The purpose of the thesis is to design transmitting antenna based on septum polarizer solution for indoor measurement range. The antenna is considered for both senses of circular polarization. The design is divided into three main sections. First section is devoted to analysis and selection of a suitable waveguide. Ridge waveguide as a crucial part of a septum polarizer is mentioned in this section. Second part is the most critical; here the septum polarizer is analyzed and based on simple procedure also designed. Two suitable horn apertures are then developed as a part of the third section. Individual transmitting antenna parts are assembled together into one model and simulated with excellent results for axial ratio, cross-polarization discrimination, return loss and isolation between ports.

Contexte : L’ocytocine (OT) et la vasopressine (VP) modulent les comportements sociaux. Leurs rôles ont été étudiés indépendamment l’un de l’autre mais des effets combinatoires de ces deux peptides sont à envisager puisqu’ils sont tous les deux libérés au cours des comportements sociaux. Dans le septum latéral (SL), une structure cérébrale intégrant des informations sociales, l’ocytocine et la vasopressine sont libérées au cours des interactions sociales et modulent la reconnaissance ainsi que la discrimination sociale.Objectif : Comprendre la fonction duale de l’ocytocine et de la vasopressine mise en jeu lors des interactions sociales dans un cadre physiologique et pathologique. Méthode : Chez la souris mâle, nous avons utilisé l’activité électroencéphalographique (EEG) comme marqueur et avons caractérisé des traces EEG dépendantes de l’OT et de la VP. Nous avons manipulé le système OT et le système VP au sein du septum au cours d’un protocole de reconnaissance/discrimination sociale en utilisant des outils pharmacologiques ou optogénétiques. Des expériences d’électrophysiologie sur tranche ont permis de caractériser la réponse électrophysiologique des neurones du septum latéral à l’application de chacun de ces peptides.Résultats : L’étude de l’activité EEG nous a permis de discriminer des effets induits par l’action septale de l’OT et la VP dans la bande de fréquence theta. Ces résultats suggèrent que la VP serait libérée dans le septum au cours de la première rencontre avec un juvénile alors que l’OT serait libérée au cours du processus d’habituation. La modulation de l’action de l’OT et de la VP sur le SL démontre que l’activation des récepteurs V1a au cours de la première rencontre est essentielle à la discrimination sociale tandis que l’activation des récepteurs à l’OT au cours du processus d’habituation permet de regain d’intérêt lorsqu’un nouveau juvénile sera présenté. Nous montrons aussi que l’OT et la VP modulent l’activité électrique de la quasi-totalité des neurones septaux. La nature de ces modulations définit 3 catégories de neurones qui communiquent entre eux via des signaux GABAergiques. Chez la souris Magel2KO, un modèle murin de troubles des comportements sociaux, la balance des effets septaux de l’OT et de la VP est altérée. Ceci suggère que cette régulation pourrait être impliquée dans certaines conditions pathologiques.Conclusion : Ces résultats mettent en évidence qu’il est essentiel, lorsque l’on étudie l’ocytocine, d’étudier le système vasopressinergique. Avec cette approche, nous avons montré que l’activation séquentielle du SL par l’OT et la VP est importante pour la régulation des interactions sociales. De plus, cette séquence d’évènements est altérée dans un modèle animal présentant des troubles sociaux. / Context : Oxytocin (OT) and vasopressin (VP) modulate social behaviors. The roles of OT and VP have been interrogated so far in isolation whereas combinatorial effects are anticipated as both hormones are secreted during social behavior. In the lateral septum (LS), a brain area processing behavioral social cues, OT and VP are released during social interaction and modulate social recognition or discrimination. Aim : To understand the dual function of OT and VP during social behavior in physiological and pathological conditions. Methods : In male mice, we used electroencephalographic (EEG) activity as a readout to characterize OT and VP dependent electrophysiological signatures and their sequence. We manipulated OT and VP systems to LS during social recognition/discrimination paradigm using pharmacology and optogenetic tools. Using slice electrophysiology, we characterized electrophysiological responses of LS neurons to both of these hormons.Results : Measurement of EEG theta activity allowed us to discriminate between OT and VP dependent LS modulation and indicated that VP would be released in the LS during 1st encounter with a juvenile while OT would be released during the habituation process. Modulation of OT and VP actions on the LS demonstrate that V1a activation during 1st encounter is essential for social discrimination and OT receptor activation during the habituation process allows the regain of interest for a new juvenile. We also demonstrated that OT and VP modulate electrical activity of almost all LS neurons. The nature of this modulation define 3 neuronal categories that communicate with each other through GABAergic signalling. Magel2KO mouse, which features social deficits, presents an altered balance of LS regulation by OT and VP. It suggests that this regulation could be involved in some pathological symptomatology.Conclusions : These results shed a light on the necessity to study vasopressin along with oxytocin. Doing this, we showed that vasopressinergic and oxytocinergic activation of the LS are sequentially important during the social recognition paradigm. Futhermore, this sequence of events is impaired in a mouse model featuring deficits of OT and social disabilities.

