scholarly journals Multiple nerve rings coordinate Hydra mechanosensory behavior

2020 ◽  
Author(s):  
Krishna N. Badhiwala ◽  
Abby S. Primack ◽  
Celina E. Juliano ◽  
Jacob T. Robinson
Keyword(s):  
Nervous System ◽  
Calcium Imaging ◽  
Neural Circuit ◽  
Model Organism ◽  
Microfluidic Devices ◽  
Mechanical Stimuli ◽  
Fundamental Properties ◽  
Spontaneous Behavior ◽  
Spontaneous Contractions ◽  
Sensorimotor Responses

AbstractHydra vulgaris is an emerging model organism for neuroscience due to its small size, transparency, genetic tractability, and regenerative nervous system; however, fundamental properties of its sensorimotor behaviors remain unknown. Here, we use microfluidic devices combined with fluorescent calcium imaging and surgical resectioning to study how the nervous system coordinates Hydra’s mechanosensory response. We find that mechanical stimuli cause animals to contract, and this response relies on both the oral and aboral nerve rings. We also find that these nerve rings work together to coordinate spontaneous contractions suggesting that spontaneous behavior and sensorimotor responses converge on to a common neural circuit. These findings improve our understanding of how Hydra’s diffuse nervous system supports sensorimotor behaviors, which is needed to increase the utility of Hydra as a model organism for neuroscience.

scholarly journals Multiple neuronal networks coordinate Hydra mechanosensory behavior

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Krishna N Badhiwala ◽  
Abby S Primack ◽  
Celina Juliano ◽  
Jacob T Robinson
Keyword(s):  
Nervous System ◽  
Calcium Imaging ◽  
Activity Patterns ◽  
Sensory Information ◽  
Model Organism ◽  
Model Organisms ◽  
Mechanical Stimuli ◽  
Hydra Vulgaris ◽  
Fundamental Properties ◽  
Neural Architecture

Hydra vulgaris is an emerging model organism for neuroscience due to its small size, transparency, genetic tractability, and regenerative nervous system; however, fundamental properties of its sensorimotor behaviors remain unknown. Here, we use microfluidic devices combined with fluorescent calcium imaging and surgical resectioning to study how the diffuse nervous system coordinates Hydra's mechanosensory response. Mechanical stimuli cause animals to contract, and we find this response relies on at least two distinct networks of neurons in the oral and aboral regions of the animal. Different activity patterns arise in these networks depending on whether the animal is contracting spontaneously or contracting in response to mechanical stimulation. Together, these findings improve our understanding of how Hydra’s diffuse nervous system coordinates sensorimotor behaviors. These insights help reveal how sensory information is processed in an animal with a diffuse, radially symmetric neural architecture unlike the dense, bilaterally symmetric nervous systems found in most model organisms.

scholarly journals Stable behavioral and neural responses to thermal stimulation despite large changes in the Hydra vulgaris nervous system

2019 ◽  
Author(s):  
Constantine N. Tzouanas ◽  
Soonyoung Kim ◽  
Krishna N. Badhiwala ◽  
Benjamin W. Avants ◽  
Jacob T. Robinson
Keyword(s):  
Nervous System ◽  
Neural Plasticity ◽  
Large Scale ◽  
Neural Circuit ◽  
Rapid Change ◽  
Model Organism ◽  
Thermal Stimulation ◽  
Model Organisms ◽  
Hydra Vulgaris ◽  
Sensory Motor

AbstractMany animals that lose neural tissue due to injury or disease have the ability to maintain their behavioral abilities by regenerating new neurons or reorganizing existing neural circuits. However, most small model organisms used for neuroscience like nematodes and flies lack this high degree of neural plasticity. These animals often show significant behavioral deficits if they lose even a single neuron. Here we show that the small freshwater cnidarian Hydra vulgaris can maintain stable sensory motor behaviors even after losing half of the neurons in its body. Specifically, we find that both the behavioral and neural response to a rapid change in temperature is maintained if we make their nervous system roughly 50% smaller by caloric restriction or surgery. These observations suggest that Hydra provides a rich model for studying how animals maintain stable sensory-motor responses within dynamic neural circuit architectures, and may lead to general principles for neural circuit plasticity and stability.Significance StatementThe ability of the nervous system to restore its function following injury is key to survival for many animals. Understanding this neural plasticity in animals across the phylogenetic tree would help reveal fundamental principles of this important ability. To our knowledge, the discovery of a set of neurons in the jellyfish polyp Hydra vulgaris that stably support a response to thermal stimulation is the first demonstration of large-scale neural plasticity in a genetically tractable invertebrate model organism. The small size and transparency of Hydra suggests that it will be possible to study large-scale neural circuit plasticity in an animal where one can simultaneously image the activity of every neuron.

