The human jaw, like all other articulated body parts, exhibits small oscillatory movements during isometric holding tasks. These movements, known as physiological tremor, arise as a consequence of the interaction of various factors. One of these factors is reflex feedback from peripheral receptors. In the human jaw, receptors that innervate the periodontium are able to transduce minute changes in force. This thesis examines the contribution of these periodontal mechanoreceptors (PMRs) to the genesis of physiological tremor of the human jaw. By using frequency domain analysis of time series recorded during isometric biting tasks, the character of physiological jaw tremor can be revealed. Physiological jaw tremor was observed in force recorded from between the teeth as well as from electromyograms recorded from the principal muscles of mastication. These recordings have shown us that jaw physiological tremor consists of a frequency invariant component between 6 and 10Hz. This frequency remains unaltered under various load conditions where the mechanical resonance of the jaw would be expected to vary greatly (Chapter 2). Such findings indicate a ‘neurogenic’ origin for this tremor. A possible candidate for this neurogenic component of physiological tremor in the jaw is the reflex feedback arising from the PMRs. Using local anaesthetisation, it has been shown in this thesis, that by blocking outflow from the PMRs, the amplitude of neurogenic physiological jaw tremor can be reduced dramatically. This procedure caused a dramatic reduction in not only the mechanical recordings of tremor but also in the coupling between masseteric muscles bilaterally (Chapter 3) and between single motor units recorded from within a homonymous muscle (Chapter 4). The obvious mechanism by which periodontal mechanoreceptor anaesthetisation could reduce the amplitude of physiological tremor in the jaw would be by reducing the amplitude of the oscillatory input to the motoneurones driving the tremor. This interpretation remains controversial however as physiological tremor in the jaw can be observed at force levels above which the PMRs are supposedly saturated in their response. In light of this knowledge, the saturating characteristics of these receptors in terms of reflex output were examined. To do this, a novel stimulation paradigm was devised whereby the incisal teeth were mechanically stimulated with identical stimulus waveforms superimposed upon increasing tooth preloads. This necessitated the use of a frequency response method to quantify the reflexes. An optimal frequency for stimulation was identified and used to confirm that the hyperbolic saturating response of PMRs observed previously, translated to a similar phenomenon in masticatory reflexes (Chapter 5). These data reinforced the idea that physiological tremor in the jaw was not just a consequence of rhythmic reflex input from PMRs, as the dynamic reflex response uncoupled from the input as the receptor-mediated reflex response saturated. An alternative hypothesis was then developed that suggested the effect of PMR suppression in physiological tremor was via tonic rather than rhythmic effects on the masseteric motoneurone pool. By utilising a novel contraction strategy to manipulate the mean firing rate of the motor neuron pool at a given level of force production, data contained in Chapter 6 shows that population motor unit firing statistics influence the expression of physiological tremor, and such manipulations mimic, to an extent, the changes in firing statistics and tremor amplitude seen during anaesthetisation of the PMRs. This thesis therefore posits a mechanism whereby periodontal input influences the firing rate of motoneurones in such a way as to promote tremulous activity (Chapter 5). However, as this proposed mechanism did not explain the full extent of tremor suppression seen during PMR anaesthetisation it can therefore only be considered a contributing factor in a multifactor process. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297555 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2007

Parkinson`s Disease is the second most common motor disorder and is also considered a progressive multisystemic disease associated to several nom motor symptoms (NMS), such as depression, with a prevalence of about 50% among PD patients. Selective serotonin reuptake inhibitors (SSIR) are the main treatment for this NMS, although researches with acutely induced parkinsonism has related fluoxetine to increased motor impairment. The aim of the present research is to evaluate the effect of the fluoxetine hydrochloride on a model of parkinsonism induced by low doses of reserpine. Sixty-four male 7-9-month-old Wistar rats were used, and were obtained from vivarium of the Department of Physiology – Federal University of Sergipe. Animals were divided into four groups: fluoxetine vehicle + reserpine vehicle (CTR); fluoxetine 10 mg/kg + reserpine vehicle (F); fluoxetine 10 mg/kg + reserpine 0,1 mg/kg (F + R); and fluoxetine vehicle + reserpine 0,1 mg/kg (R). During the treatment, the animals were submitted to open field test, catalepsy test and tremoulous jaw movement evaluation. It was shown that animals treated with