Compared to other structures, such as the amygdala, the lateral septum’s (LS) role in the regulation of anxiety and/or behavioural defense is relatively understudied. Thus, the overarching goal of this thesis was to further investigate its contribution to rats’ anxiety-related behaviours. In Chapter 2, we demonstrate, for the first time, that while the dorsal LS does not mediate rats’ appetitive motivation or anxiety in the novelty induced suppression of feeding (NISF) paradigm, it does modulate their defensive behaviours in the elevated plus maze (EPM) and shock probe burying tests (SPBT). In Chapter 3, we are the first to show that bilateral infusions of histamine, a neurochemical previously linked to anxiety, into the LS reduce rats’ anxiety-related behaviours in the EPM and NISF. In addition, we report a novel double dissociation between lateral septal H1 and H2, and H3 receptors in their regulation of rats’ defensive behaviours in those two paradigms. More specifically, the H1 and H2 receptors contribute to rats’ hyponeophagia in the NISF but not their open arm exploration in the EPM, while the H3 receptors modulate rats’ defensive behaviors in the EPM but not in the NISF. Finally, in Chapter 4, we report for the first time that infusions of histamine into the LS, which produce behavioural anxiolysis, increase rather than decrease the frequency of reticular-elicited hippocampal theta activity, a putative neurophysiological correlate of anxiolytic-drug action. Altogether, the data in this thesis increase our understanding of how the LS contributes to rats’ defensive behaviours and adds to the existing literature regarding the neurobiology of fear/anxiety. More importantly though, the data presented here could ultimately aid in the development of novel drugs to treat anxiety disorders in humans. / Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2013-12-17 17:27:34.014

Compared to other structures, such as the amygdala, the lateral septum’s (LS) role in the regulation of anxiety and/or behavioural defense is relatively understudied. Thus, the overarching goal of this thesis was to further investigate its contribution to rats’ anxiety-related behaviours. In Chapter 2, we demonstrate, for the first time, that while the dorsal LS does not mediate rats’ appetitive motivation or anxiety in the novelty induced suppression of feeding (NISF) paradigm, it does modulate their defensive behaviours in the elevated plus maze (EPM) and shock probe burying tests (SPBT). In Chapter 3, we are the first to show that bilateral infusions of histamine, a neurochemical previously linked to anxiety, into the LS reduce rats’ anxiety-related behaviours in the EPM and NISF. In addition, we report a novel double dissociation between lateral septal H1 and H2, and H3 receptors in their regulation of rats’ defensive behaviours in those two paradigms. More specifically, the H1 and H2 receptors contribute to rats’ hyponeophagia in the NISF but not their open arm exploration in the EPM, while the H3 receptors modulate rats’ defensive behaviors in the EPM but not in the NISF. Finally, in Chapter 4, we report for the first time that infusions of histamine into the LS, which produce behavioural anxiolysis, increase rather than decrease the frequency of reticular-elicited hippocampal theta activity, a putative neurophysiological correlate of anxiolytic-drug action. Altogether, the data in this thesis increase our understanding of how the LS contributes to rats’ defensive behaviours and adds to the existing literature regarding the neurobiology of fear/anxiety. More importantly though, the data presented here could ultimately aid in the development of novel drugs to treat anxiety disorders in humans. / Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2013-12-17 17:27:34.014

Neste estudo avaliou-se a eficácia da radiografia panorâmica na detecção de desvio do septo nasal. Para tanto, utilizou-se como padrão ouro o exame clínico e imagens tomográficas da face. A amostra foi composta por imagens radiográficas panorâmicas e por imagens de tomografia computadorizada da face de 70 indivíduos. Dentre os indivíduos que compuseram o estudo, 30 eram pacientes que seriam submetidos a tratamento odontológico e possuíam radiografias panorâmicas nas quais foram observadas imagens compatíveis com desvio do septo nasal. Estes pacientes foram avaliados por um otorrinolaringologista e submetidos, segundo o critério da justificação, ao exame de tomografia computadorizada da face. Os outros 40 indivíduos foram selecionados a partir de imagens panorâmicas dos prontuários de pacientes disponíveis no arquivo