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Li DH, Bartol IK, Gilly WF. Hydrodynamic Diversity of Jets Mediated by Giant and Non-Giant Axon Systems in Brief Squid. Integr Comp Biol 2023; 63:1266-1276. [PMID: 37381578 DOI: 10.1093/icb/icad086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 06/05/2023] [Accepted: 06/12/2023] [Indexed: 06/30/2023] Open
Abstract
Neural input is critical for establishing behavioral output, but understanding how neuromuscular signals give rise to behaviors remains a challenge. In squid, locomotion through jet propulsion underlies many key behaviors, and the jet is mediated by two parallel neural pathways, the giant and non-giant axon systems. Much work has been done on the impact of these two systems on jet kinematics, such as mantle muscle contraction and pressure-derived jet speed at the funnel aperture. However, little is known about any influence these neural pathways may have on the hydrodynamics of the jet after it leaves the squid and transfers momentum to the surrounding fluid for the animal to swim. To gain a more comprehensive view of squid jet propulsion, we made simultaneous measurements of neural activity, pressure inside the mantle cavity, and wake structure. By computing impulse and time-averaged forces from the wake structures of jets associated with giant or non-giant axon activity, we show that the influence of neural pathways on jet kinematics could extend to hydrodynamic impulse and force production. Specifically, the giant axon system produced jets with, on average, greater impulse magnitude than those of the non-giant system. However, non-giant impulse could exceed that of the giant system, evident by the graded range of its output in contrast to the stereotyped nature of the giant system. Our results suggest that the non-giant system offers flexibility in hydrodynamic output, while recruitment of giant axon activity can provide a reliable boost when necessary.
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Affiliation(s)
- Diana H Li
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Ian K Bartol
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23539, USA
| | - William F Gilly
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
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2
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Zhu Q. Wall effect on the start maneuver of a jet swimmer. BIOINSPIRATION & BIOMIMETICS 2023; 18:036003. [PMID: 36889000 DOI: 10.1088/1748-3190/acc293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Inspired by aquatic creatures such as squid, the novel propulsion method based on pulsed jetting is a promising way to achieve high speed and high maneuverability. To study the potential application of this locomotion method in confined space with complicated boundary conditions, it is critical to understand their dynamics in the vicinity of solid boundaries. In this study we numerically examine the start maneuver of an idealized jet swimmer near a wall. Our simulations illustrate three important mechanisms: (1) due to the blocking effect of the wall the pressure inside the body is affected so that the forward acceleration is increased during deflation and decreased during inflation; (2) the wall affects the internal flow so that the momentum flux at the nozzle and subsequently the thrust generation during the jetting phase are slightly increased; (3) the wall affects the wake so that the refilling phase is influenced, leading to a scenario in which part of the energy expended during jetting is recovered during refilling to increase forward acceleration and reduce power expenditure. In general, the second mechanism is weaker than the other two. The exact effects of these mechanisms depend on physical parameters such as the initial phase of the body deformation, the distance between the swimming body and the wall, and the Reynolds number.
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Affiliation(s)
- Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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3
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Zhu Q, Xiao Q. Physics and applications of squid-inspired jetting. BIOINSPIRATION & BIOMIMETICS 2022; 17:041001. [PMID: 35512671 DOI: 10.1088/1748-3190/ac6d37] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 05/05/2022] [Indexed: 06/14/2023]
Abstract
In the aquatic world jet propulsion is a highly successful locomotion method utilized by a variety of species. Among them cephalopods such as squids excel in their ability for high-speed swimming. This mechanism inspires the development of underwater locomotion techniques which are particularly useful in soft-bodied robots. In this overview we summarize existing studies on this topic, ranging from investigations on the underlying physics to the creation of mechanical systems utilizing this locomotion mode. Research directions that worth future investigation are also discussed.
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Affiliation(s)
- Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
| | - Qing Xiao
- Department of Naval Architecture, Ocean and Marine Engineering, University of Strathclyde, Glasgow, G4 0LZ, United Kingdom
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4
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Bi X, Zhu Q. Free swimming of a squid-inspired axisymmetric system through jet propulsion. BIOINSPIRATION & BIOMIMETICS 2021; 16:066023. [PMID: 34654001 DOI: 10.1088/1748-3190/ac3061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
An axisymmetric fluid-structure interaction model based on the immersed-boundary approach is developed to study the self-propelled locomotion of a squid-inspired swimmer in relatively low Reynolds numbers (O(102)). Through cyclic deformation, the swimmer generates intermittent jet flow, which, together with the added-mass effect associated with the body deformation, provides thrust. Through a control volume analysis we are able to determine the jet-related thrust. By adding it to the added-mass-related thrust we separate the net thrust on the body from the drag effect due to forward motion, so that the propulsion efficiency in free swimming is found. This numerical algorithm and thrust-drag decomposition method are used to study the dynamics of the bio-inspired locomotion system in different conditions, whereby the performance is characterized by the aforementioned propulsion efficiency as well as the conventionally defined cost of transport.
