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1
Jong, Pieter Job de. "Phobia: contingencies, cognitions, and reflexes." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 1994. http://arno.unimaas.nl/show.cgi?fid=7030.
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Poliakov, Andrew Victor. "Stretch reflexes in human masseter /." Title page, table of contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09php766.pdf.
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Kellett, Daniel Otto. "Central serotonergic control of cardiovascular reflexes." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1446450/.
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Central serotonergic neurones control reflex parasympathetic outflow to the heart, airways and bladder in a number of species, and different 5-HT receptor subtypes are involved in this effect. 5-HTiA and 5-HT3 receptors in the brainstem facilitate these reflexes, whilst 5-HTiB/id, 5-HT2 and 5-HT4 receptors inhibit them. Recently, central 5-HT7 receptors have been implicated in bladder reflexes. Experiments on anaesthetised rats showed that the selective 5-HT7 receptor antagonists SB-269970 and SB-656104, given intracisternally (i.e.), attenuated cardiopulmonary, baroreflex and chemoreflex bradycardias. Similarly, the selective 5-HTia receptor antagonist WAY-100635 attenuated cardiopulmonary and chemoreflex (but not baroreflex) bradycardia, whilst robalzotan and (-)-pindolol (antagonists at 5-HTiA receptors) had no effect on cardiopulmonary and baroreflex bradycardias respectively. Chemical stimulation of presumed serotonergic cell bodies in raphe magnus/pallidus evoked a bradycardia that could not be attenuated either by 5-HT receptor antagonists (given i.v.) or by prior 5-HT depletion. The latter did, however, significantly attenuate cardiovascular reflex sensitivity. Activation of nucleus tractus solitarius (NTS) neurones by the vagus was inhibited by the iontophoretic AMP A receptor antagonist DNQX or by topical SB-269970. Subsequent histology suggested that 5-HT containing terminals do not make close appositions with these neurones. Preliminary data demonstrate that SB-269970 (given i.e.) effectively attenuates the cardiopulmonary reflex in awake rats, but has variable effects on the chemoreflex. The data suggest that 5-HT7 receptors in the NTS are crucially involved in the central transmission of reflex bradycardias, at least in rats. The role of the 5-HTia receptor is less clear-cut than in the rabbit, and may reveal a species difference. The origin of 5-HT activating these receptors is unlikely to be the medullary raphe neurones, but may be primary afferents terminating in the NTS. Since recent ultrastructural evidence shows 5-HT terminals and NTS cardiovascular neurones are often separated by astroglial leaflets, astrocytes may be involved in serotonergic-glutamatergic signalling.
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JARDEL, BOUISSIERE JEANNE. "Contribution a l'etude des epilepsies reflexes." Nantes, 1991. http://www.theses.fr/1991NANT078M.
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Sammon, Michel P. "Bifurcation analyses of respiratory vagal reflexes." Case Western Reserve University School of Graduate Studies / OhioLINK, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=case1060098227.
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Thomas, Colleen J(Colleen Joy) 1965. "Influence of natriuretic peptides on cardiac reflexes." Monash University, Dept. of Physiology, 2001. http://arrow.monash.edu.au/hdl/1959.1/8347.
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Nikitina, Tatiana. "An asymmetric bilateral model of stretch reflexes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0002/MQ44031.pdf.
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Nikitina, Tatiana. "An asymmetric bilateral model of stretch reflexes /." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20512.
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A bilateral stretch reflex model was built based on asymmetric agonist---antagonist reflex connections at the ankle. The overall dynamics were analyzed using Mason's rule algebra. The model predicts the characteristic agonist and antagonist responses to stretch. Simulations with pulse displacements and random perturbations are in qualitative agreement with experimental data and suggest a mechanism whereby the mean absolute velocity of the perturbations could depress the stretch reflex at the spinal level. This implies that spinal neural circuits can calculate and carry out their own integrative functions and, in particular, modulate the stretch reflex gain.
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Arnatt, Matthew. "Contents, and criticisms as reflexes to content." Thesis, Goldsmiths College (University of London), 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.514226.
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Koningsbruggen, Martijn G. van. "On the Normal Use of Oculomotor Reflexes." Thesis, Bangor University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505945.
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Vedula, Siddharth. "Ankle stretch reflexes during anticipatory postural adjustments." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:8881/R/?func=dbin-jump-full&object_id=32517.
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McGarry, James Timothy. "On the nature of stopping a voluntary action." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0025/NQ38942.pdf.
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Tahir, Uzma H. "Modulation of Local Reflexes During Centrally Commanded Movements." Digital Archive @ GSU, 2013. http://digitalarchive.gsu.edu/biology_theses/43.
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During centrally orchestrated movements, the nervous system must distinguish between appropriate and inappropriate reflexes. I studied local postural flexion reflexes of the crayfish that are evoked by unexpected touch. An isolated abdomen was used which permitted recording and stimulating of tailfan afferents, nerve cord interneurons, and postural motor neurons. Stimulation of the afferents evoked a postural flexion response of the medium tonic and large phasic motor neurons of the superficial flexor nerve; a flexion motor program was then excited by stimulating descending interneurons. Afferent stimulation evoked a smaller motor response during the motor program than before or after. These results indicate that the postural reflex responses to sensory stimulation are inhibited at a site presynaptic to the motor neurons during the flexion motor program. Application of Picrotoxin (blocked inhibition) to the primary afferent-to-mechanosensory interneuron synapse did not prevent the modulation of the postural flexion reflex during the flexion motor program.
