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Neural Regions (neural + regions)
Selected AbstractsDevelopment and topography of the lateral olfactory tract in the mouse: Imaging by genetically encoded and injected fluorescent markersDEVELOPMENTAL NEUROBIOLOGY, Issue 8 2006Andreas Walz Abstract In mammals, conventional odorants are detected by OSNs located in the main olfactory epithelium of the nose. These neurons project their axons to glomeruli, which are specialized structures of neuropil in the olfactory bulb. Within glomeruli, axons synapse onto dendrites of projection neurons, the mitral and tufted (M/T) cells. Genetic approaches to visualize axons of OSNs expressing a given odorant receptor have proven very useful in elucidating the organization of these projections to the olfactory bulb. Much less is known about the development and connectivity of the lateral olfactory tract (LOT), which is formed by axons of M/T cells connecting the olfactory bulb to central neural regions. Here, we have extended our genetic approach to mark M/T cells of the main olfactory bulb and their axons in the mouse, by targeted insertion of IRES-tauGFP in the neurotensin locus. In NT-GFP mice, we find that M/T cells of the main olfactory bulb mature and project axons as early as embryonic day 11.5. Final innervation of central areas is accomplished before the end of the second postnatal week. M/T cell axons that originate from small defined areas within the main olfactory bulb, as visualized by localized injections of fluorescent tracers in wild-type mice at postnatal days 1 to 3, follow a dual trajectory: a branch of tightly packed axons along the dorsal aspect of the LOT, and a more diffuse branch along the ventral aspect. The dorsal, but not the ventral, subdivision of the LOT exhibits a topographical segregation of axons coming from the dorsal versus ventral main olfactory bulb. The NT-GFP mouse strain should prove useful in further studies of development and topography of the LOT, from E11.5 until 2 weeks after birth. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Oestrogen Receptor , is Essential for Female-Directed Chemo-Investigatory Behaviour but is not Required for the Pheromone-Induced Luteinizing Hormone Surge in Male MiceJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2000S. R. Wersinger The expression of normal masculine sexual behaviour requires testosterone. Testosterone can bind to androgen receptors, either in its native form, or after reduction to other androgen metabolites. In addition, testosterone can be aromatized to oestrogen, and bind to oestrogen receptor , and/or ,. Male copulatory behaviour is deficient in mice lacking functional oestrogen receptor , gene (ER,KO mice). We sought to determine which aspect(s) of masculine sexual behaviour is compromised in the ER,KOs. Specifically, we asked whether ER,KO males have reduced motivation and/or an inability to recognize oestrous females. We found significant differences between mice of different genotypes in the amount of chemo-investigatory behaviour displayed and in the target of their investigation. Wild-type males spent more time investigating ovariectomized, oestradiol-treated females, than either males, or ovariectomized females that had not received hormone priming. ER,KO males spent little time investigating any of the stimulus mice and showed no preferences. To test the hypothesis that this lack of chemo-investigatory behaviour is due to the inability of ER,KO males to detect and respond to female pheromones, we exposed males to chemosensory cues (soiled bedding) from females. Males resided in clean, or female-soiled, cage bedding for 60 min. Next, blood was collected and plasma luteinizing hormone (LH) assayed. We also assessed Fos-like immunoreactivity (Fos-ir) in several neural regions involved in processing chemosensory cues. Despite the fact that male ER,KOs spend little time engaged in chemo-investigation of females, their neuroendocrine responses to female-soiled bedding were similar to those seen in wild-type males. Our data suggest that the normal coupling between the neuroendocrine response to females and the generation of sexual behaviour is disrupted in ER,KO mice. Responses to female pheromones do not require ER,. However, normal male sexual performance requires the ER, gene. [source] New component of the limbic system: Marginal division of the neostriatum that links the limbic system to the basal nucleus of MeynertJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2003Si Yun Shu Abstract The limbic system refers to a group of connected neural regions that are associated with motivation, learning, and memory. The marginal division (MrD) is a zone located at the caudal border of the neostriatum in mammalian brains that has been shown to be involved in learning and memory. In a previous study, c-fos expression showed functional connections between the MrD, basal nucleus of Meynert (NBM) and limbic system (Shu et al., 1988a, 1999). In the present study, to explore the relationship between these regions, the expression of limbic system-associated membrane protein (LAMP) was investigated using molecular and immunohistochemical methods. Synaptic and functional connections between the MrD and the NBM were studied also using tract tracing, electron microscopic and behavioral methods. LAMP is thought to be a marker of the limbic system and expression of LAMP protein and mRNA was observed in both the MrD and the limbic system. From such results, it is concluded that the MrD is a new component of the limbic system. Fibers from the MrD were observed projecting and synapsing on cholinergic neurons of the NBM. As reduction of learning and memory was induced by lesioning the projection from the MrD to the NBM, it would seem that the MrD modulates the learning and memory function of the NBM. In conclusion, the results of these studies suggest that the MrD is a new component of the limbic system, and there are functional and structural connections between the MrD, NBM and limbic system. The MrD seems to act as a link between the limbic system and the NBM, and plays a role in learning and memory. © 2002 Wiley-Liss, Inc. [source] Changes in central steroid receptor expression, steroid synthesis, and dopaminergic activity related to the reproductive cycle of the ring doveMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2001Robert W. Lea This review examines possible neural mechanisms involved in the expression of parental behavior in the ring dove, Streptopelia risoria. This avian species has proved an excellent animal model for studies concerning endocrine-behavior interactions for many years. Studies were performed to localize the expression of central androgen and progesterone receptor in both sexes. Expression of androgen receptor (androgen receptor immunoreactivity, AR-ir) was widespread but increased, similarly in both sexes, with increasing day-length. Progesterone receptor-immunoreactivity (PR-ir) was more localized in several discrete areas of the hypothalamus. Similarly, no sex differences were observed in PR-ir, and expression increased in birds maintained on long days. AR-ir demonstrated dramatic changes over the breeding cycle, being greatest in courting birds and almost undetectable in parenting birds of both sexes brooding their young. PR-ir showed a differential expression over the breeding cycle relative to its hypothalamic localization. PR-ir decreased in the tuberal hypothalamic area in brooding birds of both sexes; whereas in the preoptic area, PR-ir was maintained. Significant increases in dopaminergic activity during the parenting phase of the breeding cycle occurred in specific neural regions including the PVM and DMA. Studies demonstrated the ability of the diencephalon of both sexes of the ring dove brain to synthesize progesterone, with indications that in the male brooding dove, synthesis is increased. Finally, a model is presented that proposes a mechanism whereby these central systems may interact to result in the expression of full parental behavior in both sexes of the ring dove. Microsc. Res. Tech. 55:12,26, 2001. © 2001 Wiley-Liss, Inc. [source] | |||||||||||||