1
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Beauséjour PA, Veilleux JC, Condamine S, Zielinski BS, Dubuc R. Olfactory Projections to Locomotor Control Centers in the Sea Lamprey. Int J Mol Sci 2024; 25:9370. [PMID: 39273317 PMCID: PMC11395479 DOI: 10.3390/ijms25179370] [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: 07/11/2024] [Revised: 08/20/2024] [Accepted: 08/26/2024] [Indexed: 09/15/2024] Open
Abstract
Although olfaction is well known to guide animal behavior, the neural circuits underlying the motor responses elicited by olfactory inputs are poorly understood. In the sea lamprey, anatomical evidence shows that olfactory inputs project to the posterior tuberculum (PT), a structure containing dopaminergic (DA) neurons homologous to the mammalian ventral tegmental area and the substantia nigra pars compacta. Olfactory inputs travel directly from the medial olfactory bulb (medOB) or indirectly through the main olfactory bulb and the lateral pallium (LPal). Here, we characterized the transmission of olfactory inputs to the PT in the sea lamprey, Petromyzon marinus. Abundant projections from the medOB were observed close to DA neurons of the PT. Moreover, electrophysiological experiments revealed that PT neurons are activated by both the medOB and LPal, and calcium imaging indicated that the olfactory signal is then relayed to the mesencephalic locomotor region to initiate locomotion. In semi-intact preparations, stimulation of the medOB and LPal induced locomotion that was tightly associated with neural activity in the PT. Moreover, PT neurons were active throughout spontaneously occurring locomotor bouts. Altogether, our observations suggest that the medOB and LPal convey olfactory inputs to DA neurons of the PT, which in turn activate the brainstem motor command system to elicit locomotion.
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Affiliation(s)
| | - Jean-Christophe Veilleux
- Research Group in Adapted Physical Activity, Department of Exercise Sciences, Faculty of Sciences, University of Quebec in Montreal, Montreal, QC H2X 1Y4, Canada
| | - Steven Condamine
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC H3T 1J4, Canada
| | - Barbara S Zielinski
- Department of Integrative Biology, Faculty of Science, University of Windsor, Windsor, ON N9B 3P4, Canada
| | - Réjean Dubuc
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC H3T 1J4, Canada
- Research Group in Adapted Physical Activity, Department of Exercise Sciences, Faculty of Sciences, University of Quebec in Montreal, Montreal, QC H2X 1Y4, Canada
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2
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Frost-Nylén J, Thompson WS, Robertson B, Grillner S. The Basal Ganglia Downstream Control of Action - An Evolutionarily Conserved Strategy. Curr Neuropharmacol 2024; 22:1419-1430. [PMID: 37563813 PMCID: PMC11097981 DOI: 10.2174/1570159x21666230810141746] [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: 12/02/2022] [Revised: 01/30/2023] [Accepted: 02/05/2023] [Indexed: 08/12/2023] Open
Abstract
The motor areas of the cortex and the basal ganglia both contribute to determining which motor actions will be recruited at any moment in time, and their functions are intertwined. Here, we review the basal ganglia mechanisms underlying the selection of behavior of the downstream control of motor centers in the midbrain and brainstem and show that the basic organization of the forebrain motor system is evolutionarily conserved throughout vertebrate phylogeny. The output level of the basal ganglia (e.g. substantia nigra pars reticulata) has GABAergic neurons that are spontaneously active at rest and inhibit a number of specific motor centers, each of which can be relieved from inhibition if the inhibitory output neurons themselves become inhibited. The motor areas of the cortex act partially via the dorsolateral striatum (putamen), which has specific modules for the forelimb, hindlimb, trunk, etc. Each module operates in turn through the two types of striatal projection neurons that control the output modules of the basal ganglia and thereby the downstream motor centers. The mechanisms for lateral inhibition in the striatum are reviewed as well as other striatal mechanisms contributing to action selection. The motor cortex also exerts a direct excitatory action on specific motor centers. An overview is given of the basal ganglia control exerted on the different midbrain/brainstem motor centers, and the efference copy information fed back via the thalamus to the striatum and cortex, which is of importance for the planning of future movements.
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Affiliation(s)
| | | | - Brita Robertson
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Sten Grillner
- Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
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3
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Lamanna F, Hervas-Sotomayor F, Oel AP, Jandzik D, Sobrido-Cameán D, Santos-Durán GN, Martik ML, Stundl J, Green SA, Brüning T, Mößinger K, Schmidt J, Schneider C, Sepp M, Murat F, Smith JJ, Bronner ME, Rodicio MC, Barreiro-Iglesias A, Medeiros DM, Arendt D, Kaessmann H. A lamprey neural cell type atlas illuminates the origins of the vertebrate brain. Nat Ecol Evol 2023; 7:1714-1728. [PMID: 37710042 PMCID: PMC10555824 DOI: 10.1038/s41559-023-02170-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 07/18/2023] [Indexed: 09/16/2023]
Abstract
The vertebrate brain emerged more than ~500 million years ago in common evolutionary ancestors. To systematically trace its cellular and molecular origins, we established a spatially resolved cell type atlas of the entire brain of the sea lamprey-a jawless species whose phylogenetic position affords the reconstruction of ancestral vertebrate traits-based on extensive single-cell RNA-seq and in situ sequencing data. Comparisons of this atlas to neural data from the mouse and other jawed vertebrates unveiled various shared features that enabled the reconstruction of cell types, tissue structures and gene expression programs of the ancestral vertebrate brain. However, our analyses also revealed key tissues and cell types that arose later in evolution. For example, the ancestral brain was probably devoid of cerebellar cell types and oligodendrocytes (myelinating cells); our data suggest that the latter emerged from astrocyte-like evolutionary precursors in the jawed vertebrate lineage. Altogether, our work illuminates the cellular and molecular architecture of the ancestral vertebrate brain and provides a foundation for exploring its diversification during evolution.
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Affiliation(s)
- Francesco Lamanna
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany.
| | | | - A Phillip Oel
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - David Jandzik
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, USA
- Department of Zoology, Comenius University, Bratislava, Slovakia
| | - Daniel Sobrido-Cameán
- Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Gabriel N Santos-Durán
- Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Megan L Martik
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Jan Stundl
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Stephen A Green
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Thoomke Brüning
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Katharina Mößinger
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Julia Schmidt
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Celine Schneider
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Mari Sepp
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Florent Murat
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- INRAE, LPGP, Rennes, France
| | - Jeramiah J Smith
- Department of Biology, University of Kentucky, Lexington, KY, USA
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - María Celina Rodicio
- Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Antón Barreiro-Iglesias
- Department of Functional Biology, CIBUS, Faculty of Biology, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Daniel M Medeiros
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Henrik Kaessmann
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany.
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4
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Hegarty BE, Gruenhagen GW, Johnson ZV, Baker CM, Streelman JT. Spatially resolved cell atlas of the teleost telencephalon and deep homology of the vertebrate forebrain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.20.549873. [PMID: 37503039 PMCID: PMC10370212 DOI: 10.1101/2023.07.20.549873] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The telencephalon has undergone remarkable diversification and expansion throughout vertebrate evolution, exhibiting striking differences in structural and functional complexity. Nevertheless, fundamental features are shared across vertebrate taxa, such as the presence of distinct regions including the pallium, subpallium, and olfactory structures. Teleost fishes have a uniquely 'everted' telencephalon, which has made it challenging to compare brain regions in fish to those in other vertebrates. Here we combine spatial transcriptomics and single-nucleus RNA-sequencing to generate a spatially-resolved transcriptional atlas of the cichlid fish telencephalon. We then compare cell-types and anatomical regions in the cichlid telencephalon with those in amphibians, reptiles, birds, and mammals. We uncover striking transcriptional similarities between cell populations in the fish telencephalon and subpallial, hippocampal, and cortical cell populations in tetrapods. Ultimately, our work lends new insights into the organization and evolution of conserved cell-types and regions in the vertebrate forebrain.
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Affiliation(s)
- Brianna E Hegarty
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
- Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
| | - George W Gruenhagen
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
- Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
| | - Zachary V Johnson
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
- Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
- Emory National Primate Research Center, Emory University, Atlanta, GA 30329
- Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta, GA 30329
| | - Cristina M Baker
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
- Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
- Kavli Institute for Systems Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
| | - Jeffrey T Streelman
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332
- Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332
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5
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Earl B. Humans, fish, spiders and bees inherited working memory and attention from their last common ancestor. Front Psychol 2023; 13:937712. [PMID: 36814887 PMCID: PMC9939904 DOI: 10.3389/fpsyg.2022.937712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 11/11/2022] [Indexed: 02/08/2023] Open
Abstract
All brain processes that generate behaviour, apart from reflexes, operate with information that is in an "activated" state. This activated information, which is known as working memory (WM), is generated by the effect of attentional processes on incoming information or information previously stored in short-term or long-term memory (STM or LTM). Information in WM tends to remain the focus of attention; and WM, attention and STM together enable information to be available to mental processes and the behaviours that follow on from them. WM and attention underpin all flexible mental processes, such as solving problems, making choices, preparing for opportunities or threats that could be nearby, or simply finding the way home. Neither WM nor attention are necessarily conscious, and both may have evolved long before consciousness. WM and attention, with similar properties, are possessed by humans, archerfish, and other vertebrates; jumping spiders, honey bees, and other arthropods; and members of other clades, whose last common ancestor (LCA) is believed to have lived more than 600 million years ago. It has been reported that very similar genes control the development of vertebrate and arthropod brains, and were likely inherited from their LCA. Genes that control brain development are conserved because brains generate adaptive behaviour. However, the neural processes that generate behaviour operate with the activated information in WM, so WM and attention must have existed prior to the evolution of brains. It is proposed that WM and attention are widespread amongst animal species because they are phylogenetically conserved mechanisms that are essential to all mental processing, and were inherited from the LCA of vertebrates, arthropods, and some other animal clades.
