Anatomical and electrophysiological study of the vomeronasal circuits: Amygdaloid response to odours and pheromones

Rodents detect information concerning the world around them mainly through two chemosensory systems: the olfactory and the vomeronasal systems. In order to develop an appropriate behavioural response to their environment, these systems exhibit both functional and physiological convergence. Further understanding of the organization and function of the olfactory systems would allow us to comprehend how their information is integrated in the brain. In a first approach we performed a thorough analysis of the connections of key structures involved in the processing of vomeronasal information: the medial (Me) and the posteromedial cortical (PMCo) amygdaloid nucleus. Then, we enquire the population activity elicited by olfactory and vomeronasal stimuli in three main structures of the vomeronasal system: the accessory olfactory bulb (AOB), Me and PMCo; and, simultaneously, the activity in the main olfactory bulb (MOB). This will allow us to investigate both the neural circuitry processing olfactory and vomeronasal information and the basic principles of integration of these stimuli. The PMCo is the unique cortical target of the AOB and should therefore be considered the primary vomeronasal cortex. It coordinates the neural processing of vomeronasal cues, as it receives information from and projects back to each of the structures of the vomeronasal system and shows significant interconnections with the main olfactory system. Also, through its projections to the Me, the ventral hippocampus and the ventral striatum, PMCo directs behavioural responses and contributes to the spatial map of the chemical environment. The Me coordinates the behavioural response to olfactory and vomeronasal cues. It shows a high connectivity among its subdivisions, with the other nuclei of the chemosensory amygdala and with structures of the olfactory system (especially the anterior Me), thus suggesting that the information from these systems is subjected to a complex intrinsic processing before being relayed to other structures. Aside from these, the main efferences of the Me are the bed nucleus of the stria terminalis (BST) and the hypothalamus, through which the subdivisions of the Me mediate different behavioural responses. The anterior and posteroventral subdivisions of the Me are mainly involved in defensive behaviours through its connections with the medial posterointermediate BST and the defensive hypothalamic circuit; and, although less dense, they also innervate reproductive-related nuclei perhaps controling the inhibition of sexual behaviours. The posterodorsal subdivision of the Me mediates reproductive behaviours through its projections to the medial posteromedial BST and the hypothalamic reproductive circuit, although some projections to defensive-related nuclei also exist. The emergence of a coherent behaviour relies on the communication between brain regions that are functionally and anatomically specialised. Communication between the AOB and the other nuclei is mediated by theta oscillations, as the AOB shows high phase coupling with the MOB, Me and PMCo. Furthermore, the circuit responds with different oscillatory rhythms depending on the perceived stimulus. The exploration of a neutral stimulus (absence of vomeronasal cues) induces a prominent theta activity with a peak at 4 - 6 Hz in both olfactory bulbs, the Me and the PMCo; while conspecific-derived stimuli (containing both olfactory and vomeronasal cues) induce oscillatory activity at around 7 Hz. The correlated activation of the bulbs suggests a coupling between the stimuli internalization in the nasal cavity (sniffing) and the vomeronasal pumping. Moreover, the Me shows a characteristic theta peak elicited by male-soiled bedding and the PMCo shows a similar theta peak in response to female-derived stimuli, thus indicating a differential processing within the amygdala related to the sex of the conspecific. During the exploration epochs, the AOB and the amygdaloid nuclei show fast-gamma frequency segments (90 - 120 Hz) modulated by the theta waves in AOB; whereas the MOB evidences an increase in the high-gamma band (60 - 80 Hz) that were also modulated by the theta in AOB. Thus, particular theta-gamma patterns in the olfactory network modulate the integration of chemosensory information in the amygdala, allowing the selection of an appropriate behaviour. In summary, the present results show the different levels of convergence of the olfactory and vomeronasal information. We describe the wiring of the amygdaloid structures receiving information from the olfactory bulbs and transferring it to hypothalamic and striatal targets. The different nodes show coupled activity and effective communication, that allow the system to work together as a network for the integration and response to chemosensory cues

Neural activity patterns in the chemosensory network encoding vomeronasal and olfactory information in mice

Rodents detect chemical information mainly through the olfactory and vomeronasal systems, which play complementary roles to orchestrate appropriate behavioral responses. To characterize the integration of chemosensory information, we have performed electrophysiological and c-Fos studies of the bulbo–amygdalar network in freely behaving female mice exploring neutral or conspecific stimuli. We hypothesize that processing conspecifics stimuli requires both chemosensory systems, and thus our results will show shared patterns of activity in olfactory and vomeronasal structures. Were the hypothesis not true, the activity of the vomeronasal structures would be independent of that of the main olfactory system. In the c-Fos analysis, we assessed the activation elicited by neutral olfactory or male stimuli in a broader network. Male urine induced a significantly higher activity in the vomeronasal system compared to that induced by a neutral odorant. Concerning the olfactory system, only the cortex–amygdala transition area showed significant activation. No differential c-Fos expression was found in the reward system and the basolateral amygdala. These functional patterns in the chemosensory circuitry reveal a strong top-down control of the amygdala over both olfactory bulbs, suggesting an active role of the amygdala in the integration of chemosensory information directing the activity of the bulbs during environmental exploration

