scholarly journals Brain-wide mapping of water flow perception in zebrafish

2020 ◽  
Author(s):  
Gilles Vanwalleghem ◽  
Kevin Schuster ◽  
Michael A. Taylor ◽  
Itia A. Favre-Bulle ◽  
Ethan K. Scott
Keyword(s):  
Water Flow ◽  
Lateral Line ◽  
Reverse Flow ◽  
Forward Direction ◽  
Brain Regions ◽  
Reverse Direction ◽  
Departure Point ◽  
Forward Flow ◽  
Larval Zebrafish ◽  
The Brain

AbstractInformation about water flow, detected by lateral line organs, is critical to the behavior and survival of fish and amphibians. While certain specific aspects of water flow processing have been revealed through electrophysiology, we lack a comprehensive description of the neurons that respond to water flow and the network that they form. Here, we use brain-wide calcium imaging in combination with microfluidic stimulation to map out, at cellular resolution, all neurons involved in perceiving and processing water flow information in larval zebrafish. We find a diverse array of neurons responding to forward flow, reverse flow, or both. Early in this pathway, in the lateral line ganglia, these are almost exclusively neurons responding to the simple presence of forward or reverse flow, but later processing includes neurons responding specifically to flow onset, representing the accumulated volume of flow during a stimulus, or encoding the speed of the flow. The neurons reporting on these more nuanced details are located across numerous brain regions, including some not previously implicated in water flow processing. A graph theory-based analysis of the brain-wide water flow network shows that a majority of this processing is dedicated to forward flow detection, and this is reinforced by our finding that details like flow velocity and the total volume of accumulated flow are only encoded for the simulated forward direction. The results represent the first brain-wide description of processing for this important modality, and provide a departure point for more detailed studies of the flow of information through this network.Significance statementIn aquatic animals, the lateral line is important for detecting water flow stimuli, but the brain networks that interpret this information remain mysterious. Here, we have imaged the activity of individual neurons across the entire brains of larval zebrafish, revealing all response types and their brain locations as water flow processing occurs. We find some neurons that respond to the simple presence of water flow, and others that are attuned to the flow’s direction, speed, duration, or the accumulated volume of water that has passed during the stimulus. With this information, we modeled the underlying network, describing a system that is nuanced in its processing of water flow simulating forward motion but rudimentary in processing flow in the reverse direction.

The Sensitivity of Counterweighted Swing Check Valve Performance to Counterweight Location

2003 ◽  
Author(s):  
L. I. Ezekoye
Keyword(s):  
Flow Resistance ◽  
Reverse Flow ◽  
Check Valve ◽  
Fast Response ◽  
Water Hammer ◽  
Flow Reversal ◽  
Reverse Direction ◽  
Valve Closure ◽  
Forward Flow ◽  
Opening And Closing

Check valves are used to minimize flow reversal. In general, the two primary design objectives of installing a check valve in a system include quick opening in forward flow and fast closure in reverse flow. The fast response requirements in both opening and closing directions are challenging. In the opening direction, the concern is to minimize forward flow resistance and, in the reverse direction, the objective is to minimize flow reversal and avoid water hammer. Check valve manufacturers have often used counterweights to permit quick opening or quick closing. The drawback of forward flow counterweight check valves is that in the flow reverse direction, the counterweights may retard valve closure. The location of the counterweight could further complicate the performance of the check valve. Misaligning the counterweight can also affect check valve performance. The use of quick closing counterweights present similar challenges. This paper examines the interaction of counterweight location and alignment on the performance of check valves.

scholarly journals Cellular resolution imaging of vestibular processing across the larval zebrafish brain

2018 ◽  
Author(s):  
Itia A. Favre-Bulle ◽  
Gilles Vanwalleghem ◽  
Michael A. Taylor ◽  
Halina Rubinsztein-Dunlop ◽  
Ethan K. Scott
Keyword(s):  
Vestibular System ◽  
Cellular Responses ◽  
Vestibular Stimulation ◽  
Brain Regions ◽  
Larval Zebrafish ◽  
Cellular Resolution ◽  
Separate Control ◽  
Resolution Imaging ◽  
Apply Physical ◽  
The Brain

