Browsing by Subject "Movement"
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Item Open Access African forest elephant movements depend on time scale and individual behavior.(Scientific reports, 2021-06-16) Beirne, Christopher; Houslay, Thomas M; Morkel, Peter; Clark, Connie J; Fay, Mike; Okouyi, Joseph; White, Lee JT; Poulsen, John RThe critically endangered African forest elephant (Loxodonta cyclotis) plays a vital role in maintaining the structure and composition of Afrotropical forests, but basic information is lacking regarding the drivers of elephant movement and behavior at landscape scales. We use GPS location data from 96 individuals throughout Gabon to determine how five movement behaviors vary at different scales, how they are influenced by anthropogenic and environmental covariates, and to assess evidence for behavioral syndromes-elephants which share suites of similar movement traits. Elephants show some evidence of behavioral syndromes along an 'idler' to 'explorer' axis-individuals that move more have larger home ranges and engage in more 'exploratory' movements. However, within these groups, forest elephants express remarkable inter-individual variation in movement behaviours. This variation highlights that no two elephants are the same and creates challenges for practitioners aiming to design conservation initiatives.Item Open Access Brain circuits for the internal monitoring of movements.(Annu Rev Neurosci, 2008) Sommer, Marc A; Wurtz, Robert HEach movement we make activates our own sensory receptors, thus causing a problem for the brain: the spurious, movement-related sensations must be discriminated from the sensory inputs that really matter, those representing our environment. Here we consider circuits for solving this problem in the primate brain. Such circuits convey a copy of each motor command, known as a corollary discharge (CD), to brain regions that use sensory input. In the visual system, CD signals may help to produce a stable visual percept from the jumpy images resulting from our rapid eye movements. A candidate pathway for providing CD for vision ascends from the superior colliculus to the frontal cortex in the primate brain. This circuit conveys warning signals about impending eye movements that are used for planning subsequent movements and analyzing the visual world. Identifying this circuit has provided a model for studying CD in other primate sensory systems and may lead to a better understanding of motor and mental disorders.Item Open Access Can Movement Speed Predict Habitat Preference? Assessing the Influence of Topography, Village Proximity, and Land Cover on Forest Elephant (Loxodonta cyclotis) Movement and Preferences in Gabon.(2019-04-24) Kim, SeokminUnderstanding animal habitat preference is crucial for the management of animal populations and planning of protected areas. However, current models for estimating habitat preference require arbitrary estimates of habitat availability, which introduce a level of uncertainty and qualitative inference that could affect model accuracy. To overcome this problem, Dickson et al. (2005) suggested that movement speed could be used as a metric of habitat preference, assuming that movement speed would be negatively related to habitat preference. However, this speed - preference model ignores potential changes in movement related to behavioral shifts or variations in terrain. To assess the generalizability and practicality of the speed-preference model, I examined the hourly movements of 56 GPS collared forest elephants (Loxodonta cyclotis) in Gabon, central Africa between 2015 and 2018 in the context of three relevant environmental covariates (land covers, topography, and village proximity). I analyzed changes in movement speed by attributing a single value for specific environmental characteristics to each movement step and estimated preferences by calculating the density of each individual’s GPS points within the covariate of interest from the individual’s travel range. I then modeled the relationship between speed and preference with a linear mixed model. Speed failed to predict preferences for different land cover types, and relationships between speed and preference for gradients of topography and village proximity changed in both direction and intensity. Therefore, although using speed to predict habitat preference avoids the limitations of other habitat preference models, this method requires further research to assess the complex interactions between speed and environmental covariates for different animal species.Item Open Access Corollary discharge across the animal kingdom.