Дисертації з теми "Activation pattern"
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1
Buettner, Karin, Thomas Kreisig, Norbert Sträter, and Thole Züchner. "Protein surface charge of trypsinogen changes its activation pattern." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-159779.
Повний текст джерелаАнотація:
Background: Trypsinogen is the inactive precursor of trypsin, a serine protease that cleaves proteins and peptides after arginine and lysine residues. In this study, human trypsinogen was used as a model protein to study the influence of electrostatic forces on protein–protein interactions. Trypsinogen is active only after its eight-amino-acid-long activation peptide has been cleaved off by another protease, enteropeptidase. Trypsinogen can also be autoactivated without the involvement of enteropeptidase. This autoactivation process can occur if a trypsinogen molecule is activated by another trypsin molecule and therefore is based on a protein–protein interaction. Results: Based on a rational protein design based on autoactivation-defective guinea pig trypsinogen, several amino acid residues, all located far away from the active site, were changed to modify the surface charge of human trypsinogen. The influence of the surface charge on the activation pattern of trypsinogen was investigated. The autoactivation properties of mutant trypsinogen were characterized in comparison to the recombinant wild-type enzyme. Surface-charged trypsinogen showed practically no autoactivation compared to the wild-type but could still be activated by enteropeptidase to the fully active trypsin. The kinetic parameters of surface-charged trypsinogen were comparable to the recombinant wild-type enzyme. Conclusion: The variant with a modified surface charge compared to the wild-type enzyme showed a complete different activation pattern. Our study provides an example how directed modification of the protein surface charge can be utilized for the regulation of functional protein–protein interactions, as shown here for human trypsinogen.
2
Buettner, Karin, Thomas Kreisig, Norbert Sträter, and Thole Züchner. "Protein surface charge of trypsinogen changes its activation pattern." BioMed Central, 2014. https://ul.qucosa.de/id/qucosa%3A13121.
Повний текст джерелаАнотація:
Background: Trypsinogen is the inactive precursor of trypsin, a serine protease that cleaves proteins and peptides after arginine and lysine residues. In this study, human trypsinogen was used as a model protein to study the influence of electrostatic forces on protein–protein interactions. Trypsinogen is active only after its eight-amino-acid-long activation peptide has been cleaved off by another protease, enteropeptidase. Trypsinogen can also be autoactivated without the involvement of enteropeptidase. This autoactivation process can occur if a trypsinogen molecule is activated by another trypsin molecule and therefore is based on a protein–protein interaction. Results: Based on a rational protein design based on autoactivation-defective guinea pig trypsinogen, several amino acid residues, all located far away from the active site, were changed to modify the surface charge of human trypsinogen. The influence of the surface charge on the activation pattern of trypsinogen was investigated. The autoactivation properties of mutant trypsinogen were characterized in comparison to the recombinant wild-type enzyme. Surface-charged trypsinogen showed practically no autoactivation compared to the wild-type but could still be activated by enteropeptidase to the fully active trypsin. The kinetic parameters of surface-charged trypsinogen were comparable to the recombinant wild-type enzyme. Conclusion: The variant with a modified surface charge compared to the wild-type enzyme showed a complete different activation pattern. Our study provides an example how directed modification of the protein surface charge can be utilized for the regulation of functional protein–protein interactions, as shown here for human trypsinogen.
3
Lebo, Timothy M. "Guiding object recognition : a shape model with co-activation networks /." Link to online version, 2005. http://hdl.handle.net/1850/993.
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Doull, Laura Elizabeth. "Inflammasome activation in ruminant cells infected with Chlamydia abortus." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/22082.
Повний текст джерелаАнотація:
Chlamydia abortus is the most common known infectious cause of ovine abortion worldwide but is rarely linked with bovine abortion. The reasons for this differential pathogenesis are unknown but may involve differences in innate immune recognition and immune responsiveness. This is supported by the observation that chlamydial abortion in sheep is associated with an inflammatory cytokine/chemokine cascade that is not commonly observed in cattle. Studies with other Chlamydia species have demonstrated that innate inflammatory pathways including inflammasome activation contribute to both pathogen clearance and pathology. Pattern recognition receptors (PRRs) activate these innate immune signalling pathways but are relatively poorly characterized in ruminants. We hypothesize that the ruminant hosts differ in their ability to innately sense C. abortus infection and activate the inflammasome. The main aims of this project were to: analyse PRR expression in innate immune cells; assess cytokine production from innate immune cells in response to C. abortus; investigate the role of PRRs in the induction of innate immune responses to C. abortus; and, conduct RNA-seq analysis on macrophages following infection with C. abortus to identify important immune signalling pathways. Ruminant oro-nasal turbinate cells, monocyte derived dendritic cells (MDDCs) and monocyte derived macrophages (MDMs) express the cell-surface PRRs TLR2 and TLR4 and also the intracellular PRRs NOD 1 and NLRP3. Oro-nasal turbinate cells produce CXCL8 late into the chlamydial developmental cycle independent of IL-1β. In contrast, ruminant MDMs and MDDCs secrete early IL-1β in response to C. abortus infection. In MDMs and MDDCs, live and UV-inactivated C. abortus induced TNF-α and CXCL8 but live infection was required for IL-1β secretion. Therefore, intracellular C. abortus multiplication is necessary to stimulate the IL-1β processing pathway within these cells. In order to determine PRR function, NOD1 and NLRP3 were knocked down in ruminant MDMs using siRNA. In both ovine and bovine MDMs, NOD1 was identified as a factor in C. abortus mediated IL-1β production. NLRP3 knockdown in bovine but not ovine MDMs also reduced IL-1β production, indicating species-specific differences in C. abortus recognition. The RNA-seq analysis of ruminant MDMs identified novel pathways of immune activation by C. abortus and potentially important species-specific differences. An improved understanding of the innate immune pathways activated in susceptible and resistant hosts following C. abortus infection will inform on disease pathogenesis and could contribute to novel chlamydial vaccine design.
5
Goede, Dieuwke de. "Verbs in spoken sentence processing: unraveling the activation pattern of the matrix verb." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2006. http://irs.ub.rug.nl/ppn/298832666.
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Doede, Aubrey L. "Electromyographic Analysis of Trunk Muscle Activation During a Throwing Pattern Following Rotator Cuff Mobilization." Scholarship @ Claremont, 2010. http://scholarship.claremont.edu/cmc_theses/90.
Повний текст джерелаАнотація:
Correct muscular activation of the body segments during an overhand throw is achieved when movement originates in the larger and more proximal legs and trunk and moves sequentially to the smaller, distal segments of the shoulder and arm. This sequence permits angular velocity to transfer progressively through the throw as part of an open kinetic chain. The athlete can summate angular velocity and segmental forces only if he is able to create a separation between the body segments during the movement pattern, and this separation is thus essential to effective segmental sequencing for activation of the trunk muscles to occur separately from distal segment motion. Limited mobility of the shoulder and scapula during the kinematic sequence will limit the ability of that segment to receive and contribute to the angular velocity of its proximal neighbors and to apply its own muscle torque to the throwing implement. This may result in compensatory motion of the proximal muscle groups to meet the demands placed on the body. To establish a link between compensatory activation of the trunk muscles and mobility in the rotator cuff and to apply this relationship to the pattern of the overhand throw, activity in the latissimus dorsi and external oblique/quadratus lumborum muscles was measured using surface electromyography in 40 college-age participants during arm flexion and lateral shoulder rotation. Muscle activation was recorded both before and after mobilization of relevant throwing muscles through targeted functional exercise. Results showed no significant change but suggested a general decrease in the level of peak muscle activation after participants engaged shoulder exercises. This is indicative of a downward trend in compensatory trunk activation during the initiation of shoulder motion. An increase in overall trunk muscle activity was also observed after exercise, which may imply a simultaneous engagement of the proximal throwing muscles in response to shoulder motion.
7
Lei, Andrea. "Inflammasome regulation and activation in the intestinal epithelium." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:6db34fe2-36ae-44f4-a4ac-2464a333c8f8.
Повний текст джерелаАнотація:
Microbiota colonisation of the intestinal tract makes it difficult for pattern recognition receptors (PRR) to discriminate between beneficial microbes and harmful pathogens. We aim to define the roles of cytosolic Nod-like receptors (NLR) in intestinal immunity and homeostasis. Upon activation, some NLR form inflammasomes that mediate the release of inflammatory cytokines and pyroptosis, an inflammatory form of cell death. NLR activation in the non-hematopoietic compartment was shown to be protective during acute intestinal infection. To identify the cell type responsible for this protection, we generated transgenic mice in which the key inflammasome adaptor molecule Asc is selectively ablated in intestinal epithelial cells (IEC) (AscΔVC) and observed that inflammasomes are important for controlling Citrobacter rodentium clearance in these mice. To further dissect the importance of pathogen clearance by IEC inflammasome, ex vivo cultures of primary IEC organoids were established. Thus far this system has revealed profound differences in inflammasome regulation between IEC organoids and bone marrow-derived macrophages (BMDM). This research will inform our understanding of cell type-specific regulation of inflammasomes.
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Fung, Joyce. "The muscle activation and reflex modulation pattern during locomotion in normal and spastic paretic subjects." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39327.
Повний текст джерелаАнотація:
The lower limb electromyographic (EMG) patterns of 5 normal and 8 spastic paretic subjects during walking were compared. A dynamic EMG profile index, proposed to quantify spastic locomotor dysfunction, was found to be homogeneously low in normal subjects and abnormally high in spastic subjects. In another study, the normally phase-dependent modulation of the soleus H-reflex during walking was found to be decreased or absent in 21 spastic paretic subjects, suggesting the possibility of defective reflex gating mechanisms. The conditioning effects of plantar cutaneomuscular stimulation were further examined in 10 normal and 10 spastic paretic subjects. The conditioned H-reflex was inhibited in a task and phase-dependent manner, such that the effects were most marked during early stance and swing, restoring a near normal modulation pattern during walking in the severely spastic subjects who showed no modulation previously. The possible underlying mechanisms and implications for rehabilitation are discussed.