SummaryThe vestibular system, which reports on motion and gravity, is essential to postural control, balance, and egocentric representations of movement and space. The motion needed to stimulate the vestibular system complicates studying its circuitry, so we previously developed a method for fictive vestibular stimulation in zebrafish, using optical trapping to apply physical forces to the otoliths. Here, we combine this fictive stimulation with whole-brain calcium imaging at cellular resolution, delivering a comprehensive map of the brain regions and cellular responses involved in basic vestibular processing. We find these responses to be broadly distributed across the brain, with unique profiles of cellular responses and topography in each brain region. The most widespread and abundant responses involve excitation that is rate coded to the stimulus strength. Other responses, localized to the telencephalon and habenulae, show excitation that is only weakly rate coded and that is sensitive to weak stimuli. Finally, numerous brain regions contain neurons that are inhibited by vestibular stimuli, and these inhibited neurons are often tightly localised spatially within their regions. By exerting separate control over the left and right otoliths, we explore the laterality of brain-wide vestibular processing, distinguishing between neurons with unilateral and bilateral vestibular sensitivity, and revealing patterns by which conflicting vestibular signals from the two ears can be mutually cancelling. Our results show a broader and more extensive network of vestibular responsive neurons than has previously been described in larval zebrafish, and provides a framework for more targeted studies of the underlying functional circuits.

scholarly journals Lateral Line Ablation by Toxins Results in Distinct Rheotaxis Profiles in Fish

2021 ◽  
Author(s):  
Kyle Newton ◽  
Dovi Kacev ◽  
Simon RO Nilsson ◽  
Sam A Golden ◽  
Lavinia Sheets
Keyword(s):  
Hair Cell ◽  
Water Flow ◽  
Lateral Line ◽  
Spectral Decomposition ◽  
Cross Correlation ◽  
Organ Damage ◽  
Swimming Behavior ◽  
Biologically Relevant ◽  
Behavioral Profiles ◽  
Larval Zebrafish

Zebrafish lateral line is an established model for hair cell organ damage, yet few studies link mechanistic disruptions to changes in biologically relevant behavior. We used larval zebrafish to determine how damage via ototoxic chemicals impact rheotaxis. Larvae were treated with CuSO4 or neomycin to disrupt lateral line function then exposed to water flow stimuli. Their swimming behavior was recorded, and DeepLabCut and SimBA software were used to track movements and classify rheotaxis behavior. Lateral line-disrupted fish performed rheotaxis, but they swam greater distances, for shorter durations, and with greater angular variance than controls. Further, spectral decomposition analyses demonstrated that lesioned fish exhibited toxin-specific behavioral profiles with distinct fluctuations in the magnitude, timing, and cross-correlation between changes in linear and angular movements. Our observations support that lateral-line input is needed for fish to perform rheotaxis efficiently in flow and reveals commonly used lesion methods have unique effects on behavior.

Design and Performance of a Directional Permeability Membrane

2019 ◽  
Author(s):  
Hamidreza Bayat ◽  
David A. Willis ◽  
Paul S. Krueger
Keyword(s):  
Hydrostatic Pressure ◽  
Flow Rate ◽  
Imaging System ◽  
Reverse Flow ◽  
Pressure Head ◽  
Forward Direction ◽  
Reverse Direction ◽  
Depth Of Field ◽  
Small Depth ◽  
Directional Permeability

Abstract Directional permeability membranes were designed, fabricated, and tested with the potential application of facilitating drug delivery. Membranes were constructed from two porous polyimide sheets with offset pores and bonded with double sided tape with thickness values of 20 or 70 μm at the perimeter. The pores ranged in diameter from 0.25 to 1.0 mm and were cut using a laser micromachining apparatus. The pores were arranged in a square array with distance of 2 mm from center to center. The membranes were tested under pressure-driven water flow in the range of 0.01–0.10 m of H2O and flow rates were measured for two configurations: one with the thicker sheet upstream (forward direction) and one with the thinner sheet upstream (reverse direction) and the ratio of forward/reverse flow was calculated. In order to better understand membrane behavior, the maximum deflection of the thinner sheet was measured using an imaging system composed of a lens with small depth of field, digital camera, motorized linear translation stage, and a motion controller. Results show that in forward flow, by increasing hydrostatic pressure from 0.01 to 0.10 m H2O the mass flow rate increased by 40–55%. Conversely, increasing the hydrostatic pressure in the reverse direction from 0.01 to 0.10 m H2O considerably reduces the flow rate. The ratio of forward to reverse flow rate of the membrane varied in the range of 1.5 to 9529, depending on the pressure head.

