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Poole RJ, Flames N, Cochella L. Neurogenesis in Caenorhabditis elegans. Genetics 2024:iyae116. [PMID: 39167071 DOI: 10.1093/genetics/iyae116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Accepted: 06/24/2024] [Indexed: 08/23/2024] Open
Abstract
Animals rely on their nervous systems to process sensory inputs, integrate these with internal signals, and produce behavioral outputs. This is enabled by the highly specialized morphologies and functions of neurons. Neuronal cells share multiple structural and physiological features, but they also come in a large diversity of types or classes that give the nervous system its broad range of functions and plasticity. This diversity, first recognized over a century ago, spurred classification efforts based on morphology, function, and molecular criteria. Caenorhabditis elegans, with its precisely mapped nervous system at the anatomical level, an extensive molecular description of most of its neurons, and its genetic amenability, has been a prime model for understanding how neurons develop and diversify at a mechanistic level. Here, we review the gene regulatory mechanisms driving neurogenesis and the diversification of neuron classes and subclasses in C. elegans. We discuss our current understanding of the specification of neuronal progenitors and their differentiation in terms of the transcription factors involved and ensuing changes in gene expression and chromatin landscape. The central theme that has emerged is that the identity of a neuron is defined by modules of gene batteries that are under control of parallel yet interconnected regulatory mechanisms. We focus on how, to achieve these terminal identities, cells integrate information along their developmental lineages. Moreover, we discuss how neurons are diversified postembryonically in a time-, genetic sex-, and activity-dependent manner. Finally, we discuss how the understanding of neuronal development can provide insights into the evolution of neuronal diversity.
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Affiliation(s)
- Richard J Poole
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Nuria Flames
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia 46012, Spain
| | - Luisa Cochella
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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2
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Ehweiner A, Duch C, Brembs B. Wings of Change: aPKC/FoxP-dependent plasticity in steering motor neurons underlies operant self-learning in Drosophila. F1000Res 2024; 13:116. [PMID: 38779314 PMCID: PMC11109550 DOI: 10.12688/f1000research.146347.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/31/2024] [Indexed: 05/25/2024] Open
Abstract
Background Motor learning is central to human existence, such as learning to speak or walk, sports moves, or rehabilitation after injury. Evidence suggests that all forms of motor learning share an evolutionarily conserved molecular plasticity pathway. Here, we present novel insights into the neural processes underlying operant self-learning, a form of motor learning in the fruit fly Drosophila. Methods We operantly trained wild type and transgenic Drosophila fruit flies, tethered at the torque meter, in a motor learning task that required them to initiate and maintain turning maneuvers around their vertical body axis (yaw torque). We combined this behavioral experiment with transgenic peptide expression, CRISPR/Cas9-mediated, spatio-temporally controlled gene knock-out and confocal microscopy. Results We find that expression of atypical protein kinase C (aPKC) in direct wing steering motoneurons co-expressing the transcription factor FoxP is necessary for this type of motor learning and that aPKC likely acts via non-canonical pathways. We also found that it takes more than a week for CRISPR/Cas9-mediated knockout of FoxP in adult animals to impair motor learning, suggesting that adult FoxP expression is required for operant self-learning. Conclusions Our experiments suggest that, for operant self-learning, a type of motor learning in Drosophila, co-expression of atypical protein kinase C (aPKC) and the transcription factor FoxP is necessary in direct wing steering motoneurons. Some of these neurons control the wing beat amplitude when generating optomotor responses, and we have discovered modulation of optomotor behavior after operant self-learning. We also discovered that aPKC likely acts via non-canonical pathways and that FoxP expression is also required in adult flies.
