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Scully J, Bourahmah J, Bloom D, Shilnikov AL. Pairing cellular and synaptic dynamics into building blocks of rhythmic neural circuits. A tutorial. FRONTIERS IN NETWORK PHYSIOLOGY 2024; 4:1397151. [PMID: 38983123 PMCID: PMC11231435 DOI: 10.3389/fnetp.2024.1397151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/16/2024] [Indexed: 07/11/2024]
Abstract
In this study we focus on two subnetworks common in the circuitry of swim central pattern generators (CPGs) in the sea slugs, Melibe leonina and Dendronotus iris and show that they are independently capable of stably producing emergent network bursting. This observation raises the question of whether the coordination of redundant bursting mechanisms plays a role in the generation of rhythm and its regulation in the given swim CPGs. To address this question, we investigate two pairwise rhythm-generating networks and examine the properties of their fundamental components: cellular and synaptic, which are crucial for proper network assembly and its stable function. We perform a slow-fast decomposition analysis of cellular dynamics and highlight its significant bifurcations occurring in isolated and coupled neurons. A novel model for slow synapses with high filtering efficiency and temporal delay is also introduced and examined. Our findings demonstrate the existence of two modes of oscillation in bicellular rhythm-generating networks with network hysteresis: i) a half-center oscillator and ii) an excitatory-inhibitory pair. These 2-cell networks offer potential as common building blocks combined in modular organization of larger neural circuits preserving robust network hysteresis.
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Affiliation(s)
- James Scully
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Jassem Bourahmah
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - David Bloom
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- TReNDS Center, Georgia State University, Atlanta, GA, United States
| | - Andrey L Shilnikov
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA, United States
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2
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Brown JW, Berg OH, Boutko A, Stoerck C, Boersma MA, Frost WN. Division of labor for defensive retaliation and preemption by the peripheral and central nervous systems in the nudibranch Berghia. Curr Biol 2024; 34:2175-2185.e4. [PMID: 38718797 DOI: 10.1016/j.cub.2024.04.038] [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: 07/26/2023] [Revised: 01/02/2024] [Accepted: 04/15/2024] [Indexed: 05/23/2024]
Abstract
Relatively little is known about how peripheral nervous systems (PNSs) contribute to the patterning of behavior in which their role transcends the simple execution of central motor commands or mediation of reflexes. We sought to draw inferences to this end in the aeolid nudibranch Berghia stephanieae, which generates a rapid, dramatic defense behavior, "bristling." This behavior involves the coordinated movement of cerata, dozens of venomous appendages emerging from the animal's mantle. Our investigations revealed that bristling constitutes a stereotyped but non-reflexive two-stage behavior: an initial adduction of proximate cerata to sting the offending stimulus (stage 1) followed by a coordinated radial extension of remaining cerata to create a pincushion-like defensive screen around the animal (stage 2). In decerebrated specimens, stage 1 bristling was preserved, while stage 2 bristling was replaced by slower, uncoordinated ceratal movements. We conclude from these observations that, first, the animal's PNS and central nervous system (CNS) mediate stages 1 and 2 of bristling, respectively; second, the behavior propagates through the body utilizing both peripheral- and central-origin nerve networks that support different signaling kinetics; and third, the former network inhibits the latter in the body region being stimulated. These findings extend our understanding of the PNS' computational capacity and provide insight into a neuroethological scheme in which the CNS and PNS both independently and interactively pattern different aspects of non-reflexive behavior.