Topology Optimization of Fixed-Geometry Fluid Diodes

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Sen Lin ◽  
Longyu Zhao ◽  
James K. Guest ◽  
Timothy P. Weihs ◽  
Zhenyu Liu
Keyword(s):  
Topology Optimization ◽  
Reverse Flow ◽  
Flow Behavior ◽  
Projection Methods ◽  
Reverse Direction ◽  
Minimum Length ◽  
Penalty Term ◽  
Forward Flow ◽  
Dependent Flow ◽  
Minimum Length Scale

This paper proposes using topology optimization to design fixed-geometry fluid diodes that allow easy passage of fluid flowing in one direction while inhibiting flow in the reverse direction. Fixed-geometry diodes do not use movable mechanical parts or deformations, but rather utilize inertial forces of the fluid to achieve this flow behavior. Diode performance is measured by diodicity, defined as the ratio of pressure drop of reverse flow and forward flow, or equivalently the ratio of dissipation of reverse and forward flow. Diodicity can then be maximized by minimizing forward dissipation while maximizing reverse dissipation. While significant research has been conducted in topology optimization of fluids for minimizing dissipation, maximizing dissipation introduces challenges in the form of small, mesh dependent flow channels and that artificial flow in solid region becomes (numerically) desirable. These challenges are circumvented herein using projection methods for controlling the minimum length scale of channels and by introducing an additional penalty term on flow through intermediate porosities. Several solutions are presented, one of which is fabricated by 3D printing and experimentally tested to demonstrate the diodelike behavior.

Management of Glioblastoma Multiforme by Phytochemicals: Applications of Nanoparticle Based Targeted Drug Delivery System

2020 ◽  
Vol 21 ◽  
Author(s):  
Sayed Md Mumtaz ◽  
Gautam Bhardwaj ◽  
Shikha Goswami ◽  
Rajiv Kumar Tonk ◽  
Ramesh K. Goyal ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Glioblastoma Multiforme ◽  
Drug Delivery System ◽  
Delivery System ◽  
Genetic Disorder ◽  
Drug Regimen ◽  
Brain Regions ◽  
Radio Therapy ◽  
Novel Drug ◽  
The Brain

: The Glioblastoma Multiforme (GBM; grade IV astrocytoma) exhort tumor of star-shaped glial cell in the brain. It is a fast-growing tumor that spreads to nearby brain regions specifically to cerebral hemispheres in frontal and temporal lobes. The etiology of GBM is unknown, but major risk factors are genetic disorder like neurofibromatosis and schwanomatosis which develop the tumor in the nervous system. The management of GBM with chemo-radio therapy leads to resistance and current drug regimen like Temozolomide (TMZ) is less efficacious. The reasons behind failure of drugs are due to DNA alkylation in cell cycle by enzyme DNA guanidase and mitochondrial dysfunction. Naturally occurring bio-active compounds from plants known as phytochemicals, serve as vital sources for anti-cancer drugs. Some typical examples include taxol analogs, vinca alkaloids such as vincristine, vinblastine, podophyllotoxin analogs, camptothecin, curcumin, aloe emodin, quercetin, berberine e.t.c. These phytochemicals often act via regulating molecular pathways which are implicated in growth and progression of cancers. However the challenges posed by the presence of BBB/BBTB to restrict passage of these phytochemicals, culminates in their low bioavailability and relative toxicity. In this review we integrated nanotech as novel drug delivery system to deliver phytochemicals from traditional medicine to the specific site within the brain for the management of GBM.

Neuro-Clinical Signatures of Language Impairments: A Theoretical Framework for Function-to-structure Mapping in Clinics

2020 ◽  
Vol 20 (9) ◽  
pp. 800-811 ◽  
Author(s):  
Ferath Kherif ◽  
Sandrine Muller
Keyword(s):  
Brain Mapping ◽  
Theoretical Framework ◽  
Brain Regions ◽  
Language Impairments ◽  
Structure Mapping ◽  
Language Functions ◽  
The Past ◽  
Language Recovery ◽  
The Brain ◽  
Bow Tie

In the past decades, neuroscientists and clinicians have collected a considerable amount of data and drastically increased our knowledge about the mapping of language in the brain. The emerging picture from the accumulated knowledge is that there are complex and combinatorial relationships between language functions and anatomical brain regions. Understanding the underlying principles of this complex mapping is of paramount importance for the identification of the brain signature of language and Neuro-Clinical signatures that explain language impairments and predict language recovery after stroke. We review recent attempts to addresses this question of language-brain mapping. We introduce the different concepts of mapping (from diffeomorphic one-to-one mapping to many-to-many mapping). We build those different forms of mapping to derive a theoretical framework where the current principles of brain architectures including redundancy, degeneracy, pluri-potentiality and bow-tie network are described.