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6
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Giarrocco F, Averbeck BB. Anatomical organization of forebrain circuits in the primate. Brain Struct Funct 2023; 228:393-411. [PMID: 36271258 PMCID: PMC9944689 DOI: 10.1007/s00429-022-02586-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 10/13/2022] [Indexed: 11/26/2022]
Abstract
The primate forebrain is a complex structure. Thousands of connections have been identified between cortical areas, and between cortical and sub-cortical areas. Previous work, however, has suggested that a number of principles can be used to reduce this complexity. Here, we integrate four principles that have been put forth previously, including a nested model of neocortical connectivity, gradients of connectivity between frontal cortical areas and the striatum and thalamus, shared patterns of sub-cortical connectivity between connected posterior and frontal cortical areas, and topographic organization of cortical-striatal-pallidal-thalamocortical circuits. We integrate these principles into a single model that accounts for a substantial amount of connectivity in the forebrain. We then suggest that studies in evolution and development can account for these four principles, by assuming that the ancestral vertebrate pallium was dominated by medial, hippocampal and ventral-lateral, pyriform areas, and at most a small dorsal pallium. The small dorsal pallium expanded massively in the lineage leading to primates. During this expansion, topological, adjacency relationships were maintained between pallial and sub-pallial areas. This maintained topology led to the connectivity gradients seen between cortex, striatum, pallidum, and thalamus.
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Affiliation(s)
- Franco Giarrocco
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Building 49 Room 1B80, 49 Convent Drive MSC 4415, Bethesda, MD, 20892-4415, USA
| | - Bruno B Averbeck
- Laboratory of Neuropsychology, National Institute of Mental Health, National Institutes of Health, Building 49 Room 1B80, 49 Convent Drive MSC 4415, Bethesda, MD, 20892-4415, USA.
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7
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Woych J, Ortega Gurrola A, Deryckere A, Jaeger ECB, Gumnit E, Merello G, Gu J, Joven Araus A, Leigh ND, Yun M, Simon A, Tosches MA. Cell-type profiling in salamanders identifies innovations in vertebrate forebrain evolution. Science 2022; 377:eabp9186. [PMID: 36048957 PMCID: PMC10024926 DOI: 10.1126/science.abp9186] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The evolution of advanced cognition in vertebrates is associated with two independent innovations in the forebrain: the six-layered neocortex in mammals and the dorsal ventricular ridge (DVR) in sauropsids (reptiles and birds). How these innovations arose in vertebrate ancestors remains unclear. To reconstruct forebrain evolution in tetrapods, we built a cell-type atlas of the telencephalon of the salamander Pleurodeles waltl. Our molecular, developmental, and connectivity data indicate that parts of the sauropsid DVR trace back to tetrapod ancestors. By contrast, the salamander dorsal pallium is devoid of cellular and molecular characteristics of the mammalian neocortex yet shares similarities with the entorhinal cortex and subiculum. Our findings chart the series of innovations that resulted in the emergence of the mammalian six-layered neocortex and the sauropsid DVR.
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Affiliation(s)
- Jamie Woych
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Alonso Ortega Gurrola
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.,Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Astrid Deryckere
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Eliza C B Jaeger
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Elias Gumnit
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Gianluca Merello
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Jiacheng Gu
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Alberto Joven Araus
- Department of Cell and Molecular Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Nicholas D Leigh
- Molecular Medicine and Gene Therapy, Wallenberg Centre for Molecular Medicine, Lund Stem Cell Center, Lund University, 221 84 Lund, Sweden
| | - Maximina Yun
- Technische Universität Dresden, CRTD/Center for Regenerative Therapies Dresden, 01307 Dresden, Germany.,Max Planck Institute for Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - András Simon
- Department of Cell and Molecular Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden
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8
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Hussan MT, Sakai A, Matsui H. Glutamatergic pathways in the brains of turtles: A comparative perspective among reptiles, birds, and mammals. Front Neuroanat 2022; 16:937504. [PMID: 36059432 PMCID: PMC9428285 DOI: 10.3389/fnana.2022.937504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 07/22/2022] [Indexed: 11/13/2022] Open
Abstract
Glutamate acts as the main excitatory neurotransmitter in the brain and plays a vital role in physiological and pathological neuronal functions. In mammals, glutamate can cause detrimental excitotoxic effects under anoxic conditions. In contrast, Trachemys scripta, a freshwater turtle, is one of the most anoxia-tolerant animals, being able to survive up to months without oxygen. Therefore, turtles have been investigated to assess the molecular mechanisms of neuroprotective strategies used by them in anoxic conditions, such as maintaining low levels of glutamate, increasing adenosine and GABA, upregulating heat shock proteins, and downregulating KATP channels. These mechanisms of anoxia tolerance of the turtle brain may be applied to finding therapeutics for human glutamatergic neurological disorders such as brain injury or cerebral stroke due to ischemia. Despite the importance of glutamate as a neurotransmitter and of the turtle as an ideal research model, the glutamatergic circuits in the turtle brain remain less described whereas they have been well studied in mammalian and avian brains. In reptiles, particularly in the turtle brain, glutamatergic neurons have been identified by examining the expression of vesicular glutamate transporters (VGLUTs). In certain areas of the brain, some ionotropic glutamate receptors (GluRs) have been immunohistochemically studied, implying that there are glutamatergic target areas. Based on the expression patterns of these glutamate-related molecules and fiber connection data of the turtle brain that is available in the literature, many candidate glutamatergic circuits could be clarified, such as the olfactory circuit, hippocampal–septal pathway, corticostriatal pathway, visual pathway, auditory pathway, and granule cell–Purkinje cell pathway. This review summarizes the probable glutamatergic pathways and the distribution of glutamatergic neurons in the pallium of the turtle brain and compares them with those of avian and mammalian brains. The integrated knowledge of glutamatergic pathways serves as the fundamental basis for further functional studies in the turtle brain, which would provide insights on physiological and pathological mechanisms of glutamate regulation as well as neural circuits in different species.
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Affiliation(s)
- Mohammad Tufazzal Hussan
- Department of Neuroscience of Disease, Brain Research Institute, Niigata University, Niigata, Japan
- Department of Anatomy and Histology, Patuakhali Science and Technology University, Barishal, Bangladesh
- *Correspondence: Mohammad Tufazzal Hussan,
| | - Akiko Sakai
- Department of Neuroscience of Disease, Brain Research Institute, Niigata University, Niigata, Japan
| | - Hideaki Matsui
- Department of Neuroscience of Disease, Brain Research Institute, Niigata University, Niigata, Japan
- Hideaki Matsui,
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9
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García-Cabezas MÁ, Hacker JL, Zikopoulos B. Homology of neocortical areas in rats and primates based on cortical type analysis: an update of the Hypothesis on the Dual Origin of the Neocortex. Brain Struct Funct 2022:10.1007/s00429-022-02548-0. [PMID: 35962240 PMCID: PMC9922339 DOI: 10.1007/s00429-022-02548-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 07/27/2022] [Indexed: 11/02/2022]
Abstract
Sixty years ago, Friedrich Sanides traced the origin of the tangential expansion of the primate neocortex to two ancestral anlagen in the allocortex of reptiles and mammals, and proposed the Hypothesis on the Dual Origin of the Neocortex. According to Sanides, paraolfactory and parahippocampal gradients of laminar elaboration expanded in evolution by addition of successive concentric rings of gradually different cortical types inside the allocortical ring. Rodents had fewer rings and primates had more rings in the inner part of the cortex. In the present article, we perform cortical type analysis of the neocortex of adult rats, Rhesus macaques, and humans to propose hypotheses on homology of cortical areas applying the principles of the Hypothesis on the Dual Origin of the Neocortex. We show that areas in the outer rings of the neocortex have comparable laminar elaboration in rats and primates, while most 6-layer eulaminate areas in the innermost rings of primate neocortex lack homologous counterparts in rats. We also represent the topological distribution of cortical types in simplified flat maps of the cerebral cortex of monotremes, rats, and primates. Finally, we propose an elaboration of the Hypothesis on the Dual Origin of the Neocortex in the context of modern studies of pallial patterning that integrates the specification of pallial sectors in development of vertebrate embryos. The updated version of the hypothesis of Sanides provides explanation for the emergence of cortical hierarchies in mammals and will guide future research in the phylogenetic origin of neocortical areas.
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Affiliation(s)
- Miguel Ángel García-Cabezas
- Department of Anatomy, Histology and Neuroscience, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain,Neural Systems Laboratory, Department of Health Sciences, Boston University, Boston, MA, USA
| | - Julia Liao Hacker
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave., Room 401D, Boston, MA 02215, USA,Present Address: Department of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Basilis Zikopoulos
- Human Systems Neuroscience Laboratory, Department of Health Sciences, Boston University, 635 Commonwealth Ave., Room 401D, Boston, MA, 02215, USA. .,Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, MA, USA. .,Graduate Program in Neuroscience, Boston University, Boston, MA, USA.