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Affiliation(s)
- Andreas Ehweiner
- Institut für Zoologie - Neurogenetik, Universität Regensburg, Regensburg, Bavaria, 93040, Germany
| | - Carsten Duch
- Institute of Developmental Biology and Neurobiology (iDN), Johannes Gutenberg Universitat Mainz, Mainz, Rhineland-Palatinate, Germany
| | - Björn Brembs
- Institut für Zoologie - Neurogenetik, Universität Regensburg, Regensburg, Bavaria, 93040, Germany
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3
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Bich L. Integrating Multicellular Systems: Physiological Control and Degrees of Biological Individuality. Acta Biotheor 2023; 72:1. [PMID: 38151680 PMCID: PMC10752842 DOI: 10.1007/s10441-023-09476-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 12/17/2023] [Indexed: 12/29/2023]
Abstract
This paper focuses on physiological integration in multicellular systems, a notion often associated with biological individuality, but which has not received enough attention and needs a thorough theoretical treatment. Broadly speaking, physiological integration consists in how different components come together into a cohesive unit in which they are dependent on one another for their existence and activity. This paper argues that physiological integration can be understood by considering how the components of a biological multicellular system are controlled and coordinated in such a way that their activities can contribute to the maintenance of the system. The main implication of this perspective is that different ways of controlling their parts may give rise to multicellular organizations with different degrees of integration. After defining control, this paper analyses how control is realized in two examples of multicellular systems located at different ends of the spectrum of multicellularity: biofilms and animals. It focuses on differences in control ranges, and it argues that a high degree of integration implies control exerted at both medium and long ranges, and that insofar as biofilms lack long-range control (relative to their size) they can be considered as less integrated than other multicellular systems. It then discusses the implication of this account for the debate on physiological individuality and the idea that degrees of physiological integration imply degrees of individuality.
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Affiliation(s)
- Leonardo Bich
- Department of Philosophy, IAS-Research Centre for Life, Mind and Society, University of the Basque Country (UPV/EHU), Avenida de Tolosa 70, Donostia-San Sebastian, 20018, Spain.
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4
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Muzik O, Diwadkar VA. Depth and hierarchies in the predictive brain: From reaction to action. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2023; 14:e1664. [PMID: 37518831 DOI: 10.1002/wcs.1664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 05/18/2023] [Accepted: 07/10/2023] [Indexed: 08/01/2023]
Abstract
The human brain is a prediction device, a view widely accepted in neuroscience. Prediction is a rational and efficient response that relies on the brain's ability to create and employ generative models to optimize actions over unpredictable time horizons. We argue that extant predictive frameworks while compelling, have not explicitly accounted for the following: (a) The brain's generative models must incorporate predictive depth (i.e., rely on degrees of abstraction to enable predictions over different time horizons); (b) The brain's implementation scheme to account for varying predictive depth relies on dynamic predictive hierarchies formed using the brain's functional networks. We show that these hierarchies incorporate the ascending processes (driven by reaction), and the descending processes (related to prediction), eventually driving action. Because they are dynamically formed, predictive hierarchies allow the brain to address predictive challenges in virtually any domain. By way of application, we explain how this framework can be applied to heretofore poorly understood processes of human behavioral thermoregulation. Although mammalian thermoregulation has been closely tied to deep brain structures engaged in autonomic control such as the hypothalamus, this narrow conception does not translate well to humans. In addition to profound differences in evolutionary history, the human brain is bestowed with substantially increased functional complexity (that itself emerged from evolutionary differences). We argue that behavioral thermoregulation in humans is possible because, (a) ascending signals shaped by homeostatic sub-networks, interject with (b) descending signals related to prediction (implemented in interoceptive and executive sub-networks) and action (implemented in executive sub-networks). These sub-networks cumulatively form a predictive hierarchy for human thermoregulation, potentiating a range of viable responses to known and unknown thermoregulatory challenges. We suggest that our proposed extensions to the predictive framework provide a set of generalizable principles that can further illuminate the many facets of the predictive brain. This article is categorized under: Neuroscience > Behavior Philosophy > Action Psychology > Prediction.
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Affiliation(s)
- Otto Muzik
- Department of Pediatrics, Wayne State University School of Medicine, Children's Hospital of Michigan, Michigan, USA
| | - Vaibhav A Diwadkar
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, Michigan, USA
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5
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Alicea B, Gordon R, Parent J. Embodied cognitive morphogenesis as a route to intelligent systems. Interface Focus 2023; 13:20220067. [PMID: 37065267 PMCID: PMC10102728 DOI: 10.1098/rsfs.2022.0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/20/2023] [Indexed: 04/18/2023] Open
Abstract
The embryological view of development is that coordinated gene expression, cellular physics and migration provides the basis for phenotypic complexity. This stands in contrast with the prevailing view of embodied cognition, which claims that informational feedback between organisms and their environment is key to the emergence of intelligent behaviours. We aim to unite these two perspectives as embodied cognitive morphogenesis, in which morphogenetic symmetry breaking produces specialized organismal subsystems which serve as a substrate for the emergence of autonomous behaviours. As embodied cognitive morphogenesis produces fluctuating phenotypic asymmetry and the emergence of information processing subsystems, we observe three distinct properties: acquisition, generativity and transformation. Using a generic organismal agent, such properties are captured through models such as tensegrity networks, differentiation trees and embodied hypernetworks, providing a means to identify the context of various symmetry-breaking events in developmental time. Related concepts that help us define this phenotype further include concepts such as modularity, homeostasis and 4E (embodied, enactive, embedded and extended) cognition. We conclude by considering these autonomous developmental systems as a process called connectogenesis, connecting various parts of the emerged phenotype into an approach useful for the analysis of organisms and the design of bioinspired computational agents.