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Coutsougera, Photini. "The semivowel and its reflexes in Cypriot Greek." Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252267.
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Brewer, Jordan. "Phonetic Reflexes of Orthographic Characteristics in Lexical Representation." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/195213.
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A large domain of linguistic inquiry concerns the nature of words. It is widely thought that words are stored and represented in our minds in a structure termed the lexicon, in which every word has a 'lexical representation'. Researchers conduct experiments and examine intuitions about words to determine the content and structure of the lexicon. One interesting component in lexical representation, for literate speakers, is an orthographic representation for words. It has been traditionally assumed that while this orthographic information is available and useful in such tasks as visual word recognition (i.e. reading) or in writing, orthographic information about words is not necessarily involved in non-visual linguistic tasks, like auditory word perception, or speech production.There has been some research however, which has challenged this notion of the isolation of orthographic information to visual processes. In a seminal study Seidenberg and Tanenhaus (1979) found an influence of orthography in an auditory rhyming judgment task. Subjects were faster to judge as rhyming those pairs which shared an orthographic representation of the rhyme than those who shared only phonology (i.e. pie-tie vs. rye-tie). Additional recent research has confirmed these effects of orthography in auditory perception tasks (Taft & Hambly, 1985; Halle, Chereau, & Sequi, 2000; Ziegler & Ferrand, 1998). Even more surprisingly, some experiments have suggested effects of orthography in speech production (Tanenhaus, Finigan & Seidenberg, 1980; Lupker, 1982; Wheeldon & Monsell, 1992; Damion & Bowers, 2003). These experiments all show facilitated naming latencies for words which share orthographic characteristics with some prime environment. As such, these results can all be explained as effects of orthography on lexical access of words rather than affecting the production process per se.In contrast, the experiments and analyses described in this dissertation show an un-ambiguous effect of orthography on speech production. Orthographic characteristics of word-final sounds, and words themselves are shown to influence the durations of spoken productions of those sounds, and whole words. These effects are robust to the mode of lexical access, whether through experimentally elicited reading aloud of words, or through the spontaneous generation of words in a modified sociolinguistic interview format.
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Cabib, Christopher. "Alteraciones de la excitabilidad refleja y del control motor en esclerosis múltiple." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/401656.
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INTRODUCCIÓN: En Esclerosis Múltiple (EM) el sustrato neuropatológico típicamente muestra un patrón de distribución aleatoria de lesiones desmielinizantes, con particular predilección por estructuras comisurales y subcorticales tales como el cuerpo calloso y el tronco del encéfalo. En estos pacientes, es común observar fenómenos subclínicos pocos explorados, tales como la hiperactividad facial, la lentitud motora y la falta de control motor, que pueden estar relacionados al daño encefálico multifocal que ocurre en vías neurales y circuitos específicos por alteración en los mecanismos de conducción y excitabilidad.
HIPÓTESIS: Los pacientes con EM presentan signos neurofisiológicos subclínicos indicativos de alteraciones en la excitabilidad de los circuitos reflejos tronco-encefálicos y del control motor en la ejecución de tareas unimanuales. Estas alteraciones se correlacionan con lesiones cerebrales subcorticales, especialmente comisurales.
MÉTODOS: Veintiún pacientes con EM en estadio leve de enfermedad fueron sometidos a 2 diseños experimentales. Primero, la excitabilidad del reflejo de parpadeo fue evaluada en ambos lados del rostro mediante el estudio del tamaño de las respuestas obtenidas por diversas técnicas electrofisiológicas (estimulación única trigeminal y somatosensorial, estimulación pareada y condicionada con prepulso somato-sensorial), y correlacionada con el patrón de distribución hemisférica de lesiones desmielinizantes. Segundo, en un paradigma de tiempo de reacción “cruzado” (extensión de la muñeca ante un estímulo somato-sensorial aplicado en la mano contralateral como señal imperativa) que involucra necesariamente la transferencia inter-hemisférica de impulsos, se estudió la asociación entre el retraso del tiempo de reacción con: el tiempo de tránsito transcalloso (medido por estimulación magnética transcraneal), la excitabilidad de estructuras subcorticales involucradas en la preparación del acto motor (mediante el estudio del efecto StartReact), y la presencia de actividad involuntaria electromiográfica “en espejo”. Tales anormalidades fueron comparadas con los datos obtenidos en sujetos sanos, y correlacionadas con medidas de daño estructural y microestructural por resonancia magnética nuclear en cuerpo calloso y tronco del encéfalo.
RESULTADOS: 1. En un subgrupo de pacientes en un estadio más precoz de enfermedad (35%) se observó una asimetría en la “excitabilidad” del reflejo de parpadeo que se asoció a una distribución asimétrica de lesiones hemisféricas, a diferencia de lo observado en pacientes en un estadio más avanzado (40%) que mostraron un retraso en la “conducción” de las respuestas del reflejo de parpadeo y una distribución hemisférica simétrica de lesiones. 2. En pacientes, se observó que la lentitud de reacción motora se asocia a una reducción en el efecto StartReact, y que el retraso del tiempo de reacción en tareas “cruzadas” se correlaciona con una prolongación en el tiempo de tránsito transcalloso. 3. En tareas motoras “cruzadas”, los pacientes mostraron una actividad “en espejo” exagerada que se asocia a un mayor daño microestructural de fibras callosas y a atrofia del tronco del encéfalo.
