Orientadores: Jose Wilson Magalhães Bassani, Antonio Carlos Guimarães de Almeida / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-12T22:48:22Z (GMT). No. of bitstreams: 1 Azevedo_GersonFlorenceCarvalheirade_D.pdf: 2274193 bytes, checksum: 9c8a1fee0426b5335f1a55b9dfcdd33d (MD5) Previous issue date: 2009 / Resumo: Durante o burst epileptiforme e a depressão alastrante (DA), são observados um aumento da [K+]o (concentração extracelular de potássio) e uma diminuição da [Ca2+]o (concentração extracelular de cálcio), evidenciando a participação deste mecanismo não-sináptico nestes padrões oscilatórios anormais. Essas variações nas [K+]o e [Ca2+]o elevam a excitabilidade neuronal. No entanto, não está claro se a alta [K+]o é um fator primário na geração destas atividades neuronais ou se apenas desempenha um papel secundário neste processo. Para melhor compreender a dinâmica não-linear destes padrões, as condições experimentais de alta [K+]o e zero [Ca2+]o foram replicadas em um modelo ampliado de Golomb, referente à região CA1 da formação hipocampal. Importantes mecanismos regulatórios de concentração iônica, como a bomba Na+/K+, a difusão iônica e o sistema de buffer da glia, foram acrescentados ao modelo de Golomb. Dentro destas condições, foi possível simular atividades elétricas neuronais tipicamente apresentadas no burst epileptiforme em sua fase ictal. A DA foi iniciada pela interrupção da atividade da bomba Na+/K+. O bloqueio da bomba Na+/K+ por meio da hipóxia celular é uma manobra experimental para se obter a DA, conhecida também como depressão alastrante hipóxica - DAH. A teoria de bifurcação e o método fast-slow analysis foram utilizados para estudar a interferência do K+ extracelular na excitabilidade celular. Este estudo indicou que o sistema perde a sua estabilidade com o aumento da [K+]o, transitando para um elevado estado de excitabilidade. Este crescimento da [K+]o provoca bifurcações no comportamento dinâmico neuronal, que determinam transições entre diferentes estágios dessas atividades elétricas. No primeiro estágio, o aumento da [K+]o propicia a deflagração do burst epileptiforme e da DA via bifurcações sela-nó e de Hopf supercrítica, respectivamente. Ao longo da atividade neuronal, o nível de excitabilidade é mantido por meio de um crescimento contínuo da [K+]o, que deprime as correntes de K+ em um processo de realimentação positiva. Neste estágio, em relação ao burst epileptiforme, a amplitude e a freqüência dos disparos dos potenciais de ação são alteradas via bifurcação de Hopf supercrítica. No último estágio, com a depressão das correntes de K+, a bomba de Na+/K+ tem uma participação importante no término da atividade neuronal. O burst epileptiforme e a DA são finalizados por meio das bifurcações sela-órbita homoclínica e sela-nó, respectivamente. Portanto, este trabalho sugere que o K+ extracelular pode desempenhar um papel fundamental na dinâmica não-linear do burst epileptiforme e da sua transição para a DA. / Abstract: During the epileptiform burst and the spreading depression (SD), it is observed an increase of [K+]o (extracellular potassium concentration) and a decrease of [Ca2+]o (extracellular calcium concentration), pointing out the participation of this nonsynaptic mechanism in these abnormal oscillatory patterns. These ionic variations raise the neuronal excitability. However, whether the high [K+]o is a primary factor in the beginning of these neuronal activities or just plays a secondary role into this process is unclear. To better understand the nonlinear dynamics of these patterns, the experimental conditions of high [K+]o and zero [Ca2+]o were replicated in an extended Golomb model in which we added important regulatory mechanisms of ion concentration as Na+/K+ pump, ion diffusion and glial buffering. Within these conditions, it was possible to simulate epileptiform burst within the ictal phase. The SD was elicited by the interruption of the Na+/K+ pump activity. The blockage of Na+/K+ pump by cellular hypoxia is an experimental procedure to elicit SD, known as hypoxic spreading depression - HSD. The bifurcation theory and the method of fast-slow analysis were used to study the interference of extracellular K+ in the cellular excitability. This analysis indicates that the system loses its stability at a high [K+]o, transiting to an elevated state of neuronal excitability. This raise of [K+]o provokes bifurcations in the neuronal dynamic behavior, that determine transitions between different stages of these electrical activities. In the initial stage, the increase of [K+]o creates favorable conditions to trigger the epileptiform burst and the SD by saddle-node and supercritical Hopf bifurcations, respectively. During the neuronal activity, the level of excitability is maintained by a continuous growth of [K+]o that depresses K+ currents in a positive feedback way. At this stage, concerning epileptiform burst, the amplitude and frequency of action potentials are changed by supercritical Hopf bifurcation. At the last stage, with the depression of K+ currents, the Na+/K+ pump plays an important role in the end of neuronal activity. The epileptiform burst and SD activities terminate by saddle-homoclinic orbit and saddle-node bifurcations, respectively. Thus, this work suggests that [K+]o may play a fundamental role in the nonlinear dynamics of the epileptiform burst and the transition to SD. / Doutorado / Engenharia Biomedica / Doutor em Engenharia Elétrica