Behavioral Effects of Volatile Anesthetics in Caenorhabditis elegans

1996 ◽  
Vol 85 (4) ◽  
pp. 901-912 ◽  
Author(s):  
Michael C. Crowder ◽  
Laynie D. Shebester ◽  
Tim Schedl
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Time Course ◽  
Model Organism ◽  
Volatile Anesthetic ◽  
Volatile Anesthetics ◽  
Effective Concentration ◽  
Forward Genetics ◽  
C Elegans ◽  
Median Effective Concentration

Background The nematode Caenorhabditis elegans offers many advantages as a model organism for studying volatile anesthetic actions. It has a simple, well-understood nervous system; it allows the researcher to do forward genetics; and its genome will soon be completely sequenced. C. elegans is immobilized by volatile anesthetics only at high concentrations and with an unusually slow time course. Here other behavioral dysfunctions are considered as anesthetic endpoints in C. elegans. Methods The potency of halothane for disrupting eight different behaviors was determined by logistic regression of concentration and response data. Other volatile anesthetics were also tested for some behaviors. Established protocols were used for behavioral endpoints that, except for pharyngeal pumping, were set as complete disruption of the behavior. Time courses were measured for rapid behaviors. Recovery from exposure to 1 or 4 vol% halothane was determined for mating, chemotaxis, and gross movement. All experiments were performed at 20 to 22 degrees C. Results The median effective concentration values for halothane inhibition of mating (0.30 vol%-0.21 mM), chemotaxis (0.34 vol%-0.24 mM), and coordinated movement (0.32 vol% - 0.23 mM) were similar to the human minimum alveolar concentration (MAC; 0.21 mM). In contrast, halothane produced immobility with a median effective concentration of 3.65 vol% (2.6 mM). Other behaviors had intermediate sensitivities. Halothane's effects reached steady-state in 10 min for all behaviors tested except immobility, which required 2 h. Recovery was complete after exposure to 1 vol% halothane but was significantly reduced after exposure to immobilizing concentrations. Conclusions Volatile anesthetics selectively disrupt C. elegans behavior. The potency, time course, and recovery characteristics of halothane's effects on three behaviors are similar to its anesthetic properties in vertebrates. The affected nervous system molecules may express structural motifs similar to those on vertebrate anesthetic targets.

Presynaptic targets for acute ethanol sensitivity

2010 ◽  
Vol 38 (1) ◽  
pp. 172-176 ◽  
Author(s):  
Jeff W. Barclay ◽  
Margaret E. Graham ◽  
Mark R. Edwards ◽  
James R. Johnson ◽  
Alan Morgan ◽  
...  
Keyword(s):  
Nervous System ◽  
Caenorhabditis Elegans ◽  
Alcohol Abuse ◽  
Synaptic Vesicle ◽  
Protein Interactions ◽  
Model Organism ◽  
Acute Exposure ◽  
Ethanol Sensitivity ◽  
Acute Ethanol ◽  
Specific Proteins

Acute exposure to ethanol is known to modulate signalling within the nervous system. Physiologically these effects are both presynaptic and postsynaptic in origin; however, considerably more research has focused primarily on postsynaptic targets. Recent research using the model organism Caenorhabditis elegans has determined a role for specific proteins (Munc18-1 and Rab3) and processes (synaptic vesicle recruitment and fusion) in transducing the presynaptic effects of ethanol. In the present paper, we review these results, identifying the proteins and protein interactions involved in ethanol sensitivity and discuss their links with mammalian studies of alcohol abuse.

scholarly journals Loss-of-function in IRF2BPL is associated with neurological phenotypes

2018 ◽  
Author(s):  
Paul C. Marcogliese ◽  
Vandana Shashi ◽  
Rebecca C. Spillmann ◽  
Nicholas Stong ◽  
Jill A. Rosenfeld ◽  
...  
Keyword(s):  
Nervous System ◽  
Population Genomics ◽  
Stop Codon ◽  
Ectopic Expression ◽  
Premature Stop Codon ◽  
Model Organism ◽  
Global Developmental Delay ◽  
Mendelian Disease ◽  
Loss Of Function ◽  
Missense Variants