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Affiliation(s)
- Xiaobo Bi
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
| | - Qiang Zhu
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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5
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Hadjisolomou SP, El-Haddad RW, Kloskowski K, Chavarga A, Abramov I. Quantifying the Speed of Chromatophore Activity at the Single-Organ Level in Response to a Visual Startle Stimulus in Living, Intact Squid. Front Physiol 2021; 12:675252. [PMID: 34220538 PMCID: PMC8250766 DOI: 10.3389/fphys.2021.675252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/27/2021] [Indexed: 11/13/2022] Open
Abstract
The speed of adaptive body patterning in coleoid cephalopods is unmatched in the natural world. While the literature frequently reports their remarkable ability to change coloration significantly faster than other species, there is limited research on the temporal dynamics of rapid chromatophore coordination underlying body patterning in living, intact animals. In this exploratory pilot study, we aimed to measure chromatophore activity in response to a light flash stimulus in seven squid, Doryteuthis pealeii. We video-recorded the head/arms, mantle, and fin when squid were presented with a light flash startle stimulus. Individual chromatophores were detected and tracked over time using image analysis. We assessed baseline and response chromatophore surface area parameters before and after flash stimulation, respectively. Using change-point analysis, we identified 4,065 chromatophores from 185 trials with significant surface area changes elicited by the flash stimulus. We defined the temporal dynamics of chromatophore activity to flash stimulation as the latency, duration, and magnitude of surface area changes (expansion or retraction) following the flash presentation. Post stimulation, the response's mean latency was at 50 ms (± 16.67 ms), for expansion and retraction, across all body regions. The response duration ranged from 217 ms (fin, retraction) to 384 ms (heads/arms, expansion). While chromatophore expansions had a mean surface area increase of 155.06%, the retractions only caused a mean reduction of 40.46%. Collectively, the methods and results described contribute to our understanding of how cephalopods can employ thousands of chromatophore organs in milliseconds to achieve rapid, dynamic body patterning.
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Affiliation(s)
- Stavros P Hadjisolomou
- Department of Social and Behavioral Sciences, College of Arts and Sciences, American University of Kuwait, Salmiya, Kuwait
| | - Rita W El-Haddad
- Department of Social and Behavioral Sciences, College of Arts and Sciences, American University of Kuwait, Salmiya, Kuwait
| | - Kamil Kloskowski
- Department of Psychology, Brooklyn College, City University of New York, Brooklyn, NY, United States
| | - Alla Chavarga
- Department of Psychology, Brooklyn College, City University of New York, Brooklyn, NY, United States
| | - Israel Abramov
- Department of Psychology, Brooklyn College, City University of New York, Brooklyn, NY, United States
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6
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Bi X, Zhu Q. Dynamics of a squid-inspired swimmer in free swimming. BIOINSPIRATION & BIOMIMETICS 2019; 15:016005. [PMID: 31726438 DOI: 10.1088/1748-3190/ab57e4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The untethered swimming performance of a two-dimensional squid-inspired swimmer is studied. Our model includes fully-coupled fluid-structure interaction and an idealized activation algorithm that drives periodic shape change of the body. We present results of both escape jetting via a single deflation-coasting motion and long-distance swimming via repeated inflation-deflation cycles. In both cases added-mass-related force is found to contribute significantly to thrust generation. Moreover, we find that the increase of the jet speed and oscillation frequency leads to higher swimming velocity. This, however, is achieved at the cost of reduced propulsion efficiency (i.e. higher cost of transport). During long-distance swimming, the system experiences three successive stages, acceleration, steady-state swimming, and off-track swimming caused by symmetry-breaking instability in the wake. Associated with these stages, three wake patterns are observed, nozzle-vortex-dominated wake, transit wake, and asymmetrical wake.