Objectives: 1) To describe the state of the evidence for interventions in pediatric migraine, 2) to survey experts regarding non-inferiority margins in migraine research and 3) to design a clinical trial in this area of research. Methods: A systematic review was carried out to identify randomized, placebo-controlled trials of pharmaceutical and nutraceutical interventions used to prevent migraine in children and adolescents, using Cochrane methods. Secondly, neurologists with expertise in Headache Medicine were invited to participate in a survey regarding their opinions on non-inferiority margins for outcomes used in clinical trials of migraine interventions. Thirdly, a protocol was written for a three-arm, parallel-group, randomized trial comparing the efficacy and safety of topiramate, levetiracetam and placebo for the prophylaxis of pediatric migraine. Results: The systematic review identified 19 articles of 12 interventions for pediatric migraine. The quality of the evidence was poor and few conclusions could be made. Ninety-nine eligible respondents completed the survey and non-inferiority margins for six outcomes were determined. A randomized controlled trial protocol was developed to determine if topiramate and levetiracetam are superior to placebo, and if levetiracetam is non-inferior to topiramate for the prevention of migraines in children and adolescents. Conclusions: It is hoped that the results of this thesis can be applied to further the evidence in this area of clinical research.

As an excellent organism for genetic study and with the many useful genetic manipulation tools developed in the past two decades, Drosophila melanogaster is an important model organism that has been utilized to understand the genetic regulation of various developmental processes. Here, we focus on the development of the Drosophila CNS midline cells to pursue a long term goal to understand (1) the regulation of programmed cell death during nervous system development and (2) the interaction between nervous system and the mesoderm structures during early embryonic development. Programmed cell death is an essential part of the development of the nervous system for vertebrate and invertebrate animals (reviewed by Oppenheim 1991). In the Drosophila CNS midline, about 70% of the glia cells die during a critical period. We found that the elimination of unwanted midline cells during embryonic nervous system development is a very well coordinated process, which ensures that specific number of midline glia survive. The others are relocated and executed by proteolytic cascade, followed by engulfment and further degradation by macrophages. We observed that three cell death regulatory genes (rpr, hid and grim) in the 75C1,2 region of the 3rd chromosome are all expressed in midline cells that are chosen to be executed. Using several mutants and genetic deficiencies, we found that in order for the appropriate number of midline cells to be eliminated, the functions of multiple genes in the 75C1,2 region are required. To further understand this cell death process, we targeted the expression of rpr and/or hid to midline cells. We found that the two genes show synergism in inducing ectopic cell death, further suggesting that they may functionally interact to regulate the proper cell death pattern. Inside the embryo, the development of the nervous system is not a isolated process. The developing nerve cells interact with the mesoderm during early embryonic development. We found that the CNS midline cells are required for the differentiation of a specific group of mesoderm cells, the dorsal median cell. The well conserved epidermal growth factor (EGF) signaling pathway is at least partially responsible for this CNS midline regulation of mesoderm cell development. In addition, we found that the proper anterior/posterior location of the dorsal median cells depends on the function of wingless or patched segmental polarity gene, and that these two genes might act through regulating the spatial differentiation of the CNS midline cells.