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Affiliation(s)
- Jeffrey W Brown
- Stanson Toshok Center for Brain Function and Repair, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA; School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Ondine H Berg
- Neuroscience Program, Lake Forest College, Lake Forest, IL 60045, USA
| | - Anastasiya Boutko
- The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Cody Stoerck
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831, USA
| | | | - William N Frost
- Stanson Toshok Center for Brain Function and Repair, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA; School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA; The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
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3
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Amin H, Nolte SS, Swain B, von Philipsborn AC. GABAergic signaling shapes multiple aspects of Drosophila courtship motor behavior. iScience 2023; 26:108069. [PMID: 37860694 PMCID: PMC10583093 DOI: 10.1016/j.isci.2023.108069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 09/06/2023] [Accepted: 09/25/2023] [Indexed: 10/21/2023] Open
Abstract
Inhibitory neurons are essential for orchestrating and structuring behavior. We use one of the best studied behaviors in Drosophila, male courtship, to analyze how inhibitory, GABAergic neurons shape the different steps of this multifaceted motor sequence. RNAi-mediated knockdown of the GABA-producing enzyme GAD1 and the ionotropic receptor Rdl in sex specific, fruitless expressing neurons in the ventral nerve cord causes uncoordinated and futile copulation attempts, defects in wing extension choice and severe alterations of courtship song. Altered song of GABA depleted males fails to stimulate female receptivity, but rescue of song patterning alone is not sufficient to rescue male mating success. Knockdown of GAD1 and Rdl in male brain circuits abolishes courtship conditioning. We characterize the around 220 neurons coexpressing GAD1 and Fruitless in the Drosophila male nervous system and propose inhibitory circuit motifs underlying key features of courtship behavior based on the observed phenotypes.
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Affiliation(s)
- Hoger Amin
- Department of Molecular Biology and Genetics and Department of Biomedicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, 8000 Aarhus, Denmark
| | - Stella S. Nolte
- Department of Molecular Biology and Genetics and Department of Biomedicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, 8000 Aarhus, Denmark
| | - Bijayalaxmi Swain
- Department of Molecular Biology and Genetics and Department of Biomedicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, 8000 Aarhus, Denmark
| | - Anne C. von Philipsborn
- Department of Molecular Biology and Genetics and Department of Biomedicine, Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus University, 8000 Aarhus, Denmark
- Department of Neuroscience and Movement Science, Medicine Section, University of Fribourg, 1700 Fribourg, Switzerland
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4
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Brown JW, Berg OH, Boutko A, Stoerck C, Boersma MA, Frost WN. Neural division of labor: the gastropod Berghia defends against attack using its PNS to retaliate and its CNS to erect a defensive screen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.29.551068. [PMID: 37577477 PMCID: PMC10418079 DOI: 10.1101/2023.07.29.551068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Relatively little is known about how the peripheral nervous system (PNS) contributes to the patterning of behavior, in which its role transcends the simple execution of central motor commands or mediation of reflexes. We sought to draw inferences to this end in the aeolid nudibranch Berghia stephanieae, which generates a rapid, dramatic defense behavior, "bristling." This behavior involves the coordinated movement of cerata, dozens of venomous appendages emerging from the animal's mantle. Our investigations revealed that bristling constitutes a stereotyped but non-reflexive two-stage behavior: an initial adduction of proximate cerata to sting the offending stimulus (Stage 1), followed by a coordinated radial extension of remaining cerata to create a pincushion-like defensive screen around the animal (Stage 2). In decerebrated specimens, Stage 1 bristling was preserved, while Stage 2 bristling was replaced by slower, uncoordinated, and ultimately maladaptive ceratal movements. We conclude from these observations that 1) the PNS and central nervous system (CNS) mediate Stages 1 and 2 of bristling, respectively; 2) the behavior propagates through the body utilizing both peripheral- and central-origin nerve networks that support different signaling kinetics; and 3) the former network inhibits the latter in the body region being stimulated. These findings extend our understanding of the PNS's computational capacity and provide insight into a neuroethological scheme that may generalize across cephalized animals, in which the CNS and PNS both independently and interactively pattern different aspects of non-reflexive behavior.