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Affiliation(s)
- Xiaobo Bi
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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7
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Li DH, Gilly WF. Hypoxia tolerance of giant axon-mediated escape jetting in California market squid ( Doryteuthis opalescens). ACTA ACUST UNITED AC 2019; 222:jeb.198812. [PMID: 30936266 DOI: 10.1242/jeb.198812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 03/26/2019] [Indexed: 11/20/2022]
Abstract
Squids display a wide range of swimming behaviors, including powerful escape jets mediated by the giant axon system. For California market squid (Doryteuthis opalescens), maintaining essential behaviors like the escape response during environmental variations poses a major challenge as this species often encounters intrusions of cold, hypoxic offshore waters in its coastal spawning habitats. To explore the effects of hypoxia on locomotion and the underlying neural mechanisms, we made in vivo recordings of giant axon activity and simultaneous pressure inside the mantle cavity during escape jets in squid exposed to acute progressive hypoxia followed by return to normal dissolved oxygen (DO) concentration (normoxia). Compared with those in normoxia (>8 mg l-1 DO), escape jets were unchanged in moderate hypoxia (4 and 2 mg l-1 DO), but giant axon activity and associated mantle contractions significantly decreased while neuromuscular latency increased under severe hypoxia (0.5 mg l-1 DO). Animals that survived exposure to severe hypoxia reliably produced escape jets under such conditions and fully recovered as more oxygen became available. The reduction in neuromuscular output under hypoxia suggests that market squid may suppress metabolic activity to maintain sufficient behavioral output, a common strategy in many hypoxia-tolerant species. The ability to recover from the deleterious effects of hypoxia suggests that this species is well adapted to cope with coastal hypoxic events that commonly occur in Monterey Bay, unless these events become more severe in the future as climate change progresses.
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Affiliation(s)
- Diana H Li
- Department of Biology, Hopkins Marine Station of Stanford University, 120 Ocean View Boulevard, Pacific Grove, CA 93950, USA
| | - William F Gilly
- Department of Biology, Hopkins Marine Station of Stanford University, 120 Ocean View Boulevard, Pacific Grove, CA 93950, USA
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8
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Circuit Robustness to Temperature Perturbation Is Altered by Neuromodulators. Neuron 2018; 100:609-623.e3. [PMID: 30244886 DOI: 10.1016/j.neuron.2018.08.035] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 12/15/2017] [Accepted: 08/24/2018] [Indexed: 11/20/2022]
Abstract
In the ocean, the crab Cancer borealis is subject to daily and seasonal temperature changes. Previous work, done in the presence of descending modulatory inputs, had shown that the pyloric rhythm of the crab increases in frequency as temperature increases but maintains its characteristic phase relationships until it "crashes" at extremely high temperatures. To study the interaction between neuromodulators and temperature perturbations, we studied the effects of temperature on preparations from which the descending modulatory inputs were removed. Under these conditions, the pyloric rhythm was destabilized. We then studied the effects of temperature on preparations in the presence of oxotremorine, proctolin, and serotonin. Oxotremorine and proctolin enhanced the robustness of the pyloric rhythm, whereas serotonin made the rhythm less robust. These experiments reveal considerable animal-to-animal diversity in their crash stability, consistent with the interpretation that cryptic differences in many cell and network parameters are revealed by extreme perturbations.
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9
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Bi X, Zhu Q. Numerical investigation of cephalopod-inspired locomotion with intermittent bursts. BIOINSPIRATION & BIOMIMETICS 2018; 13:056005. [PMID: 29972142 DOI: 10.1088/1748-3190/aad0ff] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Inspired by recent studies about the fluid dynamics of cephalopods in their escaping swimming mode, we propose a novel design of an underwater propulsion system using a deformable body with pressure chamber, which propels itself in burst-coast cycles through a combined effect of pulsed jet and added-mass related thrust. To investigate the performance of this system we create a free-swimming computational model-the body deformation is prescribed yet the forward motion is driven by hydrodynamic forces. Our focus is on a single bursting cycle, which corresponds to the case that the system rests between bursts. The results can also be applied to the starting stage of a continuous cruising motion. A numerical model using the boundary element method is developed to computationally study the swimming process and the dynamic characteristics of this system. The results show that in the bursting phase its peak speed depends on the size of the body, the deformation time, the amount of volume change during the deformation, and the size of the nozzle where the jet flow is generated. The optimal speed is found to coincide with the critical formation number, indicating that the formation of vortex rings in the wake plays a pivotal role in the dynamics of the system. The dynamics of the system in the coasting phase and the process of refilling the pressure chamber are also studied.