AbstractThe Interferon Regulatory Factor 2 Binding Protein Like (IRF2BPL) gene encodes a member of the IRF2BP family of transcriptional regulators. Currently the biological function of this gene is obscure, and the gene has not been associated with a Mendelian disease. Here we describe seven individuals affected with neurological symptoms who carry damaging heterozygous variants in IRF2BPL. Five cases carrying nonsense variants in IRF2BPL resulting in a premature stop codon display severe neurodevelopmental regression, hypotonia, progressive ataxia, seizures, and a lack of coordination. Two additional individuals, both with missense variants, display global developmental delay and seizures and a relatively milder phenotype than those with nonsense alleles. The bioinformatics signature for IRF2BPL based on population genomics is consistent with a gene that is intolerant to variation. We show that the IRF2BPL ortholog in the fruit fly, called pits (protein interacting with Ttk69 and Sin3A), is broadly expressed including the nervous system. Complete loss of pits is lethal early in development, whereas partial knock-down with RNA interference in neurons leads to neurodegeneration, revealing requirement for this gene in proper neuronal function and maintenance. The nonsense variants in IRF2BPL identified in patients behave as severe loss-of-function alleles in this model organism, while ectopic expression of the missense variants leads to a range of phenotypes. Taken together, IRF2BPL and pits are required in the nervous system in humans and flies, and their loss leads to a range of neurological phenotypes in both species.

The commensal association of Calliactis polypus and the hermit crab Dardanus gemmatus in Hawaii

1970 ◽  
Vol 48 (2) ◽  
pp. 351-357 ◽  
Author(s):  
D. M. Ross
Keyword(s):  
Nervous System ◽  
Small Area ◽  
Behavior Pattern ◽  
Mechanical Stimuli ◽  
Closely Related Species ◽  
Active Behavior ◽  
Highly Active ◽  
Hawaiian Species ◽  
The Pacific ◽  
Pedal Disc

Calliactis polypus (Forskål) lives as a commensal with various pagurids in the Pacific and Indian Oceans. In trials with the Hawaiian species, Dardanus gemmatus, the anemone, unlike the European C. parasitica, displayed only slight activity towards crabs or molluscan shells. As reported previously, crabs display a highly active behavior pattern towards C. polypus, tapping and scratching the column and eventually transferring it to its shell. The mechanical stimuli applied by the crab cause C. polypus to relax so completely that it can be lifted easily off the surface to which it was attached. Unlike C. parasitica and C. tricolor under similar circumstances, C. polypus does not release its pedal disc unaided. The tentacles and pedal disc of the detached C. polypus are extremely sticky and adhere at once to any solid surface presented to them. This enables an anemone detached by a crab to settle quickly on the shell even when only a small area of the pedal disc or only a few tentacles come into contact with the shell when placed there by the crab. The discussion emphasizes these differences in the behavior of closely related species in achieving the same ends. It also stresses that C. polypus, possessing a relatively simple nervous system, displays an impressive repertoire of responses to specific stimuli in its association with its pagurid host.

Towards understanding the neural origins of hibernation

2022 ◽  
Vol 225 (1) ◽  
Author(s):  
Madeleine S. Junkins ◽  
Sviatoslav N. Bagriantsev ◽  
Elena O. Gracheva
Keyword(s):  
Nervous System ◽  
Environmental Conditions ◽  
Calcium Imaging ◽  
Essential Role ◽  
Physiological Responses ◽  
Quiescent State ◽  
Physiological Changes ◽  
In Vivo Calcium Imaging

ABSTRACT Hibernators thrive under harsh environmental conditions instead of initiating canonical behavioral and physiological responses to promote survival. Although the physiological changes that occur during hibernation have been comprehensively researched, the role of the nervous system in this process remains relatively underexplored. In this Review, we adopt the perspective that the nervous system plays an active, essential role in facilitating and supporting hibernation. Accumulating evidence strongly suggests that the hypothalamus enters a quiescent state in which powerful drives to thermoregulate, eat and drink are suppressed. Similarly, cardiovascular and pulmonary reflexes originating in the brainstem are altered to permit the profoundly slow heart and breathing rates observed during torpor. The mechanisms underlying these changes to the hypothalamus and brainstem are not currently known, but several neuromodulatory systems have been implicated in the induction and maintenance of hibernation. The intersection of these findings with modern neuroscience approaches, such as optogenetics and in vivo calcium imaging, has opened several exciting avenues for hibernation research.