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10
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Holland LZ, Holland ND. The invertebrate chordate amphioxus gives clues to vertebrate origins. Curr Top Dev Biol 2022; 147:563-594. [PMID: 35337463 DOI: 10.1016/bs.ctdb.2021.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Amphioxus (cepholochordates) have long been used to infer how the vertebrates evolved from their invertebrate ancestors. However, some of the body part homologies between amphioxus and vertebrates have been controversial. This is not surprising as the amphioxus and vertebrate lineages separated half a billion years ago-plenty of time for independent loss and independent gain of features. The development of new techniques in the late 20th and early 21st centuries including transmission electron microscopy and serial blockface scanning electron microscopy in combination with in situ hybridization and immunocytochemistry to reveal spatio-temporal patterns of gene expression and gene products have greatly strengthened inference of some homologies (like those between regions of the central nervous system), although others (like nephridia) still need further support. These major advances in establishing homologies between amphioxus and vertebrates, together with strong support from comparative genomics, have firmly established amphioxus as a stand-in or model for the ancestral vertebrate.
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Affiliation(s)
- Linda Z Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States.
| | - Nicholas D Holland
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States
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11
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Suryanarayana SM, Robertson B, Grillner S. The neural bases of vertebrate motor behaviour through the lens of evolution. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200521. [PMID: 34957847 PMCID: PMC8710883 DOI: 10.1098/rstb.2020.0521] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/27/2021] [Indexed: 12/23/2022] Open
Abstract
The primary driver of the evolution of the vertebrate nervous system has been the necessity to move, along with the requirement of controlling the plethora of motor behavioural repertoires seen among the vast and diverse vertebrate species. Understanding the neural basis of motor control through the perspective of evolution, mandates thorough examinations of the nervous systems of species in critical phylogenetic positions. We present here, a broad review of studies on the neural motor infrastructure of the lamprey, a basal and ancient vertebrate, which enjoys a unique phylogenetic position as being an extant representative of the earliest group of vertebrates. From the central pattern generators in the spinal cord to the microcircuits of the pallial cortex, work on the lamprey brain over the years, has provided detailed insights into the basic organization (a bauplan) of the ancestral vertebrate brain, and narrates a compelling account of common ancestry of fundamental aspects of the neural bases for motion control, maintained through half a billion years of vertebrate evolution. This article is part of the theme issue 'Systems neuroscience through the lens of evolutionary theory'.
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Affiliation(s)
- Shreyas M. Suryanarayana
- Department of Neuroscience, Karolinska institutet, 17177 Stockholm, Sweden
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Brita Robertson
- Department of Neuroscience, Karolinska institutet, 17177 Stockholm, Sweden
| | - Sten Grillner
- Department of Neuroscience, Karolinska institutet, 17177 Stockholm, Sweden
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12
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Applying Principles from Medicine Back to Artificial Intelligence. Artif Intell Med 2022. [DOI: 10.1007/978-3-030-64573-1_289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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13
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Barsotti E, Correia A, Cardona A. Neural architectures in the light of comparative connectomics. Curr Opin Neurobiol 2021; 71:139-149. [PMID: 34837731 PMCID: PMC8694100 DOI: 10.1016/j.conb.2021.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/20/2021] [Accepted: 10/26/2021] [Indexed: 01/06/2023]
Abstract
Since the Cambrian, animals diversified from a few body forms or bauplans, into many extinct and all extant species. A characteristic neural architecture serves each bauplan. How the connectome of each animal differs from that of closely related species or whether it converged into an optimal architecture shared with more distant ones is unknown. Recent technological innovations in molecular biology, microscopy, digital data storage and processing, and computational neuroscience have lowered the barriers for whole-brain connectomics. Comparative connectomics of suitable, relatively small, representative species across the phylogenetic tree can infer the archetypal neural architecture of each bauplan and identify any circuits that possibly converged onto a shared and potentially optimal, structure.
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Affiliation(s)
- Elizabeth Barsotti
- MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Physiology, Development and Neuroscience, University of Cambridge, UK
| | - Ana Correia
- MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Physiology, Development and Neuroscience, University of Cambridge, UK
| | - Albert Cardona
- MRC Laboratory of Molecular Biology, Cambridge, UK; Department of Physiology, Development and Neuroscience, University of Cambridge, UK.
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14
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Abstract
The olfactory system allows animals to navigate in their environment to feed, mate, and escape predators. It is well established that odorant exposure or electrical stimulation of the olfactory system induces stereotyped motor responses in fishes. However, the neural circuitry responsible for the olfactomotor transformations is only beginning to be unraveled. A neural substrate eliciting motor responses to olfactory inputs was identified in the lamprey, a basal vertebrate used extensively to examine the neural mechanisms underlying sensorimotor transformations. Two pathways were discovered from the olfactory organ in the periphery to the brainstem motor nuclei responsible for controlling swimming. The first pathway originates from sensory neurons located in the accessory olfactory organ and reaches a single population of projection neurons in the medial olfactory bulb, which, in turn, transmit the olfactory signals to the posterior tuberculum and then to downstream brainstem locomotor centers. A second pathway originates from the main olfactory epithelium and reaches the main olfactory bulb, the neurons of which project to the pallium/cortex. The olfactory signals are then conveyed to the posterior tuberculum and then to brainstem locomotor centers. Olfactomotor behavior can adapt, and studies were aimed at defining the underlying neural mechanisms. Modulation of bulbar neural activity by GABAergic, dopaminergic, and serotoninergic inputs is likely to provide strong control over the hardwired circuits to produce appropriate motor behavior in response to olfactory cues. This review summarizes current knowledge relative to the neural circuitry producing olfactomotor behavior in lampreys and their modulatory mechanisms.
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15
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Pérez-Fernández J, Barandela M, Jiménez-López C. The Dopaminergic Control of Movement-Evolutionary Considerations. Int J Mol Sci 2021; 22:11284. [PMID: 34681941 PMCID: PMC8541398 DOI: 10.3390/ijms222011284] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 12/11/2022] Open
Abstract
Dopamine is likely the most studied modulatory neurotransmitter, in great part due to characteristic motor deficits in Parkinson's disease that arise after the degeneration of the dopaminergic neurons in the substantia nigra pars compacta (SNc). The SNc, together with the ventral tegmental area (VTA), play a key role modulating motor responses through the basal ganglia. In contrast to the large amount of existing literature addressing the mammalian dopaminergic system, comparatively little is known in other vertebrate groups. However, in the last several years, numerous studies have been carried out in basal vertebrates, allowing a better understanding of the evolution of the dopaminergic system, especially the SNc/VTA. We provide an overview of existing research in basal vertebrates, mainly focusing on lampreys, belonging to the oldest group of extant vertebrates. The lamprey dopaminergic system and its role in modulating motor responses have been characterized in significant detail, both anatomically and functionally, providing the basis for understanding the evolution of the SNc/VTA in vertebrates. When considered alongside results from other early vertebrates, data in lampreys show that the key role of the SNc/VTA dopaminergic neurons modulating motor responses through the basal ganglia was already well developed early in vertebrate evolution.
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Affiliation(s)
- Juan Pérez-Fernández
- Center for Biomedical Research (CINBIO), Neurocircuits Group, Department of Functional Biology and Health Sciences, Campus Universitario Lagoas, Marcosende, Universidade de Vigo, 36310 Vigo, Spain; (M.B.); (C.J.-L.)
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16
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Hubená P, Horký P, Slavík O. Fish self-awareness: limits of current knowledge and theoretical expectations. Anim Cogn 2021; 25:447-461. [PMID: 34655023 DOI: 10.1007/s10071-021-01566-5] [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: 02/25/2021] [Revised: 09/15/2021] [Accepted: 10/08/2021] [Indexed: 10/20/2022]
Abstract
Animal self-awareness is divided into three levels: bodily, social, and introspective self-awareness. Research has focused mainly on the introspection of so-called higher organisms such as mammals. Herein, we turn our attention to fish and provide opinions on their self-awareness based on a review of the scientific literature. Our specific aims are to discuss whether fish (A) could have a neural substrate supporting self-awareness and whether they display signs of (B) social and (C) introspective self-awareness. The present knowledge does not exclude the possibility that fish could have a simple neocortex or other structures that support certain higher cognitive processes, as the function of the primate cerebral cortex can be replaced by other neurological structures. Fish are known to display winner, loser, and audience effects, which could be interpreted as signs of social self-awareness. The audience effect may be explained not only by ethological cost and benefit theory but also by the concept of public self-awareness, which comes from human studies. The behavioural and neural manifestations of depression may be induced in fish under social subordination and may be viewed as certain awareness of a social status. The current findings on fish introspective self-awareness have been debated in the scientific community and, therefore, demand replication to provide more evidence. Further research is needed to verify the outlined ideas; however, the current knowledge indicates that fish are capable of certain higher cognitive processes, which raises questions and implications regarding ethics and welfare in fish-related research and husbandry.
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Affiliation(s)
- Pavla Hubená
- Department of Zoology and Fisheries, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6, 165 00, Suchdol, Czech Republic.
| | - Pavel Horký
- Department of Zoology and Fisheries, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6, 165 00, Suchdol, Czech Republic
| | - Ondřej Slavík
- Department of Zoology and Fisheries, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6, 165 00, Suchdol, Czech Republic
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17
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Suzuki DG. Consciousness in Jawless Fishes. Front Syst Neurosci 2021; 15:751876. [PMID: 34630051 PMCID: PMC8497754 DOI: 10.3389/fnsys.2021.751876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Jawless fishes were the first vertebrates to evolve. It is thus important to investigate them to determine whether consciousness was acquired in the common ancestor of all vertebrates. Most jawless fish lineages are extinct, and cyclostomes (lampreys and hagfish) are the sole survivors. Here, I review the empirical knowledge on the neurobiology of cyclostomes with special reference to recently proposed "markers" of primary, minimal consciousness. The adult lamprey appears to meet the neuroanatomical criteria but there is a practical limitation to behavioral examination of its learning ability. In addition, the consciousness-related neuroarchitecture of larvae and its reconstruction during metamorphosis remain largely uninvestigated. Even less is known of hagfish neurobiology. The hagfish forebrain forms the central prosencephalic complex, and the homology of its components to the brain regions of other vertebrates needs to be confirmed using modern techniques. Nevertheless, as behavioral responses to olfactory stimuli in aquariums have been reported, it is easier to investigate the learning ability of the hagfish than that of the lamprey. Based on these facts, I finally discuss the potential future directions of empirical studies for examining the existence of consciousness in jawless fishes.
