About this Research Topic
As a cornerstone of vertebrate evolution, a centralized nervous system has been a constant after the emergence of the phylum Chordata. Among the most basal structures of this centralized nervous system is the hypothalamus, as its homologous structures are found even in animals of the subphylum Cephalochordata, such as the amphioxus. The hypothalamus has been fundamentally conserved for its role in the maintenance of body homeostasis. This cardinal role cannot be executed without an enormous associated complexity since each organism will certainly find diverse environments and will need to respond appropriately to each one of them. It is natural, therefore, that animals with a more robust hypothalamus, capable of a larger spectrum of responses, had a fitness advantage against their peers, what resulted in a remarkable development in hypothalamic complexity regarding its spatial organization, connectivity, and chemical composition.
The chemical complexity of the hypothalamus is reflected in a large number of neuromodulators produced by neurons in this brain structure. Among those neuromodulators are: oxytocin, vasopressin, corticotropin-releasing factor and the urocortins, thyrotropin-releasing hormone, alpha-melanocyte-stimulating hormone, neuropeptide Y, agouti-related protein, cocaine- and amphetamine-regulated transcript, kisspeptin and the gonadotropin-releasing hormone, melanin-concentrating hormone, orexin, neurotensin, amylin, galanin, somatostatin as well as pituitary adenylate cyclase-activating peptide (PACAP), among others. Those neuromodulators display a remarkable range of structures, actions, pharmacology dynamics, and specific anatomical distributions. Due to the broad functions played by these neuromodulators in homeostasis, disturbances in these systems can lead to severe human health problems. To understand the evolution of those systems is to understand their underlying logic, creating knowledge and the tools necessary to better interfere with those systems in a clinical setting.
For this Research Topic, authors are welcome to look at the evolutionary history of hypothalamic peptides from a multidisciplinary perspective, including anatomical, hodological, functional, and pharmacological aspects. Authors should look at a wide range of species, including invertebrate animals when the origin of those hypothalamic peptides lie before the emergence of vertebrates and give special attention to non-model organisms. It is particularly encouraged that authors not only compile the information available for different species, but contextualize that information in terms of vertebrate evolution, behavior, and environment, and how those factors may have driven (or may have been driven) by evolution and natural selection. Considering the nature of the theme of this Research Topic, the main article type for publication in this issue will be Reviews. Authors who wish to publish original data in this Research Topic should strongly contextualize their data in terms of phylogeny and comparative morphology, significantly contributing to our understanding of the evolution of a particular hypothalamic neuromodulatory system. Other article types, such as general commentaries, mini-reviews, opinions, and perspectives will be evaluated on a case-by-case basis.
Keywords: evolution, hypothalamus, neural communication, vertebrates, diencephalon
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