(Nat Rev Neurosci, 2008-08) Crapse, Trinity B; Sommer, Marc AOur movements can hinder our ability to sense the world. Movements can induce sensory input (for example, when you hit something) that is indistinguishable from the input that is caused by external agents (for example, when something hits you). It is critical for nervous systems to be able to differentiate between these two scenarios. A ubiquitous strategy is to route copies of movement commands to sensory structures. These signals, which are referred to as corollary discharge (CD), influence sensory processing in myriad ways. Here we review the CD circuits that have been uncovered by neurophysiological studies and suggest a functional taxonomic classification of CD across the animal kingdom. This broad understanding of CD circuits lays the groundwork for more challenging studies that combine neurophysiology and psychophysics to probe the role of CD in perception.Item Open Access Decision rules of blue crab (Callinectes sapidus) movement in wind-driven systems(2015-04-24) Chen, JuliaBlue crabs (Callinectes sapidus) are the most economically valuable fishery in North Carolina, and the commercial harvest is mainly from the Albemarle-Pamlico Estuarine System (APES). Because of small inlets which restrict ocean tidal forcing in addition to large expanses of shallow water, circulation in the APES is primarily wind-driven. While much is known about how crabs move in tidally-dominated systems where movements are based upon selective tidal-stream transport, crab movements in wind-driven systems, and their response to environmental factors, remain poorly understood. This study aims to increase understanding of environmental controls on blue crab movements in order to inform management of crab resources in wind-driven systems. We studied crab movements in Lake Mattamuskeet National Wildlife Refuge, a 40,000-acre shallow, wind-driven system within the APES. During October 2014, free ranging crabs were tracked using radio frequency identification (RFID) tags and an antenna array deployed along the Central Canal connecting the lake to Pamlico Sound. Colocated and simultaneous meteorological and physical oceanographic data were collected to understand environmental drivers that may affect crab movements. Analyses of these data indicate: 1) a significant net export of blue crabs from the lake to the sound; the drivers of that export remain unclear; 2) crab movements coincided with the direction of water flow in the canal, and 3) at small-scales, crabs were able to move against the water flow. These results suggest that there is a fall migration, during which crabs move from the lake to the sound, and at a relatively constant rate that is slower than the mean water flow. If crabs are to move out of the lake at this time it is essential to open water control structures in order to facilitate migration. This is particularly important for the females, who because of their large size may contribute disproportionately large amounts of larvae to the Pamlico Sound broodstock. Crabs in the larger fishery may also move toward higher salinity water if they behave similarly to those studied here.Item Open Access Effect of Autologous Cord Blood Infusion on Motor Function and Brain Connectivity in Young Children with Cerebral Palsy: A Randomized, Placebo-Controlled Trial.(Stem cells translational medicine, 2017-12) Sun, Jessica M; Song, Allen W; Case, Laura E; Mikati, Mohamad A; Gustafson, Kathryn E; Simmons, Ryan; Goldstein, Ricki; Petry, Jodi; McLaughlin, Colleen; Waters-Pick, Barbara; Chen, Lyon W; Wease, Stephen; Blackwell, Beth; Worley, Gordon; Troy, Jesse; Kurtzberg, JoanneCerebral palsy (CP) is a condition affecting young children that causes lifelong disabilities. Umbilical cord blood cells improve motor function in experimental systems via paracrine signaling. After demonstrating safety, we conducted a phase II trial of autologous cord blood (ACB) infusion in children with CP to test whether ACB could improve function (ClinicalTrials.gov, NCT01147653; IND 14360). In this double-blind, placebo-controlled, crossover study of a single intravenous infusion of 1-5 × 107 total nucleated cells per kilogram of ACB, children ages 1 to 6 years with CP were randomly assigned to receive ACB or placebo at baseline, followed by the alternate infusion 1 year later. Motor function and magnetic resonance imaging brain connectivity studies were performed at baseline, 1, and 2 years post-treatment. The primary endpoint was change in motor function 1 year after baseline infusion. Additional analyses were performed at 2 years. Sixty-three children (median age 2.1 years) were randomized to treatment (n = 32) or placebo (n = 31) at baseline. Although there was no difference in mean change in Gross Motor Function Measure-66 (GMFM-66) scores at 1 year between placebo and treated groups, a dosing effect was identified. In an analysis 1 year post-ACB treatment, those who received doses ≥2 × 107 /kg demonstrated significantly greater increases in GMFM-66 scores above those predicted by age and severity, as well as in Peabody Developmental Motor Scales-2 Gross Motor Quotient scores and normalized brain connectivity. Results of this study suggest that appropriately dosed ACB infusion improves brain connectivity and gross motor function in young children with CP. Stem Cells Translational Medicine 2017;6:2071-2078.Item Open Access Emergent group level navigation: an agent-based evaluation of movement patterns in a folivorous primate.