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Affiliation(s)
- Daichi G Suzuki
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan.,Center for Human Nature, Artificial Intelligence, and Neuroscience (CHAIN), Hokkaido University, Sapporo, Japan
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18
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Tosches MA. From Cell Types to an Integrated Understanding of Brain Evolution: The Case of the Cerebral Cortex. Annu Rev Cell Dev Biol 2021; 37:495-517. [PMID: 34416113 DOI: 10.1146/annurev-cellbio-120319-112654] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
With the discovery of the incredible diversity of neurons, Cajal and coworkers laid the foundation of modern neuroscience. Neuron types are not only structural units of nervous systems but also evolutionary units, because their identities are encoded in the genome. With the advent of high-throughput cellular transcriptomics, neuronal identities can be characterized and compared systematically across species. The comparison of neurons in mammals, reptiles, and birds indicates that the mammalian cerebral cortex is a mosaic of deeply conserved and recently evolved neuron types. Using the cerebral cortex as a case study, this review illustrates how comparing neuron types across species is key to reconciling observations on neural development, neuroanatomy, circuit wiring, and physiology for an integrated understanding of brain evolution.
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19
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Construction of Roman roads toward neuroeconomics. Behav Brain Sci 2021; 44:e130. [PMID: 34588083 DOI: 10.1017/s0140525x21000303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Neuroeconomics is still "under construction." To be a leading discipline, it needs firm ecological rationale and neurobiological bases. "Vigor" supplies this infrastructure through the mathematics of the foraging theory and system-neuroscience evidence on utility and motor control. It will prepare us for the future neuroeconomics, if studied appropriately in the light of evolution.
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20
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Güntürkün O, von Eugen K, Packheiser J, Pusch R. Avian pallial circuits and cognition: A comparison to mammals. Curr Opin Neurobiol 2021; 71:29-36. [PMID: 34562800 DOI: 10.1016/j.conb.2021.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 12/27/2022]
Abstract
Cognitive functions are similar in birds and mammals. So, are therefore pallial cellular circuits and neuronal computations also alike? In search of answers, we move in from bird's pallial connectomes, to cortex-like sensory canonical circuits and connections, to forebrain micro-circuitries and finally to the avian "prefrontal" area. This voyage from macro- to micro-scale networks and areas reveals that both birds and mammals evolved similar neural and computational properties in either convergent or parallel manner, based upon circuitries inherited from common ancestry. Thus, these two vertebrate classes evolved separately within 315 million years with highly similar pallial architectures that produce comparable cognitive functions.
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Affiliation(s)
- Onur Güntürkün
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany.
| | - Kaya von Eugen
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany
| | - Julian Packheiser
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany
| | - Roland Pusch
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany
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21
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Mallatt J, Feinberg TE. Multiple Routes to Animal Consciousness: Constrained Multiple Realizability Rather Than Modest Identity Theory. Front Psychol 2021; 12:732336. [PMID: 34630245 PMCID: PMC8497802 DOI: 10.3389/fpsyg.2021.732336] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/13/2021] [Indexed: 11/13/2022] Open
Abstract
The multiple realizability thesis (MRT) is an important philosophical and psychological concept. It says any mental state can be constructed by multiple realizability (MR), meaning in many distinct ways from different physical parts. The goal of our study is to find if the MRT applies to the mental state of consciousness among animals. Many things have been written about MRT but the ones most applicable to animal consciousness are by Shapiro in a 2004 book called The Mind Incarnate and by Polger and Shapiro in their 2016 work, The Multiple Realization Book. Standard, classical MRT has been around since 1967 and it says that a mental state can have very many different physical realizations, in a nearly unlimited manner. To the contrary, Shapiro's book reasoned that physical, physiological, and historical constraints force mental traits to evolve in just a few, limited directions, which is seen as convergent evolution of the associated neural traits in different animal lineages. This is his mental constraint thesis (MCT). We examined the evolution of consciousness in animals and found that it arose independently in just three animal clades-vertebrates, arthropods, and cephalopod mollusks-all of which share many consciousness-associated traits: elaborate sensory organs and brains, high capacity for memory, directed mobility, etc. These three constrained, convergently evolved routes to consciousness fit Shapiro's original MCT. More recently, Polger and Shapiro's book presented much the same thesis but changed its name from MCT to a "modest identity thesis." Furthermore, they argued against almost all the classically offered instances of MR in animal evolution, especially against the evidence of neural plasticity and the differently expanded cerebrums of mammals and birds. In contrast, we argue that some of these classical examples of MR are indeed valid and that Shapiro's original MCT correction of MRT is the better account of the evolution of consciousness in animal clades. And we still agree that constraints and convergence refute the standard, nearly unconstrained, MRT.
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Affiliation(s)
- Jon Mallatt
- The University of Washington WWAMI Medical Education Program at The University of Idaho, Moscow, ID, United States
| | - Todd E Feinberg
- Department of Psychiatry and Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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22
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Sugahara F, Murakami Y, Pascual-Anaya J, Kuratani S. Forebrain Architecture and Development in Cyclostomes, with Reference to the Early Morphology and Evolution of the Vertebrate Head. BRAIN, BEHAVIOR AND EVOLUTION 2021; 96:305-317. [PMID: 34537767 DOI: 10.1159/000519026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 08/12/2021] [Indexed: 11/19/2022]
Abstract
The vertebrate head and brain are characterized by highly complex morphological patterns. The forebrain, the most anterior division of the brain, is subdivided into the diencephalon, hypothalamus, and telencephalon from the neuromeric subdivision into prosomeres. Importantly, the telencephalon contains the cerebral cortex, which plays a key role in higher order cognitive functions in humans. To elucidate the evolution of the forebrain regionalization, comparative analyses of the brain development between extant jawed and jawless vertebrates are crucial. Cyclostomes - lampreys and hagfishes - are the only extant jawless vertebrates, and diverged from jawed vertebrates (gnathostomes) over 500 million years ago. Previous developmental studies on the cyclostome brain were conducted mainly in lampreys because hagfish embryos were rarely available. Although still scarce, the recent availability of hagfish embryos has propelled comparative studies of brain development and gene expression. By integrating findings with those of cyclostomes and fossil jawless vertebrates, we can depict the morphology, developmental mechanism, and even the evolutionary path of the brain of the last common ancestor of vertebrates. In this review, we summarize the development of the forebrain in cyclostomes and suggest what evolutionary changes each cyclostome lineage underwent during brain evolution. In addition, together with recent advances in the head morphology in fossil vertebrates revealed by CT scanning technology, we discuss how the evolution of craniofacial morphology and the changes of the developmental mechanism of the forebrain towards crown gnathostomes are causally related.
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Affiliation(s)
- Fumiaki Sugahara
- Division of Biology, Hyogo College of Medicine, Nishinomiya, Japan.,Evolutionary Morphology Laboratory, RIKEN Cluster for Pioneering Research (CPR), Kobe, Japan
| | - Yasunori Murakami
- Graduate School of Science and Engineering, Ehime University, Matsuyama, Japan
| | - Juan Pascual-Anaya
- Evolutionary Morphology Laboratory, RIKEN Cluster for Pioneering Research (CPR), Kobe, Japan.,Department of Animal Biology, Faculty of Science, University of Málaga, Málaga, Spain.,Andalusian Centre for Nanomedicine and Biotechnology (BIONAND), Málaga, Spain
| | - Shigeru Kuratani
- Evolutionary Morphology Laboratory, RIKEN Cluster for Pioneering Research (CPR), Kobe, Japan.,Laboratory for Evolutionary Morphology, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
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23
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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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24
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Cortical control of behavior and attention from an evolutionary perspective. Neuron 2021; 109:3048-3054. [PMID: 34297915 DOI: 10.1016/j.neuron.2021.06.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/12/2021] [Accepted: 06/16/2021] [Indexed: 11/22/2022]
Abstract
For animals to survive, they must interact with their environment, taking in sensory information and making appropriate motor responses. Early on during vertebrate evolution, this was accomplished with neural circuits located mostly within the spinal cord and brainstem. As the cerebral cortex evolved, it provided additional and powerful advantages for assessing environmental cues and guiding appropriate responses. Importantly, the cerebral cortex was added onto an already functional nervous system. Moreover, every cortical area, including areas traditionally considered sensory, provides input to the subcortical motor structures that are bottlenecks for driving action. These facts have important ramifications for cognitive aspects of motor control. Here we consider the evolution of cortical mechanisms for attention from the perspective of having to work through these subcortical bottlenecks. From this perspective, many features of attention can be explained, including the preferential engagement of some cortical areas at the cost of disengagement from others to improve appropriate behavioral responses.