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Munger, Emily LaRee. "Phenotypic Pattern of Astrocyte Activation in Response to Aging and Alzheimer's-Like Pathology in Chimpanzees." Kent State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=kent1467887282.
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Geach, Timothy John. "Tolloid metalloproteases implicated in dorsal-ventral pattern and extra-cellular matrix activation in Xenopus laevis." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1446246/.
Повний текст джерелаАнотація:
Tolloid (Tld) metalloproteases are zinc dependent extra-cellular endopeptidases that have numerous roles during embryonic development. All Tlds have a highly conserved N-terminal protease domain and an array of C terminal CUB and EGF-like domains thought to play a role in substrate interactions. In Xenopus laevis three members of the Tld family have been identified, BMP-1/Tld, Xolloid and Xolloid-related. All modulate dorsal-ventral patterning of the developing embryo by cleaving the dorsalising factor Chordin, preventing it from binding and inhibiting of the signalling molecule BMP-4. Biochemical studies of mammalian Tlds have identified a wide range of substrates, many involved in formation of the extra-cellular matrix. BMP-1/Tld is identical to pro-collagen C-proteinase, an enzyme that removes the C- terminal pro-peptide of procollagen types 1, 2 and 3, the N-terminal pro-peptide of procollagen type 11 and both the N- and C-terminal pro-peptides of procollagen type 5. It also activates lysyl-oxidase (lox), an enzyme that plays an essential role in collagen maturation. In addition, BMP-1 has been implicated in the proteolytic activation of biglycan, endorepellin, myostatin, osteoglycin and the a-3 and y-2 chains of Laminin-5. In this thesis I identify and describe the expression for Xenopus homologues of procollagen 3al, 5al, 5a2 and Hal, biglycan and a laminin ct-chain like gene. I have also identified three members of the lox family and characterise their role during early Xenopus development. In addition, using a domain deletion approach, I determine the C-terminal CUB domains of Xolloid that are required for cleavage of Chordin. Finally, I study the potential role of endodermin, which displays significant homology to ct-2 macroglobulin, as an inhibitor of Tld metalloproteases.
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Lucas, Karen Rae, and karen lucas@rmit edu au. "The Effects of Latent Myofascial Trigger Points on Muscle Activation Patterns During Scapular Plane Elevation." RMIT University. Health Sciences, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080408.144402.
Повний текст джерелаАнотація:
Despite a paucity of experimental evidence, clinical opinion remains that though LTrPs allow pain-free movement, they are primarily associated with deleterious motor effects and occur commonly in 'healthy' muscles. The primary aim of this study was to investigate the effects of LTrPs on the muscle activation patterns (MAPs) of key shoulder girdle muscles during scapular plane elevation of the arm in the unloaded, loaded and fatigued states. In connection with the main aim, a preliminary study was carried out to examine the frequency with which LTrPs occur in the scapular positioning muscles in a group of normal subjects. After establishing intra-examiner reliability for the clinical examination process, 154 healthy subjects volunteered to be screened for normal shoulder girdle function, then undergo a physical examination for LTrPs in the trapezius, rhomboids, levator scapulae, serratus anterior and the pectoralis minor muscles bilaterally. Of these 'healthy' subjects, 89.8% had at least one LTrP in the scapular positioning muscles (mean=10.65 ± 6.8, range=1-27), with serratus anterior and upper trapezius harbouring the most LTrPs on average (2.46 ± 1.8 and 2.36 ± 1.3 respectively). Consistent with clinical opinion, this study found that LTrPs occur commonly in the scapular positioning muscles. To investigate the motor effects of LTrPs, surface electromyography (sEMG) was used to measure the timing of muscle activation of the upper and lower trapezius and serratus anterior (upward scapular rotators), the infraspinatus (rotator cuff) and middle deltoid (arm abductor). These studies found that LTrPs housed in the scapular upward rotator muscles affected the timing of activation and increased the variability of the activation times of this muscle group and were also associated with altered timing of activation in the functionally related but LTrP-free infraspinatus and middle deltoid. Compared with the control group (all muscles LTrP-free), the MAPs of the LTrP group appeared to be sub-optimal, particularly in relation to preserving the subacromial space and the loading of the rotator cuff muscles. After the initial sEMG evaluations, the LTrP subjects were randomly assigned to one of two interventions: superficial dry needling (SDN) followed by post-isometric relaxation (PIR) stretching to remove LTrP s or sham ultrasound, to act as a placebo treatment where LTrPs remained. Where LTrPs were removed, a subsequent sEMG evaluation found MAPs to be similar to the control group in most of the experimental conditions investigated. Of particular note, when LTrPs had been treated and the subjects repeated the fatiguing protocol, the resultant MAP showed no significant difference with that of the control group in the rested state, suggesting treating LTrPs was associated with an improved response to fatigue induced by repetitive overhead movements. In conclusion, the findings indicate that LTrPs commonly occur in scapular positioning muscles and have deleterious effects on MAPs employed to perform scapular plane elevation and thus affect motor control mechanisms. Treating LTrPs with SDN and PIR stretching increases pressure-pain thresholds, removes associated taut bands and at least transiently optimises the MAP during scapular plane elevation. Discussion includes possible neuromuscular pathophysiology that might explain these results.
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Davenport, Mary Jo. "The Effect of Sternocleidomastoid Muscle Activation Pattern and Feedback Condition on the Vestibular Evoked Myogenic Potential." Digital Commons @ East Tennessee State University, 2010. https://dc.etsu.edu/etd/1776.
Повний текст джерелаАнотація:
The vestibular evoked myogenic potential (VEMP) has been shown to be clinically useful in providing diagnostic information regarding the function of the otolith receptors, inferior vestibular nerve, and vestibulospinal pathways. The VEMP is a biphasic response elicited by loud clicks or tone bursts and recorded from the tonically contracted sternocleidomastoid (SCM) muscle. Because the VEMP is an inhibitory response, it is important to investigate stimulus and parameter characteristics in order to determine the optimal test protocol and maximize clinical usefulness. The aims of this study were 1) to evaluate the effects of 4 different methods of SCM muscle activation and the effect of visual biofeedback on VEMP latency, amplitude, asymmetry ratio, mean rectified EMG level, and difficulty ratings, and 2) to determine the influence of SCM muscle activation pattern and visual biofeedback level on test-retest reliability. Forty-eight healthy volunteers between the ages of 18 and 50 underwent VEMP testing using each of the following muscle activation patterns: supine with the head raised (SE), supine with the head turned away from the test ear (SR), supine with the head raised and turned away from the test ear (SER), and sitting with the head turned away from the test ear (SitR). Testing subjects with the SER method yielded the most robust amplitude response and sternocleidomastoid EMG activity. No statistically significant differences were found in interaural asymmetry ratios among the 4 methods of SCM activation. Subjects rated the SE and SER methods as more difficult than the SE and SitR methods at each of the 3 target levels. Test-retest reliability was high for P1/N1 amplitude and mean rectified EMG levels when subjects were provided visual biofeedback to monitor the level of tonic SCM muscle activity. The study demonstrates the importance of providing patients a means of monitoring and maintaining the amplitude of the rectified EMG at a constant target level during SCM muscle activation. Although no evidence to reject or strongly favor a specific method was found, monaural-ipsilateral recording with the SitR method was found to be advantageous for individuals with weakness or decreased endurance for sustained muscle contraction.
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You, Xiaozhen. "Principal Component Analysis and Assessment of Language Network Activation Patterns in Pediatric Epilepsy." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/176.
Повний текст джерелаАнотація:
This dissertation establishes a novel data-driven method to identify language network activation patterns in pediatric epilepsy through the use of the Principal Component Analysis (PCA) on functional magnetic resonance imaging (fMRI). A total of 122 subjects’ data sets from five different hospitals were included in the study through a web-based repository site designed here at FIU. Research was conducted to evaluate different classification and clustering techniques in identifying hidden activation patterns and their associations with meaningful clinical variables. The results were assessed through agreement analysis with the conventional methods of lateralization index (LI) and visual rating. What is unique in this approach is the new mechanism designed for projecting language network patterns in the PCA-based decisional space. Synthetic activation maps were randomly generated from real data sets to uniquely establish nonlinear decision functions (NDF) which are then used to classify any new fMRI activation map into typical or atypical. The best nonlinear classifier was obtained on a 4D space with a complexity (nonlinearity) degree of 7. Based on the significant association of language dominance and intensities with the top eigenvectors of the PCA decisional space, a new algorithm was deployed to delineate primary cluster members without intensity normalization. In this case, three distinct activations patterns (groups) were identified (averaged kappa with rating 0.65, with LI 0.76) and were characterized by the regions of: 1) the left inferior frontal Gyrus (IFG) and left superior temporal gyrus (STG), considered typical for the language task; 2) the IFG, left mesial frontal lobe, right cerebellum regions, representing a variant left dominant pattern by higher activation; and 3) the right homologues of the first pattern in Broca's and Wernicke's language areas. Interestingly, group 2 was found to reflect a different language compensation mechanism than reorganization. Its high intensity activation suggests a possible remote effect on the right hemisphere focus on traditionally left-lateralized functions. In retrospect, this data-driven method provides new insights into mechanisms for brain compensation/reorganization and neural plasticity in pediatric epilepsy.
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BURNS, Jack, and jack burns@ecu edu au. "Does training with PowerCranks(tm) affect economy of motion, cycling efficiency, oxygen uptake and muscle activation patterns in trained cyclists?" Edith Cowan University. Computing, Health And Science: School Of Exercise, Biomedical & Health Science, 2008. http://adt.ecu.edu.au/adt-public/adt-ECU2008.0017.html.