da Clínica de Estomatologia da FOB-USP e que também haviam realizado tomografia computadorizada da face para elaboração de diagnóstico e plano de tratamento odontológico. Os resultados mostraram que a radiografia panorâmica, segundo a metodologia adotada, foi eficaz na detecção do desvio do septo nasal, com 100% de Especificidade. Além disso, este exame permite a confirmação da ausência deste desvio na maioria dos casos, com 86% de Sensibilidade. / OBJECTIVE: Discern the efficacy of panoramic radiography on nasal septum deviation. Gold standard computerized tomography along with clinical examination was used for comparison. MATERIAL AND METHODS: Sample was composed of 70 subjects from Stomatology files of FOB-USP. Nasal septum deviation was assessed using the panoramic radiographies. Then, computerized tomography was analyzed and the results confronted. RESULTS: Images of nasal septum deviation were observed and confirmed in both exams on 100% of the subjects. However, in those cases with no deviation observed with the panoramic radiographies, its presence was confirmed in 86% after computerized tomography. CONCLUSION: Panoramic radiography was trustable for confirmation of nasal septum presence, with 100% of Specificity. Further, this exam allows the confirmation of the absence of this deviation in the majority of cases, with 86% of Sensibility.

INTRODUÇÃO: A área da seccção externa da narina é a parte inferior da válvula nasal externa que é o primeiro obstáculo ao fluxo de ar. Existem dúvidas e controvérsias em relação a eficácia de tratamentos cirúrgicos nessa região do nariz durante a rinoplastia. Neste estudo, compararam-se em cadáveres o uso do enxerto de reforço alar modificado de cartilagem septal e costal para analisar o aumento da área seccional externa narinária. MÉTODOS: Trinta narinas de cadáveres foram dissecados no Serviço de Verificação de Óbito da Capital- Universidade de São Paulo. A escolha dos cadáveres foi aleatória (9 mulheres e 6 homens) excluíndo-se os casos com lesão deformante nasal ou doença intra-nasal. Todos os enxertos septais e costais apresentavam as mesmas dimensões (30 x 5 x 1 mm) e foram inseridos acima do ramo lateral das cartilagens alares de maneira aleatória. A seguir, realizaram-se fotos padronizadas e mensurações das 90 áreas seccionais externas de narina com o programa Autocad®; 30 antes de qualquer procedimento; 60 após a inclusão de enxertos (30 usando cartilagem costal e 30 usando cartilagem septal). A análise estatística foi feita com um modelo de medidas repetidas e ANOVA (análise de variância) para a variável área. A comparação das médias foi feita pelo método de Tukey, sendo o coeficiente de confiança global de 95%. RESULTADOS: A área seccional externa da narina sem tratamento, com inclusão de enxerto de reforço alar modificado septal e costal é, respectivamente, 0,76 cm2, 0,85 cm2 (aumento de 11,8%) e 0,91 cm2 (aumento de 19,7%). CONCLUSÃO: O enxerto de reforço alar modificado de costela é estatisticamente mais efetivo que o enxerto de reforço alar modificado de septo para aumentar a área de secção externa da narina / INTRODUCTION: The nostril cross-sectional area (bottom of the external nasal valve) presents the first obstacle to airflow. There are doubts and controversies regarding the effectiveness of surgical treatments in this region of the nose during a rhinoplasty. In this study, we have tested two modified strategies for alar reinforcement, one using a cartilage graft from the nasal septum and the other using rib cartilage, to analyze and compare their effectiveness in augmenting nostril cross-sectional area. METHODS: Thirty corpses nostrils were dissected in the Division of Postmortem Inspection at the University of São Paulo. Corpses were chosen at random (9 women and 6 men) excluding those with deforming nasal injury or intra-nasal disease. All nasal septum and rib grafts had the same dimensions (30 x 5 x 1 mm) and were inserted randomly above the lateral crura of the alar cartilages. Then, a total of 90 standardized photographs were taken to measure nostril cross-sectional area using the Autocad® program; one per nostril on all 15 cadavers, at three separate intervals. Thirty photos were taken prior to any procedure being performed, and 60 after the insertion in each nostril, of the two different types of cartilage grafts. After one graft was tested, it was removed and replaced with the other type. The order of the procedures was randomized. Statistical analyses were conducted using a model for repeated measures and ANOVA for the variable area. The comparison of means was done with Tukeys method and a 95% confidence coefficient. RESULTS: The nostril cross-sectional area before treatment, after modified alar reinforcement using septum cartilage graft, and after modified alar reinforcement using rib graft were 0,76 cm2, 0,85 cm2 (increase of 11,8%) and 0,91 cm2 (increase 19.7%), respectively. CONCLUSION: The modified alar reinforcement using grafts of rib cartilage is statistically more effective than the modified alar reinforcement using grafts of nasal septum in increasing the nostril cross-sectional area