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25
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Suryanarayana SM, Pérez-Fernández J, Robertson B, Grillner S. The Lamprey Forebrain - Evolutionary Implications. BRAIN, BEHAVIOR AND EVOLUTION 2021; 96:318-333. [PMID: 34192700 DOI: 10.1159/000517492] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/26/2021] [Indexed: 12/20/2022]
Abstract
The forebrain plays a critical role in a broad range of neural processes encompassing sensory integration and initiation/selection of behaviour. The forebrain functions through an interaction between different cortical areas, the thalamus, the basal ganglia with the dopamine system, and the habenulae. The ambition here is to compare the mammalian forebrain with that of the lamprey representing the oldest now living group of vertebrates, by a review of earlier studies. We show that the lamprey dorsal pallium has a motor, a somatosensory, and a visual area with retinotopic representation. The lamprey pallium was previously thought to be largely olfactory. There is also a detailed similarity between the lamprey and mammals with regard to other forebrain structures like the basal ganglia in which the general organisation, connectivity, transmitters and their receptors, neuropeptides, and expression of ion channels are virtually identical. These initially unexpected results allow for the possibility that many aspects of the basic design of the vertebrate forebrain had evolved before the lamprey diverged from the evolutionary line leading to mammals. Based on a detailed comparison between the mammalian forebrain and that of the lamprey and with due consideration of data from other vertebrate groups, we propose a compelling account of a pan-vertebrate schema for basic forebrain structures, suggesting a common ancestry of over half a billion years of vertebrate evolution.
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Affiliation(s)
- Shreyas M Suryanarayana
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden.,Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Juan Pérez-Fernández
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden.,CINBIO, Universidade de Vigo, Campus Universitario Lagoas, Vigo, Spain
| | - Brita Robertson
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Sten Grillner
- Department of Neuroscience, Karolinska Institutet, Solna, Sweden
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26
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Striedter GF, Northcutt RG. The Independent Evolution of Dorsal Pallia in Multiple Vertebrate Lineages. BRAIN, BEHAVIOR AND EVOLUTION 2021; 96:200-211. [PMID: 34175847 DOI: 10.1159/000516563] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/06/2021] [Indexed: 11/19/2022]
Abstract
Comparative neurobiologists have long wondered when and how the dorsal pallium (e.g., mammalian neocortex) evolved. For the last 50 years, the most widely accepted answer has been that this structure was already present in the earliest vertebrates and, therefore, homologous between the major vertebrate lineages. One challenge for this hypothesis is that the olfactory bulbs project throughout most of the pallium in the most basal vertebrate lineages (notably lampreys, hagfishes, and lungfishes) but do not project to the putative dorsal pallia in teleosts, cartilaginous fishes, and amniotes (i.e., reptiles, birds, and mammals). To make sense of these data, one may hypothesize that a dorsal pallium existed in the earliest vertebrates and received extensive olfactory input, which was subsequently lost in several lineages. However, the dorsal pallium is notoriously difficult to delineate in many vertebrates, and its homology between the various lineages is often based on little more than its topology. Therefore, we suspect that dorsal pallia evolved independently in teleosts, cartilaginous fishes, and amniotes. We further hypothesize that the emergence of these dorsal pallia was accompanied by the phylogenetic restriction of olfactory projections to the pallium and the expansion of inputs from other sensory modalities. We do not deny that the earliest vertebrates may have possessed nonolfactory sensory inputs to some parts of the pallium, but such projections alone do not define a dorsal pallium.
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Affiliation(s)
- Georg F Striedter
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, California, USA
| | - R Glenn Northcutt
- Scripps Institution of Oceanography and Department of Neurosciences, School of Medicine, University of California San Diego, La Jolla, California, USA
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27
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Safron A. The Radically Embodied Conscious Cybernetic Bayesian Brain: From Free Energy to Free Will and Back Again. ENTROPY (BASEL, SWITZERLAND) 2021; 23:783. [PMID: 34202965 PMCID: PMC8234656 DOI: 10.3390/e23060783] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 05/12/2021] [Accepted: 05/27/2021] [Indexed: 11/24/2022]
Abstract
Drawing from both enactivist and cognitivist perspectives on mind, I propose that explaining teleological phenomena may require reappraising both "Cartesian theaters" and mental homunculi in terms of embodied self-models (ESMs), understood as body maps with agentic properties, functioning as predictive-memory systems and cybernetic controllers. Quasi-homuncular ESMs are suggested to constitute a major organizing principle for neural architectures due to their initial and ongoing significance for solutions to inference problems in cognitive (and affective) development. Embodied experiences provide foundational lessons in learning curriculums in which agents explore increasingly challenging problem spaces, so answering an unresolved question in Bayesian cognitive science: what are biologically plausible mechanisms for equipping learners with sufficiently powerful inductive biases to adequately constrain inference spaces? Drawing on models from neurophysiology, psychology, and developmental robotics, I describe how embodiment provides fundamental sources of empirical priors (as reliably learnable posterior expectations). If ESMs play this kind of foundational role in cognitive development, then bidirectional linkages will be found between all sensory modalities and frontal-parietal control hierarchies, so infusing all senses with somatic-motoric properties, thereby structuring all perception by relevant affordances, so solving frame problems for embodied agents. Drawing upon the Free Energy Principle and Active Inference framework, I describe a particular mechanism for intentional action selection via consciously imagined (and explicitly represented) goal realization, where contrasts between desired and present states influence ongoing policy selection via predictive coding mechanisms and backward-chained imaginings (as self-realizing predictions). This embodied developmental legacy suggests a mechanism by which imaginings can be intentionally shaped by (internalized) partially-expressed motor acts, so providing means of agentic control for attention, working memory, imagination, and behavior. I further describe the nature(s) of mental causation and self-control, and also provide an account of readiness potentials in Libet paradigms wherein conscious intentions shape causal streams leading to enaction. Finally, I provide neurophenomenological handlings of prototypical qualia including pleasure, pain, and desire in terms of self-annihilating free energy gradients via quasi-synesthetic interoceptive active inference. In brief, this manuscript is intended to illustrate how radically embodied minds may create foundations for intelligence (as capacity for learning and inference), consciousness (as somatically-grounded self-world modeling), and will (as deployment of predictive models for enacting valued goals).
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Affiliation(s)
- Adam Safron
- Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD 21218, USA;
- Kinsey Institute, Indiana University, Bloomington, IN 47405, USA
- Cognitive Science Program, Indiana University, Bloomington, IN 47405, USA
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28
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Spool JA, Macedo-Lima M, Scarpa G, Morohashi Y, Yazaki-Sugiyama Y, Remage-Healey L. Genetically identified neurons in avian auditory pallium mirror core principles of their mammalian counterparts. Curr Biol 2021; 31:2831-2843.e6. [PMID: 33989528 DOI: 10.1016/j.cub.2021.04.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/12/2021] [Accepted: 04/15/2021] [Indexed: 12/21/2022]
Abstract
In vertebrates, advanced cognitive abilities are typically associated with the telencephalic pallium. In mammals, the pallium is a layered mixture of excitatory and inhibitory neuronal populations with distinct molecular, physiological, and network phenotypes. This cortical architecture is proposed to support efficient, high-level information processing. Comparative perspectives across vertebrates provide a lens to understand the common features of pallium that are important for advanced cognition. Studies in songbirds have established strikingly parallel features of neuronal types between mammalian and avian pallium. However, lack of genetic access to defined pallial cell types in non-mammalian vertebrates has hindered progress in resolving connections between molecular and physiological phenotypes. A definitive mapping of the physiology of pallial cells onto their molecular identities in birds is critical for understanding how synaptic and computational properties depend on underlying molecular phenotypes. Using viral tools to target excitatory versus inhibitory neurons in the zebra finch auditory association pallium (calmodulin-dependent kinase alpha [CaMKIIα] and glutamate decarboxylase 1 [GAD1] promoters, respectively), we systematically tested predictions derived from mammalian pallium. We identified two genetically distinct neuronal populations that exhibit profound physiological and computational similarities with mammalian excitatory and inhibitory pallial cells, definitively aligning putative cell types in avian caudal nidopallium with these molecular identities. Specifically, genetically identified CaMKIIα and GAD1 cell types in avian auditory association pallium exhibit distinct intrinsic physiological parameters, distinct auditory coding principles, and inhibitory-dependent pallial synchrony, gamma oscillations, and local suppression. The retention, or convergence, of these molecular and physiological features in both birds and mammals clarifies the characteristics of pallial circuits for advanced cognitive abilities.
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Affiliation(s)
- Jeremy A Spool
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA 01003, USA
| | - Matheus Macedo-Lima
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA 01003, USA; CAPES Foundation, Ministry of Education of Brazil, Brasília 70040-020, Brazil
| | - Garrett Scarpa
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA 01003, USA
| | - Yuichi Morohashi
- Okinawa Institute of Science and Technology (OIST) Graduate University, Okinawa, Japan
| | - Yoko Yazaki-Sugiyama
- Okinawa Institute of Science and Technology (OIST) Graduate University, Okinawa, Japan
| | - Luke Remage-Healey
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, MA 01003, USA.
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Lorenzi E, Perrino M, Vallortigara G. Numerosities and Other Magnitudes in the Brains: A Comparative View. Front Psychol 2021; 12:641994. [PMID: 33935896 PMCID: PMC8082025 DOI: 10.3389/fpsyg.2021.641994] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/12/2021] [Indexed: 01/29/2023] Open
Abstract
The ability to represent, discriminate, and perform arithmetic operations on discrete quantities (numerosities) has been documented in a variety of species of different taxonomic groups, both vertebrates and invertebrates. We do not know, however, to what extent similarity in behavioral data corresponds to basic similarity in underlying neural mechanisms. Here, we review evidence for magnitude representation, both discrete (countable) and continuous, following the sensory input path from primary sensory systems to associative pallial territories in the vertebrate brains. We also speculate on possible underlying mechanisms in invertebrate brains and on the role played by modeling with artificial neural networks. This may provide a general overview on the nervous system involvement in approximating quantity in different animal species, and a general theoretical framework to future comparative studies on the neurobiology of number cognition.