(PLoS One, 2013) Bonnell, Tyler R; Campennì, Marco; Chapman, Colin A; Gogarten, Jan F; Reyna-Hurtado, Rafael A; Teichroeb, Julie A; Wasserman, Michael D; Sengupta, RajaThe foraging activity of many organisms reveal strategic movement patterns, showing efficient use of spatially distributed resources. The underlying mechanisms behind these movement patterns, such as the use of spatial memory, are topics of considerable debate. To augment existing evidence of spatial memory use in primates, we generated movement patterns from simulated primate agents with simple sensory and behavioral capabilities. We developed agents representing various hypotheses of memory use, and compared the movement patterns of simulated groups to those of an observed group of red colobus monkeys (Procolobus rufomitratus), testing for: the effects of memory type (Euclidian or landmark based), amount of memory retention, and the effects of social rules in making foraging choices at the scale of the group (independent or leader led). Our results indicate that red colobus movement patterns fit best with simulated groups that have landmark based memory and a follow the leader foraging strategy. Comparisons between simulated agents revealed that social rules had the greatest impact on a group's step length, whereas the type of memory had the highest impact on a group's path tortuosity and cohesion. Using simulation studies as experimental trials to test theories of spatial memory use allows the development of insight into the behavioral mechanisms behind animal movement, developing case-specific results, as well as general results informing how changes to perception and behavior influence movement patterns.Item Open Access Frontal eye field sends delay activity related to movement, memory, and vision to the superior colliculus.(J Neurophysiol, 2001-04) Sommer, MA; Wurtz, RHMany neurons within prefrontal cortex exhibit a tonic discharge between visual stimulation and motor response. This delay activity may contribute to movement, memory, and vision. We studied delay activity sent from the frontal eye field (FEF) in prefrontal cortex to the superior colliculus (SC). We evaluated whether this efferent delay activity was related to movement, memory, or vision, to establish its possible functions. Using antidromic stimulation, we identified 66 FEF neurons projecting to the SC and we recorded from them while monkeys performed a Go/Nogo task. Early in every trial, a monkey was instructed as to whether it would have to make a saccade (Go) or not (Nogo) to a target location, which permitted identification of delay activity related to movement. In half of the trials (memory trials), the target disappeared, which permitted identification of delay activity related to memory. In the remaining trials (visual trials), the target remained visible, which permitted identification of delay activity related to vision. We found that 77% (51/66) of the FEF output neurons had delay activity. In 53% (27/51) of these neurons, delay activity was modulated by Go/Nogo instructions. The modulation preceded saccades made into only part of the visual field, indicating that the modulation was movement-related. In some neurons, delay activity was modulated by Go/Nogo instructions in both memory and visual trials and seemed to represent where to move in general. In other neurons, delay activity was modulated by Go/Nogo instructions only in memory trials, which suggested that it was a correlate of working memory, or only in visual trials, which suggested that it was a correlate of visual attention. In 47% (24/51) of FEF output neurons, delay activity was unaffected by Go/Nogo instructions, which indicated that the activity was related to the visual stimulus. In some of these neurons, delay activity occurred in both memory and visual trials and seemed to represent a coordinate in visual space. In others, delay activity occurred only in memory trials and seemed to represent transient visual memory. In the remainder, delay activity occurred only in visual trials and seemed to be a tonic visual response. In conclusion, the FEF sends diverse delay activity signals related to movement, memory, and vision to the SC, where the signals may be used for saccade generation. Downstream transmission of various delay activity signals may be an important, general way in which the prefrontal cortex contributes to the control of movement.Item Open Access Genetic disruption of WASHC4 drives endo-lysosomal dysfunction and cognitive-movement impairments in mice and humans.