CONCLUSIONES: En pacientes con EM es frecuente encontrar alteraciones subclínicas de la excitabilidad en los circuitos reflejos y estructuras subcorticales y a falta de control motor, revelados mediante estudios neurofisiológicos. Tales alteraciones se explican mayormente por el daño multifocal encefálico con afectación predominante de los hemisferios cerebrales, cuerpo calloso y tronco del encéfalo.INTRODUCTION: Multifocal distribution of demyelinating lesions in the brain affecting mainly the brainstem and the corpus callosum (CC) are common findings in magnetic resonance (MRI) of patients with multiple sclerosis (MS). These patients may present with subclinical signs (myokymia, bradykinesia or lack of motor control) representing altered excitability in specific neural circuits. HYPOTHESIS: Signs of altered excitability in MS show in the study of brainstem reflex circuits or during the hand movement execution in reaction time paradigms requiring transcallosal pathways (“crossed” motor tasks). These abnormalities combine with distant lesions in cerebral hemispheres or with focal lesions in brainstem and CC. METHODS: We studied 21 mildly-disabled MS patients and 11 healthy volunteers in two experimental conditions. First, the blink reflex excitability was examined in both sides to single stimulation of trigeminal and median nerves, and to paired trigeminal stimulation and conditioned with a somato-sensory prepulse. These measures were associated with the distribution of hemispheric demyelinating MRI-lesions. Second, in the context of a “crossed” reaction time paradigm, participants were requested to perform unilateral wrist-extension movements to a sensory stimulus applied in the contralateral hand used as imperative signal. “Crossed” reaction time was correlated to transcallosal conduction time measured with transcranial-magnetic-stimulation, and associated to the startling- acceleration in the reaction time (a.k.a. StartReact effect) and with the presence of mirror electromyographic activity (mEMG). Abnormalities were correlated with MRI- measures of structural/ultrastructural damage in brainstem and CC. RESULTS: In 35% of patients we found an asymmetric blink reflex excitability in absence of brainstem lesions which associated with an asymmetric distribution of hemispheric lesions, whereas in 40% of patients we found delayed blink responses which associated with brainstem lesions and symmetric distribution of hemispheric lesions. In patients, slowness of reaction associated with reduced StartReact effect, and delayed “crossed” reaction time correlated with lengthening in transcallosal conduction time. In "crossed” reaction time, patients showed enhanced mEMG which associated with increased ultrastructural callosal damage and brainstem atrophy. CONCLUSIONS: MS patients show altered excitability in brainstem reflex circuits and subcortical structures and lack of motor control. These abnormalities are related to lesion involvement of cerebral hemispheres, CC and brainstem.
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Lucas, Gerald Quinlan. "A mechanical apparatus to quantify the reflex response of the human head/neck system." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/g_lucas_110106.pdf.
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Kettering, Tracy Lynne. "A comparison of procedures for unpairing conditioned reflexive establishing operations." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1217944623.
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Spring, Jesper Honig. "Reflexes: programming abstractions for highly responsive computing in Java /." Lausanne : EPFL, 2008. http://library.epfl.ch/theses/?nr=4228.
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Thèse Ecole polytechnique fédérale de Lausanne EPFL, no 4228 (2008), Faculté informatique et communications IC, Programme doctoral Informatique, Communications et Information, Institut d'informatique fondamentale IIF (Laboratoire de programmation distribuée LPD). Dir.: Rachid Guerraoui, Jan Vitek.
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Dobson, Katharine L. "Descending control in sensitization of reflexes in the rat." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13110/.
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Electrical stimulation of the heel or toes evokes short latency polysynaptic reflexes in muscles of the ankle extensor medial gastrocnemius (MG), the ankle flexor tibialis anterior (TA) and the knee flexor biceps femoris (BF), the co-ordinated actions of which form an organized protective withdrawal response. Previous studies in the rabbit have shown that such reflexes are enhanced (sensitized) or inhibited by application of the chemogenic agent mustard oil (MO) to various areas of the body surface in a manner that reinforces the protective function of these responses. The organization of these ‘sensitization fields’ was strictly controlled by supraspinal pathways from the brain. The aim of the present experiments was therefore to extend these studies of the spatial organization of sensitization of withdrawal reflexes into the rat, the species most commonly used in pain research. Patterns of facilitation and inhibition of spinal reflexes were obtained and compared in decerebrate spinalized, decerebrate non-spinal, and Alfaxan- anaesthetized rats by applying mustard oil to sixteen different body locations including sites on the ipsilateral and contralateral hindlimbs as well as other off limb areas such as the snout and tail. It was found that in decerebrate spinalized animals, MO application to ipsilateral hindlimb sites enhanced but never inhibited reflex responses in the limb, whilst MO treatment to off limb sites was without effect. In contrast in anaesthetized animals the prevalent effect of MO was inhibition from treatment sites distributed across the entire animal. Reflexes in animals with an intact spinal cord (decerebrate or anaesthetized) were facilitated or inhibited by MO application to ipsilateral hindlimb sites in a way that resembled the modular organization of reflexes per se and previous sensitization studies in the rabbit. However clear differences were also observed in the effects of MO between the two species, including modulation of the heel-MG extensor response in spinalized animals, which in rabbit was inhibited by MO application to the ipsilateral toes whereas in the rat no inhibition by MO was found in spinalized animals. Sensitization of hindlimb reflexes by MO in the rat therefore seems to be influenced by descending inhibitory and facilitatory pathways. These influences were further investigated in subsequent studies. Whilst the predominant effect of spinalization was a loss of inhibition and an expansion of sensitization fields, in the toes-evoked TA reflex the reverse was noted with regard to MO treatment of distal ipsilateral sites. In this case, facilitation found in non-spinal animals did not occur in the