scholarly journals Neuroinflammation and protein pathology in Parkinson’s disease dementia

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Antonina Kouli ◽  
Marta Camacho ◽  
Kieren Allinson ◽  
Caroline H. Williams-Gray
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
T Lymphocytes ◽  
Substantia Nigra ◽  
Amyloid Β ◽  
Brain Regions ◽  
Parkinson’S Disease Dementia ◽  
Activated Microglia ◽  
Cell Counts ◽  
The Brain

AbstractParkinson’s disease dementia is neuropathologically characterized by aggregates of α-synuclein (Lewy bodies) in limbic and neocortical areas of the brain with additional involvement of Alzheimer’s disease-type pathology. Whilst immune activation is well-described in Parkinson’s disease (PD), how it links to protein aggregation and its role in PD dementia has not been explored. We hypothesized that neuroinflammatory processes are a critical contributor to the pathology of PDD. To address this hypothesis, we examined 7 brain regions at postmortem from 17 PD patients with no dementia (PDND), 11 patients with PD dementia (PDD), and 14 age and sex-matched neurologically healthy controls. Digital quantification after immunohistochemical staining showed a significant increase in the severity of α-synuclein pathology in the hippocampus, entorhinal and occipitotemporal cortex of PDD compared to PDND cases. In contrast, there was no difference in either tau or amyloid-β pathology between the groups in any of the examined regions. Importantly, we found an increase in activated microglia in the amygdala of demented PD brains compared to controls which correlated significantly with the extent of α-synuclein pathology in this region. Significant infiltration of CD4+ T lymphocytes into the brain parenchyma was commonly observed in PDND and PDD cases compared to controls, in both the substantia nigra and the amygdala. Amongst PDND/PDD cases, CD4+ T cell counts in the amygdala correlated with activated microglia, α-synuclein and tau pathology. Upregulation of the pro-inflammatory cytokine interleukin 1β was also evident in the substantia nigra as well as the frontal cortex in PDND/PDD versus controls with a concomitant upregulation in Toll-like receptor 4 (TLR4) in these regions, as well as the amygdala. The evidence presented in this study show an increased immune response in limbic and cortical brain regions, including increased microglial activation, infiltration of T lymphocytes, upregulation of pro-inflammatory cytokines and TLR gene expression, which has not been previously reported in the postmortem PDD brain.

scholarly journals An architectonic type principle in the development of laminar patterns of cortico-cortical connections

2021 ◽  
Author(s):  
Sarah F. Beul ◽  
Alexandros Goulas ◽  
Claus C. Hilgetag
Keyword(s):  
Structural Connectivity ◽  
Macaque Monkey ◽  
Brain Regions ◽  
Adult Brain ◽  
Mammalian Brain ◽  
Cortical Connections ◽  
Cortical Projections ◽  
Structural Connections ◽  
High Degree ◽  
The Brain

AbstractStructural connections between cortical areas form an intricate network with a high degree of specificity. Many aspects of this complex network organization in the adult mammalian cortex are captured by an architectonic type principle, which relates structural connections to the architectonic differentiation of brain regions. In particular, the laminar patterns of projection origins are a prominent feature of structural connections that varies in a graded manner with the relative architectonic differentiation of connected areas in the adult brain. Here we show that the architectonic type principle is already apparent for the laminar origins of cortico-cortical projections in the immature cortex of the macaque monkey. We find that prenatal and neonatal laminar patterns correlate with cortical architectonic differentiation, and that the relation of laminar patterns to architectonic differences between connected areas is not substantially altered by the complete loss of visual input. Moreover, we find that the degree of change in laminar patterns that projections undergo during development varies in proportion to the relative architectonic differentiation of the connected areas. Hence, it appears that initial biases in laminar projection patterns become progressively strengthened by later developmental processes. These findings suggest that early neurogenetic processes during the formation of the brain are sufficient to establish the characteristic laminar projection patterns. This conclusion is in line with previously suggested mechanistic explanations underlying the emergence of the architectonic type principle and provides further constraints for exploring the fundamental factors that shape structural connectivity in the mammalian brain.

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