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Affiliation(s)
- Xiaobo Bi
- Department of Structural Engineering, University of California, San Diego, La Jolla, CA 92093, United States of America
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10
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Kim M, McKinnon D, MacCarthy T, Rosati B, McKinnon D. Regulatory evolution and voltage-gated ion channel expression in squid axon: selection-mutation balance and fitness cliffs. PLoS One 2015; 10:e0120785. [PMID: 25875483 PMCID: PMC4395378 DOI: 10.1371/journal.pone.0120785] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/27/2015] [Indexed: 11/23/2022] Open
Abstract
It has been suggested that optimization of either axonal conduction velocity or the energy efficiency of action potential conduction predominates in the selection of voltage-gated sodium conductance levels in the squid axon. A population genetics model of channel gene regulatory function was used to examine the role of these and other evolutionary forces on the selection of both sodium and potassium channel expression levels. In this model, the accumulating effects of mutations result in degradation of gene regulatory function, causing channel gene expression to fall to near-zero in the absence of positive selection. In the presence of positive selection, channel expression levels fall to the lowest values consistent with the selection criteria, thereby establishing a selection-mutation balance. Within the parameter space of sodium and potassium conductance values, the physiological performance of the squid axon model showed marked discontinuities associated with conduction failure and excitability. These discontinuities in physiological function may produce fitness cliffs. A fitness cliff associated with conduction failure, combined with the effects of phenotypic noise, can account for the selection of sodium conductance levels, without considering either conduction velocity or metabolic cost. A fitness cliff associated with a transition in axonal excitability, combined with phenotypic noise, can explain the selection of potassium channel expression levels. The results suggest that voltage-gated ion channel expression will fall to low levels, consistent with key functional constraints, even in the absence of positive selection for energy efficiency. Channel expression levels and individual variation in channel expression within the population can be explained by regulatory evolution in combination with genetic variation in regulatory function and phenotypic noise, without resorting to more complex mechanisms, such as activity-dependent homeostasis. Only a relatively small region of the large, nominally isofunctional parameter space for channel expression will normally be occupied, because of the effects of mutation.
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Affiliation(s)
- Min Kim
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America
| | - Don McKinnon
- Institute of Molecular Cardiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Thomas MacCarthy
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York, United States of America
| | - Barbara Rosati
- Institute of Molecular Cardiology, Stony Brook University, Stony Brook, New York, United States of America; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, United States of America
| | - David McKinnon
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, New York, United States of America; The Department of Research, Veterans Affairs Medical Center, Northport, New York, United States of America
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11
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Weymouth GD, Subramaniam V, Triantafyllou MS. Ultra-fast escape maneuver of an octopus-inspired robot. BIOINSPIRATION & BIOMIMETICS 2015; 10:016016. [PMID: 25643048 DOI: 10.1088/1748-3190/10/1/016016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We design and test an octopus-inspired flexible hull robot that demonstrates outstanding fast-starting performance. The robot is hyper-inflated with water, and then rapidly deflates to expel the fluid so as to power the escape maneuver. Using this robot we verify for the first time in laboratory testing that rapid size-change can substantially reduce separation in bluff bodies traveling several body lengths, and recover fluid energy which can be employed to improve the propulsive performance. The robot is found to experience speeds over ten body lengths per second, exceeding that of a similarly propelled optimally streamlined rigid rocket. The peak net thrust force on the robot is more than 2.6 times that on an optimal rigid body performing the same maneuver, experimentally demonstrating large energy recovery and enabling acceleration greater than 14 body lengths per second squared. Finally, over 53% of the available energy is converted into payload kinetic energy, a performance that exceeds the estimated energy conversion efficiency of fast-starting fish. The Reynolds number based on final speed and robot length is [Formula: see text]. We use the experimental data to establish a fundamental deflation scaling parameter [Formula: see text] which characterizes the mechanisms of flow control via shape change. Based on this scaling parameter, we find that the fast-starting performance improves with increasing size.