equivalent spinalized cohort, and thereby implies that a descending facilitatory pathway is also implicated in the control of spinal reflex excitability in this model. In decerebrate rats, the noradrenergic α2-adrenoceptor antagonist RX 821002 or the serotonergic 5-HT3 receptor antagonist ondansetron were administered directly to the spinal cord (intrathecally, i.t.) either alone (dose-response studies) or as a single dose between two successive MO applications to one of three ipsilateral skin sites on the hindlimb (heel, metatarsophalangeal joints or flexion of the ankle). Cumulative i.t. doses of RX 821002 revealed the presence of tonic descending inhibition of all reflex responses as well as preventing MO-evoked inhibition (and possibly facilitation) of reflex responses suggesting the involvement of the α2-adrenoceptor subtype in mediating these effects in this model. On the other hand, cumulative i.t. ondansetron administration resulted in a decrease in the magnitude of reflex responses, thus indicating that 5-HT3 receptors are indeed implicated in tonic descending facilitation of spinal reflexes. In addition i.t. ondansetron revealed that potentiation (and possibly inhibition) of reflexes following an acute chemogenic insult appears to involve the actions of serotonin at 5-HT3 receptors in the spinal cord. These studies therefore show that the organization of sensitization of hindlimb reflexes in the rat are modulated by supraspinal influences that exist as a balance of descending facilitatory and inhibitory pathways, mediated at least in part by serotonergic 5-HT3 receptors and noradrenergic α2-adrenoceptors.
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McPhillips, D. M. "The role of persistent primary reflexes in reading delay." Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396608.
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Lim, Elizabeth. "Crossed myotatic spinal reflexes in babies, children and adults." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324871.
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Okdeh, Atef Mohammed. "Jaw reflexes in subjects with temporomandibular disorders and bruxism." Thesis, University of Glasgow, 1997. http://theses.gla.ac.uk/6580/.
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The overall aim of this study, was to investigate the jaw-opening reflexes in TMD patients and bruxists in order to get a better understanding of these disorders. At the beginning, it was decided to study the reflexes evoked in the masseter muscle by electrical stimulation across the lip in healthy subjects. The aim was to find the threshold at which each of the significant responses occurred and to investigate the effect of reversing the polarity of the stimulus electrode on the pattern of reflexes. A sequence of inhibitor, excitatory, inhibitory and excitatory responses could be produced in the muscle by both polarities of stimuli. It was found that stimulation of nerves supplying the skin outside the mouth evokes predominantly long-latency jaw reflexes whereas short-latency responses can be evoked by stimulating nerves supplying oral mucosa. Furthermore, long-latency excitatory reflexes seem to be the most easily evoked by stimulation of the lip. Another aim of the study was to investigate whether difference could be observed between bruxists and non-bruxists in response to electrical stimulation of the lip. In both groups, there were significant differences in the thresholds of the different responses. Also, there were differences between the two groups in the presence of the short-latency excitation and the long-latency inhibitory responses. These findings suggest that long-latency inhibitory responses evoked by electrical stimulation of the lip are weaker in bruxists than in non-bruxists. Finally, jaw reflexes in TMD patients were investigated to determine whether differences could be detected in electrically-evoked inhibitory and excitatory responses. Moreover, the occlusal splint is one of the most universally accepted forms of therapy in TMD patients and it was possible that these splints might have an effect on the pattern of jaw reflexes in view of their therapeutic effect.
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Meintjes, André F. (André Francois). "Autonomic Reflexes of the Heart During Acute Myocardial Ischemia." Thesis, University of North Texas, 1993. https://digital.library.unt.edu/ark:/67531/metadc279150/.
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This study investigated whether acute myocardial ischemia of the anterior left ventricular wall induced an increase in cardiac sympathetic efferent nerve activity and thereby affected regional myocardial blood flow and contractile function.
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Forrest, Diane S. "Prevalence of retained primitive reflexes in patients with anxiety disorders." Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/28040.
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Anxiety is not only one of the mental health disorders most commonly referred to clinicians, but is also a research interest, producing subsequent modification in treatment approaches. However, there are suggestions in the literature that the effectiveness of some psychological treatments have not been systematically evaluated (Department of Health, 2001), or that treatment studies have employed methods unrepresentative of everyday clinical practice (World Health Organization.2000). Furthermore, from analysis of outcome studies, psychological therapies have been reported as effective for only half of those treated (Fisher & Durham, 1999). These findings suggest that there are individuals with anxiety who fail to respond to available therapies, and that alternative approaches for this group are not well studied. Anxiety is not only one of the mental health disorders most commonly referred to clinicians, but is also a research interest, producing subsequent modification in treatment approaches. However, there are suggestions in the literature that the effectiveness of some psychological treatments have not been systematically evaluated (Department of Health, 2001), or that treatment studies have employed methods unrepresentative of everyday clinical practice (World Health Organization.2000). Furthermore, from analysis of outcome studies, psychological therapies have been reported as effective for only half of those treated (Fisher & Durham, 1999). These findings suggest that there are individuals with anxiety who fail to respond to available therapies, and that alternative approaches for this group are not well studied. tests employed in the study. From analysis of all individual test scores, two of these, detecting involvement of labyrinthine processes, resulted in the highest scores. The findings from analysis of resulting data are discussed in relation to implications for future study and further use of the measures with differing populations.