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Affiliation(s)
- Bradly Alicea
- OpenWorm Foundation, Boston, MA, USA
- Orthogonal Research and Education Laboratory, Champaign-Urbana, IL, USA
| | - Richard Gordon
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48201, USA
| | - Jesse Parent
- Orthogonal Research and Education Laboratory, Champaign-Urbana, IL, USA
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6
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Zinchenko V, Hugger J, Uhlmann V, Arendt D, Kreshuk A. MorphoFeatures for unsupervised exploration of cell types, tissues, and organs in volume electron microscopy. eLife 2023; 12:80918. [PMID: 36795088 PMCID: PMC9934868 DOI: 10.7554/elife.80918] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 01/06/2023] [Indexed: 02/17/2023] Open
Abstract
Electron microscopy (EM) provides a uniquely detailed view of cellular morphology, including organelles and fine subcellular ultrastructure. While the acquisition and (semi-)automatic segmentation of multicellular EM volumes are now becoming routine, large-scale analysis remains severely limited by the lack of generally applicable pipelines for automatic extraction of comprehensive morphological descriptors. Here, we present a novel unsupervised method for learning cellular morphology features directly from 3D EM data: a neural network delivers a representation of cells by shape and ultrastructure. Applied to the full volume of an entire three-segmented worm of the annelid Platynereis dumerilii, it yields a visually consistent grouping of cells supported by specific gene expression profiles. Integration of features across spatial neighbours can retrieve tissues and organs, revealing, for example, a detailed organisation of the animal foregut. We envision that the unbiased nature of the proposed morphological descriptors will enable rapid exploration of very different biological questions in large EM volumes, greatly increasing the impact of these invaluable, but costly resources.
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Affiliation(s)
- Valentyna Zinchenko
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Johannes Hugger
- European Bioinformatics Institute, European Molecular Biology Laboratory (EMBL)CambridgeUnited Kingdom
| | - Virginie Uhlmann
- European Bioinformatics Institute, European Molecular Biology Laboratory (EMBL)CambridgeUnited Kingdom
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
| | - Anna Kreshuk
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL)HeidelbergGermany
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7
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Martí-Solans J, Børve A, Bump P, Hejnol A, Lynagh T. Peripheral and central employment of acid-sensing ion channels during early bilaterian evolution. eLife 2023; 12:81613. [PMID: 36821351 PMCID: PMC9949801 DOI: 10.7554/elife.81613] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 01/08/2023] [Indexed: 02/24/2023] Open
Abstract
Nervous systems are endowed with rapid chemosensation and intercellular signaling by ligand-gated ion channels (LGICs). While a complex, bilaterally symmetrical nervous system is a major innovation of bilaterian animals, the employment of specific LGICs during early bilaterian evolution is poorly understood. We therefore questioned bilaterian animals' employment of acid-sensing ion channels (ASICs), LGICs that mediate fast excitatory responses to decreases in extracellular pH in vertebrate neurons. Our phylogenetic analysis identified an earlier emergence of ASICs from the overarching DEG/ENaC (degenerin/epithelial sodium channel) superfamily than previously thought and suggests that ASICs were a bilaterian innovation. Our broad examination of ASIC gene expression and biophysical function in each major bilaterian lineage of Xenacoelomorpha, Protostomia, and Deuterostomia suggests that the earliest bilaterian ASICs were probably expressed in the periphery, before being incorporated into the brain as it emerged independently in certain deuterostomes and xenacoelomorphs. The loss of certain peripheral cells from Ecdysozoa after they separated from other protostomes likely explains their loss of ASICs, and thus the absence of ASICs from model organisms Drosophila and Caenorhabditis elegans. Thus, our use of diverse bilaterians in the investigation of LGIC expression and function offers a unique hypothesis on the employment of LGICs in early bilaterian evolution.