fluoxetine and reserpine spent more time at the catalepsy test, decreased distance travelled, lower number of rearing at the open field test, increased tremulous jaw movements and increased weight loss. The treatment only with fluoxetine caused immunohistochemistry changes, such as decrease of TH expression in the dorsal striatum and increased staining of the dorsal raphe nucleus, with no correlation with MS for this group. The F + R group showed different immunohistochemistry results for both acute and continued administrations. / A Doença de Parkinson (DP) é a segunda desordem motora mais comum e também é considerada uma doença progressiva multissistêmica ligada a vários sintomas não motores (SNM), como a depressão, que acomete cerca de 50% dos pacientes. Os inibidores seletivos da recaptação de serotonina (ISRS) são considerados os principais medicamentos para o tratamento desse SNM, embora pesquisas que utilizaram indução aguda de parkinsonismo tenham relacionado a fluoxetina ao agravamento dos sintomas motores. Diante disso, este estudo objetivou avaliar o efeito da administração de cloridrato de fluoxetina em um modelo de parkinsonismo induzido por baixas doses de reserpina. Foram utilizados 64 ratos Wistar, machos, com idade de 7 a 9 meses, provenientes do Biotério Setorial do Departamento de Fisiologia da Universidade Federal de Sergipe. Os animais foram divididos aleatoriamente em quatro grupos: veículo fluoxetina + veículo reserpina (CTR); fluoxetina 10 mg/kg + veículo reserpina (F); fluoxetina 10 mg/kg + reserpina 0,1 mg/kg (F + R); e veículo fluoxetina + reserpina 0,1 mg/kg (R). Durante o tratamento, os animais foram submetidos aos testes de campo aberto, catalepsia e avaliação dos movimentos orofaciais. Foi observado aumento da latência na barra, diminuição da distância total percorrida em campo aberto, diminuição do número de rearing, aumento dos movimentos involuntários de mandíbula e maior alteração de peso corporal dos animais do grupo F + R. O tratamento apenas com fluoxetina provocou alterações imunohistoquímicas, como a diminuição da expressão de TH no estriado dorsal e aumento da marcação para 5-HT no núcleo dorsal da rafe, sem correlação com nenhum sintoma motor para esse grupo. O grupo F + R apresentou resultados de imunorreatividade distintos para as administrações breve e continuada. / São Cristóvão, SE

The study concerns the analysis of vocal cycle length perturbations in normophonic and dysphonic speakers.A method for tracking cycle lengths in voiced speech is proposed. The speech cycles are detected via the saliences of the speech signal samples, defined as the length of the temporal interval over which a sample is a maximum. The tracking of the cycle lengths is based on a dynamic programming algorithm that does not request that the signal is locally periodic and the average period length known a priori.The method is validated on a corpus of synthetic stimuli. The results show a good agreement between the extracted and the synthetic reference length time series. The method is able to track accurately low-frequency modulations and ast cycle-to-cycle perturbations of up to 10% and 4% respectively over the whole range of vocal frequencies. Robustness with regard to the background noise has lso been tested. The results indicate that the tracking is reliable for signal-to-noise ratios higher than 15dB.A method for analyzing the size of the cycle length perturbations as well as their frequency is proposed. The cycle length time series is decomposed into a sum of oscillating components by empirical mode decomposition the instantaneous envelopes and frequencies of which are obtained via AM-FM decomposition. Based on their average instantaneous frequencies, the empirical modes are then assigned to four categories (declination, physiological tremor, neurological tremor as well as cycle length jitter) and added within each. The within-category size of the cycle length perturbations is estimated via the standard deviation of the empirical mode sum divided by the average cycle length. The neurological tremor modulation frequency and bandwidth are obtained via the instantaneous frequencies and amplitudes of empirical modes in the neurological tremor category and summarized via a weighted instantaneous frequency probability density, compensating for the effects of mode mixing.The method is applied to two corpora of vowels comprising 123 and 74 control and 456 and 205 Parkinson speaker recordings respectively. The results indicate that the neurological tremor modulation depth is statistically significantly higher for female Parkinson speakers than for female control speakers. Neurological tremor frequency differs statistically significantly between male and female speakers and increases statistically significantly for the pooled Parkinson speakers compared to the pooled control speakers. Finally, the average vocal frequency increases for male Parkinson speakers and decreases for female Parkinson speakers, compared to the control speakers. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