(eLife, 2021-03-22) Courtland, Jamie L; Bradshaw, Tyler Wa; Waitt, Greg; Soderblom, Erik J; Ho, Tricia; Rajab, Anna; Vancini, Ricardo; Kim, Il Hwan; Soderling, Scott HMutation of the Wiskott-Aldrich syndrome protein and SCAR homology (WASH) complex subunit, SWIP, is implicated in human intellectual disability, but the cellular etiology of this association is unknown. We identify the neuronal WASH complex proteome, revealing a network of endosomal proteins. To uncover how dysfunction of endosomal SWIP leads to disease, we generate a mouse model of the human WASHC4c.3056C>G mutation. Quantitative spatial proteomics analysis of SWIPP1019R mouse brain reveals that this mutation destabilizes the WASH complex and uncovers significant perturbations in both endosomal and lysosomal pathways. Cellular and histological analyses confirm that SWIPP1019R results in endo-lysosomal disruption and uncover indicators of neurodegeneration. We find that SWIPP1019R not only impacts cognition, but also causes significant progressive motor deficits in mice. A retrospective analysis of SWIPP1019R patients reveals similar movement deficits in humans. Combined, these findings support the model that WASH complex destabilization, resulting from SWIPP1019R, drives cognitive and motor impairments via endo-lysosomal dysfunction in the brain.Item Open Access Mechanistic insights into actin-driven polarity site movement in yeast.(Molecular biology of the cell, 2020-05) Ghose, Debraj; Lew, DanielDirected cell growth or migration are critical for the development and function of many eukaryotic cells. These cells develop a dynamic "front" (also called "polarity site") that can change direction. Polarity establishment involves autocatalytic accumulation of polarity regulators, including the conserved Rho-family GTPase Cdc42, but the mechanisms underlying polarity reorientation remain poorly understood. The tractable model yeast, Saccharomyces cerevisiae, relocates its polarity site when searching for mating partners. Relocation requires polymerized actin, and is thought to involve actin-mediated vesicle traffic to the polarity site. In this study, we provide a quantitative characterization of spontaneous polarity site movement as a search process and use a mechanistic computational model that combines polarity protein biochemical interactions with vesicle trafficking to probe how various processes might affect polarity site movement. Our findings identify two previously documented features of yeast vesicle traffic as being particularly relevant to such movement: tight spatial focusing of exocytosis enhances the directional persistence of movement, and association of Cdc42-directed GTPase-Activating Proteins with secretory vesicles increases the distance moved. Furthermore, we suggest that variation in the rate of exocytosis beyond simple Poisson dynamics may be needed to fully account for the characteristics of polarity site movement in vivo.Item Open Access Minor Moves: Growth, Fugitivity, and Children's Physical Movement(2014) Curseen, Allison SamanthaFrom tendencies to reduce the Underground Railroad to the imperative "follow the north star" to the iconic images of Ruby Bridges' 1960 "step forward" on the stairs of William Frantz Elementary School, America prefers to picture freedom as an upwardly mobile development. This preoccupation with the subtractive and linear force of development makes it hard to hear the palpable steps of so many truant children marching in the Movement and renders illegible the nonlinear movements of minors in the Underground. Yet a black fugitive hugging a tree, a white boy walking alone in a field, or even pieces of a discarded raft floating downstream like remnants of child's play are constitutive gestures of the Underground's networks of care and escape. Responding to 19th-century Americanists and cultural studies scholars' important illumination of the child as central to national narratives of development and freedom, "Minor Moves" reads major literary narratives not for the child and development but for the fugitive trace of minor and growth.