Seminal vesicle response to androgen with adrenaline, noradrenaline and acetylcholine

1960 ◽  
Vol 198 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Jerome A. Grunt ◽  
James T. Higgins
Keyword(s):  
Nervous System ◽  
Autonomic Nervous System ◽  
Seminal Vesicle ◽  
Testosterone Propionate ◽  
Water Soluble ◽  
Muscle System ◽  
Motor End Plate ◽  
Organ Response ◽  
Spontaneous Contractions

In a study of the end-organ response to androgen, use has been made of the seminal vesicle of the rat. Observations were made of the in vitro spontaneous contractions and responses to autonomic stimulating drugs. Vesicles of castrated rats contract spontaneously in vitro. Testosterone propionate given to the rat before sacrifice inhibits contractions, as does injection of water-soluble androgen into the in vitro chamber. Vesicles of castrates have lower thresholds to adrenaline and possibly to acetylcholine, but not to noradrenaline. The thresholds to acetylcholine but not to noradrenaline are elevated after injection of water-soluble androgen into the in vitro chamber. Several interpretations are discussed. Androgen and the autonomic nervous system probably interact at or near the cell membrane of the vesicle musculature. The three drugs tested most likely act at different loci along the nerve—motor end plate—muscle system, and noradrenaline is probably not a primary mediating agent of spontaneous contractions of the vesicle of the castrated rat.

Leech Mechanosensation

2017 ◽  
Author(s):  
Brian D. Burrell
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sensory Neurons ◽  
Receptive Fields ◽  
Model Systems ◽  
Sensory Cells ◽  
Mechanical Stimuli ◽  
Nociceptive Neurons ◽  
Mechanosensory Neurons ◽  
The Central Nervous System

The medicinal leech (Hirudo verbana) is an annelid (segmented worm) and one of the classic model systems in neuroscience. It has been used in research for over 50 years and was one of the first animals in which intracellular recordings of mechanosensory neurons were carried out. Remarkably, the leech has three main classes of mechanosensory neurons that exhibit many of the same properties found in vertebrates. The most sensitive of these neurons are the touch cells, which are rapidly adapting neurons that detect low-intensity mechanical stimuli. Next are the pressure cells, which are slow-adapting sensory neurons that respond to higher intensity, sustained mechanostimulation. Finally, there are nociceptive neurons, which have the highest threshold and respond to potentially damaging mechanostimuli, such as a pinch. As observed in mammals, the leech has separate mechanosensitive and polymodal nociceptors, the latter responding to mechanical, thermal, and chemical stimuli. The cell bodies for all three types of mechanosensitive neurons are found in the central nervous system where they are arranged as bilateral pairs. Each neuron extends processes to the skin where they form discrete receptive fields. In the touch and pressure cells, these receptive fields are arranged along the dorsal-ventral axis. For the mechano-only and polymodal nociceptive neurons, the peripheral receptive fields overlap with the mechano-only nociceptor, which also innervates the gut. The leech also has a type of mechanosensitive cell located in the periphery that responds to vibrations in the water and is used, in part, to detect potential prey nearby. In the central nervous system, the touch, pressure, and nociceptive cells all form synaptic connections with a variety of motor neurons, interneurons, and even each other, using glutamate as the neurotransmitter. Synaptic transmission by these cells can be modulated by a variety of activity-dependent processes as well as the influence of neuromodulatory transmitters, such as serotonin. The output of these sensory neurons can also be modulated by conduction block, a process in which action potentials fail to propagate to all the synaptic release sites, decreasing synaptic output. Activity in these sensory neurons leads to the initiation of a number of different motor behaviors involved in locomotion, such as swimming and crawling, as well as behaviors designed to recoil from aversive/noxious stimuli, such as local bending and shortening. In the case of local bending, the leech is able to bend in the appropriate direction away from the offending stimuli. It does so through a combination of which mechanosensory cell receptive fields have been activated and the relative activation of multiple sensory cells decoded by a layer of downstream interneurons.

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