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Affiliation(s)
- Jeffrey W. Brown
- Stanson Toshok Center for Brain Function and Repair, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
- School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Ondine H. Berg
- Neuroscience Program, Lake Forest College, Lake Forest, IL 60045
| | - Anastasiya Boutko
- The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Cody Stoerck
- Department of Psychology, California State University at Fullerton, Fullerton, CA 92831
| | | | - William N. Frost
- Stanson Toshok Center for Brain Function and Repair, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
- School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
- The Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
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5
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Ramakrishnan S, Murphy AD. Peptidergic modulation of a multi-functional central pattern generator in the pulmonate snail. J Exp Biol 2022; 225:286115. [PMID: 36533565 DOI: 10.1242/jeb.244953] [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: 08/30/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022]
Abstract
Egg laying in pulmonate snails is a well-orchestrated process that involves a period of reduced locomotion, followed by substrate cleaning with rhythmic rasping of the surface to make tiny grooves, into which eggs are deposited. Although the neurohormonal control of initiating egg laying has been well established, the signals that modulate the buccal central pattern generator to substrate cleaning during egg laying are not known. Neuropeptides of the invertebrate gonadotropin-releasing hormone/corazonin family (invGnRH/CRZ) have been shown to be involved in reproduction and allied behaviors in many vertebrates and invertebrates. Here, we show that the buccal motor pattern underlying substrate cleaning during egg laying is altered by a vertebrate GnRH agonist. Signals from the intestinal nerve innervating reproductive structures, previously shown to be both necessary and sufficient for egg-laying behaviors, are blocked by a vertebrate GnRH antagonist. Further, the vertebrate GnRH-triggered response elicits rhythmic, phase 2 and non-phase 2 activity in the buccal motor pattern, with a shutdown of phase 3, indicative of repetitive rasping without accompanied swallowing behavior. Using immunohistochemistry, intracellular electrophysiology and extracellular nerve stimulation, we show that a member of the invGnRH/CRZ family of neuropeptides could be the signal that contextually switches the multifunctional buccal CPG to a biphasic rasping rhythm that underlies substrate cleaning behavior during egg laying in the pulmonate snail Planorbella (Helisoma) trivolvis.
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Affiliation(s)
- Siddharth Ramakrishnan
- Department of Biology and Neuroscience Program, University of Puget Sound, Tacoma, WA 98416, USA
| | - A Don Murphy
- Department of Biology, University of Illinois, Chicago, IL 60607, USA
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6
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Keifer J. Emergence of In Vitro Preparations and Their Contribution to Understanding the Neural Control of Behavior in Vertebrates. J Neurophysiol 2022; 128:511-526. [PMID: 35946803 DOI: 10.1152/jn.00142.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
One of the longstanding goals of the field of neuroscience is to understand the neural control of behavior in both invertebrate and vertebrate species. A series of early discoveries showed that certain motor patterns like locomotion could be generated by neuronal circuits without sensory feedback or descending control systems. These were called fictitious, or "fictive", motor programs because they could be expressed by neurons in the absence of movement. This finding lead investigators to isolate central nervous system tissue and maintain it in a dish in vitro to better study mechanisms of motor pattern generation. A period of rapid development of in vitro preparations from invertebrate species that could generate fictive motor programs from the activity of central pattern generating circuits (CPGs) emerged that was gradually followed by the introduction of such preparations from vertebrates. Here, I will review some of the notable in vitropreparations from both mammalian and non-mammalian vertebrate species developed to study the neural circuits underlying a variety of complex behaviors. This approach has been instrumental in delineating not only the cellular substrates underlying locomotion, respiration, scratching, and other behaviors, but also mechanisms underlying the modifiability of motor pathways through synaptic plasticity. In vitro preparations have had a significant impact on the field of motor systems neuroscience and the expansion of our understanding of how nervous systems control behavior. The field is ready for further advancement of this approach to explore neural substrates for variations in behavior generated by social and seasonal context, and the environment.