Synchronized activity in the main and accessory olfactory bulbs and vomeronasal amygdala elicited by chemical signals in freely behaving mice

Chemosensory processing in mammals involves the olfactory and vomeronasal systems, but how the activity of both circuits is integrated is unknown. In our study, we recorded the electrophysiological activity in the olfactory bulbs and the vomeronasal amygdala in freely behaving mice exploring a battery of neutral and conspecific stimuli. The exploration of stimuli, including a neutral stimulus, induced synchronic activity in the olfactory bulbs characterized by a dominant theta rhythmicity, with specific theta-gamma coupling, distinguishing between vomeronasal and olfactory structures. The correlated activation of the bulbs suggests a coupling between the stimuli internalization in the nasal cavity and the vomeronasal pumping. In the amygdala, male stimuli are preferentially processed in the medial nucleus, whereas female cues induced a differential response in the posteromedial cortical amygdala. Thus, particular theta-gamma patterns in the olfactory network modulates the integration of chemosensory information in the amygdala, allowing the selection of an appropriate behaviour

Afferent and efferent projections of the anterior cortical amygdaloid nucleus in the mouse

The anterior cortical amygdaloid nucleus (ACo) is a chemosensory area of the cortical amygdala that receives afferent projections from both the main and accessory olfactory bulbs. The role of this structure is unknown, partially due to a lack of knowledge of its connectivity. In this work, we describe the pattern of afferent and efferent projections of the ACo by using fluorogold and biotinylated dextranamines as retrograde and anterograde tracers, respectively. The results show that the ACo is reciprocally connected with the olfactory system and basal forebrain, as well as with the chemosensory and basomedial amygdala. In addition, it receives dense projections from the midline and posterior intralaminar thalamus, and moderate projections from the posterior bed nucleus of the stria terminalis, mesocortical structures and the hippocampal formation. Remarkably, the ACo projects moderately to the central nuclei of the amygdala and anterior bed nucleus of the stria terminalis, and densely to the lateral hypothalamus. Finally, minor connections are present with some midbrain and brainstem structures. The afferent projections of the ACo indicate that this nucleus might play a role in emotional learning involving chemosensory stimuli, such as olfactory fear conditioning. The efferent projections confirm this view and, given its direct output to the medial part of the central amygdala and the hypothalamic ‘aggression area’, suggest that the ACo can initiate defensive and aggressive responses elicited by olfactory or, to a lesser extent, vomeronasal stimuli

Solid pseudopapillary tumor of the pancreas (SPPT). Still an unsolved enigma

Solid pseudo-papillary tumor (SPPT) is a rare cystic tumor of the pancreas (1-3% of exocrine tumors of the pancreas) which shows an “enigmatic” behavior on the clinical and molecular pattern. A retrospective analysis of the citological studies and resected specimens of pancreatic cystic tumors from May 1996 to February 2010 was carried out. Three cases of SPPT were found, which are the objective of this study. The diagnosis was established upon occasional finding in the abdominal CT, in spite of sizing between 3 and 6 cm of diameter. In the three cases the preoperative diagnosis was confirmed by citology and specific immunohistochemical staining. Cases 2 and 3 showed strong immunoreactivity for Beta-Catenina and E-Cadherina staining. Radical resection (R0) was carried out in the three cases. A young male –21 years of age (case 1)- who had duodenal infiltration and two lymph nodes metastases died of hepatic and peritoneal recurrence 20 months following surgery. The other two cases are free of disease. The current review of the literature reports roughly 800 cases since the first report in 1959, and shows the enigmatic character of this tumor regarding the cellular origin, molecular pathways, prognostic factors and clinical behavior

Neuronal diversity of the amygdala and the bed nucleus of the stria terminalis

The amygdala complex is a diverse group of more than 13 nuclei, segregated in five major groups: the basolateral (BLA), central (CeA), medial (MeA), cortical (CoA), and basomedial (BMA) amygdala nuclei. These nuclei can be distinguished depending on their cytoarchitectonic properties, connectivity, genetic, and molecular identity, and most importantly, on their functional role in animal behavior. The extended amygdala includes the CeA and the bed nucleus of the stria terminalis (BNST). Both CeA and the BNST share similar cellular organization, including common neuron types, reciprocal connectivity, and many overlapping downstream targets. In this section, we describe the advances of our knowledge on neuronal diversity in the amygdala complex and the BNST, based on recent functional studies, performed at genetic, molecular, physiological, and anatomical levels in rodent models, especially rats and mice. Molecular and connection property can be used separately, or in combinations, to define neuronal populations, leading to a multiplexed neuronal diversity-supporting different functional roles. © 2020 Elsevier B.V