Повний текст джерелаАнотація:
PowerCranks(tm) are claimed to increase economy of motion and cycling efficiency by reducing the muscular recruitment patterns that contribute to the resistive forces occurring during the recovery phase of the pedal stroke. However, scientific research examining the efficacy of training with PowerCranks(tm) is lacking. Therefore, the purpose of this study was to determine if five weeks of training with PowerCranks(tm) improves economy of motion (EOM), gross efficiency (GE), oxygen uptake (V.O2) and muscle activation patterns in trained cyclists. Sixteen trained cyclists were matched and paired into either a PowerCranks(tm) (PC) or Normal Cranks (NC) training group. Prior to training, all subjects completed a graded exercise test (GXT) using normal bicycle cranks. Additionally, on a separate day the PC group performed a modified GXT using PowerCranks? and cycled only until the end of the 200W stage (PCT). During the GXT and PCT, FeO2, FeCO2 and V.E were measured to determine EOM, GE and V.O2max. Integrated electromyography (iEMG) was also used to examine selected muscular activation patterns. Subjects then repeated the tests following the completion of training on their assigned cranks.
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Burns, Jack. "Does training with PowerCranks™ affect economy of motion, cycling efficiency, oxygen uptake and muscle activation patterns in trained cyclists?" Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/17.
Повний текст джерелаАнотація:
PowerCranks™ are claimed to increase economy of motion and cycling efficiency by reducing the muscular recruitment patterns that contribute to the resistive forces occurring during the recovery phase of the pedal stroke. However, scientific research examining the efficacy of training with PowerCranks™ is lacking. Therefore, the purpose of this study was to determine if five weeks of training with PowerCranks™ improves economy of motion (EOM), gross efficiency (GE), oxygen uptake (V.O2) and muscle activation patterns in trained cyclists. Sixteen trained cyclists were matched and paired into either a PowerCranks™ (PC) or Normal Cranks (NC) training group. Prior to training, all subjects completed a graded exercise test (GXT) using normal bicycle cranks. Additionally, on a separate day the PC group performed a modified GXT using PowerCranks™ and cycled only until the end of the 200W stage (PCT). During the GXT and PCT, FeO2, FeCO2 and V.E were measured to determine EOM, GE and V.O2max. Integrated electromyography (iEMG) was also used to examine selected muscular activation patterns. Subjects then repeated the tests following the completion of training on their assigned cranks.
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Nassar, Khaled [Verfasser]. "Pathogenesis of age related macular degeneration (AMD) : immunohistochemical evaluation of the macrophage activation pattern in human choroidal neovascular membranes / Khaled Nassar." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2011. http://d-nb.info/1013911296/34.
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Harischandra, Nalin. "Computer Simulation of the Neural Control of Locomotion in the Cat." Licentiate thesis, Stockholm : Numerisk analys och datalogi, Numerical Analysis and Computer Science, Kungliga Tekniska högskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4692.
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Hovorka, Christopher Francis. "Influencing motor behavior through constraint of lower limb movement." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54903.
Повний текст джерелаАнотація:
Limited knowledge of the neuromechanical response to use of an ankle foot orthosis-footwear combination (AFO-FC) has created a lack of consensus in understanding orthotic motion control as a therapeutic treatment. Lack of consensus may hinder the clinician’s ability to target the motion control needs of persons with movement impairment (e.g., peripheral nerve injury, stroke, etc.). Some evidence suggests a proportional relationship between joint motion and neuromuscular activity based on the notion that use of lower limb orthoses that constrain joint motion may invoke motor slacking and decreasing levels of muscle activity.
Use of AFO-FCs likely alters the biomechanical and neuromuscular output as the central control system gradually forms new movement patterns. If there is proportional relationship between muscle activation and joint motion, then it could be examined by quantifying joint motion and subsequent neuromuscular output. Considering principles of neuromechanical adjustment, my general hypothesis examines whether orthotic control of lower limb motion alters neuromuscular output in proportion to the biomechanical output as a representation of the limb’s dynamics are updated by the neural control system. The rationale for this approach is that reference knowledge of the neuromechanical response is needed to inform clinicians about how a person responds to walking with motion controlling devices such as ankle foot orthoses combined with footwear.
In the first line of research, I hypothesize that a newly developed AFO which maximizes leverage and stiffness will constrain the talocrural joint and alter joint kinematics and ground reaction force patterns. To answer the hypothesis, I sampled kinematics and kinetics of healthy subjects’ treadmill walking using an AFO-FC in a STOP condition and confirmed that the AFO substantially limited the range of talocrural plantarflexion and dorsiflexion motion to 3.7° and in a FREE condition maintained talocrural motion to 24.2° compared to 27.7° in a CONTROL (no AFO) condition. A follow up controlled static loading study sampled kinematics of matched healthy subjects limbs and cadaveric limbs in the AFO STOP and FREE conditions. Findings revealed healthy and cadaveric limbs in the AFO STOP condition substantially limited their limb segment motion similar to matched healthy subjects walking in the STOP condition and in the AFO FREE condition healthy and cadaveric limbs maintained similar limb segment motion to matched healthy subjects walking in the FREE condition. In a second line of research, I hypothesize that flexibility of a newly developed footwear system will allow normal walking kinetics due to the shape and flexibility of the footwear. To answer the hypothesis, I utilized a curved-flexible footwear system integrated with an AFO in a STOP condition and sampled kinematics and kinetics of healthy subjects during treadmill walking. Results revealed subjects elicited similar cadence, stance and swing duration and effective leg-ankle-foot roll over radius compared to walking in the curved-flexible footwear integrated with the AFO in a FREE condition and a CONTROL (no AFO) condition. To validate rollover dynamics of the curved-flexible footwear system, a follow up study of healthy subjects’ treadmill walking in newly developed flat-rigid footwear system integrated with the AFO in a STOP condition revealed interrupted leg-ankle-foot rollover compared to walking in curved-flexible footwear in STOP, FREE and CONTROL conditions. In a third line of research, I hypothesize that use of an AFO that limits talocrural motion in a STOP condition will proportionally reduce activation of Tibialis Anterior, Soleus, Medial and Lateral Gastrocnemii muscles compared to a FREE and CONTROL condition due to alterations in length dependent representation of the limb’s dynamics undergoing updates to the central control system that modify the pattern of motor output. To answer the question, the same subjects and AFO-footwear presented in the first two lines of research were used in a treadmill walking protocol in STOP, FREE, and CONTROL conditions. Findings revealed the same subjects and ipsilateral AFO-footwear system presented in Aim 1 exhibited an immediate yet moderate 30% decline in EMG activity of ipsilateral Soleus (SOL), Medial Gastrocnemius (MG) and Lateral Gastrocnemius (LG) muscles in the STOP condition compared to the CONTROL condition. The reduction in EMG activity in ipsilateral SOL, MG and LG muscles continued to gradually decline during 15 minutes of treadmill walking. On the contralateral leg, there was an immediate yet small increase of 1% to 14% in EMG activity in SOL, MG, LG muscles above baseline. After 10 minutes of walking, the EMG activity in contralateral SOL, MG and LG declined to a baseline level similar to the EMG activity in the contralateral CONTROL condition. These collective findings provide compelling evidence that the moderate 30% reduction in muscle activation exhibited by subjects as they experience substantial (85%) constraint of total talocrural motion in the AFO STOP condition is not proportionally equivalent. Further, the immediate decrease in muscle activation may be due to a reactive feedback mechanism whereas the continued decline may in part be explained by a feedforward mechanism. The clinical relevance of these findings suggests that short term use of orthotic constraint of talocrural motion in healthy subjects does not substantially reduce muscle activation. These preliminary findings could be used to inform the development of orthoses and footwear as therapeutic motion control treatments in the development of motor rehabilitation protocols.
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Kyle, Natasha Flemming. "Muscle activation patterns during gait initiation." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27147.
Повний текст джерелаАнотація:
Gait initiation is a temporary movement between upright posture and steady-state gait. The activation of several postural muscles has been identified to precede changes observed in vertical reaction force. Previous research examining gait initiation has concentrated on the electromyographic activity of muscles of the lower limbs. Few studies, however, have looked at recruitment patterns of the muscles of the thigh and trunk. This study was conducted to determine the recruitment patterns and the roles of certain muscles of the trail and lead lower limbs and trunk for the duration from quiet stance to trail leg toe-off. Eleven healthy participants initiated gait with their right leg. Electromyographic data were collected bilaterally from the erector spinae, tensor fasciae latae, adductor magnus and tibialis anterior muscles. In addition, force platform data were recorded for the duration of quiet stance to toe-off of the trail limb. (Abstract shortened by UMI.)
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Tegtmeyer, Pia-Katharina [Verfasser], Ulrich [Akademischer Betreuer] Kalinke, and Martin [Akademischer Betreuer] Messerle. "Analysis of the role of different pattern recognition receptors in murine cytomegalovirus-mediated activation of innate immunity / Pia-Katharina Tegtmeyer ; Akademische Betreuer: Ulrich Kalinke, Martin Messerle ; TWINCORE, Zentrum für Experimentelle und Klinische Infektionsforschung; Institut für Experimentelle Infektionsforschung." Hannover : Bibliothek der Medizinischen Hochschule Hannover, 2019. http://d-nb.info/1201598001/34.
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Balcı, Serdar Kemal. "Classification of whole brain fMRI activation patterns." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45854.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 59-62).
