Fish Lateral Line Research Articles

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A Pressure Sensory System Inspired by the Fish Lateral Line: Hydrodynamic Force Estimation and Wall Detection

Studies have shown that many behavioral decisions of fish are facilitated by the lateral line system which provides hydrodynamic information about the surrounding fluid. Inspired by the functionality of the system, a distributed pressure sensory system is developed. The system is intended for use on autonomous underwater vehicles to aid station keeping and accurate maneuvering by allowing the vehicle to react to the changes in the fluid environment before they result in body perturbation. The system can also be used for mission level decision making such as obstacle detection. This paper presents a prototype sensory system using differential, as opposed to absolute or gauge, pressure sensors as the sensing elements, which allows for higher measurement precision. Experimental tests are designed to characterize the system's ability to estimate the hydrodynamic force and to detect the presence of a wall. The hydrodynamic force estimated by the system is validated with an independent force measuring apparatus. The impending wall could also be detected by analyzing the pressure distribution obtained from the sensory system. Particularly, it is found that the wall distance and angle may be inferred by comparing the amplitude and phase of the Fourier components in the pressure distribution against those without the obstacle.

Effect of environmental toxins on the fish lateral line

Fishes use their lateral line system to sense nearfield water movement associated with both abiotic and biotic sources. Given the external location of lateral line sensory organs, we hypothesized that this system would be sensitive to exposure from toxins that accumulate in the aquatic environment. The toxicant bisphenol-A (BPA), a component of many plastics, is prevalent in U.S. watersheds. We found that BPA exposure did not influence lateral line development in zebrafish, but that BPA was toxic when applied acutely to mature lateral line organs. BPA also reduced the regenerative potential of the lateral line, suggesting that BPA may affect both sensory hair cells and surrounding supporting cells. As fish in urban areas are often exposed to high levels of road pollution that enters waterways during storm events, we also examined the effect of stormwater runoff on the lateral line. In contrast to BPA, stormwater was not acutely toxic to the mature lateral line, but it had a detrimental effect on lateral line development in both zebrafish and salmonids. Collectively, our results demonstrate that aquatic pollutants can negatively impact fish mechanosensory systems, perhaps leading to decreased survival.

Protective effect of an astaxanthin nanoemulsion against neomycin-induced hair-cell damage in zebrafish

The cause of those hair cells disorder is oxidative stress due to free radicals. In particular, hair cells are very susceptible to aminoglycosides. Antioxidant is known to reduce the generation of oxygen-derived free radicals. Various antioxidant is marketed, and different dosage form is developed with the same drug. Using a zebra fish lateral line, we report hair cell protection effect of astaxanthin from neomycin-induced trauma. Zebrafish larvae were exposed to the astaxanthin nanoemulsion or to the suspension for 1h, or were left unexposed. Subsequently, the larvae were exposed to neomycin for 1h by adding the neomycin solution. Results were calculated as the mean hair-cell survival as a percentage of the control. Hair cells were not protected in the group treated with astaxanthin suspension and neomycin. On the other hand, there was dose-dependent protection against neomycin-induced hair-cell death in the zebrafish lateral-line hair cells in the group treated with nano astaxanthin. The results of the current study performed using a zebra fish lateral-line, nano astaxanthin protected sensory hair cells against neomycin-induced death. This suggests that nano-astaxanthin is more efficiently absorbed in the body than astaxanthin, and may be useful as a protective drug for the inner ear.