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Affiliation(s)
| | - Aina Børve
- Department of Biological Sciences, University of BergenBergenNorway
| | - Paul Bump
- Hopkins Marine Station, Department of Biology, Stanford UniversityPacific GroveUnited States
| | - Andreas Hejnol
- Department of Biological Sciences, University of BergenBergenNorway
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8
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Moroz LL, Romanova DY. Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans). Front Cell Dev Biol 2022; 10:1071961. [PMID: 36619868 PMCID: PMC9816575 DOI: 10.3389/fcell.2022.1071961] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
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.
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Affiliation(s)
- Leonid L. Moroz
- Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States,Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States,*Correspondence: Leonid L. Moroz, ; Daria Y. Romanova,
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, 5A Butlerova, Moscow, Russia,*Correspondence: Leonid L. Moroz, ; Daria Y. Romanova,
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9
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Single-cell transcriptomics identifies conserved regulators of neuroglandular lineages. Cell Rep 2022; 40:111370. [PMID: 36130520 DOI: 10.1016/j.celrep.2022.111370] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 07/01/2022] [Accepted: 08/25/2022] [Indexed: 11/23/2022] Open
Abstract
Communication in bilaterian nervous systems is mediated by electrical and secreted signals; however, the evolutionary origin and relation of neurons to other secretory cell types has not been elucidated. Here, we use developmental single-cell RNA sequencing in the cnidarian Nematostella vectensis, representing an early evolutionary lineage with a simple nervous system. Validated by transgenics, we demonstrate that neurons, stinging cells, and gland cells arise from a common multipotent progenitor population. We identify the conserved transcription factor gene SoxC as a key upstream regulator of all neuroglandular lineages and demonstrate that SoxC knockdown eliminates both neuronal and secretory cell types. While in vertebrates and many other bilaterians neurogenesis is largely restricted to early developmental stages, we show that in the sea anemone, differentiation of neuroglandular cells is maintained throughout all life stages, and follows the same molecular trajectories from embryo to adulthood, ensuring lifelong homeostasis of neuroglandular cell lineages.
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10
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Smith SJ, von Zastrow M. A Molecular Landscape of Mouse Hippocampal Neuromodulation. Front Neural Circuits 2022; 16:836930. [PMID: 35601530 PMCID: PMC9120848 DOI: 10.3389/fncir.2022.836930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 03/30/2022] [Indexed: 12/23/2022] Open
Abstract
Adaptive neuronal circuit function requires a continual adjustment of synaptic network parameters known as “neuromodulation.” This process is now understood to be based primarily on the binding of myriad secreted “modulatory” ligands such as dopamine, serotonin and the neuropeptides to G protein-coupled receptors (GPCRs) that, in turn, regulate the function of the ion channels that establish synaptic weights and membrane excitability. Many of the basic molecular mechanisms of neuromodulation are now known, but the organization of neuromodulation at a network level is still an enigma. New single-cell RNA sequencing data and transcriptomic neurotaxonomies now offer bright new lights to shine on this critical “dark matter” of neuroscience. Here we leverage these advances to explore the cell-type-specific expression of genes encoding GPCRs, modulatory ligands, ion channels and intervening signal transduction molecules in mouse hippocampus area CA1, with the goal of revealing broad outlines of this well-studied brain structure’s neuromodulatory network architecture.
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Affiliation(s)
- Stephen J Smith
- Allen Institute for Brain Science, Seattle, WA, United States
- *Correspondence: Stephen J Smith,
| | - Mark von Zastrow
- Departments of Psychiatry and Pharmacology, University of California, San Francisco, San Francisco, CA, United States
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11
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Abstract
We propose an expansion of neuroecological comparisons to include the capabilities of brainless and non-neural organisms. We begin this enterprise by conducting a systematic search for studies on learning in echinoderms. Echinodermata are marine invertebrates comprising starfish, brittle stars, sea cucumbers, sea urchins, and sea lilies. Animals in this phylum lack any centralized brain and instead possess diffuse neural networks known as nerve nets. The learning abilities of these animals are of particular interest as, within the bilaterian clade, they are close evolutionary neighbors to chordates, a phylum whose members exhibit complex feats in learning and contain highly specialized brains. The learning capacities and limitations of echinoderms can inform the evolution of nervous systems and learning in Bilateria. We find evidence of both non-associative and associative learning (in the form of classical conditioning) in echinoderms, which was primarily focused on starfish. Additional evidence of learning is documented in brittle stars, sand dollars, and sea urchins. We then discuss the evolutionary significance of learning capabilities without a brain, the presence of embodied cognition across multiple groups, and compare the learning present in echinoderms with the impressive cognitive abilities documented in the oldest linage group within vertebrates (the major group within the phylum of chordates), fish.