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Affiliation(s)
- G D Weymouth
- Southampton Marine and Maritime Institute, University of Southampton, Southampton SO17 1BJ, UK
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12
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Mooney TA, Hanlon RT, Christensen-Dalsgaard J, Madsen PT, Ketten DR, Nachtigall PE. Sound detection by the longfin squid (Loligo pealeii) studied with auditory evoked potentials: sensitivity to low-frequency particle motion and not pressure. J Exp Biol 2010; 213:3748-59. [DOI: 10.1242/jeb.048348] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Although hearing has been described for many underwater species, there is much debate regarding if and how cephalopods detect sound. Here we quantify the acoustic sensitivity of the longfin squid (Loligo pealeii) using near-field acoustic and shaker-generated acceleration stimuli. Sound field pressure and particle motion components were measured from 30 to 10,000 Hz and acceleration stimuli were measured from 20 to 1000 Hz. Responses were determined using auditory evoked potentials (AEPs) with electrodes placed near the statocysts. Evoked potentials were generated by both stimuli and consisted of two wave types: (1) rapid stimulus-following waves, and (2) slower, high-amplitude waves, similar to some fish AEPs. Responses were obtained between 30 and 500 Hz with lowest thresholds between 100 and 200 Hz. At the best frequencies, AEP amplitudes were often >20 μV. Evoked potentials were extinguished at all frequencies if (1) water temperatures were less than 8°C, (2) statocysts were ablated, or (3) recording electrodes were placed in locations other than near the statocysts. Both the AEP response characteristics and the range of responses suggest that squid detect sound similarly to most fish, with the statocyst acting as an accelerometer through which squid detect the particle motion component of a sound field. The modality and frequency range indicate that squid probably detect acoustic particle motion stimuli from both predators and prey as well as low-frequency environmental sound signatures that may aid navigation.
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Affiliation(s)
- T. Aran Mooney
- Marine Biological Laboratory, Woods Hole, MA 02543, USA
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | | | | | - Peter T. Madsen
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Zoophysiology, Department of Biological Sciences, Aarhus University, 8000 Aarhus C, Denmark
| | - Darlene R. Ketten
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
- Harvard Medical School, Boston, MA 02114, USA
| | - Paul E. Nachtigall
- Hawaii Institute of Marine Biology, University of Hawaii, Kailua, HI 96744, USA
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13
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Tang LS, Goeritz ML, Caplan JS, Taylor AL, Fisek M, Marder E. Precise temperature compensation of phase in a rhythmic motor pattern. PLoS Biol 2010; 8. [PMID: 20824168 PMCID: PMC2930868 DOI: 10.1371/journal.pbio.1000469] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 07/20/2010] [Indexed: 11/19/2022] Open
Abstract
Most animal species are cold-blooded, and their neuronal circuits must maintain function despite environmental temperature fluctuations. The central pattern generating circuits that produce rhythmic motor patterns depend on the orderly activation of circuit neurons. We describe the effects of temperature on the pyloric rhythm of the stomatogastric ganglion of the crab, Cancer borealis. The pyloric rhythm is a triphasic motor pattern in which the Pyloric Dilator (PD), Lateral Pyloric (LP), and Pyloric (PY) neurons fire in a repeating sequence. While the frequency of the pyloric rhythm increased about 4-fold (Q(10) approximately 2.3) as the temperature was shifted from 7 degrees C to 23 degrees C, the phase relationships of the PD, LP, and PY neurons showed almost perfect temperature compensation. The Q(10)'s of the input conductance, synaptic currents, transient outward current (I(A)), and the hyperpolarization-activated inward current (I(h)), all of which help determine the phase of LP neuron activity, ranged from 1.8 to 4. We studied the effects of temperature in >1,000 computational models (with different sets of maximal conductances) of a bursting neuron and the LP neuron. Many bursting models failed to monotonically increase in frequency as temperature increased. Temperature compensation of LP neuron phase was facilitated when model neurons' currents had Q(10)'s close to 2. Together, these data indicate that although diverse sets of maximal conductances may be found in identified neurons across animals, there may be strong evolutionary pressure to restrict the Q(10)'s of the processes that contribute to temperature compensation of neuronal circuits.
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Affiliation(s)
- Lamont S. Tang
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts, United States of America
| | - Marie L. Goeritz
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts, United States of America
| | - Jonathan S. Caplan
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts, United States of America
| | - Adam L. Taylor
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts, United States of America
| | - Mehmet Fisek
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts, United States of America
| | - Eve Marder
- Volen Center and Biology Department, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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14
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Salisbury SM, Martin GG, Kier WM, Schulz JR. Venom kinematics during prey capture in Conus: the biomechanics of a rapid injection system. ACTA ACUST UNITED AC 2010; 213:673-82. [PMID: 20154182 DOI: 10.1242/jeb.035550] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cone snails use an extensile, tubular proboscis as a conduit to deliver a potent cocktail of bioactive venom peptides into their prey. Previous studies have focused mainly on understanding the venom's role in prey capture but successful prey capture requires both rapid physiological and biomechanical mechanisms. Conus catus, a fish-hunting species, uses a high-speed hydraulic mechanism to inject its hollow, spear-like radular tooth into prey. We take an integrated approach to investigating the biomechanics of this process by coupling kinematic studies with morphological analyses. Taking advantage of the opaque venom and translucent proboscis of a mollusc-hunting juvenile cone snail, Conus pennaceus, we have determined that a high-speed prey capture mechanism is not unique to cone species that hunt fish prey. Two morphological structures were found to play crucial roles in this process. A constriction of the lumen near the tip of the proboscis, composed of tall epithelial cells densely packed with microfilaments, impedes forward movement of the radular tooth prior to its propulsion. Proximal to the constriction, a muscular sphincter was found to regulate venom flow and pressurization in the proboscis. In C. pennaceus, the rapid appearance and flushing of venom within the proboscis during prey capture suggests a mechanism involving the delivery of a discrete quantity of venom. The interplay between these elements provides a unique and effective biomechanical injection system for the fast-acting cone snail venom peptides.
