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Zhang J, Zhao R, Lin S, Yang D, Lu S, Liu Z, Gao Y, Zhang Y, Hou B, Xi C, Liu J, Bing J, Pang E, Lin K, Zeng S. Comparison of genes involved in brain development: insights into the organization and evolution of the telencephalic pallium. Sci Rep 2024; 14:6102. [PMID: 38480729 PMCID: PMC10937912 DOI: 10.1038/s41598-024-51964-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 01/11/2024] [Indexed: 03/17/2024] Open
Abstract
The mechanisms underlying the organization and evolution of the telencephalic pallium are not yet clear.. To address this issue, we first performed comparative analysis of genes critical for the development of the pallium (Emx1/2 and Pax6) and subpallium (Dlx2 and Nkx1/2) among 500 vertebrate species. We found that these genes have no obvious variations in chromosomal duplication/loss, gene locus synteny or Darwinian selection. However, there is an additional fragment of approximately 20 amino acids in mammalian Emx1 and a poly-(Ala)6-7 in Emx2. Lentiviruses expressing mouse or chick Emx2 (m-Emx2 or c-Emx2 Lv) were injected into the ventricle of the chick telencephalon at embryonic Day 3 (E3), and the embryos were allowed to develop to E12-14 or to posthatchling. After transfection with m-Emx2 Lv, the cells expressing Reelin, Vimentin or GABA increased, and neurogenesis of calbindin cells changed towards the mammalian inside-out pattern in the dorsal pallium and mesopallium. In addition, a behavior test for posthatched chicks indicated that the passive avoidance ratio increased significantly. The study suggests that the acquisition of an additional fragment in mammalian Emx2 is associated with the organization and evolution of the mammalian pallium.
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Affiliation(s)
- Jiangyan Zhang
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Rui Zhao
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Shiying Lin
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Dong Yang
- Beijing Key Laboratory of Genetic Engineering Drugs and Biological Technology, Beijing Normal University, Beijing, China
| | - Shan Lu
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Zenan Liu
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Yuanyuan Gao
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Yiyun Zhang
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Bing Hou
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Chao Xi
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Jin Liu
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Jie Bing
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China
| | - Erli Pang
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Kui Lin
- MOE Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, China.
| | - Shaoju Zeng
- Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China.
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Lacalli T. The Cambrian fossil Pikaia, and the origin of chordate somites. EvoDevo 2024; 15:1. [PMID: 38302988 PMCID: PMC10832150 DOI: 10.1186/s13227-024-00222-6] [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: 11/10/2023] [Accepted: 01/17/2024] [Indexed: 02/03/2024] Open
Abstract
The Middle Cambrian fossil Pikaia has a regular series of vertical bands that, assuming chordate affinities, can be interpreted as septa positioned between serial myotomes. Whether Pikaia has a notochord and nerve cord is less certain, as the dorsal organ, which has no obvious counterpart in living chordates, is the only clearly defined axial structure extending the length of the body. Without a notochord to serve as a reference point, the location of the nerve cord is then conjectural, which begs the question of how a dorsal neural center devoted to somite innervation would first have arisen from a more diffuse ancestral plexus of intraepithelial nerves. This question is examined using hemichordates as a reference point, first for the information they provide on the organization of the ancestral deuterostome nervous system, and second, extending the analysis of E. E. Ruppert, to explain why neural infoldings like the enteropneust collar cord would first have evolved. Both implicate the medial surface of the anterior-most part of the metacoel as the likely site for the evolution of the first somites. The analysis highlights the importance of the somatobranchial condition in chordates, meaning the linkage between the anterior trunk, hox1 expression, and the beginning of the gill series and somites. This feature is arguably a valid criterion by which to assess extinct taxa from the Cambrian that resemble chordates (e.g., vetulicolians and yunnanozoans), but may be unrelated to them. In a more speculative vein, the nature of the dorsal organ is discussed, including the possibility that it is an expanded neural tube combining neural and support functions in one structure.
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Affiliation(s)
- Thurston Lacalli
- Biology Department, University of Victoria, Victoria, V8W-3N5, Canada.
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Elwood RW. Behavioural Indicators of Pain and Suffering in Arthropods and Might Pain Bite Back? Animals (Basel) 2023; 13:2602. [PMID: 37627393 PMCID: PMC10451332 DOI: 10.3390/ani13162602] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/07/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Pain in response to tissue damage functions to change behaviour so that further damage is minimised whereas healing and survival are promoted. This paper focuses on the behavioural criteria that match the function to ask if pain is likely in the main taxa of arthropods. There is evidence consistent with the idea of pain in crustaceans, insects and, to a lesser extent, spiders. There is little evidence of pain in millipedes, centipedes, scorpions, and horseshoe crabs but there have been few investigations of these groups. Alternative approaches in the study of pain are explored and it is suggested that studies on traumatic mating, agonistic interactions, and defensive venoms might provide clues about pain. The evolution of high cognitive ability, sensory systems, and flexible decision-making is discussed as well as how these might influence the evolution of pain-like states.