The purpose of this study was to determine if administering two painful stimuli used to assess motor responses in patients with brain injury, nail bed compression (NBC) and supraorbital pressure (SOP), had an effect on intracranial pressure (ICP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), heart rate (HR), and motor responses, in unconscious patients. Thirteen unconscious adult male and female subjects with brain injury were enrolled in the study. All subjects had normal ICP and CPP, and were hemodynamically stable. After collection of baseline values of the dependent variables, NBC and SOP were delivered on both sides of the body while ICP, MAP, CPP and HR were recorded from the bedside monitor. Subjects were recorded on video tape for motor responses to NBC and SOP and later given a motor score on the Glasgow Coma Scale. Pressures used to administer NBC and SOP were measured in psi by devices constructed for purposes of this study. Data were analyzed using MANOVA statistical procedures to detect differences within subjects on all physiological values from baseline. Findings from this study were that NBC and SOP administered on both sides of the body resulted in statistically significant increases in ICP, MAP, CPP, and HR from baseline for a brief, yet unsustained time period (p = $<$0.05). The ICP had returned to baseline in 30 seconds, the MAP and CPP within four minutes, and HR by the second minute after administration of NBC and SOP. ANOVA statistical procedure was used to detect differences in motor scores when NBC and SOP were given. There were no statistical differences between motor scores on the GCS with NBC or SOP. The mean pressures that were measured on NBC and SOP were 77.11 $\pm$ 30.98 and 86.1 $\pm$ 8.54 psi, respectively. These data suggest that NBC and SOP do have an effect on physiological indices of cerebral perfusion by an increasing ICP, MAP, CPP, and HR for a brief period of time but return to baseline quickly. Therefore, administering painful stimuli to evaluate motor responses in unconscious patients who have normal ICP and CPP is probably safe. Also, the data suggest that NBC and SOP produce similar motor responses and could both be used to assess unconscious patients.

The positioning component of the human arm has four kinematic degrees of freedom (DOF), three of which are used to position the end-effector. The fourth DOF, here denoted $\gamma,$ does not affect the hand position (it exclusively affects the elbow position) and may thus be considered redundant. It may be hypothesized that, in the absence of any other constraints, $\gamma$ is chosen such that some task related cost is minimized. In this work, we investigate the particular hypothesis that $\gamma$ is chosen such that the sum of the squared torques at the shoulder and elbow is minimal. A particular feature of this minimum principle is that it associates costs with both movement and static posture. This feature distinguishes the minimum-torque principle from zero-static-cost (ZSC) principles such as the well-known minimum-jerk (Flash and Hogan, 1985) and minimum-torque-change (Uno, Kawato, & Suzuki, 1989) principles. The main objectives of this work are to (1) reject the validity of ZSC principles and (2) to expose the predictions that arise from the minimum-torque principle and to compare these predictions with observed behavior. Human performance is assessed in tasks which consist of the following three components: (1) A movement that places the end-effector in a specified position, (2) a period of posture maintenance of specified duration, and (3) a movement that returns the arm to its initial position. Only one dependent variable is considered: the $\gamma$ associated with the static posture adopted during the posture maintenance period. Performances from three experiments are analyzed. The results of the first experiment disconfirm the validity of ZSC principles, the results of the second experiment are ambiguous, and the results of the third experiment provide some evidence in support of the minimum-torque principle.

A reduction in the availability of oxidizable metabolic fuels inhibits reproduction. When ovariectomized, steroid-primed hamsters are food deprived for 48 hours, estrous behavior is suppressed. However, the specific neuroendocrine alterations that mediate the suppression or restoration of estrous behavior are unknown. In the following set of experiments, I investigated various possible neuroendocrine alterations associated with nutritional infertility and I found the following. Increasing circulating levels of estradiol can increase lordosis durations in fasted animals, but the suppression of estrous behavior occurs despite increased circulating estradiol levels in ovariectomized, steroid-treated animals. Next, I found that it takes more than 24 h of metabolic inhibitor administration to inhibit lordosis, whereas only 6 h of refeeding is sufficient to restore sexual receptivity. Furthermore, neither plasma insulin nor leptin levels parallel the changes in estrous behavior, suggesting that changes in circulating leptin and insulin probably do not play a critical role in these behavioral changes. Finally, several conditions that inhibit female sexual behavior are thought to be associated with altered corticotropin-releasing hormone (CRH) activity in the brain. Intracerebroventricular (ICV) infusion of CRH or urocortin inhibited estrous behavior in ovariectomized steroid-primed hamsters. Conversely, ICV infusion of the potent CRH receptor antagonist, astressin, prevented the suppression of estrous behavior by food deprivation. Furthermore, astressin blocked the inhibition of estrous behavior by ICV administration of neuropeptide Y and CRH but did not enhance estrous behavior in animals given an inadequate dose of progesterone. Astressin treatment also induced sexual receptivity in nonresponders, animals that do not normally come into heat when treated with hormones. This effect persisted in subsequent weekly tests in the absence of any further astressin treatment. Manipulations that altered sexual behavior did so without affecting food intake and, in most cases, without affecting circulating corticosteroid levels, indicating that the animals were neither ill nor stressed. These results support the hypothesis that endogenous CRH receptor signaling mediates the inhibition of estrous behavior by undernutrition and in other instances of sexual dysfunction suggesting that CRH receptor signaling may be a final common pathway by which a number of distinct conditions inhibit female sexual behavior.