Els coneixements actuals sobre els efectes crònics de l'alcohol en el SNC són encara força limitats. Malgrat haver identificat en part els canvis que subjauen a fenòmens com la tolerància o la dependència, el mecanisme responsable de l'addicció encara és desconegut. Diversos estudis s'han centrat en la neurotransmissió GABAèrgica, glutamatèrgica, dopaminèrgica i serotoninèrgica, aquests sistemes quan son afectats crònicament per l'alcohol, responen amb adaptacions que o bé són reversibles, o es compensen i neutralitzen després d'un període d'abstinència, no poden per tan ésser el suport d'un fenomen permanent com l'addicció. Estudis fets en animals consumidors voluntaris de dosis tòxiques d'alcohol, han mostrat diferències significatives respecte als controls en diversos processos d'aprenentatge tant excitatori com inhibitori, i han estat identificants canvis tan fisiològics com moleculars en la transmissió colinèrgica de tipus nicotínic. Aquests canvis, sensibilització i regulació a l'alça del receptor nicotínic, són presumiblement irreversibles, no obstant, desconeixem si els processos d'aprenentatge, i els substrats neurals subjacents, es troben alterats en aquests animals alcohòlics durant l'abstinència. En aquesta tesi ens hem plantejat estudiar l'estat funcional de la funció colinèrgica de tipus nicotínic del feix septohipocàmpic durant l'abstinència, avaluant l'efecte d'una injecció intraseptal de nicotina en la capacitat de l'animal alcohòlic per aprendre la resposta a la palanca durant l'abstinència d'alcohol (Experiment I). D'altra banda, s'ha estudiat la capacitat d'aprenentatge inhibitòri per tal de conèixer l'estat funcional i la implicació d'aquest circuit en el control de la conducta. Amb aquest objectiu, hem avaluat mitjançant aprenentatge de discriminació (amb estímuls excitatori i inhibitori), l'efecte d'una injecció intraseptal de nicotina en la capacitat d'inhibir una resposta en la Prova de Dos Estímuls de Pavlov i en l'extinció simple, en situació d'abstinència (Experiment II). Els resultats obtinguts en l'Experiment I mostren que l'abstinència d'alcohol modifica dràsticament, en sentit negatiu, la capacitat d'aprenentatge simple en els animals alcohòlics. D'altra banda, la nicotina té efectes oposats en els subjectes alcohòlics Abstinents i No-Abstinents, en aquests empitjora l'adquisició triplicant el temps necessari per assolir l'aprenentatge a la dosi de 10nM, mentre que en el cas dels Abstinents, neutralitza l'efecte disruptor de l'abstinència, en l'aprenentatge d'aquesta resposta, a la dosi de 20nM. Els subjectes alcohòlics No-Abstinents respecte dels controls mostren una sensibilització funcional a la nicotina administrada intraseptalment, que es fa palesa amb el desplaçament de la corba dosi-resposta cap a l'esquerre i amb un increment considerable de l'efecte màxim. Els resultats obtinguts en l'Experiment II mostren que l'abstinència té un efecte disruptor sobre el control inhibitori que és més pronunciat en els animals alcohòlics (sensibilització). Pel que fa a l'efecte de la nicotina en la Prova de Dos Estímuls de Pavlov, s'observa un efecte disruptor dosi-depenent en els alcohòlics No-Abstinents mentre que els Abstinents té l'efecte contrari, millorant el seu control inhibitori. Així doncs, la corba dosi-resposta per a la nicotina intraseptal pels animals alcohòlics Abstinents, respecte a la mateixa corba dels No-Abstinents, mostra la inversió del perfil de la nicotina i un desplaçament a l'esquerre (sensibilització) de l'efecte màxim. Els resultats obtinguts permeten concloure que els subjectes alcohòlics mostren una reactivitat exacerbada a l'administració de nicotina intraseptal, en comparació amb els controls. En l'abstinència d'alcohol, la resposta dels subjectes és molt diferent a la dels alcohòlics No-Abstinents, l'administració de nicotina "normalitza" la resposta dels Abstinents, equiparant-los als No-Abstinents injectats amb salí. Tot plegat és congruent amb una sensibilització funcional de la resposta colinèrgica de tipus nicotínic a l'acció concurrent de l'alcohol i la nicotina, en l'abstinència la