Connections of the amygdaloid structures integrating olfactory and vomeronasal information in mice

La amígdala es considerada una estructura clave en el aprendizaje emocional asociativo en roedores. La mayor parte de los estudios sobre aprendizaje emocional se han centrado en paradigmas de aprendizaje aversivo, cuando al menos, parte de la amígdala es también relevante en el procesamiento de estímulos reforzantes, particularmente estímulos de naturaleza química (olores y feromonas), dado que los roedores son animales macrosmáticos. La amígala es primer relevo telencefalico en donde convergen las proyecciones provenientes del bulbo olfatorio principal (MOB), que es activado por volátiles y del bulbo olfatorio accesorio (AOB), que es activado por no volátiles. Nuestro estudio se centra en las bases anatómicas que permiten el aprendizaje emocional apetitivo en el que asocian olores con feromonas sexuales, que son estímulos vomeronasales en ratones. La hipótesis de partida es que la parte corticomedial de la amígdala (que recibe la mayoría de los inputs olfatorios sensoriales de los bulbos olfatorios principal y accesorio), es la principal candidata a jugar un papel crítico en este proceso. Dentro de la amígdala corticomedial, el núcleo medial (Me) es la principal área de convergencia de estímulos olfatorios y vomeronasales. Ha sido particularmente estudiado ya que es considerado una estructura clave en el circuito neural que controla las conductas sociosexuales. Esta es una estructura heterogénea que presenta tres subdivisiones, la anterior (MeA), posteroventral (MePV) y posterodorsal (MePD). Estas subdivisiones presentan diferencias en sus eferencias, en sus conexiones con estructuras implicadas en conductas defensivas y de reproducción y es sexualmente dimórfica. El resto de los núcleos amigdalinos en donde se ha encontrado convergencia han sido escasamente estudiados. Nuestro estudio se centrara en la descripción de las aferencias a la Me, además de la descripción de las aferencias de la área de transición córtico-amigdalina y la amígdala cortical anterior, núcleos donde también existen convergencia olfatoria y vomeronasal. Con esto buscamos aportar información acerca de las conexiones anatómicas de estos núcleos con el resto del encéfalo y la injerencia de estos circuitos en el aprendizaje asociativo de olores y feromonas y sus efectos en la conducta sociosexual

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

Sex pheromones are not always attractive: changes induced by learning and illness in mice

A male-specific major urinary protein named darcin is attractive to female mice, Mus musculus, stimulates a learned attraction to volatile components of a male's urinary odour and induces spatial learning. In this article we show that darcin also induces learned attraction for a previously neutral olfactory stimulus (the odorant isoamyl acetate), acquired by repeated presentation of both stimuli together. We hypothesize that this is a case of olfactory–vomeronasal associative learning, in which darcin acts as the unconditioned reinforcer. However, the presence of darcin is not always attractive to adult female mice. Urine from males parasitized by the nematode Aspiculuris tetraptera has no attractive value for females, despite apparently normal presence of darcin. The loss of attractive value may be due to unknown infection-derived chemicals whose detection overrides the attraction induced by darcin, or prevents detection of darcin by other (unknown) mechanisms. Other cases in which male urine (and thus the presence of darcin) does not induce attraction are discussed, namely in lactating females, which respond with aggression towards intruder males, and in prepubertal females, which show aversive responses towards unfamiliar male urine. Thus, although the darcin sex pheromone induces attraction in adult female mice that does not need to be learned, such innate pheromonal responses can be modulated by the physiological or health status of the sender and receiver. This provides a degree of flexibility in response to pheromonal signals, but such that individuals of the same class or status still share consistent predictable responses to improve their reproductive fitness. Further, by readily inducing the same response towards other odorants through associative learning, pheromones can also target responses flexibly towards odour signatures at an individual-specific level

Afferent projections to the different medial amygdala subdivisions: a retrograde tracing study in the mouse

The medial amygdaloid nucleus (Me) is a key node in the socio-sexual brain, composed of anterior (MeA), posteroventral (MePV) and posterodorsal (MePD) subdivisions. These subdivisions have been suggested to play a different role in reproductive and defensive behaviours. In the present work we analyse the afferents of the three Me subdivisions using restricted injections of fluorogold in female outbred CD1 mice. The results reveal that the MeA, MePV and MePD share a common pattern of afferents, with some differences in the density of retrograde labelling in several nuclei. Common afferents to Me subdivisions include: the accessory olfactory bulbs, piriform cortex and endopiriform nucleus, chemosensory amygdala (receiving direct inputs from the olfactory bulbs), posterior part of the medial bed nucleus of the stria terminalis (BSTM), CA1 in the ventral hippocampus and posterior intralaminar thalamus. Minor projections originate from the basolateral amygdala and amygdalo-hippocampal area, septum, ventral striatum, several allocortical and periallocortical areas, claustrum, several hypothalamic structures, raphe and parabrachial complex. MeA and MePV share minor inputs from the frontal cortex (medial orbital, prelimbic, infralimbic and dorsal peduncular cortices), but differ in the lack of main olfactory projections to the MePV. By contrast, the MePD receives preferential projections from the rostral accessory olfactory bulb, the posteromedial BSTM and the ventral premammillary nucleus. In summary, the common pattern of afferents to the Me subdivisions and their interconnections suggest that they play cooperative instead of differential roles in the various behaviours (e.g., sociosexual, defensive) in which the Me has been shown to be involved

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