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Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans)
How to make a neuron, a synapse, and a neural circuit? Is there only one ‘design’ for a neural architecture with a universally shared genomic blueprint across species? The brief answer is “No.” Four early divergent lineages from the nerveless common ancestor of all animals independently evolved dist...
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2022
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9816575/ https://www.ncbi.nlm.nih.gov/pubmed/36619868 http://dx.doi.org/10.3389/fcell.2022.1071961 |
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author | Moroz, Leonid L. Romanova, Daria Y. |
author_facet | Moroz, Leonid L. Romanova, Daria Y. |
author_sort | Moroz, Leonid L. |
collection | PubMed |
description | How to make a neuron, a synapse, and a neural circuit? Is there only one ‘design’ for a neural architecture with a universally shared genomic blueprint across species? The brief answer is “No.” Four early divergent lineages from the nerveless common ancestor of all animals independently evolved distinct neuroid-type integrative systems. One of these is a subset of neural nets in comb jellies with unique synapses; the second lineage is the well-known Cnidaria + Bilateria; the two others are non-synaptic neuroid systems in sponges and placozoans. By integrating scRNA-seq and microscopy data, we revise the definition of neurons as synaptically-coupled polarized and highly heterogenous secretory cells at the top of behavioral hierarchies with learning capabilities. This physiological (not phylogenetic) definition separates ‘true’ neurons from non-synaptically and gap junction-coupled integrative systems executing more stereotyped behaviors. Growing evidence supports the hypothesis of multiple origins of neurons and synapses. Thus, many non-bilaterian and bilaterian neuronal classes, circuits or systems are considered functional rather than genetic categories, composed of non-homologous cell types. In summary, little-explored examples of convergent neuronal evolution in representatives of early branching metazoans provide conceptually novel microanatomical and physiological architectures of behavioral controls in animals with prospects of neuro-engineering and synthetic biology. |
format | Online Article Text |
id | pubmed-9816575 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-98165752023-01-07 Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans) Moroz, Leonid L. Romanova, Daria Y. Front Cell Dev Biol Cell and Developmental Biology How to make a neuron, a synapse, and a neural circuit? Is there only one ‘design’ for a neural architecture with a universally shared genomic blueprint across species? The brief answer is “No.” Four early divergent lineages from the nerveless common ancestor of all animals independently evolved distinct neuroid-type integrative systems. One of these is a subset of neural nets in comb jellies with unique synapses; the second lineage is the well-known Cnidaria + Bilateria; the two others are non-synaptic neuroid systems in sponges and placozoans. By integrating scRNA-seq and microscopy data, we revise the definition of neurons as synaptically-coupled polarized and highly heterogenous secretory cells at the top of behavioral hierarchies with learning capabilities. This physiological (not phylogenetic) definition separates ‘true’ neurons from non-synaptically and gap junction-coupled integrative systems executing more stereotyped behaviors. Growing evidence supports the hypothesis of multiple origins of neurons and synapses. Thus, many non-bilaterian and bilaterian neuronal classes, circuits or systems are considered functional rather than genetic categories, composed of non-homologous cell types. In summary, little-explored examples of convergent neuronal evolution in representatives of early branching metazoans provide conceptually novel microanatomical and physiological architectures of behavioral controls in animals with prospects of neuro-engineering and synthetic biology. Frontiers Media S.A. 2022-12-23 /pmc/articles/PMC9816575/ /pubmed/36619868 http://dx.doi.org/10.3389/fcell.2022.1071961 Text en Copyright © 2022 Moroz and Romanova. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Cell and Developmental Biology Moroz, Leonid L. Romanova, Daria Y. Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans) |
title | Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans) |
title_full | Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans) |
title_fullStr | Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans) |
title_full_unstemmed | Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans) |
title_short | Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans) |
title_sort | alternative neural systems: what is a neuron? (ctenophores, sponges and placozoans) |
topic | Cell and Developmental Biology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9816575/ https://www.ncbi.nlm.nih.gov/pubmed/36619868 http://dx.doi.org/10.3389/fcell.2022.1071961 |
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