nicotina pot substituir l'alcohol i neutralitzar-ne l'abstinència, aquestes propietats caracteritzen el cervell alcohòlic i el distingueixen del cervell control. Paraules clau: Consum crònic i voluntari d'alcohol; Abstinència; Nicotina; Septum medial. / The current knowledge about chronic alcohol consumption effect on the CNS is still limited. Despite to have identificated some of the changes that underlie phenomenons as tolerance and dependence, we still unknown the main mechanism responsible of addiction. Several studies have focused on GABAergic, glutamatergic, dopaminergic or serotoninergic transmission. These systems, whereas they become adapted by chronic alcohol, after an abstinence period their adaptation is reverted or compensed, for this reason, they could not be the main support of a permanent fenomenon as addiction. Previous studies, done with chronic alcohol drinking animals, have shown significant differences between alcohol and control groups in several excitatory and inhibitory learning processes. On the other hand, it has been identificated several physiologic and molecular changes in the nicotinic cholinergic transmission of these alcoholic animals. These changes, sensitization by up-regulation of the nicotinic receptor, are supposed to be irreversible. However, we unknow if these learning processes, and the underlying neural substratum, are also modificated during abstinence in these alcoholic animals. One of the main objectives of this thesis is to study the functional state of the nicotinic cholinergic function of the septo-hippocampal pathway during abstinence. For this purpose, we have evaluated the effect of an intraseptal injection of nicotine upon the acquisition and extinction of lever-press response during the alcohol abstinence (Experiment I). Furthermore, we have studied the acquisition of an inhibitory learning in order to know the implication and functional state of that pathway over behaviour control during withdrawal. For this purpose, after the acquisition of a discriminative learning (with excitatory and inhibitory stimulus), we have evaluated the effect of an intraseptal injection of nicotine on the capacity of the animal to inhibit a response, in the Pavlov's Two Stimuli Test and extinction session, during alcohol abstinence (Experiment II). Results obtained in Experiment I show that alcohol abstinence drastically impaired in the alcoholic animal the acquisition of a simple learning. On the other hand, nicotine has opposed effects in Abstinent and Non-Abstinent alcoholic animals. In Non-Abstinent subgroup, subjects that received nicotine 10nM show the worst acquisition, taking threefold more time to attain the criterion compared with saline subgroup, while in the case of the Abstinent, nicotine neutralizes the disruptive effect of abstinence at the dose of 20nM. The alcoholic Non-Abstinent animals compared with those of the control group show a functional sensitization to the intraseptal nicotine with an inverted U-shaped dose-response curve that appears shifted leftwards and with a significative increase of the maximum effect. Results obtained in Experiment II show that abstinence has a disruptive effect over the inhibitory control that is more pronounced in alcoholic animals (sensitization). Regarding nicotine effect in Pavlov's Two Stimuli Test, we observe a dose-dependent disruptive effect in Non-Abstinent subgroup while in the case of Abstinent it has the opposite effect improving their inhibitory control. The dose-response curve for the intraseptal nicotine injection in the Abstinent alcoholic animals compared to the same curve for the Non-Abstinent, shows an inverted U-shaped dose-response curve that appears shifted leftwards (sensitization). Overall results show that alcoholic subjects have an exacerbated reactivity to the intraseptal nicotine when compared to the control group. During alcohol abstinence, the response of that subjects is significantly different of that one of the Non-Abstinent, while the nicotine administration "normalizes" the Abstinent animals response equaling them to the Non-Abstinent injected with saline. All these results are congruent with a functional sensitization of the nicotinic cholinergic response to the concurrent action of alcohol and nicotine. During abstinence nicotine seems to substitute the alcohol and to neutralize the abstinence caused by that drug. Those properties would characterize the alcoholic brain and would distinguish it from the control one, implications for pharmacological therapies are discussed. Keywords: Chronic voluntary alcohol; Withdrawal; Nicotine; Medial septum.

