiological signals with audible sound for aesthetic considerations, which an individual’s mental status corresponds to musical output. This project looks into how sounds can be drawn from the meditative and attentive states of the brain using the MindWave Mobile EEG biosensor from NeuroSky. With the MindWave and an Arduino microcontroller processor, sonic output is attained by inputting the data collected by the MindWave, and in real time, outputting code that deciphers it into user constructed sound output. The input is scaled from values 0 to 100, measuring the ‘attentive’ state of the mind by observing alpha waves, and distributing this information to the microcontroller. The output of sound comes from sourcing this into the Musical Instrument Shield and varying the musical tonality with different chords and delay of the notes. The manipulation of alpha states highlights the control or lack thereof for the performer and touches on the question of how much control over the output there really is, much like the experimentalist Alvin Lucier displayed with his concepts in brainwave music.

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Date Created
  • 2014-05

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Characterizing the Role of Arm Configuration on Patterns of Movement Variability in 3D Space

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

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.

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Agent

Created

Date Created
  • 2014-05

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Diurnal Cortisol Rhythms and Sleeping Patterns in Adolescence: A Longitudinal Study of the Transition to College

Description

This study examined the cross-sectional and longitudinal associations among diurnal cortisol rhythms and sleeping patterns in adolescents. 79 participants completed the study over three days during the spring semester of

This study examined the cross-sectional and longitudinal associations among diurnal cortisol rhythms and sleeping patterns in adolescents. 79 participants completed the study over three days during the spring semester of their senior year in high school, and 76 of these subjects participated again over three days during the fall semester of their freshman year in college. They completed daily saliva samples and diary entries, while wearing an actigraph to obtain objective measurements of sleep duration and efficiency. Cross-sectionally, longer sleep duration was associated with a lower cortisol awakening response, a smaller area under the cortisol curve, and a steeper cortisol slope. Longitudinally, there was no significant relationship between sleep duration and these cortisol parameters. Moreover, sleep efficiency was not associated with cortisol parameters cross-sectionally nor longitudinally. Results suggest associations between concurrent sleep duration and cortisol patterns, and may have significant impact on understanding adolescents' physiological response to stress.

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Date Created
  • 2013-05