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Affiliation(s)
- Joyce Keifer
- Neuroscience Group, Basic Biomedical Sciences, University of South Dakota Sanford School of Medicine, Vermillion, SD, United States
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7
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Lee CA, Romanova EV, Southey BR, Gillette R, Sweedler JV. Comparative Analysis of Neuropeptides in Homologous Interneurons and Prohormone Annotation in Nudipleuran Sea Slugs. Front Physiol 2022; 12:809529. [PMID: 35002782 PMCID: PMC8735849 DOI: 10.3389/fphys.2021.809529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/02/2021] [Indexed: 02/06/2023] Open
Abstract
Despite substantial research on neuronal circuits in nudipleuran gastropods, few peptides have been implicated in nudipleuran behavior. In this study, we expanded the understanding of peptides in this clade, using three species with well-studied nervous systems, Hermissenda crassicornis, Melibe leonina, and Pleurobranchaea californica. For each species, we performed sequence homology analysis of de novo transcriptome predictions to identify homologs to 34 of 36 prohormones previously characterized in the gastropods Aplysia californica and Lymnaea stagnalis. We then used single-cell mass spectrometry to characterize peptide profiles in homologous feeding interneurons: the multifunctional ventral white cell (VWC) in P. californica and the small cardioactive peptide B large buccal (SLB) cells in H. crassicornis and M. leonina. The neurons produced overlapping, but not identical, peptide profiles. The H. crassicornis SLB cells expressed peptides from homologs to the FMRFamide (FMRFa), small cardioactive peptide (SCP), LFRFamide (LFRFa), and feeding circuit activating peptides prohormones. The M. leonina SLB cells expressed peptides from homologs to the FMRFa, SCP, LFRFa, and MIP-related peptides prohormones. The VWC, previously shown to express peptides from the FMRFa and QNFLa (a homolog of A. californica pedal peptide 4) prohormones, was shown to also contain SCP peptides. Thus, each neuron expressed peptides from the FMRFa and SCP families, the H. crassicornis and M. leonina SLB cells expressed peptides from the LFRFa family, and each neuron contained peptides from a prohormone not found in the others. These data suggest each neuron performs complex co-transmission, which potentially facilitates a multifunctional role in feeding. Additionally, the unique feeding characteristics of each species may relate, in part, to differences in the peptide profiles of these neurons. These data add chemical insight to enhance our understanding of the neuronal basis of behavior in nudipleurans and other gastropods.
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Affiliation(s)
- Colin A Lee
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Elena V Romanova
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States.,Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Bruce R Southey
- Department of Animal Sciences, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Rhanor Gillette
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States.,Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Jonathan V Sweedler
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States.,Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, United States
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8
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Expanding evolutionary neuroscience: insights from comparing variation in behavior. Neuron 2021; 109:1084-1099. [PMID: 33609484 DOI: 10.1016/j.neuron.2021.02.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/25/2021] [Accepted: 01/28/2021] [Indexed: 01/01/2023]
Abstract
Neuroscientists have long studied species with convenient biological features to discover how behavior emerges from conserved molecular, neural, and circuit level processes. With the advent of new tools, from viral vectors and gene editing to automated behavioral analyses, there has been a recent wave of interest in developing new, "nontraditional" model species. Here, we advocate for a complementary approach to model species development, that is, model clade development, as a way to integrate an evolutionary comparative approach with neurobiological and behavioral experiments. Capitalizing on natural behavioral variation in and investing in experimental tools for model clades will be a valuable strategy for the next generation of neuroscience discovery.
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9
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Kuo DH, De-Miguel FF, Heath-Heckman EAC, Szczupak L, Todd K, Weisblat DA, Winchell CJ. A tale of two leeches: Toward the understanding of the evolution and development of behavioral neural circuits. Evol Dev 2020; 22:471-493. [PMID: 33226195 DOI: 10.1111/ede.12358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 10/23/2020] [Accepted: 11/02/2020] [Indexed: 11/29/2022]
Abstract
In the animal kingdom, behavioral traits encompass a broad spectrum of biological phenotypes that have critical roles in adaptive evolution, but an EvoDevo approach has not been broadly used to study behavior evolution. Here, we propose that, by integrating two leech model systems, each of which has already attained some success in its respective field, it is possible to take on behavioral traits with an EvoDevo approach. We first identify the developmental changes that may theoretically lead to behavioral evolution and explain why an EvoDevo study of behavior is challenging. Next, we discuss the pros and cons of the two leech model species, Hirudo, a classic model for invertebrate neurobiology, and Helobdella, an emerging model for clitellate developmental biology, as models for behavioral EvoDevo research. Given the limitations of each leech system, neither is particularly strong for behavioral EvoDevo. However, the two leech systems are complementary in their technical accessibilities, and they do exhibit some behavioral similarities and differences. By studying them in parallel and together with additional leech species such as Haementeria, it is possible to explore the different levels of behavioral development and evolution.