In four chapters, I trace the physical gestures of Nathaniel Hawthorne's Pearl, Harriet Beecher Stowe's Topsy, Harriet Wilson's Frado, and Mark Twain's Huck against the historical backdrop of the Fugitive Slave Act and the passing of the first compulsory education bills that made truancy illegal. I ask how, within a discourse of independence that fails to imagine any serious movements in the minor, we might understand the depictions of moving children as interrupting a U.S. preoccupation with normative development and recognize in them the emergence of an alternative imaginary. To attend to the movement of the minor is to attend to what the discursive order of a development-centered imaginary deems inconsequential and what its grammar can render only as mistakes. Engaging the insights of performance studies, I regard what these narratives depict as childish missteps (Topsy's spins, Frado's climbing the roof) as dances that trouble the narrative's discursive order. At the same time, drawing upon the observations of black studies and literary theory, I take note of the pressure these "minor moves" put on the literal grammar of the text (Stowe's run-on sentences and Hawthorne's shaky subject-verb agreements). I regard these ungrammatical moves as poetic ruptures from which emerges an alternative and prior force of the imaginary at work in these narratives--a force I call "growth."
Reading these "minor moves" holds open the possibility of thinking about a generative association between blackness and childishness, one that neither supports racist ideas of biological inferiority nor mandates in the name of political uplift the subsequent repudiation of childishness. I argue that recognizing the fugitive force of growth indicated in the interplay between the conceptual and grammatical disjunctures of these minor moves opens a deeper understanding of agency and dependency that exceeds notions of arrested development and social death. For once we interrupt the desire to picture development (which is to say the desire to picture), dependency is no longer a state (of social death or arrested development) of what does not belong, but rather it is what Édouard Glissant might have called a "departure" (from "be[ing] a single being"). Topsy's hard-to-see pick-pocketing and Pearl's running amok with brown men in the market are not moves out of dependency but indeed social turns (a dance) by way of dependency. Dependent, moving and ungrammatical, the growth evidenced in these childish ruptures enables different stories about slavery, freedom, and childishness--ones that do not necessitate a repudiation of childishness in the name of freedom, but recognize in such minor moves a fugitive way out.
Item Open Access Molecular mapping of movement-associated areas in the avian brain: a motor theory for vocal learning origin.(PLoS One, 2008-03-12) Feenders, Gesa; Liedvogel, Miriam; Rivas, Miriam; Zapka, Manuela; Horita, Haruhito; Hara, Erina; Wada, Kazuhiro; Mouritsen, Henrik; Jarvis, Erich DVocal learning is a critical behavioral substrate for spoken human language. It is a rare trait found in three distantly related groups of birds-songbirds, hummingbirds, and parrots. These avian groups have remarkably similar systems of cerebral vocal nuclei for the control of learned vocalizations that are not found in their more closely related vocal non-learning relatives. These findings led to the hypothesis that brain pathways for vocal learning in different groups evolved independently from a common ancestor but under pre-existing constraints. Here, we suggest one constraint, a pre-existing system for movement control. Using behavioral molecular mapping, we discovered that in songbirds, parrots, and hummingbirds, all cerebral vocal learning nuclei are adjacent to discrete brain areas active during limb and body movements. Similar to the relationships between vocal nuclei activation and singing, activation in the adjacent areas correlated with the amount of movement performed and was independent of auditory and visual input. These same movement-associated brain areas were also present in female songbirds that do not learn vocalizations and have atrophied cerebral vocal nuclei, and in ring doves that are vocal non-learners and do not have cerebral vocal nuclei. A compilation of previous neural tracing experiments in songbirds suggests that the movement-associated areas are connected in a network that is in parallel with the adjacent vocal learning system. This study is the first global mapping that we are aware for movement-associated areas of the avian cerebrum and it indicates that brain systems that control vocal learning in distantly related birds are directly adjacent to brain systems involved in movement control. Based upon these findings, we propose a motor theory for the origin of vocal learning, this being that the brain areas specialized for vocal learning in vocal learners evolved as a