Search results for "OLFACTORY"

Differential genomic imprinting regulates paracrine and autocrine roles of IGF2 in mouse adult neurogenesis

2015

Genomic imprinting is implicated in the control of gene dosage in neurogenic niches. Here we address the importance of Igf2 imprinting for murine adult neurogenesis in the subventricular zone (SVZ) and in the subgranular zone (SGZ) of the hippocampus in vivo. In the SVZ, paracrine IGF2 is a cerebrospinal fluid and endothelial-derived neurogenic factor requiring biallelic expression, with mutants having reduced activation of the stem cell pool and impaired olfactory bulb neurogenesis. In contrast, Igf2 is imprinted in the hippocampus acting as an autocrine factor expressed in neural stem cells (NSCs) solely from the paternal allele. Conditional mutagenesis of Igf2 in blood vessels confirms t…

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

2015

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 …

The Forebrain of the Blind Cave Fish <i>Astyanax hubbsi </i>(Characidae)

1997

This paper presents a survey of the cell groups in the telencephalon of the teleost Astyanax hubbsi, based on series of transverse sections stained with the Nissl-Kluver-Barrera and Bodian procedures. The work was conducted for two reasons. Firstly, it was intended to determine the contribution of the forebrain of blind cave fish to certain forms of behavior. An understanding of the anatomy of the telencephalic organization is essential for such a neuroethological approach. The second purpose was to provide the cytoarchitectural basis for the experimental analysis of the fiber connectivity of the telencephalon of A. hubbsi. Furthermore, information about the forebrain of characids is widely…

Zur Bedeutung des Geruchssinnes beim Nahrungserwerb von Kröten (Amphibia, Anura, Bufonidae): Versuche mit der Kreuzkröte (Bufo calamita Laur.)

1975

The influence of olfactory and visual prey stimuli on the feeding behaviour of toads was studied as well as their response to lasting olfactory cues. A further aim was to find simple methods for testing olfactory responsiveness in anurans. Subjects were 8 adult specimens of the European species Bufo calamita (natterjack) kept in captivity one year at least. The results point to the role of olfaction in these animals.

Food-attraction conditioning in the snail, Helix pomatia

1995

Adult pulmonate snails (Helix pomatia) were released equidistant between two types of food, carrot and potato, respectively. Naive snails moved in different directions and did not locate either food above chance, although both foods were readily eaten upon direct contact. After a single carrot feeding episode, 75% of the carrot-fed snails moved directly towards the carrot and ate it. Conversely, potato-fed snails located the potato in 67% of the cases. Snails that were fed apple or lettuce behaved like naive animals, with the majority of animals (75% in both cases) locating neither the carrot nor the potato. The ability of snails to locate this particular food after a single feeding episode…

Doublecortin expression in the adult rat telencephalon

2001

Doublecortin (DCX) is a protein required for normal neuronal migration in the developing cerebral cortex, where it is widely expressed in both radially and tangentially migrating neuroblasts. Moreover, it has been observed in the adult rostral migratory stream, which contains the neuronal precursors traveling to the olfactory bulb. We have performed DCX immunocytochemistry in the adult rat brain to identify precisely the neuronal populations expressing this protein. Our observations confirm the presence of DCX immunoreactive cells with the characteristic morphology of migrating neuroblasts in the subventricular zone, rostral migratory stream and the main and accessory olfactory bulbs. We ha…

Pheromone-induced odor learning modifies Fos expression in the newborn rabbit brain.

2013

Research report; International audience; Associative learning contributes crucially to adjust the behavior of neonates to the permanently changing environment. In the European rabbit, the mammary pheromone (MP) excreted in milk triggers sucking behavior in newborns, and additionally promotes very rapid learning of initially neutral odor cues. Such stimuli become then as active as the MP itself to elicit the orocephalic motor responses involved in suckling. In this context, the rabbit is an interesting model to address the question of brain circuits early engaged by learning and memory. Here, we evaluated the brain activation (olfactory bulb and central regions) induced in 4-day-old pups by …

2019

The olfactory epithelium is continuously exposed to exogenous chemicals, including odorants. During the past decade, the enzymes surrounding the olfactory receptors have been shown to make an important contribution to the process of olfaction. Mammalian xenobiotic metabolizing enzymes, such as cytochrome P450, esterases and glutathione transferases (GSTs), have been shown to participate in odorant clearance from the olfactory receptor environment, consequently contributing to the maintenance of sensitivity toward odorants. GSTs have previously been shown to be involved in numerous physiological processes, including detoxification, steroid hormone biosynthesis, and amino acid catabolism. The…

Symptomatic bodies: reading and writing the odor of sanctity in French culture (1868-1901)

2021

Using examples from novels by the Goncourt brothers, Huysmans, Zola and Lemonnier, this paper explores the literary representation of the odor of sanctity in regard to the main epistemological discourses of the second half of the 19th century. In this deeply anticlerical intellectual context, the Christian myth of the odor of sanctity is analyzed by medical professionals and scientists as a pathological phenomenon. Although taking into account the divergent aesthetics of the selected authors, the study focuses mostly on the ambiguity literary texts maintain between the unspeakable experience of religious ecstasy and a symptomatic vision of the body.

Hierarchical cross-scale analysis identifies parallel ventral striatal networks coding for dynamic and stabilized olfactory reward predictions

2021

SUMMARYThe unbiased identification of brain circuits responsible for behavior and their local cellular computations is a challenge for neuroscience. We establish here a hierarchical cross-scale approach from behavioral modeling and fMRI in task-performing mice to cellular network dynamics to identify how reward predictions are represented in the forebrain upon olfactory conditioning. fMRI identified functional segregation in reward prediction and error computations among olfactory cortices and subcortical circuits. Among them, the olfactory tubercle contributed both to dynamic reward predictions and prediction error. In this region, cellular recordings revealed two parallel neuronal populat…