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Affiliation(s)
- Dian-Han Kuo
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Francisco F De-Miguel
- Instituto de Fisiología Celular - Neurociencias, Universidad Nacional Autónoma de México, México City, México
| | | | - Lidia Szczupak
- Departamento de Fisiología Biología Molecular y Celular, Universidad de Buenos Aires, and IFIBYNE UBA-CONICET, Buenos Aires, Argentina
| | - Krista Todd
- Department of Neuroscience, Westminster College, Salt Lake City, Utah, USA
| | - David A Weisblat
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Christopher J Winchell
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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10
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Lodi M, Shilnikov AL, Storace M. Design Principles for Central Pattern Generators With Preset Rhythms. IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 2020; 31:3658-3669. [PMID: 31722491 DOI: 10.1109/tnnls.2019.2945637] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This article is concerned with the design of synthetic central pattern generators (CPGs). Biological CPGs are neural circuits that determine a variety of rhythmic activities, including locomotion, in animals. A synthetic CPG is a network of dynamical elements (here called cells) properly coupled by various synapses to emulate rhythms produced by a biological CPG. We focus on CPGs for locomotion of quadrupeds and present our design approach, based on the principles of nonlinear dynamics, bifurcation theory, and parameter optimization. This approach lets us design the synthetic CPG with a set of desired rhythms and switch between them as the parameter representing the control actions from the brain is varied. The developed four-cell CPG can produce four distinct gaits: walk, trot, gallop, and bound, similar to the mouse locomotion. The robustness and adaptability of the network design principles are verified using different cell and synapse models.
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11
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Vaasjo LO, Quintana AM, Habib MR, Mendez de Jesus PA, Croll RP, Miller MW. GABA-like immunoreactivity in Biomphalaria: Colocalization with tyrosine hydroxylase-like immunoreactivity in the feeding motor systems of panpulmonate snails. J Comp Neurol 2018; 526:1790-1805. [PMID: 29633264 DOI: 10.1002/cne.24448] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 03/24/2018] [Accepted: 03/26/2018] [Indexed: 12/24/2022]
Abstract
The simpler nervous systems of certain invertebrates provide opportunities to examine colocalized classical neurotransmitters in the context of identified neurons and well defined neural circuits. This study examined the distribution of γ-aminobutyric acid-like immunoreactivity (GABAli) in the nervous system of the panpulmonates Biomphalaria glabrata and Biomphalaria alexandrina, major intermediate hosts for intestinal schistosomiasis. GABAli neurons were localized in the cerebral, pedal, and buccal ganglia of each species. With the exception of a projection to the base of the tentacle, GABAli fibers were confined to the CNS. As GABAli was previously reported to be colocalized with markers for dopamine (DA) in five neurons in the feeding network of the euopisthobranch gastropod Aplysia californica (Díaz-Ríos, Oyola, & Miller, 2002), double-labeling protocols were used to compare the distribution of GABAli with tyrosine hydroxylase immunoreactivity (THli). As in Aplysia, GABAli-THli colocalization was limited to five neurons, all of which were located in the buccal ganglion. Five GABAli-THli cells were also observed in the buccal ganglia of two other intensively studied panpulmonate species, Lymnaea stagnalis and Helisoma trivolvis. These findings indicate that colocalization of the classical neurotransmitters GABA and DA in feeding central pattern generator (CPG) interneurons preceded the divergence of euopisthobranch and panpulmonate taxa. These observations also support the hypothesis that heterogastropod feeding CPG networks exhibit a common universal design.