specialization of a pre-existing motor pathway that controls movement.Item Open Access Moving New Futures: Embodied Movement for a Just Society(2023) Emanuel, BrooksMy Moving New Futures workshop uses improvisatory movement to help social justice practitioners—organizers, activists, civil rights lawyers, and others—imagine new possibilities for a just society. The workshop grew out of my own backgrounds in dance and social justice work. It has two major philosophical underpinnings: (1) the radical imagination necessary for prison-industrial complex abolition and (2) the growing body of scholarship showing that our entire bodies, not just our brains, produce thought. Facilitating the workshop for two separate groups of social justice practitioners, I recorded discussion portions and used a survey to gather data. Discussions and survey responses affirmed my hope that movement would be a source of new knowledge and imagination for social justice practitioners. After these two iterations, I performed a public lecture-demonstration in which I discussed the development of the workshop and results. In a co-creative process with practitioners, I will continue developing the workshop as a tool for their work.
Item Open Access Pinning down response inhibition in the brain--conjunction analyses of the Stop-signal task.(Neuroimage, 2010-10-01) Boehler, CN; Appelbaum, LG; Krebs, RM; Hopf, JM; Woldorff, MGSuccessful behavior requires a finely-tuned interplay of initiating and inhibiting motor programs to react effectively to constantly changing environmental demands. One particularly useful paradigm for investigating inhibitory motor control is the Stop-signal task, where already-initiated responses to Go-stimuli are to be inhibited upon the rapid subsequent presentation of a Stop-stimulus (yielding successful and unsuccessful Stop-trials). Despite the extensive use of this paradigm in functional neuroimaging, there is no consensus on which functional comparison to use to characterize response-inhibition-related brain activity. Here, we utilize conjunction analyses of successful and unsuccessful Stop-trials that are each contrasted against a reference condition. This conjunction approach identifies processes common to both Stop-trial types while excluding processes specific to either, thereby capitalizing on the presence of some response-inhibition-related activity in both conditions. Using this approach on fMRI data from human subjects, we identify a network of brain structures that was linked to both types of Stop-trials, including lateral-inferior frontal and medial frontal cortical areas and the caudate nucleus. In addition, comparisons with a reference condition matched for visual stimulation identified additional activity in the right inferior parietal cortex that may play a role in enhancing the processing of the Stop-stimuli. Finally, differences in stopping efficacy across subjects were associated with variations in activity in the left anterior insula. However, this region was also associated with general task accuracy (which furthermore correlated directly with stopping efficacy), suggesting that it might actually reflect a more general mechanism of performance control that supports response inhibition in a relatively nonspecific way.Item Open Access POCS-based reconstruction of multiplexed sensitivity encoded MRI (POCSMUSE): A general algorithm for reducing motion-related artifacts.(Magn Reson Med, 2015-11) Chu, Mei-Lan; Chang, Hing-Chiu; Chung, Hsiao-Wen; Truong, Trong-Kha; Bashir, Mustafa R; Chen, Nan-kueiPURPOSE: A projection onto convex sets reconstruction of multiplexed sensitivity encoded MRI (POCSMUSE) is developed to reduce motion-related artifacts, including respiration artifacts in abdominal imaging and aliasing artifacts in interleaved diffusion-weighted imaging. THEORY: Images with reduced artifacts are reconstructed with an iterative projection onto convex sets (POCS) procedure that uses the coil sensitivity profile as a constraint. This method can be applied to data obtained with different pulse sequences and k-space trajectories. In addition, various constraints can be incorporated to stabilize the reconstruction of ill-conditioned matrices. METHODS: The POCSMUSE technique was applied to abdominal fast spin-echo imaging data, and its effectiveness in respiratory-triggered scans was evaluated. The POCSMUSE method was also applied to reduce aliasing artifacts due to shot-to-shot phase variations in interleaved diffusion-weighted imaging data corresponding to different k-space trajectories and matrix condition numbers. RESULTS: Experimental results show that the POCSMUSE technique can effectively reduce motion-related artifacts in data obtained with different pulse sequences, k-space trajectories and contrasts. CONCLUSION: POCSMUSE is a general post-processing algorithm for reduction of motion-related artifacts. It is compatible with different pulse sequences, and can also be used to further reduce residual artifacts in data produced by existing motion artifact reduction methods.Item Open Access PPAR-δ is repressed in Huntington's disease, is required for normal neuronal function and can be targeted therapeutically.