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Snyder RR, Blitz DM. Multiple intrinsic membrane properties are modulated in a switch from single- to dual-network activity. J Neurophysiol 2022; 128:1181-1198. [PMID: 36197020 PMCID: PMC9621714 DOI: 10.1152/jn.00337.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/14/2022] [Accepted: 10/01/2022] [Indexed: 11/22/2022] Open
Abstract
Neural network flexibility includes changes in neuronal participation between networks, such as the switching of neurons between single- and dual-network activity. We previously identified a neuron that is recruited to burst in time with an additional network via modulation of its intrinsic membrane properties, instead of being recruited synaptically into the second network. However, the modulated intrinsic properties were not determined. Here, we use small networks in the Jonah crab (Cancer borealis) stomatogastric nervous system (STNS) to examine modulation of intrinsic properties underlying neuropeptide (Gly1-SIFamide)-elicited neuronal switching. The lateral posterior gastric neuron (LPG) switches from exclusive participation in the fast pyloric (∼1 Hz) network, due to electrical coupling, to dual-network activity that includes periodic escapes from the fast rhythm via intrinsically generated oscillations at the slower gastric mill network frequency (∼0.1 Hz). We isolated LPG from both networks by pharmacology and hyperpolarizing current injection. Gly1-SIFamide increased LPG intrinsic excitability and rebound from inhibition and decreased spike frequency adaptation, which can all contribute to intrinsic bursting. Using ion substitution and channel blockers, we found that a hyperpolarization-activated current, a persistent sodium current, and calcium or calcium-related current(s) appear to be primary contributors to Gly1-SIFamide-elicited LPG intrinsic bursting. However, this intrinsic bursting was more sensitive to blocking currents when LPG received rhythmic electrical coupling input from the fast network than in the isolated condition. Overall, a switch from single- to dual-network activity can involve modulation of multiple intrinsic properties, while synaptic input from a second network can shape the contributions of these properties.NEW & NOTEWORTHY Neuropeptide-elicited intrinsic bursting was recently determined to switch a neuron from single- to dual-network participation. Here we identified multiple intrinsic properties modulated in the dual-network state and candidate ion channels underlying the intrinsic bursting. Bursting at the second network frequency was more sensitive to blocking currents in the dual-network state than when neurons were synaptically isolated from their home network. Thus, synaptic input can shape the contributions of modulated intrinsic properties underlying dual-network activity.
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Affiliation(s)
- Ryan R Snyder
- Department of Biology and Center for Neuroscience, Miami University, Oxford, Ohio
| | - Dawn M Blitz
- Department of Biology and Center for Neuroscience, Miami University, Oxford, Ohio
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Cook AP, Nusbaum MP. Feeding State-Dependent Modulation of Feeding-Related Motor Patterns. J Neurophysiol 2021; 126:1903-1924. [PMID: 34669505 DOI: 10.1152/jn.00387.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Studies elucidating modulation of microcircuit activity in isolated nervous systems have revealed numerous insights regarding neural circuit flexibility, but this approach limits the link between experimental results and behavioral context. To bridge this gap, we studied feeding behavior-linked modulation of microcircuit activity in the isolated stomatogastric nervous system (STNS) of male Cancer borealis crabs. Specifically, we removed hemolymph from a crab that was unfed for ≥24 h ('unfed' hemolymph) or fed 15 min - 2 h before hemolymph removal ('fed' hemolymph). After feeding, the first significant foregut emptying occurred >1 h later and complete emptying required ≥6 h. We applied the unfed or fed hemolymph to the stomatogastric ganglion (STG) in an isolated STNS preparation from a separate, unfed crab to determine its influence on the VCN (ventral cardiac neuron)-triggered gastric mill (chewing)- and pyloric (filtering of chewed food) rhythms. Unfed hemolymph had little influence on these rhythms, but fed hemolymph from each examined time-point (15 min, 1- or 2 h post-feeding) slowed one or both rhythms without weakening circuit neuron activity. There were also distinct parameter changes associated with each time-point. One change unique to the 1 h time-point (i.e. reduced activity of one circuit neuron during the transition from the gastric mill retraction to protraction phase) suggested the fed hemolymph also enhanced the influence of a projection neuron which innervates the STG from a ganglion isolated from the applied hemolymph. Hemolymph thus provides a feeding state-dependent modulation of the two feeding-related motor patterns in the C. borealis STG.