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12
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Williams EA, Jékely G. Nervous systems: Neuropeptides define enigmatic comb-jelly neurons. Curr Biol 2021; 31:R1515-R1517. [PMID: 34875238 DOI: 10.1016/j.cub.2021.10.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The apparently simple nerve net of comb-jellies has long intrigued biologists. A new study identifies multiple unique neuropeptides in the comb-jelly nervous system and exploits these as indicators of neuronal identity and morphology.
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Affiliation(s)
- Elizabeth A Williams
- College of Live and Environmental Sciences, Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
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13
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Fitch WT. Information and the single cell. Curr Opin Neurobiol 2021; 71:150-157. [PMID: 34844102 DOI: 10.1016/j.conb.2021.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/17/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022]
Abstract
Understanding the evolution of cognition requires an understanding of the costs and benefits of neural computation. This requires analysis of neuronal circuitry in terms of information-processing efficiency, ultimately cashed out in terms of ATP expenditures relative to adaptive problem-solving abilities. Despite a preoccupation in neuroscience with the synapse as the source of stored neural information, it is clear that, along with synaptic weights and electrochemical dynamics, neurons have multiple mechanisms which store and process information, including 'wetware' (protein phosphorylation, gene transcription, and so on) and cell morphology (dendritic form). Insights into non-synaptic information-processing can be gained by examining the surprisingly complex abilities of single-celled organisms ('cellular cognition') because neurons share many of the same abilities. Cells provide the fundamental level at which information processing interfaces with gene expression, and cell-internal information-processing mechanisms are both powerful and energetically efficient. Understanding cellular computation should be a central goal of research on cognitive evolution.
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14
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Burkhardt P, Jékely G. Evolution of synapses and neurotransmitter systems: The divide-and-conquer model for early neural cell-type evolution. Curr Opin Neurobiol 2021; 71:127-138. [PMID: 34826676 DOI: 10.1016/j.conb.2021.11.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/09/2021] [Accepted: 11/02/2021] [Indexed: 01/08/2023]
Abstract
Nervous systems evolved around 560 million years ago to coordinate and empower animal bodies. Ctenophores - one of the earliest-branching lineages - are thought to share a few neuronal genes with bilaterians and may have evolved neurons convergently. Here we review our current understanding of the evolution of neuronal molecules in nonbilaterians. We also reanalyse single-cell sequencing data in light of new cell-cluster identities from a ctenophore and uncover evidence supporting the homology of one ctenophore neuron-type with neurons in Bilateria. The specific coexpression of the presynaptic proteins Unc13 and RIM with voltage-gated channels, neuropeptides and homeobox genes pinpoint a spiking sensory-peptidergic cell in the ctenophore mouth. Similar Unc13-RIM neurons may have been present in the first eumetazoans to rise to dominance only in stem Bilateria. We hypothesise that the Unc13-RIM lineage ancestrally innervated the mouth and conquered other parts of the body with the rise of macrophagy and predation during the Cambrian explosion.
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Affiliation(s)
- Pawel Burkhardt
- Sars International Centre for Marine Molecular Biology, University of Bergen, Norway.
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, UK.
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15
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Paganos P, Voronov D, Musser JM, Arendt D, Arnone MI. Single-cell RNA sequencing of the Strongylocentrotus purpuratus larva reveals the blueprint of major cell types and nervous system of a non-chordate deuterostome. eLife 2021; 10:70416. [PMID: 34821556 PMCID: PMC8683087 DOI: 10.7554/elife.70416] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 11/24/2021] [Indexed: 12/15/2022] Open
Abstract
Identifying the molecular fingerprint of organismal cell types is key for understanding their function and evolution. Here, we use single-cell RNA sequencing (scRNA-seq) to survey the cell types of the sea urchin early pluteus larva, representing an important developmental transition from non-feeding to feeding larva. We identify 21 distinct cell clusters, representing cells of the digestive, skeletal, immune, and nervous systems. Further subclustering of these reveal a highly detailed portrait of cell diversity across the larva, including the identification of neuronal cell types. We then validate important gene regulatory networks driving sea urchin development and reveal new domains of activity within the larval body. Focusing on neurons that co-express Pdx-1 and Brn1/2/4, we identify an unprecedented number of genes shared by this population of neurons in sea urchin and vertebrate endocrine pancreatic cells. Using differential expression results from Pdx-1 knockdown experiments, we show that Pdx1 is necessary for the acquisition of the neuronal identity of these cells. We hypothesize that a network similar to the one orchestrated by Pdx1 in the sea urchin neurons was active in an ancestral cell type and then inherited by neuronal and pancreatic developmental lineages in sea urchins and vertebrates.