(Nat Med, 2016-01) Dickey, Audrey S; Pineda, Victor V; Tsunemi, Taiji; Liu, Patrick P; Miranda, Helen C; Gilmore-Hall, Stephen K; Lomas, Nicole; Sampat, Kunal R; Buttgereit, Anne; Torres, Mark-Joseph Manalang; Flores, April L; Arreola, Martin; Arbez, Nicolas; Akimov, Sergey S; Gaasterland, Terry; Lazarowski, Eduardo R; Ross, Christopher A; Yeo, Gene W; Sopher, Bryce L; Magnuson, Gavin K; Pinkerton, Anthony B; Masliah, Eliezer; La Spada, Albert RHuntington's disease (HD) is a progressive neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the huntingtin (HTT) gene, which encodes a polyglutamine tract in the HTT protein. We found that peroxisome proliferator-activated receptor delta (PPAR-δ) interacts with HTT and that mutant HTT represses PPAR-δ-mediated transactivation. Increased PPAR-δ transactivation ameliorated mitochondrial dysfunction and improved cell survival of neurons from mouse models of HD. Expression of dominant-negative PPAR-δ in the central nervous system of mice was sufficient to induce motor dysfunction, neurodegeneration, mitochondrial abnormalities and transcriptional alterations that recapitulated HD-like phenotypes. Expression of dominant-negative PPAR-δ specifically in the striatum of medium spiny neurons in mice yielded HD-like motor phenotypes, accompanied by striatal neuron loss. In mouse models of HD, pharmacologic activation of PPAR-δ using the agonist KD3010 improved motor function, reduced neurodegeneration and increased survival. PPAR-δ activation also reduced HTT-induced neurotoxicity in vitro and in medium spiny-like neurons generated from stem cells derived from individuals with HD, indicating that PPAR-δ activation may be beneficial in HD and related disorders.Item Open Access Stimulation of GABAergic neurons of the lateral septum and its effect on movement speed(2016-06-06) Stackmann, MichelleThe lateral septum is associated with the regulation of innate behavior, motivation, and locomotion. Its complex interconnections with cognitive and affective regions such as the hippocampus, hypothalamus, and medial septum have made it an attractive region for studying how motivation regulates behavior in context-specific settings. This GABAergic brain region’s main output is the lateral hypothalamus, which provides downstream signaling of motor commands. Even though stimulation of lateral septum projections to the hypothalamus have shown to decrease running speed in free behaving mice, characterizing movement kinematics due to LS activation has not been studied. GABAergic medium spiny neurons of the lateral septum were selectively activated through the use of optogenetic techniques in transgenic mice. Photostimulation of the lateral septum at theta frequencies caused a non-significant decrease in head and back speed. 3D motion analysis of body movement under photostimulation was quantified, revealing a slow, linear decrease of body speed as photostimulation progressed. These results support the role of lateral septum activation in movement regulation and shed light on the specific manner in which stimulation of the LS gradually decreases movement speed.Item Open Access The Habitat, Movements, and Management of Dolphin, Coryphaena hippurus, in the Western North Atlantic, Caribbean, and Gulf of Mexico(2009-04-23T20:55:42Z) Farrell, EdwardDolphin, Coryphaena hippurus, is a highly migratory cosmopolitan pelagic fish that is found seasonally in the Caribbean, Gulf of Mexico, and along the Atlantic coast of the United States. Dolphin are considered as one unit stock throughout the study area. This study used release-recapture data from a long-term tagging project to investigate baseline environmental preferences, habitat suitability based on dynamic ecogeographical variables, spatio-temporal movement through marine cadastral zones, and related policy implications. The data was collected from hundreds of recreational fishermen that tagged dolphin and also recaptured dolphin. A combination of in situ observations from recreational taggers and remotely sampled physical and biological variables (depth, bathymetric slope, distance to shore, distance to continental shelf, sea surface temperature, and sea surface chlorophyll-a) were used to establish an updated and novel baseline of environmental characteristics. A presence-only