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15
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Szabo TM, Brookings T, Preuss T, Faber DS. Effects of temperature acclimation on a central neural circuit and its behavioral output. J Neurophysiol 2008; 100:2997-3008. [PMID: 18922942 DOI: 10.1152/jn.91033.2008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we address the impact of temperature acclimation on neuronal properties in the Mauthner (M-) system, a brain stem network that initiates the startle-escape behavior in goldfish. The M-cell can be studied at cellular and behavioral levels, since it is uniquely identifiable physiologically within the intact vertebrate brain, and a single action potential in this neuron determines not only whether a startle response will occur but also the direction of the escape. Using animals acclimated to 15 degrees C as a control, 25 degrees C-acclimated fish showed a significant increase in escape probability and a decrease in the ability to discriminate escape directionality. Intracellular recordings demonstrated that M-cells in this population possessed decreased input resistance and reduced strength and duration of inhibitory inputs. In contrast, fish acclimated to 5 degrees C were behaviorally similar to 15 degrees C fish and had increased input resistance, increased strength of inhibitory transmission, and reduced excitatory transmission. We show here that alterations in the balance between excitatory and inhibitory synaptic transmission in the M-cell circuit underlie differences in behavioral responsiveness in acclimated populations. Specifically, during warm acclimation, synaptic inputs are weighted on the side of excitation and fish demonstrate hyperexcitability and reduced left-right discrimination during rapid escapes. In contrast, cold acclimation results in transmission weighted on the side of inhibition and these fish are less excitable and show improved directional discrimination.
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16
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Weiss SA, Zottoli SJ, Do SC, Faber DS, Preuss T. Correlation of C-start behaviors with neural activity recorded from the hindbrain in free-swimming goldfish (Carassius auratus). J Exp Biol 2006; 209:4788-801. [PMID: 17114411 DOI: 10.1242/jeb.02582] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYStartle behaviors in teleost fishes are well suited for investigations of mechanisms of sensorimotor integration because the behavior is quantifiable and much of the underlying circuitry has been identified. The teleost C-start is triggered by an action potential in one of the two Mauthner (M) cells. To correlate C-start behavior with electrophysiology, extracellular recordings were obtained from the surface of the medulla oblongata in the hindbrain,close to the M-axons, in freely swimming goldfish monitored using high-speed video. The recordings included action potentials generated by the two M-axons,as well as neighboring axons in the dorsal medial longitudinal fasciculus. Axonal backfills indicated that the latter originate from identifiable reticulospinal somata in rhombomeres 2-8 and local interneurons. Diverse auditory and visual stimuli evoked behaviors with kinematics characteristic of the C-start, and the amplitude of the first component of the hindbrain field potential correlated with the C-start direction. The onset of the field potential preceded that of the simultaneously recorded trunk EMG and movement initiation by 1.08±0.04 and 8.13±0.17 ms, respectively. A subsequent longer latency field potential was predictive of a counterturn. These results indicate that characteristic features of the C-start can be extracted from the neural activity of the M-cell and a population of other reticulospinal neurons in free-swimming goldfish.