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Affiliation(s)
- Periklis Paganos
- Stazione Zoologica Anton Dohrn, Department of Biology and Evolution of Marine Organisms, Naples, Italy
| | - Danila Voronov
- Stazione Zoologica Anton Dohrn, Department of Biology and Evolution of Marine Organisms, Naples, Italy
| | - Jacob M Musser
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany
| | - Detlev Arendt
- European Molecular Biology Laboratory, Developmental Biology Unit, Heidelberg, Germany
| | - Maria Ina Arnone
- Stazione Zoologica Anton Dohrn, Department of Biology and Evolution of Marine Organisms, Naples, Italy
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16
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Smith SJ. Transcriptomic evidence for dense peptidergic networks within forebrains of four widely divergent tetrapods. Curr Opin Neurobiol 2021; 71:100-109. [PMID: 34775262 DOI: 10.1016/j.conb.2021.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/21/2021] [Accepted: 09/27/2021] [Indexed: 12/15/2022]
Abstract
The primary function common to every neuron is communication with other neurons. Such cell-cell signaling can take numerous forms, including fast synaptic transmission and slower neuromodulation via secreted messengers, such as neuropeptides, dopamine, and many other diffusible small molecules. Individual neurons are quite diverse, however, in all particulars of both synaptic and neuromodulatory communication. Neuron classification schemes have therefore proven very useful in exploring the emergence of network function, behavior, and cognition from the communication functions of individual neurons. Recently published single-cell mRNA sequencing data and corresponding transcriptomic neuron classifications from turtle, songbird, mouse, and human provide evidence for a long evolutionary history and adaptive significance of localized peptidergic signaling. Across all four species, sets of at least twenty orthologous cognate pairs of neuropeptide precursor protein and receptor genes are expressed in individually sparse but heavily overlapping patterns suggesting that all forebrain neuron types are densely interconnected by local peptidergic signals.
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17
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Musser JM, Schippers KJ, Nickel M, Mizzon G, Kohn AB, Pape C, Ronchi P, Papadopoulos N, Tarashansky AJ, Hammel JU, Wolf F, Liang C, Hernández-Plaza A, Cantalapiedra CP, Achim K, Schieber NL, Pan L, Ruperti F, Francis WR, Vargas S, Kling S, Renkert M, Polikarpov M, Bourenkov G, Feuda R, Gaspar I, Burkhardt P, Wang B, Bork P, Beck M, Schneider TR, Kreshuk A, Wörheide G, Huerta-Cepas J, Schwab Y, Moroz LL, Arendt D. Profiling cellular diversity in sponges informs animal cell type and nervous system evolution. Science 2021; 374:717-723. [PMID: 34735222 DOI: 10.1126/science.abj2949] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Jacob M Musser
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Klaske J Schippers
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Michael Nickel
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Friedrich-Schiller-Universität Jena, Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, 07743 Jena, Germany.,GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 München, Germany
| | - Giulia Mizzon
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Andrea B Kohn
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Constantin Pape
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Paolo Ronchi
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Nikolaos Papadopoulos
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Jörg U Hammel
- Friedrich-Schiller-Universität Jena, Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, 07743 Jena, Germany.,Institute for Materials Physics, Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Florian Wolf
- Friedrich-Schiller-Universität Jena, Institut für Zoologie und Evolutionsforschung mit Phyletischem Museum, Ernst-Haeckel-Haus und Biologiedidaktik, 07743 Jena, Germany
| | - Cong Liang
- Center for Applied Mathematics, Tianjin University, Tianjin 300072, China
| | - Ana Hernández-Plaza
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain
| | - Carlos P Cantalapiedra
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain
| | - Kaia Achim
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Nicole L Schieber
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Leslie Pan
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Fabian Ruperti
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Collaboration for joint Ph.D. degree between EMBL and Heidelberg University, Faculty of Biosciences 69117 Heidelberg, Germany
| | - Warren R Francis
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 München, Germany
| | - Sergio Vargas
- Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 München, Germany
| | - Svenja Kling
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
| | - Maike Renkert
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Maxim Polikarpov
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory, Hamburg, 22607 Germany.,Department of Information Technology and Electrical Engineering, ETH Zurich, CH-8092 Zurich, Switzerland