Lateral line makes Pachón cavefish sleepless

As life choices go, it might seem extreme, but for blind Mexican cavefish, the choice to forgo sight was probably a no-brainer: eye running-costs are high in the dark, oxygen-poor cave waters where the fish make their homes. In addition, many truly sightless cavefish also make do with very little sleep, requiring as little as 5–20% of the sleep required by their surface-dwelling cousins. But Alex Keene, from Florida Atlantic University, USA, highlights that ‘little was known about the neural mechanisms underlying this dramatic behavioural shift’. Intrigued by the phenomenon, Keene and graduate student James Jaggard began investigating the neural mechanisms that have led cavefish populations to reduce their dependence on sleep.Explaining that sleep is defined as occurring when animals are slow to respond to physical stimuli, Jaggard focused on the Pachón cavefish population – which have dramatically reduced their eyes – filming the fish for 24 h to determine how long they sleep. Categorizing fish as asleep when they ceased moving for 60 s or more, Jaggard noticed that the cave fish took fewer sleep bouts, only achieving a total of ∼1 h of sleep a day, compared with the ∼7 h taken in more frequent bouts by the sighted relatives above ground. But what mechanism has caused the cavefish to cut their sleep so dramatically?As sensory systems – such as vision, hearing and smell – are known to play a significant role in regulating sleep, Jaggard and Keene decided to inactivate the fish's lateral line – which senses water flow and the presence of prey – to find out whether that system affected the fish's sleep pattern. Bathing the fish in the antibiotic gentamicin, which damages vibration-sensitive hair cells in the hearing systems of mammals, Keene recorded the fish's sleep patterns and was impressed to see that the cavefish now slept as much as their surface cousins. This suggests that enhanced sensory input underlies the evolutionarily derived sleep loss in Pachón cavefish, and the team adds, ‘these findings reveal a wake-promoting role for the lateral line’. However, when Jaggard tested the impact of gentamicin on other sleepless cavefish populations (Molino, Tinaja, Los Sabinos and Chica cavefish), none of them gained more sleep time, suggesting that each of the subterranean populations has independently evolved distinct mechanisms for regulating sleep.Another question that intrigued Jaggard and Keene was why cavefish miss out on sleep. As sleep loss could extend the time available for foraging in their barren cave homes, the duo starved Pachón fish and discovered that the hungry animals increased the amount of sleep to ∼6 h day−1. So, the fish may be able to modulate the amount of sleep that they take depending on food availability to maximise foraging opportunities when food is available.Finally, Jaggard tested which flow sensitive receptors on the surface of the Pachon fish are responsible for keeping the fish awake longer, by selectively coating the flow sensors on different portions of the body with adhesive. Recording how much the fish slept, Jaggard could see that the flow sensors on the fish's head and trunk were essential for regulating sleep, as the treated fish slept more. And when he compared the amount of time that the fish indulged in sleep between individuals – which can vary significantly – it was clear that the fish that slept the least had the greatest numbers of flow sensors.Summing up, Keene says, ‘The evolution of enhanced sensory capabilities contributes to sleep loss in cavefish’, and he is eager to selectively disable the lateral line sensors in order to learn more about their contribution to sleep regulation in these extraordinary fish.

Analysis of MEMS Piezoelectric Hydrophone at High Sensitivity for underwater application

Micro-electromechanical systems (MEMS), is a technology that is used to design small integrated devices that combines both electrical (voltage, resistance) and mechanical components (stress, displacement). These devices are assembled using integrated circuit batch processing methods and their size can vary from Micrometers (µm) to Millimeters (mm). MEMS devices have the capability to sense and control the environment. These devices are fabricated using System Integrated chip technology and micro-level segments are manufactured using silicon. To remove the selective parts of silicon i.e. extra silicon parts, Processes such as back etching, high-aspect-ratio micromachining are used to remove selective parts of silicon or to add the extra layers to form the electromechanical components. The study is concerned to design a T- Shape vector Hydrophone using MEMS Technology and to analyses mechanical properties like induced stresses, deformation and to analyses the piezoelectric hydrophone characteristics like frequency response, sensitivity and Voltage to achieve improved sensitivity. MEMS Directional Hydrophone PZT is simulated. Both the structure resembles the fish lateral line and auditory cilia system which converts acoustic pressure into voltage

Weakly electric fish learn both visual and electrosensory cues in a multisensory object discrimination task

Weakly electric fish use electrosensory, visual, olfactory and lateral line information to guide foraging and navigation behaviors. In many cases they preferentially rely on electrosensory cues. Do fish also memorize non-electrosensory cues? Here, we trained individuals of gymnotiform weakly electric fish Apteronotus albifrons in an object discrimination task. Objects were combinations of differently conductive materials covered with differently colored cotton hoods. By setting visual and electrosensory cues in conflict we analyzed the sensory hierarchy among the electrosensory and the visual sense in object discrimination. Our experiments show that: (i) black ghost knifefish can be trained to solve discrimination tasks similarly to the mormyrid fish; (ii) fish preferentially rely on electrosensory cues for object discrimination; (iii) despite the dominance of the electrosense they still learn the visual cue and use it when electrosensory information is not available; (iv) fish prefer the trained combination of rewarded cues over combinations that match only in a single feature and also memorize the non-rewarded combination.