spatially explicit multivariate modeling approach was used to reveal the bio-physical seasonal preferences of dolphin that define the ecological niche. The results of the models show strong spatial sensitivity to sea surface temperature and surface chlorophyll-a concentration. The tagrecapture analysis showed that dolphin are capable of crossing multiple national and international marine jurisdictional zones throughout their lives. These movements bring the current management insufficiencies to light. Recommendations based on this multifaceted analysis focus on horizontal domestic and international fisheries integration.Item Open Access The incidence of unacceptable movement with motor evoked potentials during craniotomy for aneurysm clipping.(World Neurosurg, 2014-01) Hemmer, Laura B; Zeeni, Carine; Bebawy, John F; Bendok, Bernard R; Cotton, Mathew A; Shah, Neil B; Gupta, Dhanesh K; Koht, AntounOBJECTIVE: To review the experience at a single institution with motor evoked potential (MEP) monitoring during intracranial aneurysm surgery to determine the incidence of unacceptable movement. METHODS: Neurophysiology event logs and anesthetic records from 220 craniotomies for aneurysm clipping were reviewed for unacceptable patient movement or reason for cessation of MEPs. Muscle relaxants were not given after intubation. Transcranial MEPs were recorded from bilateral abductor hallucis and abductor pollicis muscles. MEP stimulus intensity was increased up to 500 V until evoked potential responses were detectable. RESULTS: Out of 220 patients, 7 (3.2%) exhibited unacceptable movement with MEP stimulation-2 had nociception-induced movement and 5 had excessive field movement. In all but one case, MEP monitoring could be resumed, yielding a 99.5% monitoring rate. CONCLUSIONS: With the anesthetic and monitoring regimen, the authors were able to record MEPs of the upper and lower extremities in all patients and found only 3.2% demonstrated unacceptable movement. With a suitable anesthetic technique, MEP monitoring in the upper and lower extremities appears to be feasible in most patients and should not be withheld because of concern for movement during neurovascular surgery.Item Open Access The investigation on the location effect of external markers in respiratory-gated radiotherapy.(Journal of applied clinical medical physics, 2008-04-16) Yan, Hui; Zhu, Guopei; Yang, James; Lu, Mei; Ajlouni, Munther; Kim, Jae Ho; Yin, Fang-FangPURPOSE:To investigate the effect of the marker placement on the correlation relationship between the motions of external markers and the internal target under different breathing patterns for several lung cancer patients. METHOD AND MATERIAL:To monitor and record simultaneous motions of internal target and associated surrogate markers during respiratory gated radiotherapy, an infrared camera system synchronized with a medical simulator was installed in our institute. Multiple external markers were placed on the patients' chest wall with proper geometrical arrangement in closely monitoring the motion of skin near tumor. The motion signals of three breathing sessions (free breathing, breath-holding, and free breathing after breath-holding) were recorded and the quality of correlation between them was analyzed. For a single marker motion, its correlation with the internal target was analyzed using cross-covariance function. For the multiple markers, their correlation with the internal target was analyzed based on additive model. RESULT:Seven patients undergoing radiotherapy with right upper or middle lobe lesions were enrolled in this study. Statistic analysis based on the internal-external motion signals shows that the effect of marker location on the quality of its correlation with the internal target is varied from patient to patient. There was no specific marker location where consistently demonstrated superior quality of correlation with the internal target motion over three breathing sessions for all patients. As the composite surrogate signal which was generated from the motions of multiple external markers was used to correlate the internal target motion, significant improvement of the quality of correlation was achieved. CONCLUSION:The correlation of external marker to the internal target could be influenced by several factors such as patient population, marker locations, and breathing patterns, considerably. The quality of correlation and predictability to the internal target furnished by a single external marker is inferior to that of the composite signal generated from multiple external markers. The use of composite signal shows great potential in improving the predictability of internal target motion and presents an effective way to track tumor more accurately.