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Affiliation(s)
- Lee O Vaasjo
- Institute of Neurobiology and Department of Anatomy & Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
| | - Alexandra M Quintana
- Institute of Neurobiology and Department of Anatomy & Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
| | - Mohamed R Habib
- Medical Malacology Laboratory, Theodor Bilharz Research Institute, Giza, Egypt
| | - Paola A Mendez de Jesus
- Institute of Neurobiology and Department of Anatomy & Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
| | - Roger P Croll
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Mark W Miller
- Institute of Neurobiology and Department of Anatomy & Neurobiology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
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12
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Webber MP, Thomson JWS, Buckland-Nicks J, Croll RP, Wyeth RC. GABA-, histamine-, and FMRFamide-immunoreactivity in the visual, vestibular and central nervous systems of Hermissenda crassicornis. J Comp Neurol 2017; 525:3514-3528. [PMID: 28726311 DOI: 10.1002/cne.24286] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/23/2017] [Accepted: 02/28/2017] [Indexed: 11/12/2022]
Abstract
Hermissenda crassicornis is a model for studying the molecular and cellular basis for classical conditioning, based on its ability to associate light with vestibular stimulation. We used confocal microscopy to map histamine (HA), FMRF-amide, and γ-aminobutyric acid (GABA) immunoreactivity in the central nervous system (CNS), eyes, optic ganglia and statocysts of the nudibranchs. For HA immunoreactivity, we documented both consistently and variably labeled CNS structures across individuals. We also noted minor differences in GABA immunoreactivity in the CNS compared to previous work on Hermissenda. Contrary to expectations, we found no evidence for GABA inside the visual or vestibular systems. Instead, we found only FMRFamide- and HA immunoreactivity (FMRFamide: 4 optic ganglion cells, 4-5 hair cells; HA: 3 optic ganglion cells, 8 hair cells). Overall, our results can act as basis for comparisons of nervous systems across nudibranchs, and suggest further exploration of intraspecific plasticity versus evolutionary changes in gastropod nervous systems.
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Affiliation(s)
- Marissa P Webber
- Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
| | - James W S Thomson
- Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
| | - Johnny Buckland-Nicks
- Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
| | - Roger P Croll
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Russell C Wyeth
- Department of Biology, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
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13
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Chávez-Viteri YE, Brown FD, Pérez OD. Deviating from the Norm: Peculiarities of Aplysia cf. californica Early Cleavage Compared to Traditional Spiralian Models. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 328:72-87. [PMID: 28032453 DOI: 10.1002/jez.b.22718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 09/08/2016] [Accepted: 10/03/2016] [Indexed: 11/09/2022]
Abstract
Spiralia represents one of the main clades of bilaterally symmetrical metazoans (Bilateria). This group is of particular interest due to the remarkable conservation of its early developmental pattern despite of the high diversity of larval and adult body plans. Variations during embryogenesis are considered powerful tools to determine ancestral and derived characters under a phylogenetic framework. By direct observation of embryos cultured in vitro, we analyzed the early cleavage of the euopisthobranchs Aplysia cf. californica. We used tubulin immunocytochemistry to stain mitotic spindles during early cleavages, and followed each division with the aid of an autofluorescent compound inside yolk platelets, which differed from the characteristic pink-brownish pigment of the vegetal cytoplasm in zygotes and early embryos. We found that this species exhibits an unequal cleavage characterized by ooplasmic segregation, oblique inclination of mitotic spindles, and differences in size and positioning of the asters in relation to the cellular cortex. Furthermore, we detected asynchrony in cleavage timing between the two large macromeres C and D, which increases the number of cleavage rounds required to reach a particular cell stage in comparison to other spiralians. Here, we report the presence of a transient and previously undescribed U-shaped embryo in this species. The present detailed description of A. californica early development deviates considerably from stereotypical patterns described in other spiralians. Our observations demonstrate that early spiralian development can be more plastic than previously thought.