Functional magnetic resonance imaging (fMRI) is an imaging technology which is primarily used to perform brain activation studies by measuring neural activity in the brain. It is an interesting question whether patterns of activity in the brain as measured by fMRI can be used to predict the cognitive state of a subject. Researchers successfully employed a discriminative approach by training classifiers on fMRI data to predict the mental state of a subject from distributed activation patterns in the brain. In this thesis, we investigate the utility of feature selection methods in improving the prediction accuracy of classifiers trained on functional neuroimaging data. We explore the use of classification methods in the context of an event related functional neuroimaging experiment where participants viewed images of scenes and predicted whether they would remember each scene in a post-scan recognition-memory test. We view the application of our tool to this memory encoding task as a step toward the development of tools that will enhance human learning. We train support vector machines on functional data to predict participants' performance in the recognition test and compare the classifier's performance with participants' subjective predictions. We show that the classifier achieves better than random predictions and the average accuracy is close to that of the subject's own prediction. Our classification method consists of feature extraction, feature selection and classification parts.
(cont.) We employ a feature extraction method based on the general linear model. We use the t-test and an SVM-based feature ranking method for feature selection. We train a weighted linear support vector machine, which imposes different penalties for misclassification of samples in different groups. We validate our tool on a simple motor task where we demonstrate an average prediction accuracy of over 90%. We show that feature selection significantly improves the classification accuracy compared to training the classifier on all features. In addition, the comparison of the results between the motor and the memory encoding task indicates that the classifier performance depends significantly on the complexity of the mental process of interest.
by Serdar Kemal Balcı.
S.M.
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Gabriel, David Abraham. "Muscle activation patterns for goal-directed multijoint arm movements." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28748.
Повний текст джерелаАнотація:
The purpose of this dissertation was to determine if the CNS produces relatively simple alterations in muscle activity to accomplish goal-directed reaching motions of the upper limb under a variety of movement conditions.To this end, six subjects performed goal-directed arm movements in the horizontal plane. Two movement amplitudes (300 mm and 400 mm) were completed at a moderate speed (1050 mm/s) and as-fast-as possible. The speed and amplitude conditions were repeated for the 45$ sp circ$ and 90$ sp circ$ movement directions. Finally, each of the movement conditions mentioned thus far, were performed within the right and left sections of the work-space. Surface electro-myographic activity was recorded from the pectoralis major, posterior deltoid, biceps brachii short head, brachioradialis, triceps brachii long head, and triceps brachii lateral head. Motion recordings were obtained with a spatial imaging system that monitored the positions of infrared emitting diodes attached to the subject's upper arm and forearm-hand complex.
Several simplification schemes were found to be operative at the level of the electro-myogram. These include: (a) simple timing relationships for agonists between joints and agonist/antagonist intermuscle latencies within each joint; (b) tightly coupled timing between agonists within a single joint; (c) for a particular movement direction, the form and shape of EMG burst activity followed a strategy associated with modulation of pulse height and width; (d) the slope, duration, and onset were further affected by the direction of hand movement which resulted in the greatest RMS-EMG signal amplitude, changing in a predictable manner, and finally (e) there was tuning in which elbow muscles were activated earlier for goal-directed arm movements in the left area of the work-space.
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Lee, Seungyup. "Mapping the Characteristics of Atrial Activation Patterns During Atrial Fibrillation." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1354634723.
Повний текст джерела
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Smith, Nigel Anthony. "Oxygen consumption and muscle activation patterns during constant load exercise." Thesis, Queensland University of Technology, 2000. https://eprints.qut.edu.au/36769/1/36769_Digitised%20Thesis.pdf.
Повний текст джерелаАнотація:
The collective purpose of these two studies was to determine a link between the V02 slow component and the muscle activation patterns that occur during cycling. Six,
male subjects performed an incremental cycle ergometer exercise test to determine asub-TvENT (i.e. 80% of TvENT) and supra-TvENT (TvENT + 0.75*(V02 max - TvENT)
work load. These two constant work loads were subsequently performed on either three or four occasions for 8 mins each, with V02 captured on a breath-by-breath basis
for every test, and EMO of eight major leg muscles collected on one occasion. EMG was collected for the first 10 s of every 30 s period, except for the very first 10 s
period. The V02 data was interpolated, time aligned, averaged and smoothed for both intensities. Three models were then fitted to the V02 data to determine the kinetics
responses. One of these models was mono-exponential, while the other two were biexponential. A second time delay parameter was the only difference between the two
bi-exponential models. An F-test was used to determine significance between the biexponential models using the residual sum of squares term for each model. EMO was
integrated to obtain one value for each 10 s period, per muscle. The EMG data was analysed by a two-way repeated measures ANOV A. A correlation was also used to
determine significance between V02 and IEMG. The V02 data during the sub-TvENT intensity was best described by a mono-exponential response. In contrast, during
supra-TvENT exercise the two bi-exponential models best described the V02 data. The resultant F-test revealed no significant difference between the two models and
therefore demonstrated that the slow component was not delayed relative to the onset of the primary component. Furthermore, only two parameters were deemed to be
significantly different based upon the two models. This is in contrast to other findings. The EMG data, for most muscles, appeared to follow the same pattern as V02 during
both intensities of exercise. On most occasions, the correlation coefficient demonstrated significance. Although some muscles demonstrated the same relative increase in IEMO based upon increases in intensity and duration, it cannot be assumed that these muscles increase their contribution to V02 in a similar fashion. Larger muscles with a higher percentage of type II muscle fibres would have a larger increase in V02 over the same increase in intensity.
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Kelson, Denean M. "Muscle Activation Patterns and Chronic Neck-Shoulder Pain in Computer Work." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83759.
Повний текст джерелаАнотація:
Prolonged computer work is associated with high rates of neck and shoulder pain symptoms, and as computers have become increasingly more common, it is becoming critical that we develop sustainable interventions targeting this issue. Static muscle contractions for prolonged periods often occur in the neck/shoulder during computer work and may underlie muscle pain development in spite of rather low relative muscle load levels. Causal mechanisms may include a stereotypical recruitment of low threshold motor units (activating type I muscle fibers), characterized by a lack of temporal as well as spatial variation in motor unit recruitment. Based on this theory, although studies have postulated that individuals with chronic neck-shoulder pain will show less variation in muscle activity compared to healthy individuals when engaged in repetitive/monotonous work, this has seldom been verified in empirical studies of actual computer work.
Studies have rarely addressed temporal patterns in muscle activation, even though there is a consensus that temporal activation patterns are important for understanding fatigue and maybe even risks of subsequent musculoskeletal disorders. This study applied exposure variation analysis (EVA) to study differences in temporal patterns of trapezius muscle activity as individuals with and without pain performed computer work. The aims of this study were to: Assess the reliability of EVA to measure variation in trapezius muscle activity in healthy individuals during the performance of computer work; Determine the extent to which healthy subjects differ from those with chronic pain in trapezius muscle activity patterns during computer work, measured using EVA.
Thirteen touch-typing, right-handed participants were recruited in this study (8 healthy; 5 chronic pain). The participants were asked to complete three 10-minute computer tasks (TYPE, CLICK and FORM) in two pacing conditions (self-paced, control-paced), with the healthy group completing two sessions and the pain group completing one. Activation of the upper trapezius muscle was measured using surface electromyography (EMG). EMG data were organized into 5x5 EVA matrices with five amplitude classes (0-6.67, 6.67-20, 20-46.67, 46.67-100, >100% Reference Voluntary Exertion) and five duration classes (0-
1, 1-3, 3-7, 7-15, >15 seconds). EVA marginal distributions (along both amplitude and duration classes) for each EVA class, as well as summary measures (mean and SD) of the marginal sums along each axis were computed. Finally, “resultant” mean and SD across all EVA cells were computed. The reliability in
EVA indices was estimated using intra-class correlation coefficients (ICC), coefficient of variation (CV) and standard error of measurement (SEM), computed from repeated measurements of healthy individuals (aim 1), and EVA indices were compared between groups (aim 2).
Reliability of EVA amplitude marginal sums ranged from moderate to high in the self-paced condition and low to moderate in the control-paced condition. The duration marginal sums were moderate in the self-paced condition and moderate to high in the control-paced condition. The summary measures (means and
SDs) were moderate to high in both the self-paced and control-paced condition. Group comparisons revealed that individuals with chronic pain spent longer durations of work time in higher EVA duration categories, exhibited larger means along the amplitude, duration and in the resultant, and higher EVA SD
in the amplitude and duration axes as compared to the healthy group.
To our knowledge, this is the first study to report on the reliability of EVA applied specifically to computer work. Furthermore, EVA was used to assess differences in muscle activation patterns as individuals with and without chronic pain engaged in computer work. Individuals in the pain group seemed to exhibit prolonged sustained activation of the trapezius muscle to a significantly greater extent than controls, even though they did not experience pain during the performance of the computer tasks (as obtained through self-reports). Thus, these altered muscle recruitment patterns observed in the pain subjects, even in the absence of task-based pain/discomfort, are suggestive of chronic motor control changes occurring in adaptation to pain, and may have implications for the etiology of neck and upper-limb musculoskeletal disorders.Master of Science
This study aims to assess the reliability of exposure variation analysis (EVA) to measure variation in trapezius muscle activity in healthy individuals during the performance of computer work, and to determine the extent to which healthy subjects differ from those with chronic pain in trapezius muscle activity patterns during computer work, measured using EVA. Muscle activation was recorded for eight healthy individual and five suffering from chronic neck-shoulder pain. The data were then categorized into amplitude and continuous time categories, and summary measures of resulting distributions were calculated. These measures were used to assess the reliability of participant responses to computer work of healthy individuals, as well as quantify differences between those with and without chronic pain. We found that individuals with pain activated their neck-shoulder muscles for longer continuous durations than healthy individuals, thus showing an inability to relax their muscles when performing work.
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JAMES, LINDSAY R. "AN fMRI STUDY OF ACTIVATION PATTERNS IN WOMEN DURING PICTURE PROCESSING." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1179411457.