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Rosengren, Sally Marie Clinical School Prince of Wales Hospital Faculty of Medicine UNSW. "Vestibular evoked potentials: Properties and clinical applications of extraocular reflexes." Publisher:University of New South Wales. Clinical School - Prince of Wales Hospital, 2008. http://handle.unsw.edu.au/1959.4/41331.
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Vestibular-dependent surface potentials can be recorded from over the scalp following stimulation with intense air- (AC) and bone-conducted (BC) sound. However, sound-evoked responses may be confounded by parallel stimulation of the auditory system. To demonstrate the pure vestibular origin of the cortical potentials, patients with severe to profound bilateral hearing loss were stimulated with AC and BC sound. The responses had the same amplitude as those recorded in normal subjects, and were only present in patients with preserved vestibular function, confirming their vestibular origin. One negative surface potential, the N15, was largest when measured over the forehead, and detailed mapping of this potential localised it to the eyes. This extraocular response had the same polarity on each side of the eye and was altered by changing gaze direction, suggesting an extraocular muscle origin (i.e. an ocular vestibular evoked myogenic potential, or OVEMP). Galvanic vestibular stimulation (GVS) produces large eye movements with horizontal and torsional components directed away from the cathode. A modified electrode montage was used to characterise the OVEMPs produced by GVS. OVEMPs recorded from beneath the eyes had the appropriate polarity to produce the torsional eye movement and likely originated in the inferior oblique muscles. Sound-evoked OVEMPs were investigated in patients with superior canal dehiscence (SCD), as they have vestibular hypersensitivity to sound. The SCD patients had large sound-evoked OVEMPs with low threshold, similar to the VEMP. OVEMP amplitude was much larger in the patients than controls and could be an additional diagnostic marker for this condition. Although SCD patients have large VEMPs and eye movements evoked by AC sound, little is known about other vestibular reflexes. It was shown that patients also have large sound-evoked vestibulo-spinal reflexes, similar to those evoked by GVS. However, despite these large reflexes, there was little consistent whole body sway. Finally, a case is reported in which the combination of VEMP and OVEMP results indicated the location and nature of a central nervous system lesion. The patient had delayed potentials when stimulated on the left side, indicating a demyelinating lesion in the root entry zone of the left vestibulocochlear nerve.
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Zair, Nicholas. "The Reflexes of the Proto-Indo-European Laryngeals in Celtic." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523104.
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Taylor, Julian Scott. "Opioid and monoamine modulation of spinal reflexes in the rabbit." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385277.
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Goodwin, C. N. "Vibration- and strech-evoked reflexes in human flexor carpri radialis." Thesis, University of Manchester, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383131.
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Mackenzie, Stuart William. "Reflexes evoked by electrical vestibular stimulation and their clinical application." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8594/.
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The vestibular system provides vital information about head position and motion; which is used for the control of balance through vestibulospinal reflexes. Chapter 2 explores the process of transforming head position to body coordinates, with and without vision. The results show when vision is available, the evoked response is less precise. Chapter 3 explores the transformation process before and after 60 days of bedrest. After this period of inactivity, participants swayed more, and their EVS-evoked sway response was less precise. This decrement in precision appears to begin recovery 6 days postbedrest. Chapter 4 focuses on vestibulo-ocular reflexes rather than postural reflexes. Electrical vestibular stimulation is used to evoke measurable torsional eye-movements. The magnitude of the response is modulated by stimulus frequency. Results suggest that CNS interprets electrical vestibular stimulation as a velocity signal rather than a position or acceleration signal. This technique is an ideal measure of pure vestibular function, Chapter 5 utilised the technique in a clinical environment. Vestibular schwannoma patients, with known unilateral vestibular deficit, were tested to identify if the proposed technique can detect this deficit. Results showed that asymmetries could be detected, and, the test may be more sensitive than previously used measures of vestibular asymmetries.
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Jones, Karen Elizabeth. "High frequency acoustic reflexes in cochlea-impaired and normal ears." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/4096.
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The acoustic reflex refers to the contraction of a middle ear muscle in response to sound. The contraction causes a stiffening of the middle ear system and, consequently, the flow of acoustic energy to the cochlea is impeded. By measuring the change in admittance in the auditory system during sound stimulation it is possible to indirectly monitor the middle ear muscle contractions. Such measurements provide useful information regarding the integrity of the auditory system and the location of the auditory pathology.
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Sergio, Lauren E. (Lauren Elisabeth). "The kinematic organization of the wipe relfex in the spinal frog /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59638.
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The kinematics of wiping movements to the back were examined in spinal adult Rana Catesbeiana. The aim was to identify the elements of the back wipe and their functional role. The data show that there are three essential phases of the wiping movement: a placing phase; a flexion of the hip and knee; and a whisk/extension phase. The first phase is the only one which is dependent upon stimulus location. The spinal frog adjusts the hindlimb to account for stimulus location in the rostro-caudal direction. There is no adjustment for stimulus position along the medial-lateral axis of the body. It is proposed that the second phase serves as a preparatory movement for the extension portion of the wipe. When the wipe is partitioned into these phases, the motion was found to be planar for the first and third phases. At the end of the first phase there was a transition between the two planes.