| | - Gleb Bourenkov
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory, Hamburg, 22607 Germany
| | - Roberto Feuda
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Imre Gaspar
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Department of Totipotency, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Pawel Burkhardt
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5008 Bergen, Norway
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.,Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Peer Bork
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Martin Beck
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Thomas R Schneider
- Hamburg Unit c/o DESY, European Molecular Biology Laboratory, Hamburg, 22607 Germany
| | - Anna Kreshuk
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Gert Wörheide
- GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 München, Germany.,Department of Earth and Environmental Sciences, Paleontology & Geobiology, Ludwig-Maximilians-Universität München, 80333 München, Germany.,Bayerische Staatssammlung für Paläontologie und Geologie (SNSB), 80333 München, Germany
| | - Jaime Huerta-Cepas
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) and Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), 28223 Madrid, Spain.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Yannick Schwab
- Electron Microscopy Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Leonid L Moroz
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA.,Department of Neuroscience and Brain Institute, University of Florida, Gainesville, FL 32610, USA.,McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany
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18
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Marshall PJ, Houser TM, Weiss SM. The Shared Origins of Embodiment and Development. Front Syst Neurosci 2021; 15:726403. [PMID: 34483853 PMCID: PMC8416067 DOI: 10.3389/fnsys.2021.726403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 07/21/2021] [Indexed: 11/13/2022] Open
Abstract
As a domain of study centering on the nature of the body in the functioning of the individual organism, embodiment encompasses a diverse array of topics and questions. One useful organizing framework places embodiment as a bridge construct connecting three standpoints on the body: the form of the body, the body as actively engaged in and with the world, and the body as lived experience. Through connecting these standpoints, the construct of embodiment shows that they are not mutually exclusive: inherent in form is the capacity for engagement, and inherent in engagement is a lived perspective that confers agency and meaning. Here, we employ this framework to underscore the deep connections between embodiment and development. We begin with a discussion of the origins of multicellularity, highlighting how the evolution of bodies was the evolution of development itself. The evolution of the metazoan (animal) body is of particular interest, because most animals possess complex bodies with sensorimotor capacities for perceiving and acting that bring forth a particular sort of embodiment. However, we also emphasize that the thread of embodiment runs through all living things, which share an organizational property of self-determination that endows them with a specific kind of autonomy. This realization moves us away from a Cartesian machine metaphor and instead puts an emphasis on the lived perspective that arises from being embodied. This broad view of embodiment presents opportunities to transcend the boundaries of individual disciplines to create a novel integrative vision for the scientific study of development.
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19
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Grillner S. Evolution of the vertebrate motor system - from forebrain to spinal cord. Curr Opin Neurobiol 2021; 71:11-18. [PMID: 34450468 DOI: 10.1016/j.conb.2021.07.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/12/2021] [Accepted: 07/27/2021] [Indexed: 11/29/2022]
Abstract
A comparison of the vertebrate motor systems of the oldest group of now living vertebrates (lamprey) with that of mammals shows that there are striking similarities not only in the basic organization but also with regard to synaptic properties, transmitters and neuronal properties. The lamprey dorsal pallium (cortex) has a motor, a visual and a somatosensory area, and the basal ganglia, including the dopamine system, are organized in a virtually identical way in the lamprey and rodents. This also applies to the midbrain, brainstem and spinal cord. However, during evolution additional capabilities such as systems for the control of foreleg/arms, hands and fingers have evolved. The findings suggest that when the evolutionary lineages of mammals and lamprey became separate around 500 million years ago, the blueprint of the vertebrate motor system had already evolved.
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Affiliation(s)
- Sten Grillner
- Department of Neuroscience, Karolinska Institutet, SE 17177, Stockholm, Sweden.