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Affiliation(s)
- Yolanda E Chávez-Viteri
- Laboratorio de Biología del Desarrollo 113, Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador.,Centro Nacional de Acuicultura e Investigaciones Marinas, Escuela Politécnica del Litoral, San Pedro, Santa Elena, Ecuador
| | - Federico D Brown
- Centro Nacional de Acuicultura e Investigaciones Marinas, Escuela Politécnica del Litoral, San Pedro, Santa Elena, Ecuador.,Evolutionary Developmental Biology Laboratory, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia.,Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, SP, Brazil.,Instituto Nacional de Ciência e Tecnologia em Estudos Interdisciplinares e Transdisciplinares em Ecologia e Evolução (IN-TREE), Salvador, BA, Brazil
| | - Oscar D Pérez
- Laboratorio de Biología del Desarrollo 113, Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
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Katz PS. Evolution of central pattern generators and rhythmic behaviours. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150057. [PMID: 26598733 DOI: 10.1098/rstb.2015.0057] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Comparisons of rhythmic movements and the central pattern generators (CPGs) that control them uncover principles about the evolution of behaviour and neural circuits. Over the course of evolutionary history, gradual evolution of behaviours and their neural circuitry within any lineage of animals has been a predominant occurrence. Small changes in gene regulation can lead to divergence of circuit organization and corresponding changes in behaviour. However, some behavioural divergence has resulted from large-scale rewiring of the neural network. Divergence of CPG circuits has also occurred without a corresponding change in behaviour. When analogous rhythmic behaviours have evolved independently, it has generally been with different neural mechanisms. Repeated evolution of particular rhythmic behaviours has occurred within some lineages due to parallel evolution or latent CPGs. Particular motor pattern generating mechanisms have also evolved independently in separate lineages. The evolution of CPGs and rhythmic behaviours shows that although most behaviours and neural circuits are highly conserved, the nature of the behaviour does not dictate the neural mechanism and that the presence of homologous neural components does not determine the behaviour. This suggests that although behaviour is generated by neural circuits, natural selection can act separately on these two levels of biological organization.
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Affiliation(s)
- Paul S Katz
- Neuroscience Institute, Georgia State University, Atlanta, GA 30302-5030, USA
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15
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Katz PS. Phylogenetic plasticity in the evolution of molluscan neural circuits. Curr Opin Neurobiol 2016; 41:8-16. [PMID: 27455462 DOI: 10.1016/j.conb.2016.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/17/2016] [Accepted: 07/13/2016] [Indexed: 01/06/2023]
Abstract
Recent research on molluscan nervous systems provides a unique perspective on the evolution of neural circuits. Molluscs evolved large, encephalized nervous systems independently from other phyla. Homologous body-patterning genes were re-specified in molluscs to create a plethora of body plans and nervous system organizations. Octopuses, having the largest brains of any invertebrate, independently evolved a learning circuit similar in organization and function to the mushroom body of insects and the hippocampus of mammals. In gastropods, homologous neurons have been re-specified for different functions. Even species exhibiting similar, possibly homologous behavior have fundamental differences in the connectivity of the neurons underlying that behavior. Thus, molluscan nervous systems provide clear examples of re-purposing of homologous genes and neurons for neural circuits.
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Affiliation(s)
- Paul S Katz
- Neuroscience Institute, Georgia State University, PO Box 5030, Atlanta, GA 30302-5030, USA.
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Gunaratne CA, Katz PS. Comparative Mapping of GABA-Immunoreactive Neurons in the Buccal Ganglia of Nudipleura Molluscs. J Comp Neurol 2015; 524:1181-92. [DOI: 10.1002/cne.23895] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 09/01/2015] [Accepted: 09/08/2015] [Indexed: 11/08/2022]
Affiliation(s)
| | - Paul S. Katz
- Neuroscience Institute; Georgia State University; Atlanta Georgia 30302-5030
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