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Guillem, Sanchez Maria De La Salud. "Activation patterns in atrial fibrillation: contributions of body surface potential mapping." Doctoral thesis, Universitat Politècnica de València, 2009. http://hdl.handle.net/10251/3922.
Повний текст джерелаАнотація:
La fibrilación auricular (FA) es una de las arritmias cardiacas más comunes, afectando a alrededor del 10 % de los mayores de 70 años. A pesar de su alta incidencia en la población, los mecanismos que desencadenan y mantienen la FA son inciertos. Aunque existen diversos tratamientos quirúrgicos y farmacológicos, el éxito de los tratamientos contra la FA es muy bajo. La causa de esta baja tasa de éxito de las diferentes terapias es que no existen criterios de selección de pacientes que permitan pronosticar qué terapia puede ser más efectiva para cada paciente. Una de las formas que se han propuesto para determinar el grado de gravedad de la arritmia en cada paciente y, por tanto, poder predecir qué tratamiento es el más apropiado es la medida de la organización auricular.
Esta tesis doctoral se enmarca dentro de la determinación no invasiva del grado de organización espacial de la activación del miocardio auricular a partir del estudio de registros multiderivación del electrocardiograma de superficie (ECG). El ECG es una representación simplificada del campo eléctrico del corazón basada en las proyecciones de este campo eléctrico en 8 ejes. Esta simplificación es considerada como aceptable en el caso de ritmos no fibrilantes en los que la activación miocárdica puede ser modelada como un dipolo. Sin embargo, su validez no ha sido demostrada para el caso de ritmos fibrilantes en los cuales la asunción de un modelo dipolar es cuestionable. Uno de los objetivos de esta tesis ha sido la evaluación del electrocardiograma de superficie para la obtención de parámetros espaciales de las ondas de FA. Se compararon las representaciones tridimensionales de las ondas de FA registradas a partir de tres derivaciones ortogonales con las representaciones tridimensionales estimadas a partir del ECG, llegando a la conclusión de que estas representaciones estimadas no son fieles a las representaciones registradas. Los resultados de nuestro estudio ponen de manifiesto que la falta de dGuillem Sanchez, MDLS. (2008). Activation patterns in atrial fibrillation: contributions of body surface potential mapping [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/3922
Palancia
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NGUYEN, CHRISTIE JENNY. "ACTIVATION PATTERNS OF THE IEG ARC IN RATS FOLLOWING ELECTROCONVULSIVE SHOCK TREATMENTS." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/613350.
Повний текст джерелаАнотація:
The immediate early gene Arc is rapidly expressed in hippocampal subregions following
excitatory neuronal activity including electroconvulsive shock treatments. Arc has been shown to
play a role in synaptic plasticity and gaining insight into its regulation and mechanisms is critical
to understanding the intricacies of learning and memory. This study aims to see if reducing the
current of the electroconvulsive shock treatments will reduce the number of Arc mRNA-positive
cells in the dentate gyrus and CA1 to further understand Arc’s role in the hippocampus. Fischer
344 (F344) rats were assigned to six different treatments: 0 mA, 20 mA, 40 mA, 65 mA, 77 mA,
and 85 mA. The brains were extracted five minutes after the treatment, quick frozen, sectioned,
and thaw mounted onto super frost slides. The number of Arc mRNA-positive cells were counted
using compartmental analysis of temporal activity by fluorescence in situ hybridization
(catFISH) combined with confocal microscopy in the dentate gyrus and CA1. This revealed a
sharp increase in the number of Arc mRNA-positive cells between the 65 mA counts and the 77
mA counts in the dentate gyrus (~2.8% of cells to ~85% of cells) and CA1 (distal ~27.4% of
cells to ~70.1% of cells, medial ~26% of cells to 71% of cells, proximal ~17.4% of cells to
72.1% of cells) suggesting a threshold for activation.
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Zanghieri, Marcello. "sEMG-based hand gesture recognition with deep learning." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18112/.
Повний текст джерелаАнотація:
Hand gesture recognition based on surface electromyographic (sEMG) signals is a promising approach for the development of Human-Machine Interfaces (HMIs) with a natural control, such as intuitive robot interfaces or poly-articulated prostheses. However, real-world applications are limited by reliability problems due to motion artifacts, postural and temporal variability, and sensor re-positioning.
This master thesis is the first application of deep learning on the Unibo-INAIL dataset, the first public sEMG dataset exploring the variability between subjects, sessions and arm postures, by collecting data over 8 sessions of each of 7 able-bodied subjects executing 6 hand gestures in 4 arm postures. In the most recent studies, the variability is addressed with training strategies based on training set composition, which improve inter-posture and inter-day generalization of classical (i.e. non-deep) machine learning classifiers, among which the RBF-kernel SVM yields the highest accuracy.
The deep architecture realized in this work is a 1d-CNN implemented in Pytorch, inspired by a 2d-CNN reported to perform well on other public benchmark databases. On this 1d-CNN, various training strategies based on training set composition were implemented and tested.
Multi-session training proves to yield higher inter-session validation accuracies than single-session training. Two-posture training proves to be the best postural training (proving the benefit of training on more than one posture), and yields 81.2% inter-posture test accuracy. Five-day training proves to be the best multi-day training, and yields 75.9% inter-day test accuracy. All results are close to the baseline. Moreover, the results of multi-day trainings highlight the phenomenon of user adaptation, indicating that training should also prioritize recent data.
Though not better than the baseline, the achieved classification accuracies rightfully place the 1d-CNN among the candidates for further research.
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Lockhart, Daniel Bruce. "Prediction of Muscle Activation Patterns During Postural Control Using a Feedback Control Model." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7280.
Повний текст джерелаАнотація:
Neural mechanisms determining temporal muscle activity patterns during postural control are not well understood. We hypothesize that a feedback control mechanism can predict both temporal extensor muscle EMG and CoM kinematics (acceleration, velocity, and displacement) during postural perturbations before and following peripheral neuropathy to group I afferents induced by pyridoxine intoxication. We introduce a feedback model for analyzing temporal EMG patterns that decomposes recorded electromyogram (EMG) signals into the sum of three center of mass (CoM) feedback components. EMG and CoM kinematics during postural responses due to support surface translations were measured before and 14 days after somatosensory loss in cats. We successfully predicted EMG before and after peripheral neuropathy by modeling a standing cat as an inverted pendulum and decomposing temporal EMG patterns using a simulation with time delayed feedback loop of CoM kinematics. This model accounts for over 60% of the total temporal variability of recorded extensor EMG patterns. Feedback gains for acceleration, velocity and position necessary to predict EMGs before and after sensory loss were different. For intact animals, more that 90% of the initial burst of EMG were due to CoM acceleration feedback, while later portions were due entirely to velocity and position feedback. After peripheral neuropathy, the initial burst was absent and the acceleration gain was significantly reduced when compared to the acceleration gain of intact animals for extensor muscles (p lt 0.05). By successfully decomposing EMG into three kinematic gains, a quantitative comparison of temporal EMG patterns before and after peripheral neuropathy is possible. The reduction of acceleration gain in sensory loss cats suggests that group I afferents provide necessary information that is used as acceleration feedback.
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Stone, T. A. "Characteristics of muscle activation patterns at the ankle in stroke patients during walking." Thesis, Bournemouth University, 2006. http://eprints.bournemouth.ac.uk/10537/.
Повний текст джерелаАнотація:
Stroke causes impairment of the sensory and motor systems; this can lead to difficulties in walking and participation in society. For effective rehabilitation it is important to measure the essential characteristics of impairment and associate these with the nature of disability. Efficient gait requires a complex interplay of muscles. Surface electromyography(sEMG) can be used to measure muscle activity and to observe disruption to this interplay after stroke. Yet, classification of this disruption in stroke patients has not been achieved. It is hypothesised that features identified from the sEMG signal can be used to classify underlying impairments. A clinically viable gait analysis system has been developed, integrating an in-house wireless sEMG system synchronised with bilateral video and inertial orientation sensors. Signal processing techniques have been extended and implemented, appropriate for use with sEMG. These techniques have focussed on frequency domain features using wavelet analysis and muscle activation patterns using principal component analysis. The system has been used to measure gait from stroke patients and un-impaired subjects. Characteristic patterns of activity from the ankle musculature were defined using principal component analysis of the linear envelope. Patients with common patterns of tibialis anterior activity did not necessarily share common patterns of gastrocnemius or soleus activity. Patients with similar linear envelope patterns did not always present with the same kinematic profiles. The relationship between observable impairments, kinematics and sEMG is seen to be complex and there is therefore a need for a multidimensional view of gait data in relation to stroke impairment. The analysis of instantaneous mean frequency and time-frequency has revealed additional periods of activity not obvious in the linear or raw signal representation. Furthermore, characteristic calf activity was identified that may relate to abnormal reflex activity. This has provided additional information with which to group characteristic muscle activity. An evaluation of the co-activation of gastrocnemius and tibialis anterior muscles using a sub-band filtering technique revealed three groups; those with distinct co-activation, those with little co-activation and those with continuous activity in the antagonistic pair across the stride. Signal features have been identified in sEMG recordings from stroke patients whilst walking extending current signal processing techniques. Common features of the sEMG and movement have been grouped creating a decision matrix. These results have contributed to the field of clinical measurement and diagnosis because interpretation of this decision matrix is related to underlying impairment. This has provided a framework from which subsequent studies can classify characteristic patterns of impairment within the stroke population; and thus assist in the provision of rehabilitative interventions.
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Sohn, Mark Hongchul. "A computational framework to quantify neuromechanical constraints in selecting functional muscle activation patterns." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53591.