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Affiliation(s)
- Elena Lorenzi
- Centre for Mind/Brain Science, CIMeC, University of Trento, Rovereto, Italy
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30
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Causal cognitive architecture 1: Integration of connectionist elements into a navigation-based framework. COGN SYST RES 2021. [DOI: 10.1016/j.cogsys.2020.10.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Sobrido-Cameán D, Yáñez-Guerra LA, Deber A, Freire-Delgado M, Cacheiro-Vázquez R, Rodicio MC, Tostivint H, Anadón R, Barreiro-Iglesias A. Differential expression of somatostatin genes in the central nervous system of the sea lamprey. Brain Struct Funct 2021; 226:1031-1052. [PMID: 33532926 DOI: 10.1007/s00429-021-02224-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/19/2021] [Indexed: 01/29/2023]
Abstract
The identification of three somatostatin (SST) genes (SSTa, SSTb, and SSTc) in lampreys (Tostivint et al. Gen Comp Endocrinol 237:89-97 https://doi.org/10.1016/j.ygcen.2016.08.006 , 2016) prompted us to study their expression in the brain and spinal cord of the sea lamprey by in situ hybridization. These three genes were only expressed in equivalent neuronal populations in the hypothalamus. In other regions, SST transcripts showed clear differential expression. In the telencephalon, SSTc-positive cells were observed in the medial pallium, ventral part of the lateral pallium, striatum, subhippocampal lobe, and preoptic region. In the diencephalon, SSTa-positive cells were observed in the thalamus and SSTc-positive cells in the prethalamus, posterior tubercle, pretectal area, and nucleus of the medial longitudinal fascicle. In the midbrain, SSTc-positive cells were observed in the torus semicircularis, lateral reticular area, and perioculomotor tegmentum. Different SSTa- and SSTc-positive populations were observed in the isthmus. SSTc neurons were also observed in the rostral octavolateralis area and caudal rhombencephalon. In the spinal cord, SSTa was expressed in cerebrospinal-fluid-contacting (CSF-c) neurons and SSTc in non-CSF-c interneurons. Comparison with previous immunohistochemical studies using anti-SST-14 antibodies strongly suggests that SST-14-like neurons correspond with the SSTa populations. Thus, the SSTc populations were not reported previously in immunohistochemical studies. Cluster-based analyses and alignments of mature peptides suggested that SSTa is an ortholog of SST1 and that SSTb is closely related to SST2 and SST6. These results provide important new insights into the evolution of the somatostatinergic system in vertebrates.
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Affiliation(s)
- D Sobrido-Cameán
- Department of Functional Biology, Faculty of Biology, CIBUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, A Coruña, Spain.,Department of Zoology, University of Cambridge, Cambridge, UK
| | | | - A Deber
- Department of Functional Biology, Faculty of Biology, CIBUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, A Coruña, Spain
| | - M Freire-Delgado
- Department of Functional Biology, Faculty of Biology, CIBUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, A Coruña, Spain
| | - R Cacheiro-Vázquez
- Department of Functional Biology, Faculty of Biology, CIBUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, A Coruña, Spain
| | - M C Rodicio
- Department of Functional Biology, Faculty of Biology, CIBUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, A Coruña, Spain
| | - H Tostivint
- Molecular Physiology and Adaptation, UMR7221, CNRS and Muséum National D'Histoire Naturelle, Paris, France
| | - R Anadón
- Department of Functional Biology, Faculty of Biology, CIBUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, A Coruña, Spain
| | - A Barreiro-Iglesias
- Department of Functional Biology, Faculty of Biology, CIBUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, A Coruña, Spain.
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32
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Ebbesson SOE. How the parcellation theory of comparative forebrain specialization emerged from the Division of Neuropsychiatry at the Walter Reed Army Institute of Research. JOURNAL OF THE HISTORY OF THE NEUROSCIENCES 2021; 30:24-55. [PMID: 32511057 DOI: 10.1080/0964704x.2020.1763759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The Golgi method gave birth to modern neuroscience. The Nauta method, developed in a novel Army think tank at the Walter Reed Army Medical Center, was the next major breakthrough before neuroscience emerged as a separate discipline. Dr. Walle Nauta's (1916-1994) method allowed for the first time the ability to trace interneuronal connections accurately to their termination. The think tank, created by Dr. David Rioch (1900-1985), provided a unique intellectual environment for interdisciplinary neuroscience research, the first of its kind. Rioch hired exceptional senior faculty and recruited outstanding young investigators who were drafted into the Army, typically after finishing their M.D.s or Ph.D.s, and were interested in brain research. Many of these young investigators went on to illustrious careers in neuroscience. I worked with Walle Nauta at a time when the technique was first being applied to nonmammalian vertebrate brains. Along with other Army draftees, I was encouraged to pursue my own research interests. This led me on a quest to understand interspecific variability of connections in relation to evolution and ontogeny of the brain. By 1980, I had found that the variability of all known connections could be explained by a theory to the effect that new structures such as the neocortex were not formed by one system invading another and mingling, as Clarence Luther Herrick (1858-1904) had proposed, but by selective proliferation and differentiation sometimes involving the select loss of connections to reduce cross-modality interference as in the case of the parcellation and differentiation of cortical areas. The resulting parcellation theory predicts that elements of a primordial neocortex existed from the beginning of vertebrate evolution and did not originate by an invasion of nonolfactory modalities into the olfactory lobe, as commonly believed before the introduction of the Nauta method. This theory would not have been created if it were not for the brilliant environment that was Walter Reed in the 1960s.
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Affiliation(s)
- Sven O E Ebbesson
- Professor Emeritus, University of Alaska Fairbanks , Fairbanks, Alaska, USA
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Suryanarayana SM, Pérez-Fernández J, Robertson B, Grillner S. Olfaction in Lamprey Pallium Revisited-Dual Projections of Mitral and Tufted Cells. Cell Rep 2021; 34:108596. [PMID: 33406414 DOI: 10.1016/j.celrep.2020.108596] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/19/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
The presence of two separate afferent channels from the olfactory glomeruli to different targets in the brain is unravelled in the lamprey. The mitral-like cells send axonal projections directly to the piriform cortex in the ventral part of pallium, whereas the smaller tufted-like cells project separately and exclusively to a relay nucleus called the dorsomedial telencephalic nucleus (dmtn). This nucleus, located at the interface between the olfactory bulb and pallium, in turn projects to a circumscribed area in the anteromedial, ventral part of pallium. The tufted-like cells are activated with short latency from the olfactory nerve and terminate with mossy fibers on the dmtn cells, wherein they elicit large unitary excitatory postsynaptic potentials (EPSPs). In all synapses along this tufted-like cell pathway, there is no concurrent inhibition, in contrast to the mitral-like cell pathway. This is similar to recent findings in rodents establishing two separate exclusive projection patterns, suggesting an evolutionarily conserved organization.
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Affiliation(s)
| | - Juan Pérez-Fernández
- Department of Neuroscience, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden
| | - Brita Robertson
- Department of Neuroscience, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden
| | - Sten Grillner
- Department of Neuroscience, Karolinska Institutet, Solnavägen 9, 171 65 Solna, Sweden.
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34
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Applying Principles from Medicine Back to Artificial Intelligence. Artif Intell Med 2021. [DOI: 10.1007/978-3-030-58080-3_289-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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35
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Grillner S, Robertson B, Kotaleski JH. Basal Ganglia—A Motion Perspective. Compr Physiol 2020; 10:1241-1275. [DOI: 10.1002/cphy.c190045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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36
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The evolutionary origin of visual and somatosensory representation in the vertebrate pallium. Nat Ecol Evol 2020; 4:639-651. [DOI: 10.1038/s41559-020-1137-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 02/05/2020] [Indexed: 12/16/2022]
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37
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Cholecystokinin in the central nervous system of the sea lamprey Petromyzon marinus: precursor identification and neuroanatomical relationships with other neuronal signalling systems. Brain Struct Funct 2019; 225:249-284. [PMID: 31807925 DOI: 10.1007/s00429-019-01999-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 11/27/2019] [Indexed: 12/23/2022]
Abstract
Cholecystokinin (CCK) is a neuropeptide that modulates processes such as digestion, satiety, and anxiety. CCK-type peptides have been characterized in jawed vertebrates and invertebrates, but little is known about CCK-type signalling in the most ancient group of vertebrates, the agnathans. Here, we have cloned and sequenced a cDNA encoding a sea lamprey (Petromyzon marinus L.) CCK-type precursor (PmCCK), which contains a CCK-type octapeptide sequence (PmCCK-8) that is highly similar to gnathostome CCKs. Using mRNA in situ hybridization, the distribution of PmCCK-expressing neurons was mapped in the CNS of P. marinus. This revealed PmCCK-expressing neurons in the hypothalamus, posterior tubercle, prethalamus, nucleus of the medial longitudinal fasciculus, midbrain tegmentum, isthmus, rhombencephalic reticular formation, and the putative nucleus of the solitary tract. Some PmCCK-expressing neuronal populations were only observed in adults, revealing important differences with larvae. We generated an antiserum to PmCCK-8 to enable immunohistochemical analysis of CCK expression, which revealed that GABA or glutamate, but not serotonin, tyrosine hydroxylase or neuropeptide Y, is co-expressed in some PmCCK-8-immunoreactive (ir) neurons. Importantly, this is the first demonstration of co-localization of GABA and CCK in neurons of a non-mammalian vertebrate. We also characterized extensive cholecystokinergic fibre systems of the CNS, including innervation of habenular subnuclei. A conspicuous PmCCK-8-ir tract ascending in the lateral rhombencephalon selectively innervates a glutamatergic population in the dorsal isthmic grey. Interestingly, this tract is reminiscent of the secondary gustatory/visceral tract of teleosts. In conclusion, this study provides important new information on the evolution of the cholecystokinergic system in vertebrates.