Piezoresistive foam sensor arrays for marine applications

Spatially-dense pressure measurements are needed on curved surfaces in marine environments to provide marine vehicles with the detailed, real-time measurements of the near-field flow necessary to improve performance through flow control. To address this challenge, a waterproof and conformal pressure sensor array comprising carbon black-doped-silicone closed-cell foam (CBPDMS foam) was developed for use in marine applications. The response of the CBPDMS foam sensor arrays was characterized underwater using periodic hydrodynamic pressure stimuli from vertical plunging and surface water waves, from which a piecewise polynomial calibration was developed to describe the sensor response. Inspired by the distributed pressure and velocity sensing capabilities of the fish lateral line, the CBPDMS foam sensor arrays have significant advantages over existing commercial sensors for distributed flow reconstruction and control. Experimental results have shown the sensor arrays to have sensitivity underwater on the order of 5Pa, dynamic range of 50⬜500Pa; are contained in a waterproof and completely flexible package, and have material cost less than $10 per sensor.

Computer Simulation of AUV Navigation System Using Fish Lateral Line Sensing Mechanism

Based on the study of fish lateral line sensing mechanism, integrated fluid dynamics, boundary layer theory, coupling theory and so on. To establish a neural network model similar to the fish neuromas model. After the numerical calculation and simulation analysis to simulate fish lateral line system, we can get the conclusions to apply to autonomous underwater vehicle (AUV) navigation and target recognition. Provided a new method for AUV navigation and environment perception. Computer simulation results presented that based on the fish lateral line sensing mechanism to build a perception model, AUV can identify a new water condition distinguishably. This discovery can be used in navigation and positioning of AUV.

Joint Estimation of Bulk Flow Velocity and Angle Using a Lateral Line Probe

Measurement of complex natural flows, especially those occurring in rivers due to man-made structures, is often hampered by the limitations of existing flow measurement methods. Furthermore, there is a growing need for new measurement devices that are capable of measuring the hydrodynamic characteristics of complex natural flows required in environmental studies that often use fish as an indicator of ecological health. In this paper, we take the first step toward in situ natural flow measurements with a new biologically inspired probe design in conjunction with signal processing methods. The device presented in this paper is a dedicated hydrodynamically sensitive sensor array following the fish lateral line sensor modality. Low-level multidimensional sensor signals are transformed to the two key hydrodynamic primitives, bulk flow velocity and bulk flow angle. We show that this can be achieved via canonical signal transformation and kernel ridge regression, allowing velocity estimates with a less than 10 cm/s error. The approach provides robust velocity estimates not only when the sensor is ideally oriented parallel to the bulk flow, but also across the full range of angular deviations up to a completely orthogonal orientation by correcting the pressure field asymmetry for large angular deviations. Furthermore, we show that their joint estimation becomes feasible above a threshold current velocity of 0.45 m/s. The method demonstrated an error of 14 cm/s in velocity estimation in a river environment after training in laboratory conditions.

Macrophage Recruitment Contributes to Regeneration of Mechanosensory Hair Cells in the Zebrafish Lateral Line.

In vertebrates, damage to mechanosensory hair cells elicits an inflammatory response, including rapid recruitment of macrophages and neutrophils. While hair cells in amniotes usually become permanently lost, they readily regenerate in lower vertebrates such as fish. Damage to hair cells of the fish lateral line is followed by inflammation and rapid regeneration; however the role of immune cells in this process remains unknown. Here, we show that recruited macrophages are required for normal regeneration of lateral line hair cells after copper damage. We found that genetic ablation or local ablation using clodronate liposomes of macrophages recruited to the site of injury, significantly delays hair cell regeneration. Neutrophils, on the other hand, are not needed for this process. We anticipate our results to be a starting point for a more detailed description of extrinsic signals important for regeneration of mechanosensory cells in vertebrates. J. Cell. Biochem. 117: 1880-1889, 2016. © 2016 Wiley Periodicals, Inc.

Simulation Research in Water Condition Recognition Method Based on Fish Lateral Line Sensing Mechanism

Simulation Research in Water Condition Recognition Method Based on Fish Lateral Line Sensing Mechanism

A μ-biomimetic flow sensor for medical and pharmaceutical applications.

Flow sensing is pivotal in many medical and pharmaceutical applications. Most commercial flow sensors are either expensive, complex, or consume a lot of energy, while low cost sensors usually lack sensitivity, robustness, or long-term stability. In addition, the maintenance and sterilization of most commercial flow sensors is difficult to perform. Here, we present a new μ-biomimetic flow sensor based on the fish lateral line. It measures flow velocity and detects the transition between laminar and turbulent flow, thereby fulfilling most requirements for medical and pharmaceutical applications. Additionally, it has a modular setup featuring a screened or passive bypass configuration, enabling it not only to meter flow in medical applications but also under harsh or well-defined environmental conditions, such as found in pharmaceutical applications. The sensor is robust and can be easily cleaned. Individual parts of the sensor can even be replaced or sterilized. In sum, this sensor opens up a whole new field of applications in the area of medical and pharmaceutical related flow monitoring.