Повний текст джерелаАнотація:
Understanding possible variations in muscle activation patterns and its functional implications to movement control is crucial for rehabilitation. Inter-/intra-subject variability is often observed in muscle activity used for performing the same task in both healthy and impaired individuals. However, the extent to which muscle activation patterns can vary under specific neuromuscular conditions and differ in function are still not well understood. Current musculoskeletal modeling approaches using optimization techniques to identify a unique solution cannot adequately address such questions. Here I developed a novel computational framework using detailed musculoskeletal model to reveal the latitude the nervous system has in selecting muscle activation patterns for a given task regarding neuromechanical constraints. I focused on isometric hindlimb endpoint force generation task relevant to balance behavior in cats. By identifying the explicit bounds on activation of individual muscles defined by biomechanical constraints, I demonstrate ample range of feasible activation patterns that account for experimental variability. By investigating the possible neuromechanical bases of using the same muscle activation pattern across tasks, I demonstrate that demand for generalization can affect the selection of muscle activation pattern. By characterizing the landscape of the solution space with respect to multiple functional properties, I demonstrate a possible trade-off between effort and stability. This framework is a useful tool for understanding principles underlying functional or impaired movements. We may gain valuable insights to developing effective rehabilitation strategies and biologically-inspired control principles for robots.
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Reed, Darren Scott. "An electromyographic study of normal shoulder muscle activation patterns during abduction and adduction." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11573.
Повний текст джерелаАнотація:
Background: Abduction and adduction are common movements of the shoulder used in everyday functional activities, clinical assessment of the shoulder and rehabilitation/ exercise programs to improve the function at the shoulder. However, the normal recruitment patterns of the shoulder muscles during these movements are not fully understood. Aim: To establish a normative data base of muscle activation patterns and levels during adduction and abduction and to determine whether load and plane of movement affect these parameters. Methods: Eleven shoulder muscles were investigated using a combination of intramuscular and surface electrodes during adduction and abduction in five experiments involving cohorts of 15 asymptomatic subjects. Exercises were performed at low, medium and high loads. Abduction was also performed in three different planes and as a shoulder press exercise. Results: Normative data bases of shoulder muscle activation patterns and levels were established for adduction, abduction and the shoulder press. Load did not change the activation pattern in any exercise and plane of movement had no effect on activation parameters in the majority of muscles tested during abduction. No single muscle was shown to initiate abduction. Activation patterns during abduction and the shoulder press were very different. Conclusions: Adduction and abduction are complex exercises that require coordinated muscle activity of axio/scapulo-humeral (latissimus dorsi, pectoralis major, middle deltoid, teres major), rotator cuff (subscapularis, infraspinatus and supraspinatus) and axio-scapular muscles (upper trapezius, lower trapezius, serratus anterior and rhomboid major). These results may be useful in planning effective rehabilitation and exercise programs.
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García, López Diego. "Computational Modeling to Explore Unconventional Reactivity Patterns in C−H Activation and Boron Chemistry." Doctoral thesis, Universitat Rovira i Virgili, 2018. http://hdl.handle.net/10803/586092.
Повний текст джерелаАнотація:
La química computacional és indispensable avui en dia atès que pot proporcionar una visió més profunda dels processos moleculars. Aquesta tesi es divideix en dues parts, la primera de les quals tracta l'activació d'enllaços C−H inerts per part de metalls de transició pobres i rics en electrons. Pel que fa al primer cas, es va determinar computacionalment el mecanisme d'activació C−H remota observat en complexos dinuclears de titani. Tal mecanisme genera un alquilidè transitori capaç de potenciar l'activació dels enllaços C(sp3)−H en el titani adjacent. Pel que fa al segon cas, es va caracteritzar la naturalesa d'un enllaç (an)agòstic de Ni−(C[Ar]−H) observat en estat sòlid per mitjà de la topologia de la densitat electrònica.
La segona part d'aquest treball es centra en la química del bor. Tot cercant un model predictiu, es van desenvolupar relacions quantitatives estructura-activitat (QSAR) per a l'activitat nucleòfila de compostos de bor trivalents, cobrint fragments boríl·lics de metalls alcalins, alcalinoterris, de transició, i també unitats diboríl·liques. Es van dur a terme tècniques de regressió multivariant per determinar una relació quantitativa entre les propietats de l'estat fonamental i aquesta activitat nucleòfila. L'ús de descriptors químicament significatius va permetre la identificació dels factors que regeixen la nucleofilia i el model QSAR es va emprar per fer prediccions a priori.
També es van estudiar reaccions no convencionals de bor a molècules orgàniques insaturades. En un cas, es va racionalitzar la formació d'enllaços geminals C–Bpin i C–Bdan mitjançant càlculs DFT, mostrant un mecanisme concertat però asincrònic i aconseguint diastereoselctivitat en substrats cíclics. D'altra banda, els càlculs teòrics van revelar la regio i estereoselectivitat observada en l'anti-3,4-selenoboració a triples enllaços fent servir quantitats catalítiques de fosfina. L'estudi computacional va descobrir un nou mecanisme que difereix de les propostes mecanístiques prèvies per a les anàlogues carboboració, silaboració i diboració selectives.La química computacional resulta indispensable hoy en día dado que puede proporcionar una visión más profunda de los procesos moleculares. Esta tesis se divide en dos partes, la primera de las cuales trata la activación de enlaces C−H inertes por parte de metales de transición pobres y ricos en electrones. Respecto al primer caso, se determinó computacionalmente el mecanismo de activación C−H remota observado en complejos dinucleares de titanio. Tal mecanismo genera un alquilideno transitorio capaz de potenciar la activación de los enlaces C(sp3)−H en el titanio adyacente. Respecto al segundo caso, se caracterizó la naturaleza de un enlace (an)agóstico de Ni−(C[Ar]−H) observado en estado sólido por medio de la topología de la densidad electrónica. La segunda parte de este trabajo se centra en la química del boro. En búsqueda de un modelo predictivo, se desarrollaron relaciones cuantitativas estructura-actividad (QSAR) para la actividad nucleófila de compuestos de boro trivalentes, cubriendo fragmentos borílicos de metales alcalinos, alcalino-térreos, de transición, así como unidades de diboro. Se llevaron a cabo técnicas de regresión multivariante para determinar una relación cuantitativa entre las propiedades del estado fundamental y dicha actividad nucleófila. El uso de descriptores químicamente significativos permitió la identificación de los factores que rigen la nucleofilia y el modelo QSAR se usó para hacer predicciones a priori. También se estudiaron reacciones no convencionales de boro a moléculas orgánicas insaturadas. En un caso, se racionalizó la formación de enlaces geminales C–Bpin y C–Bdan mediante cálculos DFT, mostrando un mecanismo concertado También se estudiaron reacciones no convencionales de boro a moléculas orgánicas insaturadas. En un caso, se racionalizó la formación de enlaces geminales C-Bpin y C-Bdan mediante cálculos DFT, mostrando un mecanismo concertado aunque asincrónico y alcanzando diastereoselctividad para sustratos cíclicos. Por otro lado, los cálculos teóricos dilucidaron la regio y estereoselectividad observada en la anti-3,4-selenoboración a triples enlaces usando cantidades catalíticas de fosfina. El estudio computacional descubrió un nuevo mecanismo que difiere de las propuestas mecanísticas previas para las análogas carboboración, silaboración y diboración selectivas.
Computational chemistry turns out to be indispensable nowadays since it can provide deeper insights to molecular processes. This thesis can be divided in two parts, the first of which deals with the activation of inert C−H bonds by early- and late-transition-metal systems. Regarding the former case, computationally the mechanism of remote C−H activation observed on titanium dinuclear complexes was determined. Such mechanism generates a transient titanium alkylidene capable of enhancing the activation of C(sp3)−H bonds on the adjacent titanium center. Concerning in late-transition-metal systems, the nature of a rare (an)agostic Ni−(C[Ar]−H) bond observed in solid state was characterized by means of the topology of the electronic density. The second part of this work focuses on boron chemistry. Seeking for a predictive model, a quantitative structure-activity relationships (QSAR) for the nucleophilic activity of trivalent boron compounds was developed, covering boryl fragments bonded to alkali and alkaline-earth metals, to transition metals, and to sp3 boron units in diboron reagents. Multivariate regression techniques were carried out for determining a quantitative relationship between ground-state properties and nucleophilic activity. The use of chemically meaningful descriptors allowed identification of the factors governing the boron nucleophilicity. Also, the QSAR model was used to make a priori predictions of experimentally untested compounds. Unconventional boron reactions to unsatured organic molecules were studied as well. In one case, the formation of two geminal C–Bpin and C–Bdan bonds was rationalised based on DFT calculations to occur via a concerted yet asynchronous mechanism, attaining diastereoselctivity for cyclic substrates. On the other hand, theoretical calculations rationalized the observed regio- and stereoselectivity of the anti-3,4-selenoboration to triple bonds using catalytic amounts of phosphine. The computational study discovered a novel mechanism which differs from previous mechanistic proposals for analogous anti-selective carboration, silaboration and diboration.
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Koenig, Alexander C. "Simulation of agonist and antagonist muscle activation patterns in bidirectional postural perturbation in cats." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11576.
Повний текст джерелаАнотація:
We studied the effects of varying perturbation magnitude and direction on the postural control process of the central nervous system (CNS) caused by perturbation, before and after sensory loss. The electromyogram (EMG) response to a postural perturbation can be composed by a weighted sum of the center of mass (CoM) kinematics. We extended an existing CoM feedback model which predicted EMG of one muscle for unidirectional perturbations; we used recorded data of bidirectional perturbations, which caused muscle activity in anterior as well as posterior muscles. Modeling the CNS as two delayed feedback controllers, we reconstructed the EMGs of two antagonistic muscles simultaneously that were recorded during postural perturbation experiments on cats. Minimizing the error between predicted and recorded EMG and CoM kinematics, we were able to identify controller gains that would result in the best prediction of the recorded EMGs.