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20
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Hobert O. Homeobox genes and the specification of neuronal identity. Nat Rev Neurosci 2021; 22:627-636. [PMID: 34446866 DOI: 10.1038/s41583-021-00497-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2021] [Indexed: 12/27/2022]
Abstract
The enormous diversity of cell types that characterizes any animal nervous system is defined by neuron-type-specific gene batteries that endow cells with distinct anatomical and functional properties. To understand how such cellular diversity is genetically specified, one needs to understand the gene regulatory programmes that control the expression of cell-type-specific gene batteries. The small nervous system of the nematode Caenorhabditis elegans has been comprehensively mapped at the cellular and molecular levels, which has enabled extensive, nervous system-wide explorations into whether there are common underlying mechanisms that specify neuronal cell-type diversity. One principle that emerged from these studies is that transcription factors termed 'terminal selectors' coordinate the expression of individual members of neuron-type-specific gene batteries, thereby assigning unique identities to individual neuron types. Systematic mutant analyses and recent nervous system-wide expression analyses have revealed that one transcription factor family, the homeobox gene family, is broadly used throughout the entire C. elegans nervous system to specify neuronal identity as terminal selectors. I propose that the preponderance of homeobox genes in neuronal identity control is a reflection of an evolutionary trajectory in which an ancestral neuron type was specified by one or more ancestral homeobox genes, and that this functional linkage then duplicated and diversified to generate distinct cell types in an evolving nervous system.
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Affiliation(s)
- Oliver Hobert
- Department of Biological Sciences, Columbia University, Howard Hughes Medical Institute, New York, NY, USA.
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21
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Moroz LL. Multiple Origins of Neurons From Secretory Cells. Front Cell Dev Biol 2021; 9:669087. [PMID: 34307354 PMCID: PMC8293673 DOI: 10.3389/fcell.2021.669087] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/26/2021] [Indexed: 12/12/2022] Open
Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, United States
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22
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Lyon P, Keijzer F, Arendt D, Levin M. Reframing cognition: getting down to biological basics. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190750. [PMID: 33487107 PMCID: PMC7935032 DOI: 10.1098/rstb.2019.0750] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
The premise of this two-part theme issue is simple: the cognitive sciences should join the rest of the life sciences in how they approach the quarry within their research domain. Specifically, understanding how organisms on the lower branches of the phylogenetic tree become familiar with, value and exploit elements of an ecological niche while avoiding harm can be expected to aid understanding of how organisms that evolved later (including Homo sapiens) do the same or similar things. We call this approach basal cognition. In this introductory essay, we explain what the approach involves. Because no definition of cognition exists that reflects its biological basis, we advance a working definition that can be operationalized; introduce a behaviour-generating toolkit of capacities that comprise the function (e.g. sensing/perception, memory, valence, learning, decision making, communication), each element of which can be studied relatively independently; and identify a (necessarily incomplete) suite of common biophysical mechanisms found throughout the domains of life involved in implementing the toolkit. The articles in this collection illuminate different aspects of basal cognition across different forms of biological organization, from prokaryotes and single-celled eukaryotes-the focus of Part 1-to plants and finally to animals, without and with nervous systems, the focus of Part 2. By showcasing work in diverse, currently disconnected fields, we hope to sketch the outline of a new multidisciplinary approach for comprehending cognition, arguably the most fascinating and hard-to-fathom evolved function on this planet. Doing so has the potential to shed light on problems in a wide variety of research domains, including microbiology, immunology, zoology, biophysics, botany, developmental biology, neurobiology/science, regenerative medicine, computational biology, artificial life and synthetic bioengineering. This article is part of the theme issue 'Basal cognition: conceptual tools and the view from the single cell'.
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Affiliation(s)
- Pamela Lyon
- Southgate Institute for Health, Society and Equity, College of Medicine and Public Health, Flinders University, Adelaide, SA 5042, Australia
| | - Fred Keijzer
- Department of Theoretical Philosophy, Universityof Groningen, Oude Boteringestraat 52, Groningen 9712GL, The Netherlands
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69012 Heidelberg, Germany
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
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23
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Levin M, Keijzer F, Lyon P, Arendt D. Uncovering cognitive similarities and differences, conservation and innovation. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200458. [PMID: 33550950 DOI: 10.1098/rstb.2020.0458] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Fred Keijzer
- Department of Theoretical Philosophy, University of Groningen, Oude Boteringestraat 52, Groningen 9712GL, The Netherlands
| | - Pamela Lyon
- Southgate Institute for Health, Society and Equity, College of Medicine and Public Health, Flinders University, Adelaide SA 5042, Australia
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69012 Heidelberg, Germany.,Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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