Spatial Variation in the Mercury Concentration of Muscle Myomeres in Steaks of Farmed Southern Bluefin Tuna.

Mercury concentration in the muscular tissue of farmed southern bluefin tuna, Thunnus maccoyii (SBT) is known to vary. Data suggests that mercury concentration is negatively correlated with the lipid concentration of tissues. Those areas that accumulate higher levels of lipid are noted to have a lower mercury concentration than lean tissues. Here we further delineate variation in mercury concentration within SBT muscular tissues by determining the concentration of mercury in the muscle myomeres (those sections within whole muscles) of transverse sectional steaks of farmed SBT. Mercury concentration in myomeres is observed to significantly decrease with dorsal and ventral distance from the spine or lateral line of fish. By extension, evidence is provided for the variation of mercury concentration within tissue cuts present in SBT steaks. This paper provides the first documentation of variation in mercury concentration within muscular tissue of fish.

μ-biomimetic flow-sensors—introducing light-guiding PDMS structures into MEMS

In the area of biomimetics, engineers use inspiration from natural systems to develop technical devices, such as sensors. One example is the lateral line system of fish. It is a mechanoreceptive system consisting of up to several thousand individual sensors called neuromasts, which enable fish to sense prey, predators, or conspecifics. So far, the small size and high sensitivity of the lateral line is unmatched by man-made sensor devices. Here, we describe an artificial lateral line system based on an optical detection principle. We developed artificial canal neuromasts using MEMS technology including thick film techniques. In this work, we describe the MEMS fabrication and characterize a sensor prototype. Our sensor consists of a silicon chip, a housing, and an electronic circuit. We demonstrate the functionality of our -biomimetic flow sensor by analyzing its response to constant water flow and flow fluctuations. Furthermore, we discuss the sensor robustness and sensitivity of our sensor and its suitability for industrial and medical applications. In sum, our sensor can be used for many tasks, e.g. for monitoring fluid flow in medical applications, for detecting leakages in tap water systems or for air and gas flow measurements. Finally, our flow sensor can even be used to improve current knowledge about the functional significance of the fish lateral line.

Size control during organogenesis: Development of the lateral line organs in zebrafish.

Many genes that play essential roles in organ growth have been identified across a range of organisms. However, the mechanisms by which growing organs can sense their sizes and stop growing when they reach their proper sizes remain poorly understood. The mechanosensory organs of the fish lateral line system (neuromasts) provide an ideal system to address this question for the following reasons. First, each superficial neuromast is composed of a small number of cells situated on the body surface, making it relatively easy to quantify organ size throughout development. Second, while the sensory cells of superficial neuromasts are continuously renewed, overall organ size is homeostatically maintained. Third, there is another type of neuromast showing an opposite mode of growth: that is, canal neuromasts increase in size in proportion to organism body size. Here, we review recent findings regarding the mechanisms that control organ size in the zebrafish lateral line.

Bionic Research and it’s Application of Artificial Lateral Line System

Nowadays, lots of efforts have been made to develop new technology for navigation system of underwater vehicle with the increasingly improved requirements of precise positioning, obstacles-avoidance, energy-saving in locomotion and stabilization in response to turbulent currents. In nature, fish have a great ability to localize prey, school, navigate, rheotaxis, etc. using the lateral-line organ. The biological lateral line system has inspired the researchers’ efforts to artificial lateral lines for applications in underwater vehicles and robots. In this paper, the working mechanism of the fish lateral line system has been described. Then the research status both at biology and at mechanics on the artificial lateral line system at home and abroad has been reviewed. To make a comparison with acoustic navigation system USBL,The key technologies and developing tendency as well as potential applications are described. At last, an insight on the future research directions and route of artificial lateral-line system have been given.