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Magzoub, Mohammed Salah Edlin Mohammed Ali. "The representation of respiratory movements in the inferior olive." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321646.
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Delaney, Erin Paul. "Muscle metaboreflex sensitivity in hypertensive adults." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 108 p, 2009. http://proquest.umi.com/pqdweb?did=1891555381&sid=4&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Sonnenberg, Douglas C. "Effects of visual cortex lesions on modulation of the cutaneous and acoustic blink reflexes and choice reaction time /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418065.
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Thesis (M.S.)--University of Missouri-Columbia, 2003.Figure 1 referred to on leaf 2 is shown on leaf 20. Typescript. Includes bibliographical references (leaves 35-36). Also available on the Internet.
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Fornari, Maria Carolina dos Santos. "Padrão eletromiográfico de membros inferiores em resposta a perturbações posturais." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/47/47135/tde-03042009-104150/.
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A manutenção do equilíbrio depende da ativação sinérgica de músculos dos dois hemicorpos, e há evidências de que essa coordenação é mediada por circuitos medulares, que estão sob controle supra-segmentar. O objetivo desse trabalho é descrever mecanismos neurofisiológicos e biomecânicos envolvidos no controle postural de sujeitos saudáveis frente a uma perturbação provocada por uma contração reflexa, enfatizando-se os mecanismos associados à coordenação entre membros. A perturbação postural ocorreu em resposta a um estímulo elétrico unilateral no nervo tibial. Devido a restrições em estudos anteriores, utilizou-se uma ampla abordagem (múltiplos músculos, reflexos cruzados) e estimulação precisamente controlada. Os resultados mostraram um complexo padrão de ativação dos músculos dos membros inferiores bilateralmente. Logo após o estímulo, foram encontradas respostas de curta e média latência em músculos da perna e da coxa. Posteriormente, foram observadas algumas ações musculares de longa latência nos músculos mais distais, que provavelmente foram ativadas em resposta às oscilações posturais. As respostas musculares iniciais sugerem que as informações aferentes e os reflexos medulares possuem uma função muito importante na regulação da coordenação entre membros, durante a manutenção da postura ereta quieta.Balance depends on the synergic activation of muscles bilaterally, and there is evidence that this coordination is mediated by spinal circuits, which are under supra-spinal control. The objective of this study is to describe neurophysiologic and biomechanical mechanisms involved in the postural control of healthy subjects submitted to a disturbance provoked by a muscular reflex contraction. The postural perturbation was caused by a unilateral electric stimulation to the popliteal fossa. The analysis emphasizes the mechanisms associated with interlimb coordination. In this work, methodological approaches expanded those of previous work, the recordings being done bilaterally and the stimulus being precisely controlled. The results showed a complex pattern of bilateral muscular activation. Short and medium latency responses were found in the leg and thigh muscles. These were followed by some muscular activity at longer latencies, probably occurring due to the postural oscillations. The initial muscular responses suggest that the afferent inflow and the spinal cord reflexes have an important function in the between-limb coordination during the standing posture.
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Paulin, M. G. (Michael Geoffrey). "A mathematical and comparative study on cerebellar control of vestibular reflexes." Thesis, University of Auckland, 1985. http://hdl.handle.net/2292/2041.
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The first aim of this thesis is an introduction to some basic aspects of multivariate control theory which are relevant to the question of how the brain controls movements. A regulator is a device which forces a system to follow a specified trajectory in the presence of perturbations which might cause it to diverge from that trajectory. Regulation involves constructing an additional control input which depends upon the difference between the actual system state and the desired state. This requires the construction of a state estimate from raw data about system input and output. For effective state estimation, the sensor input gain to the state estimator needs to be time-varying. Under certain assumptions, the appropriate input gain can be specified analytically. The feedback regulation signal can then be constructed as a function of the state estimate. For effective regulation, the gain of the feedback function has to vary during maneuvers. Under certain assumptions an appropriate feedback gain can be specified analytically. The state observer input gain equations have a simple relationship to the feedback gain equations, so that gain specification is essentially the same task in each case. Cerebellar research has been dominated for the past 25 years by the theories of James Albus and David Marr. These mathematicians proposed similar models in which certain synapses in the cerebellar cortex are continuously modified by experience in such a way that movements which are consistently repeated under a given set of circumstances come to be performed automatically by the cerebellum. Much experimental work has focussed on the role of the vestibulo-cerebellum in fine control and learning of the vestibulo-ocular reflex. The state of the art along this line is formally described by Fujita's adaptive filter model of the cerebellar cortex. In chapter 4 it is shown that a basic feature of Fujita's model is inconsistent with available evidence. The 'Tensorial theory of brain function' is discussed in chapter 5. This is a novel theory of brain function which has been used in an attempt two explain cerebellar function. The attempt is a failure, based on sophistocated misconceptions and flawed by poor reasoning and clumsy analysis. The approach serves to confuse rather than clarify the question of cerebellar function. The final chapter of the first part of the thesis presents a basis for a new approach to cerebellar function based on the engineering theory of control of multivariate dynamical systems. It is proposed that the cerebellum is involved in movement