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Affiliation(s)
- Aaron P Cook
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Michael P Nusbaum
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Golowasch J. Neuromodulation of central pattern generators and its role in the functional recovery of central pattern generator activity. J Neurophysiol 2019; 122:300-315. [PMID: 31066614 DOI: 10.1152/jn.00784.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Neuromodulators play an important role in how the nervous system organizes activity that results in behavior. Disruption of the normal patterns of neuromodulatory release or production is known to be related to the onset of severe pathologies such as Parkinson's disease, Rett syndrome, Alzheimer's disease, and affective disorders. Some of these pathologies involve neuronal structures that are called central pattern generators (CPGs), which are involved in the production of rhythmic activities throughout the nervous system. Here I discuss the interplay between CPGs and neuromodulatory activity, with particular emphasis on the potential role of neuromodulators in the recovery of disrupted neuronal activity. I refer to invertebrate and vertebrate model systems and some of the lessons we have learned from research on these systems and propose a few avenues for future research. I make one suggestion that may guide future research in the field: neuromodulators restrict the parameter landscape in which CPG components operate, and the removal of neuromodulators may enable a perturbed CPG in finding a new set of parameter values that can allow it to regain normal function.
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Affiliation(s)
- Jorge Golowasch
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University-Newark , Newark, New Jersey
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Jékely G, Melzer S, Beets I, Kadow ICG, Koene J, Haddad S, Holden-Dye L. The long and the short of it - a perspective on peptidergic regulation of circuits and behaviour. J Exp Biol 2018; 221:jeb166710. [PMID: 29439060 DOI: 10.1242/jeb.166710] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Neuropeptides are the most diverse class of chemical modulators in nervous systems. They contribute to extensive modulation of circuit activity and have profound influences on animal physiology. Studies on invertebrate model organisms, including the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans, have enabled the genetic manipulation of peptidergic signalling, contributing to an understanding of how neuropeptides pattern the output of neural circuits to underpin behavioural adaptation. Electrophysiological and pharmacological analyses of well-defined microcircuits, such as the crustacean stomatogastric ganglion, have provided detailed insights into neuropeptide functions at a cellular and circuit level. These approaches can be increasingly applied in the mammalian brain by focusing on circuits with a defined and identifiable sub-population of neurons. Functional analyses of neuropeptide systems have been underpinned by systematic studies to map peptidergic networks. Here, we review the general principles and mechanistic insights that have emerged from these studies. We also highlight some of the challenges that remain for furthering our understanding of the functional relevance of peptidergic modulation.
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Affiliation(s)
- Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Sarah Melzer
- Howard Hughes Medical Institute, Department of Neurobiology, 200 Longwood Avenue, Boston, MA 02115, USA
| | - Isabel Beets
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Ilona C Grunwald Kadow
- Technical University of Munich, TUM School of Life Sciences, ZIEL - Institute for Food and Health, 85354 Freising, Germany
| | - Joris Koene
- Vrije Universiteit - Ecological Science, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Sara Haddad
- Volen Center for Complex Systems, Brandeis University, Mailstop 013, 415 South Street, Waltham, MA 02454, USA
| | - Lindy Holden-Dye
- Biological Sciences, Highfield Campus, University of Southampton, Southampton, SO17 1BJ, UK
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Schulz DJ, Lane BJ. Homeostatic plasticity of excitability in crustacean central pattern generator networks. Curr Opin Neurobiol 2017; 43:7-14. [PMID: 27721084 PMCID: PMC5382137 DOI: 10.1016/j.conb.2016.09.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 08/24/2016] [Accepted: 09/24/2016] [Indexed: 12/14/2022]
Abstract
Plasticity of excitability can come in two general forms: changes in excitability that alter neuronal output (e.g. long-term potentiation of intrinsic excitability) or excitability changes that stabilize neuronal output (homeostatic plasticity). Here we discuss the latter form of plasticity in the context of the crustacean stomatogastric nervous system, and a second central pattern generator circuit, the cardiac ganglion. We discuss this plasticity at three levels: rapid homeostatic changes in membrane conductance, longer-term effects of neuromodulation on excitability, and the impacts of activity-dependent feedback on steady-state channel mRNA levels. We then conclude with thoughts on the implications of plasticity of excitability for variability of conductance levels across populations of motor neurons.
