The anatomical record : advances in integrative anatomy and evolutionary biology
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Within the central nervous system, the olfactory system represents one of the most exciting scenarios since it presents relevant examples of long-life sustained neurogenesis and continuous axonal outgrowth from the olfactory epithelium with the subsequent plasticity phenomena in the olfactory bulb. The olfactory nerve is composed of nonmyelinated axons with interesting ontogenetic interpretations. However, the centripetal projections from the olfactory bulb are myelinated axons which project to more caudal areas along the lateral olfactory tract. ⋯ Recently, we have described a new patho-physiological role of this protein in the absence of spontaneous remyelination in multiple sclerosis. In the present review, we hypothesize about how both main and satellite neurological symptoms of Kallmann syndrome may be explained by alterations in the myelination. We revisit the relationship between the olfactory system and myelin highlighting that minor histological changes should not be forgotten as putative causes of olfactory malfunction.
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Review Comparative Study
Of pheromones and kairomones: what receptors mediate innate emotional responses?
Some chemicals elicit innate emotionally laden behavioral responses. Pheromones mediate sexual attraction, parental care or agonistic confrontation, whereas predators' kairomones elicit defensive behaviors in their preys. This essay explores the hypothesis that the detection of these semiochemicals relies on highly specific olfactory and/or vomeronasal receptors. ⋯ Our results confirm that both mouse strains avoid TMT, which increases immobility in C57BL/J6, but not CD1 mice. However, mice of both strains sniff at TMT throughout the test and show no trace of TMT-induced contextual conditioning (immobility or avoidance). This suggests that TMT is not a kairomone but, similar to a loud noise, in high concentrations it induces aversion and stress as unspecific responses to a strong olfactory stimulation.