regulation by controlling the gains of brainstem motor pathways, and in mapping the animal's environment by controlling the gains of sensory inputs to the midbrain. While learning undoubtedly does occur in the cerebellar cortex, this is not specifically a 'learning device', as commonly conceived. The second part of the thesis is concerned with the development and application of a method of system identification for characterising the dynamics of the vestibulo-ocular reflex and its components in an elasmobranch. The chosen method involves pulse-rate modulated bilateral electrical stimulation of the horizontal semicircular canal ampullary nerves. This produces a synthetic vestibulo-ocular reflex in a stationary preparation. The stimulus pattern is a pseudorandom binary sequence of pulse rates, so that cross-correlation of the stimulus pattern with the response signal gives a Unit Impulse Response dynamic signature for the system. Computer software for signal generation, recording, analysis and display was written by the author. The identification system was applied first to characterise the dynamics of the eye movement response to horizontal canal ampullary nerve stimulation, and compare this to the dynamics of the eye motor plant alone. The eye motor preparation acts as a first order low-pass filter with a time constant of about 0.2 seconds (16°C), while the ampullary preparation acts as a second order low-pass filter with a dominant time constant of about 0.75 seconds (16°C). Central pathways of the elasmobranch vestibulo-ocular reflex extend the time constant of the motor plant by a factor of 3-4, as in other animals. Eye movements predicted by fitted linear models accurately mimic eye movements recorded during experiments, suggesting both that central pathways of the reflex operate normally during this somewhat un-naturally evoked response and that the identification procedure is effective. Furthermore, combination of the ampullary nerve to eye movement transfer function obtained in this study, with head rotation to ampullary nerve transfer functions obtained by other workers, gives a consistent picture of elasmobranch vestibulo-ocular reflex function predicting compensatory eye movements in the band 0.2 - 4.0 Hz., and perhaps higher. The identification method has also been applied to produce models of vestibulocerebellar Purkinje cell dynamics during electrically evoked vestibular eye movements. Linear identification gives a poor characterisation of Purkinje cell activity during the high frequency vestibulo-ocular reflex. This is incompatible with linear phase-compensator models of the cerebellar cortex, but consistent with the reflex gain modulation theory of cerebellar function advocated in the first part of the thesis.
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Zehr, Elwood Paul. "A functional interpretation of electrically evoked cutaneous reflexes during human walking." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ29132.pdf.
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潘明施 and Ming-see Angela Poon. "Modulation of cutaneous reflexes in a finger muscle during voluntary contractions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1990. http://hub.hku.hk/bib/B31209956.
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McKaigue, James Patrick. "Effects of adrenergic drugs on control of cardiovascular reflexes in man." Thesis, Queen's University Belfast, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317537.
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Zheng, Fashan. "Baroreceptors and cardiopulmonary reflexes : afferent pathways and the influence of cold." Thesis, University of Aberdeen, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262348.
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A study was performed on decerebrate ferrets to define the contribution of vagal afferent non-myelinated fibres to the baroreceptor heart rate reflex produced by bolus i.v. injection of phenylephrine, using capsaicin as a selective C fibre blocker. Capsaicin blocked pulmonary chemoreflex substantially without any effects on bradycardia evoked by electrical stimulation of vagal efferent fibres to the heart. The significance of the contribution to bradycardia in response to marked increases in blood pressure by vagal C fibres are discussed in relation to findings in electrophysiological studies. A further study was performed on decerebrate ferrets and chloralose anaesthetised lambs. Baroreflex sensitivity was assessed by the relationship between cardiac interval changes and a rise in systolic blood pressure produced by bolus injection of phenylephrine and descending aorta occlusion. Moderate hypothermia (30-34oC) enhanced the baroreflex heart rate reflex substantially and was without effect on the sensitivity of pulmonary J receptor reflex pathways involved in the heart rate control. Action of vagal efferent fibres in altering heart rate was increased by moderate cooling. Such an effect may be partially responsible for the enhanced heart rate component of baroreflex response. Other possible mechanisms of enhanced baroreflex sensitivity are discussed. The consequence of enhanced vagal efferent fibre on heart was studied by electrical stimulation of the peripheral end of cervical vagus nerves in decerebrate ferrets and anaesthetised lambs. Moderate cooling substantially increases cardiac arrhythmias, such as sinus bradycardia, sinoatrial block, sinus arrest and A-V block. In addition vagal stimulation resulted in lethal ventricular arrythmia during infusion of noradrenaline. The possible mechanisms underlying the collapse and sudden death following rescue are discussed.
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Pac-Soo, Chen Knien. "Effects of inhalational anaesthetics on spontaneous sympathetic activity and somatosympathetic reflexes." Thesis, University of Aberdeen, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322526.
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Reynolds, Sandra. "The effect of adenosine on airway reflexes in the guinea pig." Thesis, King's College London (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416875.
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Wareham, Kate Victoria. "Aminergic neuromodulation of walking leg reflexes in the crayfish, Pacifastacus leniusculus." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393097.
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Atassi, Mounir. "Mechanical monitoring of inhibitory jaw reflexes in health and simulated dysfunction." Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/abca297e-8951-447b-8c9e-0bb529d211a9.