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Affiliation(s)
- Shennan A Weiss
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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Lenz PH, Hower AE, Hartline DK. Temperature compensation in the escape response of a marine copepod, Calanus finmarchicus (Crustacea). THE BIOLOGICAL BULLETIN 2005; 209:75-85. [PMID: 16110095 DOI: 10.2307/3593143] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Calanus finmarchicus, the dominant mesozooplankter of the North Atlantic, is an important food source for many fishes and other planktivores. This species, which has limited diel vertical migration, depends on its fast-start escape response to evade predators. It has myelinated neuronal axons, which contribute to its rapid and powerful escape response. The thermal environment that C. finmarchicus inhabits ranges from below 0 degrees C to 16 degrees C. Previous studies have shown that respiration, growth, and reproductive rates are strongly dependent on temperature, with Q10 > 2.5. A comparable dependence of the escape response could place the animal at higher risk for cold-compensated predators. Our work focused on the temperature dependence of the behavioral response to stimuli that mimic predatory attacks. We found that in contrast to other biological processes, all aspects of the escape response showed a low dependence on temperature, with Q10 values below 2. This low temperature dependence was consistent for escape parameters that involved neural as well as muscle components of the behavioral response. These findings are discussed in the contexts of the predator-prey relations of copepods and the thermal dependence of behavior in other taxa.
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Affiliation(s)
- P H Lenz
- Pacific Biosciences Research Center, University of Hawaii at Manoa, 1993 East-West Rd., Honolulu, Hawaii 96822, USA.
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18
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Abstract
Physiological systems that must operate over a range of temperatures often incorporate temperature-compensatory mechanisms to maintain their output within a relatively narrow, functional range of values. We analyze here an example in the accessory radula closer (ARC) neuromuscular system, a representative part of the feeding neuromusculature of the sea slug Aplysia. The ARC muscle's two motor neurons, B15 and B16, release, in addition to ACh that contracts the muscle, modulatory peptide cotransmitters that, through a complex network of effects in the muscle, shape the ACh-induced contractions. It is believed that this modulation is critical in optimizing the performance of the muscle for successful, efficient feeding behavior. However, previous work has shown that the release of the modulatory peptides from the motor neurons decreases dramatically with increasing temperature. From 15 to 25 degrees C, for example, release decreases 20-fold. Yet Aplysia live and feed successfully not only at 15 degrees C, but at 25 degrees C and probably at higher temperatures. Here, working with reduced B15/B16-ARC preparations in vitro as well as a mathematical model of the system, we have found a resolution of this apparent paradox. Although modulator release decreases 20-fold when the temperature is raised from 15 to 25 degrees C, the observed modulation of contraction shape does not decrease at all. Two mechanisms are responsible. First, further downstream within the modulatory network, the modulatory effects themselves-experimentally dissected by exogenous modulator application-have temperature dependencies opposite to that of modulator release, increasing with temperature. Second, the saturating curvature of the dose-response relations within the network diminishes the downstream impact of the decrease of modulator release. Thus two quite distinct mechanisms, one depending on the characteristics of the individual components of the network and the other emerging from the network's structure, combine to compensate for temperature changes to maintain the output of this physiological system.
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Affiliation(s)
| | - Vladimir Brezina
- Author for correspondence and proofs: Dr. Vladimir Brezina, Department of Neuroscience, Box 1218, Mt. Sinai School of Medicine, 1 Gustave L. Levy Place, New York, NY 10029, tel. (212) 241-6532; fax (212) 860-3369, email
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Schulz JR, Norton AG, Gilly WF. The projectile tooth of a fish-hunting cone snail: Conus catus injects venom into fish prey using a high-speed ballistic mechanism. THE BIOLOGICAL BULLETIN 2004; 207:77-79. [PMID: 15501848 DOI: 10.2307/1543581] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Affiliation(s)
- Joseph R Schulz
- Hopkins Marine Station, Department of Biological Sciences, Stanford University, 120 Ocean View Blvd., Pacific Grove, California 93950, USA.
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20
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Buskey EJ, Hartline DK. High-speed video analysis of the escape responses of the copepod Acartia tonsa to shadows. THE BIOLOGICAL BULLETIN 2003; 204:28-37. [PMID: 12588742 DOI: 10.2307/1543493] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The copepod Acartia tonsa exhibits a vigorous escape jump in response to rapid decreases in light intensity, such as those produced by the shadow of an object passing above it. In the laboratory, decreases in light intensity were produced using a fiber optic lamp and an electronic shutter to abruptly either nearly eliminate visible light or reduce light intensity to a constant proportion of its original intensity. The escape responses of A. tonsa to these rapid decreases in visible light were recorded on high-speed video using infrared illumination. The speed, acceleration, and direction of movement of the escape response were quantified from videotape by using automated motion analysis techniques. A. tonsa typically responds to decreases in light intensity with an escape jump comprising an initial reorientation followed by multiple power strokes of the swimming legs. These escape jumps can result in maximum speeds of over 800 mm s(-1) and maximum accelerations of over 200 m s(-2). In A. tonsa, photically stimulated escape responses differ from hydrodynamically stimulated responses mainly in the longer latencies of photically stimulated responses and in the increased number of power strokes, even when the stimulus is near threshold; these factors result in longer escape jumps covering greater distances. The latency of responses of A. tonsa to this photic stimulus ranged from a minimum of about 30 ms to a maximum of more than 150 ms, compared to about 4 ms for hydrodynamically stimulated escape jumps. Average response latency decreased with increasing light intensity or increasing proportion of light eliminated. Little change was observed in the vigor of the escape response to rapid decreases in visible light over a wide range of adaptation intensities.
