Motor control in the epaxial musculature of bluegill sunfish in feeding and locomotion

2021 ◽  
Vol 224 (21) ◽  
Author(s):  
Yordano E. Jimenez ◽  
Elizabeth L. Brainerd

ABSTRACT Fishes possess an impressive repertoire of feeding and locomotor behaviors that in many cases rely on the same power source: the axial musculature. As both functions employ different skeletal systems, head versus body, integrating these functions would likely require modular motor control. Although there have been many studies of motor control in feeding or locomotion in fishes, only one study to date has examined both functions in the same individuals. To characterize bilateral motor control of the epaxial musculature in feeding and locomotion, we measured muscle activity and shortening in bluegill sunfish (Lepomis macrochirus) using electromyography and sonomicrometry. We found that sunfish recruit epaxial regions in a dorsal-to-ventral manner to increase feeding performance, such that high-performance feeding activates all the epaxial musculature. In comparison, sunfish seemed to activate all three epaxial regions irrespective of locomotor performance. Muscle activity was present on both sides of the body in nearly all feeding and locomotor behaviors. Feeding behaviors used similar activation intensities on the two sides of the body, whereas locomotor behaviors consistently used higher intensities on the side undergoing muscle shortening. In all epaxial regions, fast-starts used the highest activation intensities, although high-performance suction feeding occasionally showed near-maximal intensity. Finally, active muscle volume was positively correlated with the peak rate of body flexion in feeding and locomotion, indicating a continuous relationship between recruitment and performance. A comparison of these results with recent work on largemouth bass (Micropterus salmoides) suggests that centrarchid fishes use similar motor control strategies for feeding, but interspecific differences in peak suction-feeding performance are determined by active muscle volume.

2001 ◽  
Vol 41 (6) ◽  
pp. 1266-1279 ◽  
Author(s):  
Michael E. Alfaro ◽  
Jeff Janovetz ◽  
Mark W. Westneat

2001 ◽  
Vol 41 (6) ◽  
pp. 1266-1279 ◽  
Author(s):  
Michael E. Alfaro ◽  
Jeff Janovetz ◽  
Mark W. Westneat

2019 ◽  
Author(s):  
Aref Arzan Zarin ◽  
Brandon Mark ◽  
Albert Cardona ◽  
Ashok Litwin-Kumar ◽  
Chris Q. Doe

AbstractAnimals generate diverse motor behaviors, yet how the same motor neurons generate distinct behaviors remains an open question.Drosophilalarvae have multiple behaviors – e.g. forward crawling, backward crawling, self-righting and escape – and all of the body wall motor neurons (MNs) driving these behaviors have been identified. Despite impressive progress in mapping larval motor circuits, the role of most motor neurons in locomotion remains untested, the majority of premotor neurons (PMNs) remain to be identified, and a full understanding of proprioceptor-PMN-MN connectivity is missing. Here we report a comprehensive larval proprioceptor-PMN-MN connectome; describe individual muscle/MN phase activity during both forward and backward locomotor behaviors; identify PMN-MN connectivity motifs that could generate muscle activity phase relationships, plus selected experimental validation; identify proprioceptor-PMN connectivity that provides an anatomical explanation for the role of proprioception in promoting locomotor velocity; and identify a new candidate escape motor circuit. Finally, we generate a recurrent network model that produces the observed sequence of motor activity, showing that the identified pool of premotor neurons is sufficient to generate two distinct larval behaviors. We conclude that different locomotor behaviors can be generated by a specific group of premotor neurons generating behavior-specific motor rhythms.


2019 ◽  
Vol 19 (11) ◽  
pp. 1382-1387
Author(s):  
Ahmet M. Şenışık ◽  
Çiğdem İçhedef ◽  
Ayfer Y. Kılçar ◽  
Eser Uçar ◽  
Kadir Arı ◽  
...  

Background: Peptide-based agents are used in molecular imaging due to their unique properties, such as rapid clearance from the circulation, high affinity and target selectivity. Many of the radiolabeled peptides have been clinically experienced with diagnostic accuracy. The aim of this study was to investigate in vivo biological behavior of [99mTc(CO)3(H2O)3]+ radiolabeled glycylglycine (GlyGly). Methods: Glycylglycine was radiolabeled with a high radiolabeling yield of 94.69±2%, and quality control of the radiolabeling process was performed by thin layer radiochromatography (TLRC) and High-Performance Liquid Radiochromatography (HPLRC). Lipophilicity study for radiolabeled complex (99mTc(CO)3-Gly-Gly) was carried out using solvent extraction. The in vivo evaluation was performed by both biodistribution and SPECT imaging. Results: The high radiolabelling yield of 99mTc(CO)3-GlyGly was obtained and verified by TLRC and HPLRC as well. According to the in vivo results, SPECT images and biodistribution data are in good accordance. The excretion route from the body was both hepatobiliary and renal. Conclusion: This study shows that 99mTc(CO)3-GlyGly has the potential to be used as a peptide-based imaging agent. Further studies, 99mTc(CO)3-GlyGly can be performed on tumor-bearing animals.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michal Sitina ◽  
Heiko Stark ◽  
Stefan Schuster

AbstractIn humans and higher animals, a trade-off between sufficiently high erythrocyte concentrations to bind oxygen and sufficiently low blood viscosity to allow rapid blood flow has been achieved during evolution. Optimal hematocrit theory has been successful in predicting hematocrit (HCT) values of about 0.3–0.5, in very good agreement with the normal values observed for humans and many animal species. However, according to those calculations, the optimal value should be independent of the mechanical load of the body. This is in contradiction to the exertional increase in HCT observed in some animals called natural blood dopers and to the illegal practice of blood boosting in high-performance sports. Here, we present a novel calculation to predict the optimal HCT value under the constraint of constant cardiac power and compare it to the optimal value obtained for constant driving pressure. We show that the optimal HCT under constant power ranges from 0.5 to 0.7, in agreement with observed values in natural blood dopers at exertion. We use this result to explain the tendency to better exertional performance at an increased HCT.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Fiona Li ◽  
Justin W. Hicks ◽  
Lihai Yu ◽  
Lise Desjardin ◽  
Laura Morrison ◽  
...  