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Affiliation(s)
- Robert W Elwood
- School of Biological Sciences, Queen's University Belfast, Belfast BT9 5DL, UK
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Farnsworth KD, Elwood RW. Why it hurts: with freedom comes the biological need for pain. Anim Cogn 2023:10.1007/s10071-023-01773-2. [PMID: 37029847 DOI: 10.1007/s10071-023-01773-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 03/23/2023] [Accepted: 03/30/2023] [Indexed: 04/09/2023]
Abstract
We argue that pain is not needed to protect the body from damage unless the organism is able to make free choices in action selection. Then pain (including its affective and evaluative aspects) provides a necessary prioritising motivation to select actions expected to avoid it, whilst leaving the possibility of alternative actions to serve potentially higher priorities. Thus, on adaptive grounds, only organisms having free choice over action selection should experience pain. Free choice implies actions must be selected following appraisal of their effects, requiring a predictive model generating estimates of action outcomes. These features give organisms anticipatory behavioural autonomy (ABA), for which we propose a plausible system using an internal predictive model, integrated into a system able to produce the qualitative and affective aspects of pain. Our hypothesis can be tested using behavioural experiments designed to elicit trade-off responses to novel experiences for which algorithmic (automaton) responses might be inappropriate. We discuss the empirical evidence for our hypothesis among taxonomic groups, showing how testing for ABA guides thinking on which groups might experience pain. It is likely that all vertebrates do and plausible that some invertebrates do (decapods, cephalopods and at least some insects).
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Affiliation(s)
- Keith D Farnsworth
- School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT95DL, UK.
| | - Robert W Elwood
- School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT95DL, UK
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5
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Bozzo M, Bellitto D, Amaroli A, Ferrando S, Schubert M, Candiani S. Retinoic Acid and POU Genes in Developing Amphioxus: A Focus on Neural Development. Cells 2023; 12:cells12040614. [PMID: 36831281 PMCID: PMC9953854 DOI: 10.3390/cells12040614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 01/27/2023] [Accepted: 02/07/2023] [Indexed: 02/16/2023] Open
Abstract
POU genes are a family of evolutionarily conserved transcription factors with key functions in cell type specification and neurogenesis. In vitro experiments have indicated that the expression of some POU genes is controlled by the intercellular signaling molecule retinoic acid (RA). In this work, we aimed to characterize the roles of RA signaling in the regulation of POU genes in vivo. To do so, we studied POU genes during the development of the cephalochordate amphioxus, an animal model crucial for understanding the evolutionary origins of vertebrates. The expression patterns of amphioxus POU genes were assessed at different developmental stages by chromogenic in situ hybridization and hybridization chain reaction. Expression was further assessed in embryos subjected to pharmacological manipulation of endogenous RA signaling activity. In addition to a detailed description of the effects of these treatments on amphioxus POU gene expression, our survey included the first description of Pou2 and Pou6 expression in amphioxus embryos. We found that Pit-1, Pou2, Pou3l, and Pou6 expression are not affected by alterations of endogenous RA signaling levels. In contrast, our experiments indicated that Brn1/2/4 and Pou4 expression are regulated by RA signaling in the endoderm and the nerve cord, respectively. The effects of the treatments on Pou4 expression in the nerve cord revealed that, in developing amphioxus, RA signaling plays a dual role by (1) providing anteroposterior patterning information to neural cells and (2) specifying neural cell types. This finding is coherent with a terminal selector function of Pou4 for GABAergic neurons in amphioxus and represents the first description of RA-induced changes in POU gene expression in vivo.
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Affiliation(s)
- Matteo Bozzo
- Dipartimento di Scienze della Terra dell’Ambiente e della Vita (DISTAV), Università degli Studi di Genova, 16132 Genoa, Italy
- Correspondence: (M.B.); (S.C.); Tel.: +39-0103358043 (M.B.); +39-0103358051 (S.C.)
| | - Deianira Bellitto
- Dipartimento di Scienze della Terra dell’Ambiente e della Vita (DISTAV), Università degli Studi di Genova, 16132 Genoa, Italy
| | - Andrea Amaroli
- Dipartimento di Scienze della Terra dell’Ambiente e della Vita (DISTAV), Università degli Studi di Genova, 16132 Genoa, Italy
| | - Sara Ferrando
- Dipartimento di Scienze della Terra dell’Ambiente e della Vita (DISTAV), Università degli Studi di Genova, 16132 Genoa, Italy
| | - Michael Schubert
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Institut de la Mer de Villefranche, Sorbonne Université, CNRS, 06230 Villefranche-sur-Mer, France
| | - Simona Candiani
- Dipartimento di Scienze della Terra dell’Ambiente e della Vita (DISTAV), Università degli Studi di Genova, 16132 Genoa, Italy
- Correspondence: (M.B.); (S.C.); Tel.: +39-0103358043 (M.B.); +39-0103358051 (S.C.)