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Affiliation(s)
- Edward J Buskey
- Marine Science Institute, 750 Channel View Drive, Port Aransas, Texas 78373, USA.
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21
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Rosenthal JJC, Bezanilla F. A comparison of propagated action potentials from tropical and temperate squid axons: different durations and conduction velocities correlate with ionic conductance levels. J Exp Biol 2002; 205:1819-30. [PMID: 12042340 DOI: 10.1242/jeb.205.12.1819] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYTo determine which physiological properties contribute to temperature adaptation in the squid giant axon, action potentials were recorded from four species of squid whose habitats span a temperature range of 20°C. The environments of these species can be ranked from coldest to warmest as follows: Loligo opalescens>Loligo pealei>Loligo plei>Sepioteuthis sepioidea. Action potential conduction velocities and rise times,recorded at many temperatures, were equivalent for all Loligospecies, but significantly slower in S. sepioidea. By contrast, the action potential's fall time differed among species and correlated well with the thermal environment of the species (`warmer' species had slower decay times). The biophysical underpinnings of these differences were examined in voltage-clamped axons. Surprisingly, no differences were found between the activation kinetics or voltage-dependence of Na+ and K+currents. Conductance levels, however, did vary. Maximum Na+conductance (gNa) in S. sepiodea was significantly less than in the Loligo species. K+ conductance (gK) was highest in L. pealei, intermediate in L. plei and smallest in S. sepiodea. The time course and magnitude of gK and gNa were measured directly during membrane action potentials. These data reveal clear species-dependent differences in the amount of gK and gNa recruited during an action potential.
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Clay JR, Shrier A. Action potentials occur spontaneously in squid giant axons with moderately alkaline intracellular pH. THE BIOLOGICAL BULLETIN 2001; 201:186-192. [PMID: 11687390 DOI: 10.2307/1543333] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This report demonstrates a novel finding from the classic giant axon preparation of the squid. Namely, the axon can be made to fire autonomously (spontaneously occurring action potentials) when the intracellular pH (pH(i)) was increased to about 7.7, or higher. (Physiological pH(i) is 7.3.) The frequency of firing was 33 Hz (T = 5 degrees ). No changes in frequency or in the voltage waveform itself were observed when pH(i) was increased from 7.7 up to 8.5. In other words, the effect has a threshold at a pH(i) of about 7.7. A mathematical model that is sufficient to mimic these results is provided using a modified version of the Clay (1998) description of the axonal ionic currents.
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Affiliation(s)
- J R Clay
- Laboratory of Neurophysiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Sweedler JV, Li L, Floyd P, Gilly W. Mass spectrometric survey of peptides in cephalopods with an emphasis on the FMRFamide-related peptides. J Exp Biol 2000; 203:3565-73. [PMID: 11060217 DOI: 10.1242/jeb.203.23.3565] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) survey of the major peptides in the stellar, fin and pallial nerves and the posterior chromatophore lobe of the cephalopods Sepia officinalis, Loligo opalescens and Dosidicus gigas has been performed. Although a large number of putative peptides are distinct among the three species, several molecular masses are conserved. In addition to peptides, characterization of the lipid content of the nerves is reported, and these lipid peaks account for many of the lower molecular masses observed. One conserved set of peaks corresponds to the FMRFamide-related peptides (FRPs). The Loligo opalescens FMRFa gene has been sequenced. It encodes a 331 amino acid residue prohormone that is processed into 14 FRPs, which are both predicted by the nucleotide sequence and confirmed by MALDI MS. The FRPs predicted by this gene (FMRFa, FLRFa/FIRFa and ALSGDAFLRFa) are observed in all three species, indicating that members of this peptide family are highly conserved across cephalopods.
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Affiliation(s)
- J V Sweedler
- Beckman Institute, University of Illinois, Urbana, IL 61801, USA.
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