Design of a monolithic integrated three-dimensional MEMS bionic vector hydrophone

In this paper, micro-electromechanical systems (MEMS) technology and the bionic principle are used to develop a low-frequency high-sensitivity three-dimensional omni-vector hydrophone that can obtain vector information of an underwater sound field by imitating the auditory principle of a fish's lateral line organ. The key features are smaller size, better consistency, better low-frequency characteristic, higher sensitivity, and rigid mounting, which thus allow a spatial acoustic source to be detected directionally by a single hydrophone. The bionic MEMS microstructure was designed and fabricated and consists of two components: the vertical detection unit including a four-beam-cilium structure and a level detection unit including a double T-shaped beam structure. On the basis of theoretical analysis, the structure size and layout location of the piezoresistors are determined by simulation analysis and the double cilia type microstructure is fabricated integrally by MEMS manufacturing technology; after which the acoustic package of the microstructure is complete and the prototype is produced. Finally, this paper presents the experimental characterization of the microdevice, validating the concept and the analytical models used. The test results show that the three-dimensional vector hydrophone has a flat frequency response curve, exhibits a sensitivity of ?185 dB (X, Y) and ?181 dB (Z) (1 kHz, 0 dB reference 1 V/uPa) and shows a good directivity pattern in the form of an "8" shaped. More importantly, the depth of the concave point reaches 47.7 dB, and the asymmetry is only 0.5 dB, indicating that the three-dimensional vector hydrophone has great advantages in spatial orientation, which is suitable for applications in sonar systems.

The Nogo-C2/Nogo Receptor Complex Regulates the Morphogenesis of Zebrafish Lateral Line Primordium through Modulating the Expression of dkk1b, a Wnt Signal Inhibitor

The fish lateral line (LL) is a mechanosensory system closely related to the hearing system of higher vertebrates, and it is composed of several neuromasts located on the surface of the fish. These neuromasts can detect changes in external water flow, to assist fish in maintaining a stationary position in a stream. In the present study, we identified a novel function of Nogo/Nogo receptor signaling in the formation of zebrafish neuromasts. Nogo signaling in zebrafish, like that in mammals, involves three ligands and four receptors, as well as three co-receptors (TROY, p75, and LINGO-1). We first demonstrated that Nogo-C2, NgRH1a, p75, and TROY are able to form a Nogo-C2 complex, and that disintegration of this complex causes defective neuromast formation in zebrafish. Time-lapse recording of the CldnB::lynEGFP transgenic line revealed that functional obstruction of the Nogo-C2 complex causes disordered morphogenesis, and reduces rosette formation in the posterior LL (PLL) primordium during migration. Consistent with these findings, hair-cell progenitors were lost from the PLL primordium in p75, TROY, and Nogo-C2/NgRH1a morphants. Notably, the expression levels of pea3, a downstream marker of Fgf signaling, and dkk1b, a Wnt signaling inhibitor, were both decreased in p75, TROY, and Nogo-C2/NgRH1a morphants; moreover, dkk1b mRNA injection could rescue the defects in neuromast formation resulting from knockdown of p75 or TROY. We thus suggest that a novel Nogo-C2 complex, consisting of Nogo-C2, NgRH1a, p75, and TROY, regulates Fgf signaling and dkk1b expression, thereby ensuring stable organization of the PLL primordium.

Mexican blind cavefish use mouth suction to detect obstacles

Fish commonly use their lateral line system to detect moving bodies such as prey and predators. A remarkable case is the Mexican blind cavefish Astyanax fasciatus, which evolved the ability to detect non-moving obstacles. The swimming body of A. fasciatus generates fluid disturbances, the alteration of which by an obstacle can be sensed by the fish's lateral line system. It is generally accepted that these alterations can provide information on the distance to the obstacle. We observed that A. fasciatus swimming in an unfamiliar environment open and close their mouths at high frequency (0.7-4.5 Hz) in order to generate suction flows. We hypothesized that repeated mouth suction generates a hydrodynamic velocity field, which is altered by an obstacle, inducing pressure gradients in the neuromasts of the lateral line and corresponding strong lateral line stimuli. We observed that the frequency and rate of mouth-opening events varied with the fish's distance to obstacles, a hallmark of pulse-based navigation mechanisms such as echolocation. We formulated a mathematical model of this hitherto unrecognized mechanism of obstacle detection and parameterized it experimentally. This model suggests that suction flows induce lateral line stimuli that are weakly dependent on the fish's speed, and may be an order of magnitude stronger than the correspondent stimuli induced by the fish's gliding body. We illustrate that A. fasciatus can navigate non-visually using a combination of two deeply ancestral and highly conserved mechanisms of ray-finned fishes: the mechanism of sensing water motion by the lateral line system and the mechanism of generating water motion by mouth suction.