We hypothesized that the weights on the CoM kinematics remained constant independent of variations in perturbation magnitude or reversed perturbation direction. We applied our model to data from bidirectional perturbations with varying magnitude, with which the cats were perturbed for a short time in one direction and a longer time in the opposite direction.
The gains showed small variation for EMG predictions following long perturbations; however, the prediction of EMG following the initial displacement resulted in large gain variations. We showed that these variations were caused by our optimization methods, which was not able to consistently identify controller gains for short initial movements. Using the weights identified for unidirectional perturbations, we were able to predict muscle activity for both directions with the same gains. This suggests that the weights of the CoM kinematics for each muscle did not change for varying perturbation magnitude. We conclude that varying EMG shapes were induced solely by the variation of the CoM kinematics.
We repeated the investigations on data that was recorded from cats suffering from sensory loss and found reduced CoM acceleration feedback.
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Poon, Wai Ming, and n/a. "Gait analysis of lumbar muscle activation patterns during constant speed locomotion using Surface Electromyography." RMIT University. Electrical and Computer System Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20090713.115553.
Повний текст джерелаАнотація:
This thesis reports research on analysis of the variance of surface electromyogram (sEMG) for healthy participants and people suffering with Lower Back Pain (LBP) when they are walking and running. SEMG signal recorded when the participants were walking and running on a treadmill. The strength and duration of the muscle activity for each heel strike were the features. The results indicate that there was no significant difference in the variance and in the change of variance over time of the amplitude between the two groups when the participants were walking. However when the participants were running, there was a significant difference in the two cohorts. While there was an increase in the total variance over the duration of the exercise for both the groups, the increase in variance of the LBP group was much greater (order of ten times) compared with the participants with healthy backs. The difference between the two groups was also very significant when observing the change of variance over the duration of the exercise. From these results, it is suggested that variance of sEMG of the muscles of the lower back, recorded when the participants are running, can be used to identify LBP patients.
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Vries, Paulien Maria de. "Cervical dystonia abnormal cerebral activation patterns related to preparation and execution of hand movement /." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2008. http://irs.ub.rig.nl/ppn/.
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Lee, Jae-Min. "Characterization of spatial and temporal brain activation patterns in functional magnetic resonance imaging data." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0013024.
Повний текст джерела
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Newmark, Jordan A. "Sex Differences in Orexin Activation Patterns of Fear-Cue Induced Inhibition of Eating in Rats." Thesis, Boston College, 2013. http://hdl.handle.net/2345/bc-ir:104427.
Повний текст джерелаАнотація:
Thesis advisor: Gorica PetrovichThesis advisor: Christina Reppucci
In order to understand the neurobiological basis for the phenomenon in which environmental cues override physiological cues to influence the behavioral control of feeding, we utilized an animal model for fear-cue induced inhibition of eating. Female rats that had learned to associate a tone with foot-shocks showed inhibition of eating across three extinction tests, whereas male rats that had received tone-shock pairings extinguished their inhibition of eating after the first test day. We assessed activation of orexin (ORX), a neuropeptide involved in eating and arousal, in the lateral hypothalamic area (LHA) of the brains of male and female control and experimental rats during the final test day. Female rats exhibited greater recruitment of ORX neurons in the LHA than male rats; there was no difference in ORX activation between control and experimental groups of either sex, indicating that ORX is involved in sex differences in fear-cue induced inhibition of eating
Thesis (BS) — Boston College, 2013
Submitted to: Boston College. College of Arts and Sciences
Discipline: College Honors Program
Discipline: Psychology
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Baird, Brenda Ratcliff. "EEG activation patterns in the frontal lobes of stutterers and nonstutterers during working memory tasks." Diss., Virginia Tech, 1996. http://hdl.handle.net/10919/40327.
Повний текст джерелаАнотація:
Developmental stuttering is a physiological disorder of speech motor control. Unlike acquired conditions, developmental stuttering is responsive to fluency-inducing conditions involving the manipulation or elimination of auditory feedback. It was hypothesized that stutterers experience interference effects from competing sensory
feedback during the working memory interval in which contextual information is held on-line in order to prepare subsequent motor responses. Behavior and EEG activity of stutterers and non stutterers were compared during working memory tasks.
Participants were 22 male, right-handed stutterers, mean age 28.2 years, age matched with 22 male, right-handed nonstutterers. Behavioral measures included a written verbal fluency task, an auditory delayed match-to-sample key press task, and a written digit span task. As hypothesized, there were no group differences in verbal
fluency. Also as hypothesized, stutterers had higher error scores (more false positives) on the auditory delayed match-to-sample key press task. This suggests increased sensitivity to auditory stimuli and difficulty inhibiting response to stimulation. Groups did not differ in digit span, but there was a trend toward significance (p=.07).
If stutterers do experience overlapping or excessive sensory stimulation during the working memory phase of speech motor plan assembly, the EEG of stutterers should evidence differences consistent with excessive or inefficient processing of "extra" sensory stimuli. Monopolar recordings were collected from 19 sites in accordance with the international 10-20 system of electrode placement. EEG was recorded during 60
seconds of resting-eyes-closed and resting-eyes-open~ 60 seconds during a silent backwards-subtraction math task; 120 seconds during an auditory delayed match-to-sample key press task.
As hypothesized, stutterers exhibited more theta activity than nonstutterers in frontal regions in all conditions, both in the low theta subband (3-5 Hz) and the high theta subband (5.5-7.5 Hz). Also as hypothesized, stutterers produced more alpha activity in the low alpha subband (8-10 Hz) in frontal regions in all conditions. There were no group differences in the high alpha subband (10.5-13 Hz). There were no hemispheric differences in frontal regions. Increased cortical activity and inl;;reased sensitivity to stimuli support the proposed hypothesis that stutterers experience excess sensory stimulation while attempting motor plan assembly, suggestive of stuttering as a disorder
of attention.Ph. D.
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Macrum, Elisabeth Corliss Padua Darin A. "The relationship between dorsiflexion range of motion and lower extremity movement patterns and muscle activation." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1882.
Повний текст джерелаАнотація:
Thesis (M.A.)--University of North Carolina at Chapel Hill, 2008.Title from electronic title page (viewed Dec. 11, 2008). "... in partial fulfillment of the requirements for the degree of Master of Art in the Department of Exercise & Sport Science in the College of Arts & Sciences." Discipline: Exercise and Sports Science; Department/School: Exercise and Sport Science.
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Anderson, JoAnna Todd. "Characterization of a sacral dorsal column pathway activating autonomic and hindlimb motor pattern generation." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42849.
Повний текст джерелаАнотація:
Spinal cord injuries (SCI) sever communication between supraspinal centers and the central pattern generator (CPG) responsible for locomotion. Because the CPG is intact and retains the ability to initiate locomotor activity, it can be accessed electrically and pharmacologically. The goal of this thesis was to identify and characterize a novel spinal cord surface site along the sacral dorsal column (sDC) for electrically evoking locomotor-like activity in the neonatal rat spinal cord. Stimulation of the sDC robustly activated rhythmic left-right alternation in flexor-related ventral roots that was dependent on the activation of high-threshold C fiber afferents. The C fibers synapsed onto spinal neurons, which project to the lumbar segments as part of a pathway dependent on purinergic, adrenergic, and cholinergic receptor activation. In ventral roots containing only somatic efferents, rhythmic activity was rarely recruited. However, in ventral roots containing both autonomic and somatic efferents, sacral dorsal column stimulation recruited autonomic efferent rhythms, which subsequently recruited somatic efferent motor rhythms. The efferent rhythms revealed a half-center organization with very low stimulation frequencies, and the evoked alternating bursts entrained to the stimuli. Similar entrainment was seen when sDC stimuli were applied during ongoing neurochemically-induced locomotor rhythms. The rhythmic patterns evoked by sDC stimulation operated over a limited frequency range, with a discrete burst structure of fast-onset, frequency-independent peaks. In comparison, neurochemically-induced locomotor bursts operated over a wide frequency range and had slower time to peaks that varied with burst frequency. The overall findings support the discovery of an autonomic efferent pattern generator that is recruited by sacral visceral C fiber afferents. It is hoped that this research will advance the understanding of afferent activation of the lumbar central pattern generator and potentially provide insight useful for future development and design of neuroprosthetic devices.
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Crook, Tracy. "The functional anatomy of equine hind limb muscles and their activation patterns during different locomotor tasks." Thesis, Royal Veterinary College (University of London), 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572457.
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Bigham, Heather Jean. "Sex Differences in Lower Limb Muscle Activation Patterns in Participants with Knee Osteoarthritis and Healthy Controls." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32377.
Повний текст джерелаАнотація:
Muscular stabilisation strategies during activities of daily living alter in the presence of knee osteoarthritis (OA). By examining neuromuscular adaptations using our weight-bearing target match protocol, the main objective of this research is to establish sex differences in adaptations of neuromuscular control that are associated with older males and females with and without OA. 66 participants completed the protocol while EMG, ground reaction forces (GRF), and kinematics were recorded. Muscle activation patterns were presented in polar plots with an EMG vector representing normalised muscle activation in twelve directions, each representing a GRF vector scaled to 30% maximal effort. Asymmetry about the polar plot (activation occurring in one direction more than another) was determined and specificity index (SI) and mean direction of activation were calculated when appropriate.
Healthy females demonstrated greater rectus femoris (RF) mean muscle magnitude (XEMG) (p=0.067) and less biceps femoris (BF) XEMG than healthy males (p=0.084) and females with OA (p=0.041), and males and females with OA demonstrated greater RF XEMG than healthy controls of the same sex (p=0.016, 0.072, respectively). Females with OA had significantly greater medial gastrocnemius XEMG than healthy females (p=0.031) and males with OA (p=0.020). Females with OA have less specificity in all muscles compared to males with OA and OA participants generally had less specificity compared to healthy controls of the same sex. Healthy males had the largest SI for lateral gastrocnemius with an asymmetrical activation pattern contrasting the more symmetrical activation pattern of all other groups.