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Lacalli T. On the origins and evolution of qualia: An experience-space perspective. Front Syst Neurosci 2022; 16:945722. [PMID: 36032325 PMCID: PMC9399462 DOI: 10.3389/fnsys.2022.945722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
This paper elaborates on a proposal for mapping a configuration space for selector circuits (SCs), defined as the subset of neural correlates of consciousness (NCCs) responsible for evoking particular qualia, to its experiential counterpart, experience-space (E-space), as part of an investigation into the nature of conscious experience as it first emerged in evolution. The dimensionality of E-space, meaning the degrees of freedom required to specify the properties of related sets of qualia, is at least two, but the utility of E-space as a hypothetical construct is much enhanced by assuming it is a large dimensional space, with at least several times as many dimensions as there are categories of qualia to occupy them. Phenomenal consciousness can then be represented as having originated as one or more multidimensional ur-experiences that combined multiple forms of experience together. Taking this as a starting point, questions concerning evolutionary sequence can be addressed, including how the quale best suited to a given sensory modality would have been extracted by evolution from a larger set of possibilities, a process referred to here as dimensional sorting, and how phenomenal consciousness would have been experienced in its earliest manifestations. There is a further question as to whether the E-space formulation is meaningful in analytical terms or simply a descriptive device in graphical form, but in either case it provides a more systematic way of thinking about early stages in the evolution of consciousness than relying on narrative and conjecture alone.
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Abstract
The nervous system is a product of evolution. That is, it was constructed through a long series of modifications, within the strong constraints of heredity, and continuously subjected to intense selection pressures. As a result, the organization and functions of the brain are shaped by its history. We believe that this fact, underappreciated in contemporary systems neuroscience, offers an invaluable aid for helping us resolve the brain's mysteries. Indeed, we think that the consideration of evolutionary history ought to take its place alongside other intellectual tools used to understand the brain, such as behavioural experiments, studies of anatomical structure and functional characterization based on recordings of neural activity. In this introduction, we argue for the importance of evolution by highlighting specific examples of ways that evolutionary theory can enhance neuroscience. The rest of the theme issue elaborates this point, emphasizing the conservative nature of neural evolution, the important consequences of specific transitions that occurred in our history, and the ways in which considerations of evolution can shed light on issues ranging from specific mechanisms to fundamental principles of brain organization. This article is part of the theme issue ‘Systems neuroscience through the lens of evolutionary theory’.
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Affiliation(s)
- Paul Cisek
- Department of Neuroscience, University of Montréal, 2960 chemin de la tour, local 1107 Montréal, QC H3T 1J4 Canada
| | - Benjamin Y Hayden
- Department of Neuroscience, Department of Biomedical Engineering, and Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN 55455, USA
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Lacalli T. Consciousness as a Product of Evolution: Contents, Selector Circuits, and Trajectories in Experience Space. Front Syst Neurosci 2021; 15:697129. [PMID: 34744646 PMCID: PMC8564397 DOI: 10.3389/fnsys.2021.697129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 09/24/2021] [Indexed: 11/22/2022] Open
Abstract
Conscious experience can be treated as a complex unified whole, but to do so is problematic from an evolutionary perspective if, like other products of evolution, consciousness had simple beginnings, and achieved complexity only secondarily over an extended period of time as new categories of subjective experience were added and refined. The premise here is twofold, first that these simple beginnings can be investigated regardless of whether the ultimate source of subjective experience is known or understood, and second, that of the contents known to us, the most accessible for investigation will be those that are, or appear, most fundamental, in the sense that they resist further deconstruction or analysis. This would include qualia as they are usually defined, but excludes more complex experiences (here, formats) that are structured, or depend on algorithmic processes and/or memory. Vision and language for example, would by this definition be formats. More formally, qualia, but not formats, can be represented as points, lines, or curves on a topological experience space, and as domains in a configuration space representing a subset of neural correlates of consciousness, the selector circuits (SCs), responsible for ensuring that a particular experience is evoked rather than some other. It is a matter of conjecture how points in SC-space map to experience space, but both will exhibit divergence, insuring that a minimal distance separates points in experience space representing different qualia and the SCs that evoke them. An analysis of how SCs evolve over time is used to highlight the importance of understanding patterns of descent among putative qualia, i.e., their homology across species, and whether this implies descent from an ancestral experience, or ur-quale, that combines modes of experience that later came to be experienced separately. The analysis also provides insight into the function of consciousness as viewed from an evolutionary perspective, defined here in terms of the access it allows to regions of SC-space that would otherwise be unavailable to real brains, to produce consciously controlled behaviors that could otherwise not occur.
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Affiliation(s)
- Thurston Lacalli
- Biology Department, University of Victoria, Victoria, BC, Canada
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