Tolosa-Hunt syndrome is a rare neurological disorder with an incidence of one case per million. It is a granulomatous inflammatory condition that affects the cavernous sinus and is characterized by painful ophthalmoplegia and headaches. We present a 57-year-old male veteran with past medical history of alcohol use disorder, hepatitis c, hypertension and tobacco use who presented with complaints of double vision and headaches for 2 days. The patient also had a history of well controlled cluster headaches treated with sumatriptan. But, he reported that from several days prior to admission, the headaches were getting more frequent, sharp, localized to the left side, and preventing him from sleeping. On physical exam, vitals were stable, the neck was supple, the pupils were equal in size and reactive to light but limited left eye abduction and external rotation were noted. The remainder of physical exam was unremarkable including the remaining cranial nerves. Computerized tomography (CT) head was done which showed no evidence of acute stroke. Magnetic resonance imagining (MRI) brain was performed which showed an asymmetric bulge of the left cavernous sinus which raised suspicion for cavernous sinus inflammation. Systemic high dose steroid trial was given. Patient’s symptoms improved within 72 hours and diagnosis of Tolosa-Hunt Syndrome was confirmed. According to the National Organisation for Rare Disorders (NORD) the average age of onset for this condition is 41 years. The pathogenesis is thought to be inflammation of unknown etiology. The criteria for diagnosis fo Tolosa-Hunt syndrome is given by International Headache Society, which includes: Unilateral headache; MRI or biopsy demonstrating granulomatous inflammation of cavernous sinus, superior orbital fissure or orbit; ipsilateral nerve palsy involving one or more of 3rd, 4th and/or 6th cranial nerves; no alternate diagnosis based on the symptoms; specific history of ipsilateral headache localized to the ipsilateral brow and eye and it should occur 2 week before the oculomotor palsy or along with it. Our patient met all the criteria mentioned above. Ruling out other causes of headache and ophthalmoplegia is important in making the diagnosis. A differential diagnosis includes cavernous sinus thrombosis, stroke, vasculitis, myasthenia gravis, Miller Fisher variant of GBS, multiple sclerosis and idiopathic intracranial hypertension. Currently, inadequate data is available to determine the best route and duration of treatment with steroids. Our patient received oral steroid 100 mg for 3 days followed by slow steroid taper and had improvement in symptoms. Although a rare disorder, it is important to consider Tolosa-Hunt syndrome in the differential diagnosis of patients who presents with headaches and visual changes, especially after ruling out other common causes.

Sensory systems flexibly adapt their processing properties across a wide range of environmental and behavioral conditions. Such variable processing complicates attempts to extract mechanistic understanding of sensory computations. This is evident in the highly constrained, canonical Drosophila motion detection circuit, where the core computation underlying direction selectivity is still debated despite extensive studies. Here, I use the high temporal resolution method of in vivo whole-cell patch clamp electrophysiology to measure the filtering properties of neural inputs to the OFF motion-detecting T5 cell in Drosophila. I find state and stimulus dependent changes in the shape of these signals, which become more biphasic under specific conditions. Summing these inputs within the framework of a connectomic-constrained model of the circuit demonstrates that these changes in shape are sufficient to explain T5 responses to various motion stimuli. Thus, my stimulus and state dependent measurements reconcile motion computation with the anatomy of the circuit. These findings provide a clear example of how a basic circuit supports flexible sensory computation.