Le propos de cette thèse est centré sur la fictionnalisation des violences terroristes qui ont ébranlé l’Algérie et les États-Unis au tournant des XXe et XXIe siècles. Deux perspectives polarisent le traitement de ces violences dans les littératures dites « de l’urgence » et « du 11 septembre » : d’un côté, la radicalisation et le passage à l’acte des personnages terroristes ; de l’autre, la terreur et la reconstruction des témoins. Appréhendées suivant le prisme du tremblement, ces perspectives qui sont traitées tout au long de la thèse mettent en jeu des questions d’ordre esthétique, poétique et éthique. Ces trois questions organisent la progression de notre étude. En engageant une réflexion relative à l’incidence du thème sur la forme, elles montrent que les romans examinés ne se contentent pas de décrire le terrorisme ; ils en dégagent les invariants : coupures, dé-liaison, instabilité sémantique, enchevêtrements complexes, sont autant de traits saillants dont les romans du corpus se saisissent, autant d’aspects par lesquels ils illustrent et cristallisent les années noires et le 11 septembre. Si ces invariants mettent en évidence la ténuité du thème et du traitement littéraire, ils ménagent par ailleurs la percée de l’équivoque du sens, du non-totalisable, du non-rapport. Cela, que Jacques Lacan formalise sous l’angle de l’impossible, du réel, ouvre la voie à un décryptage tout à fait singulier de la transgression des terroristes, du faire face des témoins, et des questions portées par le roman contemporain. / The subject of this dissertation is the fictionalization of the terrorist violence that shook Algeria and the United States at the turn of the XXth and the XXIst centuries. Two predominant viewpoints polarize the treatment of this violence in what has been dubbed by French literary critics as « littérature de l’urgence » (« emergency literature ») and « 9/11 literature »: on the one hand, the reader is exposed to the radicalization process of the terrorist characters and to their acting-out, and on the other, to the terror experienced by the witness characters and their reconstruction. These two perspectives, examined throughout the thesis, are apprehended via the prism of the tremor (understood as indecision, doubt and shaking) and involve issues of an aesthetic, poetic and ethical nature. These three issues provide coherence to the general outline and determine the organization of our study. They question the effect of theme on form, thereby demonstrating that the novels studied do not only describe terrorism ; they also bring out the underlying invariables: interruptions, disconnections, semantic instability and complex entanglements are some of the salient features whereby the novels of our corpus describe and crystallize the Algerias’ dark decade and the events of 9/11. While these invariants highlight the subtlety of the theme and its literary treatment, they also point out the equivocal meaning and give the lion’s share to the « non-totalizable » and the « non-rapport ». These aspects, which Jacques Lacan theorized from the angle of the « impossible », the Real, pave the way for a singular decoding of the terrorists’ transgression, of the witnesses’ coping, and of the issues raised by the contemporary novel.

Positron emission tomography (PET) is a functional imaging method that allows studying physiological, biochemical or pharmacological processes in vivo. PET is being used in both research and clinical practice. In the brain, it has been used to investigate metabolism, receptor binding, and alterations in regional blood flow. This thesis involves both preclinical and clinical dual-tracer PET imaging studies of different neurological disorders. In this way, different radiotracers were used along the projects. The first project focused on the implementation and in vivo validation of the simultaneous dual-tracer PET imaging technique on the rat brain and its applications in the study of cerebral ischemia. In particular, in this project two biological processes were studied at the same time: cerebral blood flow and cerebral glucose metabolism. The second project consisted in a clinical correlation study of the GABAergic and serotonin systems in a population with Essential Tremor (ET), the most commonly movement disorders. / La tomografia per emissió de positrons (PET) és un mètode d'imatge funcional que permet l'estudi in vivo de processos fisiològics, bioquímics i farmacològics. La PET s'utilitza tant en la pràctica clínica com en la recerca. Al cervell, s'ha utilitzat per investigar el metabolisme, la neurotransmissió, i les alteracions en el flux sanguini regional. Aquesta tesi implica estudis preclínics i clínics de la tècnica PET en diversos trastorns neurològics. D'aquesta manera, es van utilitzar diferents radiotraçadors al llarg dels projectes. El primer projecte es va centrar en la implementació i validació in vivo de la tècnica PET del doble-marcador simultani en el cervell de rata i les seves aplicacions en l'estudi de la isquèmia cerebral. En particular, en aquest projecte es van estudiar en el mateix moment dos processos biològics: el flux sanguini cerebral i el metabolisme cerebral de la glucosa. El segon projecte va consistir en un estudi clínic de correlació dels sistemes GABAèrgic i serotoninèrgic en una població amb tremolor essencial (TE), el trastorn del moviment més comú