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38
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Fernández M, Morales C, Durán E, Fernández‐Colleman S, Sentis E, Mpodozis J, Karten HJ, Marín GJ. Parallel organization of the avian sensorimotor arcopallium: Tectofugal visual pathway in the pigeon (
Columba livia
). J Comp Neurol 2019; 528:597-623. [DOI: 10.1002/cne.24775] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Máximo Fernández
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | - Cristian Morales
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | - Ernesto Durán
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | | | - Elisa Sentis
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | - Jorge Mpodozis
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
| | - Harvey J. Karten
- Department of Neurosciences, School of MedicineUniversity of California San Diego California
| | - Gonzalo J. Marín
- Departamento de Biología, Facultad de CienciasUniversidad de Chile Santiago Chile
- Facultad de MedicinaUniversidad Finis Terrae Santiago Chile
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39
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Grillner S, El Manira A. Current Principles of Motor Control, with Special Reference to Vertebrate Locomotion. Physiol Rev 2019; 100:271-320. [PMID: 31512990 DOI: 10.1152/physrev.00015.2019] [Citation(s) in RCA: 238] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vertebrate control of locomotion involves all levels of the nervous system from cortex to the spinal cord. Here, we aim to cover all main aspects of this complex behavior, from the operation of the microcircuits in the spinal cord to the systems and behavioral levels and extend from mammalian locomotion to the basic undulatory movements of lamprey and fish. The cellular basis of propulsion represents the core of the control system, and it involves the spinal central pattern generator networks (CPGs) controlling the timing of different muscles, the sensory compensation for perturbations, and the brain stem command systems controlling the level of activity of the CPGs and the speed of locomotion. The forebrain and in particular the basal ganglia are involved in determining which motor programs should be recruited at a given point of time and can both initiate and stop locomotor activity. The propulsive control system needs to be integrated with the postural control system to maintain body orientation. Moreover, the locomotor movements need to be steered so that the subject approaches the goal of the locomotor episode, or avoids colliding with elements in the environment or simply escapes at high speed. These different aspects will all be covered in the review.
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Affiliation(s)
- Sten Grillner
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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40
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Abstract
The neural circuits that control elasmobranch fins and the mammalian limbs have been found to exhibit striking similarities at the molecular, cellular and behavioral levels. The implication is that the neural substrate underlying limb control had already evolved 420 million years ago.
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Affiliation(s)
- Sten Grillner
- Department of Neuroscience, Karolinska Institutet, SE-17177 Stockholm, Sweden.
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41
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Abstract
The dramatic evolutionary expansion of the neocortex, together with a proliferation of specialized cortical areas, is believed to underlie the emergence of human cognitive abilities. In a broader phylogenetic context, however, neocortex evolution in mammals, including humans, is remarkably conservative, characterized largely by size variations on a shared six-layered neuronal architecture. By contrast, the telencephalon in non-mammalian vertebrates, including reptiles, amphibians, bony and cartilaginous fishes, and cyclostomes, features a great variety of very different tissue structures. Our understanding of the evolutionary relationships of these telencephalic structures, especially those of basally branching vertebrates and invertebrate chordates, remains fragmentary and is impeded by conceptual obstacles. To make sense of highly divergent anatomies requires a hierarchical view of biological organization, one that permits the recognition of homologies at multiple levels beyond neuroanatomical structure. Here we review the origin and diversification of the telencephalon with a focus on key evolutionary innovations shaping the neocortex at multiple levels of organization.
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Affiliation(s)
- Steven D Briscoe
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
| | - Clifton W Ragsdale
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA; Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
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42
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Tosches MA, Laurent G. Evolution of neuronal identity in the cerebral cortex. Curr Opin Neurobiol 2019; 56:199-208. [PMID: 31103814 DOI: 10.1016/j.conb.2019.04.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 03/04/2019] [Accepted: 04/22/2019] [Indexed: 12/20/2022]
Abstract
To understand neocortex evolution, we must define a theory for the elaboration of cell types, circuits, and architectonics from an ancestral structure that is consistent with developmental, molecular, and genetic data. To this end, cross-species comparison of cortical cell types emerges as a very informative approach. We review recent results that illustrate the contribution of molecular and transcriptomic data to the construction of plausible models of cortical cell-type evolution.
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Affiliation(s)
| | - Gilles Laurent
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
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43
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44
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Binks D, Watson C, Puelles L. A Re-evaluation of the Anatomy of the Claustrum in Rodents and Primates-Analyzing the Effect of Pallial Expansion. Front Neuroanat 2019; 13:34. [PMID: 30971901 PMCID: PMC6443842 DOI: 10.3389/fnana.2019.00034] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 03/06/2019] [Indexed: 12/15/2022] Open
Abstract
The components of the claustrum have been identified by gene expression in mice, but there is still uncertainty about the location of homologous components in primates. To aid interpretation of homologous elements between rodents and primates, we used a current understanding of pallial topology, species-specific telencephalic deformation, and gene expression data. In both rodents and primates, pallial areas maintain conserved topological relationships regardless of relative differences in pallial expansion. The components of the claustrum in primates can, therefore, be identified on the basis of their conserved topological relationships and patterns of gene expression. In rodents, a fairly straight telencephalic long axis runs between the early septopreoptic and amygdalar poles of the pallium. In primates, however, the remarkable dorsal pallial expansion causes this axis to be distorted to form a C shape. This has resulted in a number of errors in the interpretation of the location of claustral components. These errors are likely to have resulted from the unexpected topographical positioning of claustral components due to the bent telencephalic axis. We argue that, once the telencephalic distortion has been accounted for, both rodents and primates have homologous claustral components, and that the topological relationships of these components are conserved regardless of differences in the relative expansion of pallial areas.
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Affiliation(s)
- Daniel Binks
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia.,The Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Charles Watson
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Luis Puelles
- Department of Human Anatomy and IMIB-Arrixaca Institute, School of Medicine, University of Murcia, El Palmar, Spain
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45
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Shepherd GM, Marenco L, Hines ML, Migliore M, McDougal RA, Carnevale NT, Newton AJH, Surles-Zeigler M, Ascoli GA. Neuron Names: A Gene- and Property-Based Name Format, With Special Reference to Cortical Neurons. Front Neuroanat 2019; 13:25. [PMID: 30949034 DOI: 10.3389/fnana.2019.00025/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/07/2019] [Indexed: 05/25/2023] Open
Abstract
Precision in neuron names is increasingly needed. We are entering a new era in which classical anatomical criteria are only the beginning toward defining the identity of a neuron as carried in its name. New criteria include patterns of gene expression, membrane properties of channels and receptors, pharmacology of neurotransmitters and neuropeptides, physiological properties of impulse firing, and state-dependent variations in expression of characteristic genes and proteins. These gene and functional properties are increasingly defining neuron types and subtypes. Clarity will therefore be enhanced by conveying as much as possible the genes and properties in the neuron name. Using a tested format of parent-child relations for the region and subregion for naming a neuron, we show how the format can be extended so that these additional properties can become an explicit part of a neuron's identity and name, or archived in a linked properties database. Based on the mouse, examples are provided for neurons in several brain regions as proof of principle, with extension to the complexities of neuron names in the cerebral cortex. The format has dual advantages, of ensuring order in archiving the hundreds of neuron types across all brain regions, as well as facilitating investigation of a given neuron type or given gene or property in the context of all its properties. In particular, we show how the format is extensible to the variety of neuron types and subtypes being revealed by RNA-seq and optogenetics. As current research reveals increasingly complex properties, the proposed approach can facilitate a consensus that goes beyond traditional neuron types.
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Affiliation(s)
- Gordon M Shepherd
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Luis Marenco
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Michael L Hines
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Michele Migliore
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Robert A McDougal
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Nicholas T Carnevale
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Adam J H Newton
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, NY, United States
| | - Monique Surles-Zeigler
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Giorgio A Ascoli
- Bioengineering Department and Center for Neural Informatics, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
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46
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Shepherd GM, Marenco L, Hines ML, Migliore M, McDougal RA, Carnevale NT, Newton AJH, Surles-Zeigler M, Ascoli GA. Neuron Names: A Gene- and Property-Based Name Format, With Special Reference to Cortical Neurons. Front Neuroanat 2019; 13:25. [PMID: 30949034 PMCID: PMC6437103 DOI: 10.3389/fnana.2019.00025] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/07/2019] [Indexed: 12/15/2022] Open
Abstract
Precision in neuron names is increasingly needed. We are entering a new era in which classical anatomical criteria are only the beginning toward defining the identity of a neuron as carried in its name. New criteria include patterns of gene expression, membrane properties of channels and receptors, pharmacology of neurotransmitters and neuropeptides, physiological properties of impulse firing, and state-dependent variations in expression of characteristic genes and proteins. These gene and functional properties are increasingly defining neuron types and subtypes. Clarity will therefore be enhanced by conveying as much as possible the genes and properties in the neuron name. Using a tested format of parent-child relations for the region and subregion for naming a neuron, we show how the format can be extended so that these additional properties can become an explicit part of a neuron's identity and name, or archived in a linked properties database. Based on the mouse, examples are provided for neurons in several brain regions as proof of principle, with extension to the complexities of neuron names in the cerebral cortex. The format has dual advantages, of ensuring order in archiving the hundreds of neuron types across all brain regions, as well as facilitating investigation of a given neuron type or given gene or property in the context of all its properties. In particular, we show how the format is extensible to the variety of neuron types and subtypes being revealed by RNA-seq and optogenetics. As current research reveals increasingly complex properties, the proposed approach can facilitate a consensus that goes beyond traditional neuron types.