Automação da correção da primeira velocidade em medidas eletrônicas de distância com base em rede de observação de parâmetros ambientais multi-estações

Orientador: Prof. Dr. Luís Augusto Koenig VeigaCoorientador: Prof. Dr. Wilson de Alcântara SoaresDissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Terra, Programa de Pós-Graduação em Ciências Geodésicas. Defesa : Curitiba, 17/12/2018Inclui referências: p.142-148Resumo: O uso de medidores eletrônicos de distânica (MED) é uma técnica empregada em estações totais para a determinação de distancias entre estas e uma superfície refletora. Esta técnica baseia-se na propagação de ondas eletromagnéticas, a qual, através do conhecimento da velocidade de propagação e o tempo gasto em se deslocar no sistema emissor-refletor e viceversa, permite obter a distância entre eles. A velocidade de propagação da onda depende do estado do meio de propagação, sendo que a densidade deste varia em função do comportamento dos parâmetros ambientais de pressão, umidade e temperatura, sendo esta última a que gera maior incerteza. A variação da velocidade é determinada através do cálculo do índice de refração, e sua quantificação em metros é obtida a partir da primeira correção de velocidade. Ambos os parâmetros são calculados de forma automática mediante inserção dos parâmetros de pressão, temperatura e umidade a serem aplicados no instante da observação de distância. Nesta pesquisa foi desenvolvida e automatizada uma rede de sensores de temperatura com objetivo de avaliar e considerar as variações deste parâmetro e sua incidência na determinação de distâncias no contexto do monitoramento geodésico de barragens. O sistema foi projetado e programado para que as observações de distâncias e medições de temperatura fossem realizadas simultaneamente. Portanto, foi possível determinar em tempo real as variações de temperatura, e verificar como estas afetam às distâncias. Os resultados mostraram a funcionalidade do método proposto, confirmando a necessidade de medir valores de temperatura durante a observação de redes de controle, bem como no decurso de coleta de pontos de monitoramento, já que em diferentes locações a temperatura apresentou variações em torno de 5 graus. Palavras chaves: Distanciómetros eletrônicos. Refração. Primeira correção de Velocidade. Automação. Temperatura.Abstract: The electronic distance meters is a technique used in total stations to determine the distances between this and a reflecting surface. This technique is based on the propagation of electromagnetic waves, which, through the knowledge of the propagation velocity and the time spent in moving from the system transmitter-receiver and vice versa, allows obtaining the distance between them. The wave propagation velocity depends on the conditions of the propagation medium which, its density varies according to the behavior of the environmental parameters such as pressure, humidity and temperature. The last one generates very significant uncertainties. The velocity variation is determined through the refraction index calculation, and its quantification in meters obtained from the first velocity correction. Both parameters are calculated automatically by inserting pressure, temperature and humidity parameters to be applied in the instant of distance observation. In this research, a temperature sensors network was developed and automated with the aim to evaluate and take into account the variations of this parameter and its incidence in the determination of distances in the context of dams geodetic monitoring. The system was designed and programmed for simultaneous distances observations and temperature measurements. Therefore, it was possible to determine in real time the temperature variations, and to verify how they affect the distances. The results showed the functionality of the developed system, confirming the need to measure temperature values during the observation of control networks, as well as while the collection of monitoring points, since at different locations the temperature showed variations around 5 degrees. Key- words: Electronic meters. Refraction. First correction of Velocity. Automation. Temperature

The genus Cloeodes (Ephemeroptera: Baetidae) in Madagascar

Volume: 108Start Page: 387End Page: 40

Solid pseudopapillary tumor of the pancreas (SPPT). Still an unsolved enigma

Solid pseudo-papillary tumor (SPPT) is a rare cystic tumor of the pancreas (1-3% of exocrine tumors of the pancreas) which shows an “enigmatic” behavior on the clinical and molecular pattern. A retrospective analysis of the citological studies and resected specimens of pancreatic cystic tumors from May 1996 to February 2010 was carried out. Three cases of SPPT were found, which are the objective of this study. The diagnosis was established upon occasional finding in the abdominal CT, in spite of sizing between 3 and 6 cm of diameter. In the three cases the preoperative diagnosis was confirmed by citology and specific immunohistochemical staining. Cases 2 and 3 showed strong immunoreactivity for Beta-Catenina and E-Cadherina staining. Radical resection (R0) was carried out in the three cases. A young male –21 years of age (case 1)- who had duodenal infiltration and two lymph nodes metastases died of hepatic and peritoneal recurrence 20 months following surgery. The other two cases are free of disease. The current review of the literature reports roughly 800 cases since the first report in 1959, and shows the enigmatic character of this tumor regarding the cellular origin, molecular pathways, prognostic factors and clinical behavior