Extensive evidence suggests that glucose has both positive and negative effects on memory and these effects likely involve an influence on the brain. For instance, direct infusions of glucose into the septum (MS) or hippocampus can enhance or impair memory. The present set of experiments attempted to determine the different conditions that dissociate the memory-enhancing and -impairing effects of glucose in rats. Specifically, these experiments examined the effects of glucose in spontaneous alternation, a measure of spatial working memory and shock avoidance, an index of emontional long-term memory. The results showed that the memory-impairing effects of MS infusions of glucose are not concentration-dependent. These data also indicated that the memory-impairing effects of MS glucose elevations are specific to gamma-aminobutyric acid GABA receptor activation but do not depend on increases in MS GABA synthesis or release. Importantly, we showed that the memory-impairing interaction between MS glucose and GABA agonists does not generalize to the hippocampus, suggesting the memory-modulating effects of glucose are brain region-dependent. We showed further that these brain region-dependent effects of glucose are not due to difference in basal extracellular glucose levels. Moreover, these findings showed that the memory-enhancing effects of hippocampus glucose override the memory-impairing interaction between MS glucose and GABA. These findings are important because they are the first to show that the memory-modulating effects of glucose are both neurotransmitter- and brain region-dependent. Furthermore, these findings provide preliminary evidence suggesting that the memory-impairing effects of MS glucose may involve compromised hippocampal function. These data also suggest the memory-impairing effects of MS co-infusions of glucose with GABA agonists likely involve an influence on the GABAergic SH projection. Finally, these findings demonstrate the mnemonic and neurochemical consequences of glucose in the MS and hippocampus, two brain regions affected by normal aging, Alzheimer’s disease, and diabetes.

<p>Forebrain cholinergic projection systems innervate the entire cortex and hippocampus. These cholinergic systems are involved in a wide range of cognitive and behavioral functions, including learning and memory, attention, and sleep-waking modulation. However, the <italic>in vivo</italic> physiological mechanisms of cholinergic functions, particularly their fast dynamics and the consequent modulation on the hippocampus and cortex, are not well understood. In this dissertation, I investigated these issues using a number of convergent approaches.</p><p> First, to study fast acetylcholine (ACh) dynamics and its interaction with field potential theta oscillations, I developed a novel technique to acquire second-by-second electrophysiological and neurochemical information simultaneously with amperometry. Using this technique on anesthetized rats, I discovered for the first time the tight <italic>in vivo</italic> coupling between phasic ACh release and theta oscillations on fine spatiotemporal scales. In addition, with electrophysiological recording, putative cholinergic neurons in medial setpal area (MS) were found with firing rate dynamics matching the phasic ACh release. </p><p> Second, to further elucidate the dynamic activities and physiological functions of cholinergic neurons, putative cholinergic MS neurons were identified in behaving rats. These neurons had much higher firing rates during rapid-eye-movement (REM) sleep, and brief responses to auditory stimuli. Interestingly, their firing promoted theta/gamma oscillations, or small-amplitude irregular activities (SIA) in a state-dependent manner. These results suggest that putative MS cholinergic neurons may be a generalized hippocampal activation/arousal network. </p><p> Third, I investigated the hypothesis that ACh enhances cortical and hippocampal immediate-early gene (IEG) expression induced by novel sensory experience. Cholinergic transmission was manipulated with pharmacology or lesion. The resultant cholinergic impairment suppressed the induction of <italic>arc</italic>, a representative IEG, suggesting that ACh promotes IEG induction. </p><p> In conclusion, my results have revealed that the firing of putative cholinergic neurons promotes hippocampal activation, and the consequent phasic ACh release is tightly coupled to theta oscillations. These fast cholinergic activities may provide exceptional opportunities to dynamically modulate neural activity and plasticity on much finer temporal scales than traditionally assumed. By the subsequent promotion of IEG induction, ACh may further substantiate its function in neural plasticity and memory consolidation.</p> / Dissertation

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