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Affiliation(s)
- Gordon M. Shepherd
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Luis Marenco
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Michael L. Hines
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
| | - Michele Migliore
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Robert A. McDougal
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | | | - Adam J. H. Newton
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, NY, United States
| | - Monique Surles-Zeigler
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, United States
- Yale Center for Medical Informatics, New Haven, CT, United States
| | - Giorgio A. Ascoli
- Bioengineering Department and Center for Neural Informatics, Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, United States
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Puelles L, Alonso A, García-Calero E, Martínez-de-la-Torre M. Concentric ring topology of mammalian cortical sectors and relevance for patterning studies. J Comp Neurol 2019; 527:1731-1752. [PMID: 30737959 DOI: 10.1002/cne.24650] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 01/05/2019] [Accepted: 01/28/2019] [Indexed: 01/07/2023]
Abstract
Models aiming to explain causally the evolutionary or ontogenetic emergence of the pallial isocortex and its regional/areal heterogeneity in mammals use simple or complex assumptions about the pallial structure present in basal mammals and nonmammals. The question arises: how complex is the pattern that needs to be accounted for in causal models? This topic is also paramount for comparative purposes, since some topological relationships may be explained as being ancestral, rather than newly emerged. The mouse pallium is apt to be reexamined in this context, due to the breadth of available molecular markers and correlative experimental patterning results. We center the present essay on a recapitulative glance at the classic theory of concentric mammalian allo-, meso-, and neocortex domains. In its simplest terms, this theory postulates a central neocortical island (6 layers) separated by a surrounding mesocortical ring (4-5 layers) from a peripheral allocortical ring (3 layers). These territories show additional partition into regional or areal subdivisions. There are also borderline amygdalar, claustral, and septal areas of the pallium, nuclear in structure. There has been little effort so far to contemplate the full concentric ring model in current "cortex patterning" models. In this essay, we recapitulate the ring idea in mammals (mouse) and consider a potential causal patterning scenario using topologic models. Finally, we briefly explore how far this theory may apply to pallium models proposed recently for sauropsids.
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Affiliation(s)
- Luis Puelles
- Department of Human Anatomy and IMIB-Arrixaca Institute, School of Medicine, University of Murcia, Murcia, Spain
| | - Antonia Alonso
- Department of Human Anatomy and IMIB-Arrixaca Institute, School of Medicine, University of Murcia, Murcia, Spain
| | - Elena García-Calero
- Department of Human Anatomy and IMIB-Arrixaca Institute, School of Medicine, University of Murcia, Murcia, Spain
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Daghfous G, Auclair F, Clotten F, Létourneau JL, Atallah E, Millette JP, Derjean D, Robitaille R, Zielinski BS, Dubuc R. GABAergic modulation of olfactomotor transmission in lampreys. PLoS Biol 2018; 16:e2005512. [PMID: 30286079 PMCID: PMC6191151 DOI: 10.1371/journal.pbio.2005512] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 10/16/2018] [Accepted: 09/18/2018] [Indexed: 12/21/2022] Open
Abstract
Odor-guided behaviors, including homing, predator avoidance, or food and mate searching, are ubiquitous in animals. It is only recently that the neural substrate underlying olfactomotor behaviors in vertebrates was uncovered in lampreys. It consists of a neural pathway extending from the medial part of the olfactory bulb (medOB) to locomotor control centers in the brainstem via a single relay in the caudal diencephalon. This hardwired olfactomotor pathway is present throughout life and may be responsible for the olfactory-induced motor behaviors seen at all life stages. We investigated modulatory mechanisms acting on this pathway by conducting anatomical (tract tracing and immunohistochemistry) and physiological (intracellular recordings and calcium imaging) experiments on lamprey brain preparations. We show that the GABAergic circuitry of the olfactory bulb (OB) acts as a gatekeeper of this hardwired sensorimotor pathway. We also demonstrate the presence of a novel olfactomotor pathway that originates in the non-medOB and consists of a projection to the lateral pallium (LPal) that, in turn, projects to the caudal diencephalon and to the mesencephalic locomotor region (MLR). Our results indicate that olfactory inputs can induce behavioral responses by activating brain locomotor centers via two distinct pathways that are strongly modulated by GABA in the OB. The existence of segregated olfactory subsystems in lampreys suggests that the organization of the olfactory system in functional clusters may be a common ancestral trait of vertebrates.
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Affiliation(s)
- Gheylen Daghfous
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, Québec, Canada
| | - François Auclair
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Felix Clotten
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Jean-Luc Létourneau
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, Québec, Canada
| | - Elias Atallah
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Jean-Patrick Millette
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Dominique Derjean
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, Québec, Canada
| | - Richard Robitaille
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
| | - Barbara S. Zielinski
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada
- Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada
| | - Réjean Dubuc
- Groupe de Recherche sur le Système Nerveux Central, Département de neurosciences, Université de Montréal, Montréal, Québec, Canada
- Groupe de Recherche en Activité Physique Adaptée, Département des sciences de l'activité physique, Université du Québec à Montréal, Montréal, Québec, Canada
- * E-mail:
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Takagi S, Nose A. Circuit architecture for somatotopic action selection in invertebrates. Neurosci Res 2018; 140:37-42. [PMID: 30130542 DOI: 10.1016/j.neures.2018.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/06/2018] [Accepted: 08/10/2018] [Indexed: 11/24/2022]
Abstract
Invertebrate species have significantly contributed to neuroscience owing to the accessibility they provide to cellular- and molecular-level understanding of brain functions. Somatotopic action selection is one of the key features of animal behavior, and studying this process in invertebrates is potentially a sweet spot in understanding the general relationship between neuronal morphology, circuit structure, and animal behavior. In this review, we introduce circuit architectures that realize somatotopic action selection, from simple reflexes to patterned motor outputs, in different invertebrate species. We then discuss future directions towards understanding the general principles underlying the development and evolution of the circuit architecture that enables sensorimotor transformation and action selection in the animal kingdom.
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Affiliation(s)
- Suguru Takagi
- Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
| | - Akinao Nose
- Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, Japan; Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo, Japan
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Cerebrospinal Fluid-Contacting Neurons Sense pH Changes and Motion in the Hypothalamus. J Neurosci 2018; 38:7713-7724. [PMID: 30037834 DOI: 10.1523/jneurosci.3359-17.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 07/04/2018] [Accepted: 07/15/2018] [Indexed: 01/20/2023] Open
Abstract
CSF-contacting (CSF-c) cells are present in the walls of the brain ventricles and the central canal of the spinal cord and found throughout the vertebrate phylum. We recently identified ciliated somatostatin-/GABA-expressing CSF-c neurons in the lamprey spinal cord that act as pH sensors as well as mechanoreceptors. In the same neuron, acidic and alkaline responses are mediated through ASIC3-like and PKD2L1 channels, respectively. Here, we investigate the functional properties of the ciliated somatostatin-/GABA-positive CSF-c neurons in the hypothalamus by performing whole-cell recordings in hypothalamic slices. Depolarizing current pulses readily evoked action potentials, but hypothalamic CSF-c neurons had no or a very low level of spontaneous activity at pH 7.4. They responded, however, with membrane potential depolarization and trains of action potentials to small deviations in pH in both the acidic and alkaline direction. Like in spinal CSF-c neurons, the acidic response in hypothalamic cells is mediated via ASIC3-like channels. In contrast, the alkaline response appears to depend on connexin hemichannels, not on PKD2L1 channels. We also show that hypothalamic CSF-c neurons respond to mechanical stimulation induced by fluid movements along the wall of the third ventricle, a response mediated via ASIC3-like channels. The hypothalamic CSF-c neurons extend their processes dorsally, ventrally, and laterally, but as yet, the effects exerted on hypothalamic circuits are unknown. With similar neurons being present in rodents, the pH- and mechanosensing ability of hypothalamic CSF-c neurons is most likely conserved throughout vertebrate phylogeny.SIGNIFICANCE STATEMENT CSF-contacting neurons are present in all vertebrates and are located mainly in the hypothalamic area and the spinal cord. Here, we report that the somatostatin-/GABA-expressing CSF-c neurons in the lamprey hypothalamus sense bidirectional deviations in the extracellular pH and do so via different molecular mechanisms. They also serve as mechanoreceptors. The hypothalamic CSF-c neurons have extensive axonal ramifications and may decrease the level of motor activity via release of somatostatin. In conclusion, hypothalamic somatostatin-/GABA-expressing CSF-c neurons, as well as their spinal counterpart, represent a novel homeostatic mechanism designed to sense any deviation from physiological pH and thus constitute a feedback regulatory system intrinsic to the CNS, possibly serving a protective role from damage caused by changes in pH.
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