Abstract Background In molecular imaging with dynamic PET, the binding and dissociation of a targeted tracer is characterized by kinetics modeling which requires the arterial concentration of the tracer to be measured accurately. Once in the body the radiolabeled parent tracer may be subjected to hydrolysis, demethylation/dealkylation and other biochemical processes, resulting in the production and accumulation of different metabolites in blood which can be labeled with the same PET radionuclide as the parent. Since these radio-metabolites cannot be distinguished by PET scanning from the parent tracer, their contribution to the arterial concentration curve has to be removed for the accurate estimation of kinetic parameters from kinetic analysis of dynamic PET. High-performance liquid chromatography has been used to separate and measure radio-metabolites in blood plasma; however, the method is labor intensive and remains a challenge to implement for each individual patient. The purpose of this study is to develop an alternate technique based on thin layer chromatography (TLC) and a sensitive commercial autoradiography system (Beaver, Ai4R, Nantes, France) to measure radio-metabolites in blood plasma of two targeted tracers—[18F]FAZA and [18F]FEPPA, for imaging hypoxia and inflammation, respectively. Results Radioactivity as low as 17 Bq in 2 µL of pig’s plasma can be detected on the TLC plate using autoradiography. Peaks corresponding to the parent tracer and radio-metabolites could be distinguished in the line profile through each sample (n = 8) in the autoradiographic image. Significant intersubject and intra-subject variability in radio-metabolites production could be observed with both tracers. For [18F]FEPPA, 50% of plasma activity was from radio-metabolites as early as 5-min post injection, while for [18F]FAZA, significant metabolites did not appear until 50-min post. Simulation study investigating the effect of radio-metabolite in the estimation of kinetic parameters indicated that 32–400% parameter error can result without radio-metabolites correction. Conclusion TLC coupled with autoradiography is a good alternative to high-performance liquid chromatography for radio-metabolite correction. The advantages of requiring only small blood samples (~ 100 μL) and of analyzing multiple samples simultaneously, make the method suitable for individual dynamic PET studies.


Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 525
Author(s):  
Ana Kiš ◽  
Snježana Brnada ◽  
Stana Kovačević

In this work, aramid fibers were used to develop new, high-performance fabrics for high-temperature protective clothing. The research was based on the impact of the weave structure on fabric resistance to radiant heat. The goals of the research were primarily related to the development of new fabric structures created by the weave structure, which gives better protection of the body against high temperatures in relation to the standard weave structures that are used today. According to the results obtained it can be concluded that the fabric weave significantly affects the fabric structure, which consequently determines the effectiveness of protection against high temperatures. The justification for the use of multi-weft and strucks weave structure, which provides greater thermal protection and satisfactory breathability than commonly used weave structures, was ascertained.


2004 ◽  
Vol 27 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Rick Grush

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language.


2010 ◽  
Vol 55 (1) ◽  
pp. 326-330 ◽  
Author(s):  
José Moltó ◽  
Marta Valle ◽  
Cristina Miranda ◽  
Samandhy Cedeño ◽  
Eugenia Negredo ◽  
...  

ABSTRACTThe aim of this open-label, fixed-sequence study was to investigate the potential ofEchinacea purpurea, a commonly used botanical supplement, to interact with the boosted protease inhibitor darunavir-ritonavir. Fifteen HIV-infected patients receiving antiretroviral therapy including darunavir-ritonavir (600/100 mg twice daily) for at least 4 weeks were included.E. purpurearoot extract capsules were added to the antiretroviral treatment (500 mg every 6 h) from days 1 to 14. Darunavir concentrations in plasma were determined by high-performance liquid chromatography immediately before and 1, 2, 4, 6, 8, 10, and 12 h after a morning dose of darunavir-ritonavir on days 0 (darunavir-ritonavir) and 14 (darunavir-ritonavir plus echinacea). Individual darunavir pharmacokinetic parameters were calculated by noncompartmental analysis and compared between days 0 and 14 with the geometric mean ratio (GMR) and its 90% confidence interval (CI). The median age was 49 (range, 43 to 67) years, and the body mass index was 24.2 (range, 18.7 to 27.5) kg/m2. Echinacea was well tolerated, and all participants completed the study. The GMR for darunavir coadministered with echinacea relative to that for darunavir alone was 0.84 (90% CI, 0.63-1.12) for the concentration at the end of the dosing interval, 0.90 (90% CI, 0.74-1.10) for the area under the concentration-time curve from 0 to 12 h, and 0.98 (90% CI, 0.82-1.16) for the maximum concentration. In summary, coadministration ofE. purpureawith darunavir-ritonavir was safe and well tolerated. Individual patients did show a decrease in darunavir concentrations, although this did not affect the overall darunavir or ritonavir pharmacokinetics. Although no dose adjustment is required, monitoring darunavir concentrations on an individual basis may give reassurance in this setting.


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