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Objectives: Previous studies in the Oral Neurophysiology Laboratories in Dundee have defined the electromyographic properties of the inhibitory jaw reflex that can be evoked in human subjects by electrical stimulation of the lip. This reflex, in contrast with the more widely studied biphasic inhibitory reflexes evoked by stimulation of intra-oral nerves, consists of just a single phase of inhibition and usually requires the application of stimuli which excite nociceptive nerves. The aims of the present studies were to define the mechanical manifestations of this reflex in the form of changes in biting forces, and to investigate whether the mechanical manifestation of the inhibitory jaw reflex evoked by stimulation of the human upper lip, can be modulated by experimentally-controlled conditions that mimic symptoms of a myogenous temporomandibular disorder. Methods: Three series of experiments were performed on 49 volunteer subjects in total. The experiments involved recording bite forces between the anterior teeth and electromyograms (EMGs) from the masseter muscles. Transcutaneous electrical stimuli were applied to the hairy skin of upper lip while the subjects maintained a biting force of around 50N with the aid of visual feedback. In the first series of experiments, a range of electrical stimuli below and above the nociceptive threshold was delivered. In the second set of experiments, double stimuli with a range of different inter-stimulus intervals were applied. Finally in a third series of experiments, electrical stimulation was repeated before, immediately after, and 5 and 10 minutes following a 3-minute accelerated chewing task. This task consisted of chewing 1.5g of a tough chewing gum at 1.5 times the subject’s natural chewing rate and in 18 cases, muscle fatigue and/or pain were reported by the subjects. Results: Following stimulation at intensities that were described as sharp or painful, all the subjects showed both a suppression of the masseter EMG and a reduction of biting force. When analysing the maximum responses in each subject, the mean reduction in the EMG inhibition was to 15.78 ± 14.4% and 10.39 ± 7.92% of the baseline (for the ipsi- and contra-lateral EMGs respectively), whereas the biting force was reduced only to 83.98 ± 11.04% of baseline (+ S.D.). The latencies of onset of these responses were: 38.17 ± 3.58ms, 38.97 ± 4.49ms and 51.83 ± 6.23ms respectively. The response observed in the force record was weaker than in that observed in either EMG (Paired t tests, P < 0.005 in both cases). When applying double stimuli, it was found that the prolongation of the EMG inhibitory jaw reflex (to 144.70 ± 46.93% of the control level) evoked by double stimulation of the upper lip (with a 10 ms inter-stimulus interval) resulted in a greater increase in the depth of the accompanied relaxation (to 223.63 ± 70.88% of that seen in the control responses) compared to a relatively smaller increase in the duration of the relaxation (to 128.32 ± 27.23% of that seen in the control responses). Following the accelerated chewing task, 17 out of 22 subjects reported pain and/or fatigue in one or both of the masseter muscles. The integral for the bite force relaxation significantly decreased in size immediately following the conditioning procedure (to 76.04 ± 35.63% of the control level, P = 0.014; single sample t-test with Bonferroni correction, test value 100). Conclusion: The inhibitory jaw reflex evoked by stimulation of the human lip can be demonstrated mechanically as well as electromyographically although the mechanical version of the response appears less marked. In addition to that, the onset of reflex relaxation in bite force lags several milliseconds behind the corresponding reductions in electromyographic activity. The depth of force relaxation can be increased by increasing the duration of EMG recorded inhibitory reflex. Finally, the results from a chewing task suggest that induced acute pain and/or fatigue cause clear changes in the mechanical manifestation of this inhibitory jaw reflex.
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Wilson, Erin Lawall. "Effects of Fatigue & Gender on Peroneal Reflexes After Ankle Inversion." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/42445.
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An estimated 23,000 ankle injuries occur every day in the U.S. Ankle sprains account for 85% of all ankle injuries and inversion ankle sprains account for 85% of all ankle sprains. There is growing evidence that suggests gender and fatigue may increase the risk for inversion ankle sprains. Investigating the effects of fatigue and gender on peroneal reflex response after ankle inversion may help explain the differences in sprain rates with fatigue and gender. Therefore, the purpose of this study was to investigate the effects of fatigue and gender on peroneus brevis and peroneus longus reflexes after ankle inversion. A "trap-door" platform was used to elicit peroneal reflexes from sixteen males and fifteen females by suddenly inverting the ankle to 20°. Five unfatigued peroneal reflex measurements were performed before and after a fatigue protocol that attempted to fatigue the ankle evertors over 12 minutes to 75% of the unfatigued MVC torque. Results showed that reflex delay was not affected by fatigue, gender, or their interaction. PL reflex amplitude was not affected by fatigue or gender but was affected by their interaction. Results showed that PL reflex amplitude decreased by 11.3% in males and increased 22.1% in females with fatigue. A secondary analysis attempted to rule out extraneous factors that could have contributed to the differences in reflex response, but no experimental explanations were found. The differences in PL reflex amplitude were attributed to biomechanical, physiological, and anatomical differences between males and females.Master of Science
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Mariano, Timothy Yu. "Electrical Stimulation of Afferent Neural Pathways for Suppression of Urethral Reflexes." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1246392300.
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Goode, Christopher T. "The development and recovery of vestibular reflexes in the domestic chicken /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/10632.
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Poon, Ming-see Angela. "Modulation of cutaneous reflexes in a finger muscle during voluntary contractions /." Hong Kong : University of Hong Kong, 1990. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13019260.
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Laat, A. De. "Masseteric reflexes and their relationship towards occlusion and temporomandibular joint dysfunction." Leuven, Belgium : Catholic University of leuven, Faculty of Medicine, School of Dentistry, Oral Pathology and Oral Suregry, 1985. http://catalog.hathitrust.org/api/volumes/oclc/38265081.html.
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