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Affiliation(s)
- David J Schulz
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO 65211 USA.
| | - Brian J Lane
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO 65211 USA
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Northcutt AJ, Lett KM, Garcia VB, Diester CM, Lane BJ, Marder E, Schulz DJ. Deep sequencing of transcriptomes from the nervous systems of two decapod crustaceans to characterize genes important for neural circuit function and modulation. BMC Genomics 2016; 17:868. [PMID: 27809760 PMCID: PMC5096308 DOI: 10.1186/s12864-016-3215-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 10/26/2016] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Crustaceans have been studied extensively as model systems for nervous system function from single neuron properties to behavior. However, lack of molecular sequence information and tools have slowed the adoption of these physiological systems as molecular model systems. In this study, we sequenced and performed de novo assembly for the nervous system transcriptomes of two decapod crustaceans: the Jonah crab (Cancer borealis) and the American lobster (Homarus americanus). RESULTS Forty-two thousand, seven hundred sixty-six and sixty thousand, two hundred seventy-three contigs were assembled from C. borealis and H. americanus respectively, representing 9,489 and 11,061 unique coding sequences. From these transcripts, genes associated with neural function were identified and manually curated to produce a characterization of multiple gene families important for nervous system function. This included genes for 34 distinct ion channel types, 17 biogenic amine and 5 GABA receptors, 28 major transmitter receptor subtypes including glutamate and acetylcholine receptors, and 6 gap junction proteins - the Innexins. CONCLUSION With this resource, crustacean model systems are better poised for incorporation of modern genomic and molecular biology technologies to further enhance the interrogation of fundamentals of nervous system function.
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Affiliation(s)
- Adam J. Northcutt
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Kawasi M. Lett
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Virginia B. Garcia
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Clare M. Diester
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Brian J. Lane
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
| | - Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, MA USA
| | - David J. Schulz
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO USA
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Daur N, Nadim F, Bucher D. The complexity of small circuits: the stomatogastric nervous system. Curr Opin Neurobiol 2016; 41:1-7. [PMID: 27450880 DOI: 10.1016/j.conb.2016.07.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 06/14/2016] [Accepted: 07/13/2016] [Indexed: 11/20/2022]
Abstract
The crustacean stomatogastric nervous system is a long-standing test bed for studies of circuit dynamics and neuromodulation. We give a brief update on the most recent work on this system, with an emphasis on the broader implications for understanding neural circuits. In particular, we focus on new findings underlining that different levels of dynamics taking place at different time scales all interact in multiple ways. Dynamics due to synaptic and intrinsic neuronal properties, neuromodulation, and long-term gene expression-dependent regulation are not independent, but influence each other. Extensive research on the stomatogastric system shows that these dynamic interactions convey robustness to circuit operation, while facilitating the flexibility of producing multiple circuit outputs.
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Affiliation(s)
- Nelly Daur
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, 323 Martin Luther King Blvd, Newark, NJ 07102, United States
| | - Farzan Nadim
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, 323 Martin Luther King Blvd, Newark, NJ 07102, United States
| | - Dirk Bucher
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, 323 Martin Luther King Blvd, Newark, NJ 07102, United States.
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