In conclusion, we suggest OA-affected adults and healthy females use a quadriceps dominant strategy to stabilise the joint, and that this strategy may be a compensatory mechanism for reduced quadriceps function. We suggest RF, BF, MG, and LG should be targeted for prophylactic intervention as they displayed altered activation strategies in participants with OA and healthy females.
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Maneshi, Anali. "The effects of the menstrual cycle on muscle activation patterns and fuel utilization in cold exposure." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28413.
Повний текст джерелаАнотація:
Cold-induced shivering is characterized by two distinct muscle contraction patterns: continuous low-intensity shivering [at ∼1 to 5% of maximal voluntary contraction (MVC)] and bursts of high-intensity shivering (at 10 to 35% MVC) (Meigal, 2002, Haman et al., 2004). In this context, Haman et al. (2004) showed that carbohydrate (CHO) oxidation rate is directly related to burst shivering rate which increases the proportional recruitment of glycolitic type II fibers. Because most of these studies have been carried out in men, little is still know on the effects of hormonal fluctuations during the menstrual cycle on the dual shivering pattern and energy metabolism in women.
Therefore, the purpose of this study was to quantify differences in muscle recruitment pattern and fuel selection in two phases of the menstrual cycle. Muscle recruitment in eight muscles and whole body fuel selection were monitored in women exposed to 120 min of cold exposure (5°C liquid-perfusion suit) during FP and LP. Results show that there is no difference in the onset of shivering, shivering intensity, burst duration and burst shivering rate between LP and FP during steady state shivering (in last 15 min). Similarly, during steady state shivering (T=105-120 min), absolute rates and relative contributions of metabolic fuels to total heat production did not differ between FP and LP. We conclude that hormonal fluctuations during the menstrual cycle do not affect muscle recruitment patterns or substrate utilization in the cold. Whether this important difference in fuel selection modifies muscle shivering activity and/or confers a survival advantage remains to be established.
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Schramek, Tania Elaine. "Changes in brain activation patterns as a function of pharmacologically lowered glucocorticoid levels : a preliminary study." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98794.
Повний текст джерелаАнотація:
The goal of this study was to develop a method by which to examine the effects of pharmacologically lowered levels of a class of stress hormones known as glucocorticoids on neural activity induced by a memory task as measured by pharmacological functional resonance imaging (phfMRI). It is known that an excess of glucocorticoids can interfere with learning and memory processing and affect neural activity within brain regions that subserve these processes. Although the behavioural effects of lowered glucocorticoids are known and resemble those of excessive glucocorticoids, the impact of low glucocorticoid levels on brain activation patterns is not. We conducted a within-subject double-blind placebo controlled study in which participants performed a verbal memory task in the scanner under both placebo and Metyrapone (potent inhibitor of glucocorticoid synthesis) conditions. There were three functional runs in the study, encoding, immediate old/new recognition, and delayed recognition old/new recognition. Retention was also assessed at two instances of free recall, immediately after the scans and 24hrs later. As expected, glucocorticoid levels were significantly lower in the Metyrapone condition relative to placebo. There were no significant effects of the drug manipulation on either measure of memory performance. In terms of neural activity, the activations observed under the placebo condition alone were consistent with those found in the literature using similar tasks including left and right inferior frontal and hippocampus regions at encoding, and right inferior frontal regions at both immediate and delayed recognition. When we contrasted the drug and placebo sessions, we found task-specific activation patterns, which were of greater magnitude in the Metyrapone condition. These results suggest that a decrease in circulating glucocorticoid levels can have a significant impact on brain activation patterns irrespective of behavioural change. It is possible that increased cognitive effort was required under the influence of Metyrapone, which was reflected in the increased activity observed. Our findings also raised important issues with respect to the development of phfMRI protocols.
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Lischinsky, Julieta E. "Embryonic Transcription Factor Expression Predicts Neuronal Identity and Innate Behavioral Activation Patterns in the Limbic System." Thesis, The George Washington University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10263849.
Повний текст джерелаАнотація:
Instinctive behaviors such as mating and aggression are key for the survival and propagation of species. As innate behaviors manifest without prior training, there must be embryonic genetic mechanisms that specify these innate behavioral circuits. Focusing on the MeA and hypothalamus, both major integration centers of olfactory inputs, first, we sought to elucidate the link between embryonic transcription factor expression, neuronal identity and innate behavioral activation patterns in the MeA, and second, the link between embryonic transcription factor expression and instinctive behavioral activation patterns in hypothalamic subnuclei. Using mice as a model organism, we observed that the MeA progenitor niche in the preoptic area (POA) is comprised of distinct progenitor populations differentially marked by the transcription factors Dbx1 and Foxp2. Both embryonically and postnatally, Dbx1-derived and Foxp2+ subpopulations remain spatially segregated. We also observed that Dbx1-derived and Foxp2+ neurons differentially express sets of sex-steroid pathway proteins. Furthermore, both subpopulations differed in their intrinsic and extrinsic electrophysiological properties. Additionally, behavioral activation patterns were investigated in both subpopulations by determining the co-expression of the immediate early gene c-fos, an indirect marker of neuronal activity. During aggressive encounters, both Dbx1-derived and Foxp2+ neurons were activated in male and female mice; however, during mating cues, Dbx1-derived neurons in male and female mice were activated while only Foxp2+ neurons in male mice were activated and not in female mice. This denotes sex-specific differences in behavioral activation patterns in the MeA. Thus, parcellation of MeA neuronal subpopulations based on developmental genetics predicts molecular, electrophysiological, and behavioral specificity. Secondly, we were interested in determining whether embryonic transcription factor expression would be predictive of innate behavioral activation patterns in other limbic system structures implicated in the generation of innate behaviors such as the hypothalamus. Interestingly, we observed the presence of Dbx1-derived neurons in the lateral (LH), arcuate (Arc) and ventromedial (VMH) hypothalamic subnuclei. As Foxp2+ neurons are not present in the hypothalamus, we only analyzed Dbx1-derived neurons in these three hypothalamic regions. We show that Dbx1-derived neurons are activated in these structures during mating and aggression in both male and female mice. Thus, embryonic transcription factor expression in the hypothalamus is also linked to postnatal behavioral activation patterns. Taken together our findings indicate that embryonic transcription factor expression is predictive of behavioral activation patterns in the limbic system. We found that progenitor populations present in the same region but expressing distinct transcription factors, can generate MeA postnatal diversity based on molecular, electrophysiological and behavioral activation patterns. Furthermore, this can be generalized to other limbic system structures such as the hypothalamus, in which embryonic transcription factor expression of Dbx1 is also predictive of activation patterns during instinctive behavioral cues.
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Irving, Stephanie [Verfasser], and Andreas [Akademischer Betreuer] Zwergal. "Gaze behaviour and brain activation patterns during real-space navigation in hippocampal dysfunction / Stephanie Irving ; Betreuer: Andreas Zwergal." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1198111895/34.
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Welch, Torrence David Jesse. "A feedback model for the evaluation of the adaptive changes to temporal muscle activation patterns following postural disturbance." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29674.
Повний текст джерелаАнотація:
Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Ting, Lena; Committee Member: Chang, Young-Hui; Committee Member: Nichols, T. Richard; Committee Member: Schumacher, Eric; Committee Member: Thoroughman, Kurt. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Hartzheim, Daphne U. "Comparison of Neurological Activation Patterns of Children with and without Autism Spectrum Disorders when Verbally Responding to a Pragmatic Task." DigitalCommons@USU, 2015. https://digitalcommons.usu.edu/etd/4497.
Повний текст джерелаАнотація:
This study examined the neurological activation of children with autism spectrum disorders (ASD) while performing a pragmatic judgment task. In this study, children between the ages of 9 and 15 years responded to questions regarding a social situation, taken from the Comprehensive Assessment of Spoken Language, while concurrently having their brain activity measured. We targeted four brain regions for analysis: dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex (OFC), superior temporal gyrus (STG), and the inferior parietal lobule (IPL).
Ten children with ASD and 20 typically developing (TD) children participated. Matching occurred in a bracketing manner with each child in the ASD group being matched to two control children to account for natural variability. Neuroimgaging was conducted utilizing functional Near‐Infrared Spectroscopy (fNIRS). Oxygenated and deoxygenated blood concentration levels were measured through Near‐Infrared light cap with 44 channels. The cap was placed over frontal lobe and the left lateral cortex. The placement was spatially registered using the Polhemus.
Analysis indicated that children in the ASD group performed significantly poorer than their controls on the pragmatic judgment task. Mixed repeated measures analysis of variance of neurological data indicated that the children with ASD had lower concentration levels of oxygenated and total hemoglobin across the four regions. There were significantly higher concentration levels for oxygenated and total hemoglobin in the STG. Analysis of correct and incorrect responses revealed significantly more activation in the OFC when responses were correct. Additionally, there was a significant interaction of Accuracy and Group in left DLPFC. Children with ASD presented higher oxygenated hemoglobin concentration values when responding correctly, while children in the control group presented higher oxygenated hemoglobin concentration values for the incorrect items. Statistical Parametric Mapping was performed for each triad to assess the diffusion of neural activation across the frontal cortex and the left lateral cortex. Individual comparisons revealed that 7 out of 10 children with ASD demonstrated patterns consistent with more diffuse brain activation than their TD controls.
Findings from this study suggest that an fNIRS study can provide important information about the level and diffusion of neural processing of verbal children and adolescents with ASD.