The CGRP monoclonal antibodies are the first class of medication developed specifically for migraine prevention, in contrast to previous preventative medications, that were in the anti-hypertensive, anti-epileptic and anti-depressant class. There are two notable divisions within the CGRP inhibitor class: the CGRP monoclonal antibodies (CGRP mAbs), and the small molecule CGRP antagonists (gepants). This thesis conducts a retrospective analysis of notable clinical trials such as the ACHIEVE I, ACHIEVE II, LIBERTY, ARISE, STRIVE, PREEMPT, and COMPEL studies to determine the efficacy of CGRP inhibitors. In ACHIEVE I, 38.6% of participants in the 50 mg ubrogepant group experienced pain freedom 2 hours post dose (p=0.002) and in ACHIEVE II trial in the 50 mg ubrogepant group, 21.8% reported pain freedom 2 hours. In participants that received Rimegepant at a 75mg dose, 21%of participants reported more freedom from pain at 2 hours than placebo (p<0.0001).^40 In another study, participants received placebo, 50 mg and 100 mg of sumatriptan.^43 Results of the study showed that more than half of participants, 57%, in the 100 mg Sumatriptan group and exactly half of participants in the 50 mg group had pain relief at 2 hours post-dose.^43 In the LIBERTY trial, at 12 weeks, 30% of individuals that received erenumab reported a fifty percent or more reduction in the monthly number of migraine days than individuals in the placebo group (p=0.002).^45 In the STRIVE trial, the average number of migraine days experienced by the participant at baseline was 8.3, and was assessed by the 4th month through the 6th month. This baseline decreased to 5.1 days (a 3.2 difference) in the participants that received an injection of 70 mg of erenumab (p<0.001).^46 The participants that received an injection of 140 mg erenumab, decreased from the baseline to 4.6 days of migraine (a 3.7 difference) (p<0.001) . 46 Participants that received placebo reported the least change from baseline, only a 1.8 day change (p<0.001).46 In the ARISE Trial patients receiving erenumab experienced a change of 2.9 monthly migraine days, a 1.1 increase from the reported change of 1.8 days reported by study participants for the monthly migraine days in the placebo group (p<0.001).^47 The PREEMPT1 trial did not meet statistical significance for their primary endpoint or study measure, which was to assess for a mean change in monthly mean headache episode frequency between baseline and week 24 of the trial (p=0.344)^48. Participants in the PREEMPT2 trial experienced a reduction by 9 days when compared to placebo for the primary end point, frequency of headache days per 28 days relative to baseline (p<0.001)^49. In the COMPEL study, participants experienced -10.7 day reduction in headache days by 108 weeks (p<0.0001).^50 There are several advantages to CGRP mAbs. Patients are more likely to adhere to CGRP mAbs medication and tolerate this medication than other medication options^17, CGRP mAbs do not give rise to toxicity in the liver because these medications do not interact with the liver^17, and CGRP mAbs have a long duration in the human body as they have a half-life of 20 to 30 days which provides patients with the opportunity to not take the medication as frequently.^51 Another reason why CGRP mAbs are advantageous compared to traditional treatment options is that they have a strong affinity and specificity for the CGRP receptor or CGRP molecule. This high specificity prevents the medication from causing undesirable effects on other receptors^51.

Sexual behavior in female guinea pigs and rats is dependent upon circulating ovarian steroid hormones. The actions of these hormones on behavior are mediated by intracellular receptors located within interconnected brain regions. This complex neural network integrates somatosensory and hormonal information relevant to sexual behavior. An understanding of the anatomy of this network is important for understanding how behavior is generated. This dissertation investigated the neural projections from a region important for the induction of sexual behavior, the ventrolateral hypothalamus. Based on the steroid-sensitive neural network model described in rats, several experiments were designed to test predictions of this neural model in guinea pigs. In the first experiment, estrogen receptor- and estradiol-induced progestin receptor-containing cells were localized in the midbrain, a major projection site of the steroid receptor-rich region within the ventrolateral hypothalamus. In the second experiment, the anterograde tracer Phaseolus vulgaris-Leucoagglutinin, an anterograde tract-tracer, was deposited within the estrogen receptor-containing region of the ventrolateral hypothalamus. Projections from this area were found in most other estrogen receptor-containing sites, including the midbrain central gray, often closely associated with estrogen receptor-containing cells. The third experiment examined the distributions of substance P, a peptide found in ovarian steroid hormone receptor-containing cells in the ventrolateral hypothalamus and estrogen receptor-containing cells in the midbrain central gray. Substance P-immunoreactive boutons were found closely associated with some estrogen receptor-containing cells suggesting substance P modulation of ovarian steroid hormone receptor-containing cells. These connections, taken together with the hypothalamic projections closely associated with estrogen receptor-containing cells in the midbrain, support the idea that some estrogen receptor-containing cells may be directly linked. These studies provide information on the neural connections between estrogen receptor-containing regions and cells which may be important for regulating functions of the steroid hormone sensitive neural network.